Aloctin A, an active substance of Aloe Arborescens Miller as an immunomodulator

Article by Kenichi Imanishi
Department of Microbiology Immunology, Tokyo Womens Medical College Phytotherapy Research (1993) Vol 7, No. Special issue, pp. S20-S22. 15 ref.

Aloe has been used as a folk medicine for centuries all over the world. Among the components of Aloe, the low-molecular weight components have been well studied and used as purgatives. In the last few decades, the clinical application of Aloe extract, probably the components of high molecular weight, in skin injury and burns, as well as an anti-inflammatory, has been reported. Aloctin A (Alo A) is a highly purified glycoprotein with molecular weight of 1.8 x 10⁴ Da from the leaves of Aloe arborescens and exhibits various biological activities, such as mitogenic activity for T lymphocytes, binding reactivity for human a2-macroglobulin and activation of component 3 of complement system via the alternative pathway¹.

In this article, I would like to describe the antitumor activity of Alo A using methylcholanthrene-induced nurine fibrosarcoma (Meth A)² and lymphocytic leukemia (P388) (unpublished data) in syngeneic mouse systems.

One million of Meth A cells were implanted into the peritoneal cavity of BALB/c mice. Alo A were administered i.p. at an appropriate concentration in saline, once daily for 5 days, starting 24 hours after tumor implantation. Antitumor activity was evaluated by total cell packed cell volume ratio (Alo A-treated mice/control mice) calculated from collected whole ascites obtained from mice anesthetized with ether. A representative experiment is shown in table 1. Alo A obviously inhibited the growth of the tumor cells and administration at a dose of 10 mg/kg/day, for 5 days, remarkably inhibited it (p<0.001). It was important to determine whether this activity was due to cytotoxicity of Alo A for tumor cells or host-mediated effects of Alo A, since Alo A was administered i.p. Therefore, the effect of Alo A on the growth in vitro of Meth A and the other cell lines was examined by ³H-thymidine uptake. Alo A had almost no inhibitory effect on the growth of tumor cell lines tested including Meth A up to a concentration of 200 ug/ml, the highest concentration tested (table 2). This result suggests that Alo A is not directly cytotoxic to tumor cells.

One million of P388 cells were implanted intraperitoneally in CDF1 mice. Alo A was administered i.p. at an appropriate concentration in saline, once daily on the 1st and 5th days after tumor implantation. Antitumor activity was evaluated by survival time. The antitumor activity of Alo A is also obvious in this system (table 3).

The mechanisms of antitumor activity of Alo A seemed to be host-mediated. We have reported a couple of immunomodulatory activities, such as elevation of natural killer cell activity, augmentation of cytotoxicity of peritoneal exudate cells and generation of lymphokine-activated killer cells. We consider that Alo A is a promising candidate as an immunomodulator.

Table 1
The anti-tumor activity of Aloctin A against sarcoma Meth A (ascites form) in BALB/c mice

Antitumor test, 5-week-old BALB/c mice were used for this test. The tumor used was methylcholanthrene-induced fibrosarcoma (Meth A) maintained in the ascites form, 1 x 10⁶ Da washed cells of Meth A were implanted i.p. into the mouse. Aloctin A as injected i.p. once daily for 5 days, starting 24 h after tumor implantation. Antitumor activity was evaluated by the total packed cell volume ratio (T/C %) on the 7th day.

^aTotal packed cell volume, *p<0.001, Significantly different from control.

Table 2
Cytotoxicity of Aloctin A in vitro

Cytotoxicity test: Various concentrations of Aloctin A in 00ul of cell suspension, each containing 5 x 10³ Da cells. The mixture was incubated at 37 ^oC for 28 h in a humidified atmosphere of 5% CO₂ and 95% air. After 24h, 1 uCi/well of ³H-thymidine was added. After a further 4 h of incubation, radioactivity incorporated into DNA was determined.

^aMean cpm of 3 wells.

Table 3
The anti-tumor activity of Aloctin A against P388 in CDF₁ mice

M. S. T., Median Survival Time, T/C % = M. S. T. of treated group / M. S. T. of Control x 100.
Evaluation of anti-tumor activity; T/C % in life-span *, **,
Significantly different from Control * P<0.01, ** P<0.001.

References
¹ Suzuki et al. (1979) J. Biochem. 85: 163.
² Imanishi et al. (1981) Experientia 37: 1186.

 

Phytother Res. 2001 Dec;15(8):705-11.

Inhibition of azoxymethane-induced aberrant crypt foci formation in rat colorectum by whole leaf Aloe arborescens Miller var. natalensis Berger.

Shimpo K, Chihara T, Beppu H, Ida C, Kaneko T, Nagatsu T, Kuzuya H.

Fujita Memorial Institute of Pharmacognosy, Fujita Health University , Hisai, Mie 514-1296, Japan .
We examined the modifying effect of whole-leaf Aloe arborescens Miller var. natalensis Berger (designated as 'ALOE') on azoxymethane (AOM)-induced aberrant crypt foci (ACF), putative preneoplastic lesions, in the rat colorectum. Male F344 rats (4 weeks old) were fed the basal diet, or experimental diets containing 1% or 5% ALOE for 5 weeks. One week later, all rats except those in the vehicle-treated groups were injected s.c. with AOM (15 mg/kg, once weekly for 3 weeks). At 9 weeks of age, all the rats were killed, and the colorectum and liver were evaluated for ACF and cytosolic quinone reductase (QR; a phase 2 enzyme), respectively. In rats given AOM and ALOE (1% or 5% in diet) the numbers of ACF/colorectum, aberrant crypts/colorectum, aberrant crypts/focus and large ACF/colorectum were significantly decreased compared with those of rats given AOM alone (all p < 0.01). No ACF were found in rats treated without AOM. In addition, ALOE significantly increased cytosolic QR activity in the liver (p < 0.01). These results indicated that ALOE inhibited the development of AOM-induced ACF in the rat colorectum, with increased QR activity in the liver, and therefore suggested that ALOE might have a chemopreventive effect against colon carcinogenesis at least in the initiation stage. Copyright 2001 John Wiley & Sons, Ltd.

PMID: 11746864 [PubMed - indexed for MEDLINE]

Purification & Characterization Of Two Lectins
from Aloe Arborescens Miller.

Suzuki I; Saito H; Inoue S; Migita S; Takahashi T
J Biochem (Tokyo) 85(1):163-71 1979 Jan

Two lectins have been isolated from leaves of Aloe arborescens Mill by salt precipitation, pH-dependent fractionation and gel filtration. One lectin (P-2) has a molecular weight of approximately 18,000, consists of two subunits (alphabeta) and contains more than 18% by weight of neutral carbohydrate. The smaller subunit (alpha) has a molecular weight of approximately 7,500 and the larger subunit (beta) a molecular weight of approximately 10,500. The other lectin (S-1) has a molecular weight of approximately 24,000, consists of two subunits (gamma2) with a molecular weight of approximately 12,000 and contains more than 50% by weight of neutral carbohydrate. An interesting feature of the amino acid compositions of these lectins is the high proportion of acidic amino acids, such as aspartic acid and glutamic acid, and the low proportion of methionine and histidine. S-1 has a strong hemagglutinating activity. On the other hand, P-2 has not only hemagglutinating activity but also mitogenic activity on lymphocytes, precipitate-forming reactivity with serum proteins, one of which is alpha2-macroglobulin, and complement C3 activating activity via the alternate pathway.

 

 

A 35 kDa Mannose-Binding Lectin With Hemagglutinating & Mitogenic Activities From "Kidachi Aloe" (Aloe Arborescens Miller var. natalensis Berger)

Koike T; Beppu H; Kuzuya H; Maruta K; Shimpo K; Suzuki M; Titani K; Fujita K
Institute Of Pharmacognosy, Fujita Health University
J Biochem (Tokyo) 118(6):1205-10 1995 Dec

A novel lectin was isolated from the leaf skin of "Kidachi Aloe" (Aloe arborescens Miller var. natalensis Berger) by sequential chromatographies on Sephadex G-25 gel filtration, DEAE ion exchange, and Superdex 75 gel filtration columns. The native lectin exhibited a molecular mass of about 35 kDa on both gel filtration on a Superdex 75 column and native-PAGE under nonreducing conditions. SDS-PAGE in the presence or absence of beta-mercaptoethanol revealed two distinct peptides with molecular masses of about 5.5 and 2.3 kDa, respectively, in addition to a major 9.2 kDa subunit, indicating the presence of a partially processed subunit. The N-terminal amino acid sequence of the intact subunit showed homology with that of snowdrop lectin. The native lectin showed hemagglutinating activity toward rabbit but not human and sheep erythrocytes, and specifically bound to mannose like snowdrop lectin did, indicating that the Aloe and snowdrop lectins are structurally and functionally similar proteins. In addition, the native lectin showed strong mitogenic activity toward mouse lymphocytes.

Asian Pacific Jou nal of Cance P evention, Vol 1, 2000

RESEARCH COMMUNICATION
Inhibition of N-ethyl-N'-nitro-N-nitrosoguanidine induced Duodenal Tumorigenesis in Mice by Whole leaf Aloe arborescens Miller.

Takeshi Chihara 1, Kan Shimpo 1, Masanori Shinzato 2, Hidehiko Beppu 1, Takaaki Kaneko 1, Chikako Ida 1, Kaoru Kawai 1, Iwao Hirono 3, Mikihiro Shamoto 2, Toshiharu Nagatsu 2, Hiroshi Kuzuya 1

Abstract
We examined the modifying effects of freeze dried whole leaf Aloe arborescens Miller var. natalensis Berger (designated as 'ALOE') on N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) induced duodenal tumorigenesis in C57BL/ 6 mice. Experiment 1: Male mice were given ENNG in drinning water for the first 4 weeks, and then 10% ALOE in basal diet for 16 weeks. Experiment 2: Female mice were given ENNG for 5 weeks, and then 5%, 1% or 0.2% ALOE in the diet were given for 15 weeks. In Experiment 1, the tumor incidence and tumor multiplicity (tumors per mouse) of the duodenum in the ENNG + 10% ALOE group were significantly decreased compared with that in the ENNG alone group. Erythrocyte polyamine levels in the ENNG + 10% ALOE group were also significantly decreased. In Experiment 2, the incidence of duodenal tumors in the ENNG + 5% ALOE group were significantly decreased compared with that in the ENNG alone group. These results indicated that ALOE, especially at 10% in the diet, inhibits ENNG-induced duodenal tumorigenesis in mice.

Asian Pacific J Cance P ev, 1, 283-288

SCIENTIFIC RESEARCH ON "ALOE ARBORESCENS MILLER" (KIDACHI ALOE):

01) J Chromatogr B Biomed Sci Appl. 2001 Mar 5;752(1):91-7.
Determination of aloenin, barbaloin and isobarbaloin in aloe species by micellar electrokinetic chromatography.
Kuzuya H, Tamai I, Beppu H, Shimpo K, Chihara T.
Fujita Memorial Institute of Pharmacognosy, Fujita Health University, Hisai, Mie, Japan. hkuzu@fujita-hu.ac.jp
Aloenin, barbaloin and isobarbaloin in JP Aloe, Aloe barbadensis (Aloe vera) and Aloe arborescens Miller var. natalensis Berger (Aloe arborescens Miller) were determined by micellar electrokinetic chromatography (MEKC) with 50 mM sodium dodecyl sulfate. Aloenin, barbaloin and isobarbaloin were well separated by MEKC and as little as 5.5 pg/11 nl of the three compounds could be detected. The determination took around 14 min.
PMID: 11254203 [PubMed - indexed for MEDLINE]

02) Biochem Biophys Res Commun. 1995 Sep 5;214(1):163-70.
The complete amino acid sequence of a mannose-binding lectin from "Kidachi Aloe" (Aloe arborescens Miller var. natalensis Berger).
Koike T, Titani K, Suzuki M, Beppu H, Kuzuya H, Maruta K, Shimpo K, Fujita K.
Institute of Pharmacognosy, Fujita Health University, Mie, Japan.
The complete amino acid sequence of a mannose-binding lectin purified from the leaf skin of "Kidachi Aloe" (Aloe arborescens Miller var. natalensis Berger) is presented. The 109-residue sequence of the subunit was determined by analysis of peptides of the intact or S-pyridylethylated protein generated by digestion with cyanogen bromide, BNPS-skatole, Achromobacter protease I, or trypsin. The subunit contains an intrachain disulfide bridge. The sequence is highly homologous to that of a mannose-binding lectin from snowdrop bulb.
PMID: 7669035 [PubMed - indexed for MEDLINE]

03) J Agric Food Chem. 1999 Sep;47(9):3702-5.
Aroma chemicals isolated and identified from leaves of Aloe arborescens Mill. Var. Natalensis Berger.
Umano K, Nakahara K, Shoji A, Shibamoto T.
Department of Environmental Toxicology, University of California, Davis, California 95616, USA.
Extracts from leaves of aloe (Aloe arborescens Mill. var. natalensis Berger) were obtained using two methods: steam distillation under reduced pressure followed by dichloromethane extraction (DRP) and simultaneous purging and extraction (SPE). A total of 123 aroma chemicals were identified in the extracts obtained by both methods using gas chromatography and gas chromatography/mass spectrometry. There were 42 alcohols, 23 terpenoids, 21 aldehydes, 9 esters, 8 ketones, 6 acids, 5 phenols, and 9 miscellaneous compounds. The major aroma constituents of this extract by DRP were (Z)-3-hexenol (29.89%), (Z)-3-hexenal (18.86%), (E)-hexenal (7.31%), 4-methyl-3-pentenol (5.66%), and butanol (4.29%). The major aroma constituents of this extract by SPE were (E)-2-hexenal (45.46%), (Z)-3-hexenal (32.12%), hexanal (9.14%), (Z)-3-hexenol (1.60%), and 3-pentanone (1.41%). Terpenoids were also found as one of the major constituents. The fresh green note of aloe leaves is due to the presence of these C(6) alcohols and aldehydes as well as terpenoids.
PMID: 10552708 [PubMed - indexed for MEDLINE]

04) Gene. 2000 Feb 8;243(1-2):85-92.
An isozyme of the NADP-malic enzyme of a CAM plant, Aloe arborescens, with variation on conservative amino acid residues.
Honda H, Akagi H, Shimada H.
Life Sciences Laboratory, Mitsui Chemicals, Inc., 1144 Togo, Mobara, Japan.
In Aloe arborescens, an obligate CAM plant, Western analysis detected three major isoforms of NADP-malic enzyme (NADP-ME), 72kDa with a pI of 6.0, 65kDa with a pI of 5.6 and 65kDa with a pI of 5.5. Among them, the 65kDa protein with a pI of 5.5 was leaf-specific, and the 65kDa protein with a pI of 5.6 was found only in roots, whereas the 72kDa protein was uniformly detected in both organs. Activity staining indicated enzyme activity of both 65kDa NADP-MEs but little activity of the 72kDa protein. A cDNA clone encoding a leaf-abundant NADP-ME, AME1, was isolated. Deduced amino acid sequence of AME1 showed a high degree of homology to known NADP-MEs, but it was also found that AME1 contained substitutions on five conservative amino acid residues, some of which have been predicted to be important for their enzyme activity. Transgenic rice carrying the aloe AME1 gene efficiently produced an additional 65kDa protein with a pI of 5.5 as an active NADP-ME. These results indicate that AME1 corresponds to the leaf-specific 65kDa NADP-ME, which may be involved in CAM photosynthesis. It was also shown that substitutions of these conservative amino acid residues identified in AME1 still allowed it to give enzyme activity.
PMID: 10675616 [PubMed - indexed for MEDLINE]

05) Asian Pacific Journal of Cancer Prevention, Vol 1, 2000
A 35 kDa Mannose-Binding Lectin With Hemagglutinating & Mitogenic Activities From "Kidachi Aloe" (Aloe Arborescens Miller var. natalensis Berger)
Koike T; Beppu H; Kuzuya H; Maruta K; Shimpo K; Suzuki M; Titani K; Fujita K.
Institute Of Pharmacognosy, Fujita Health University. J Biochem (Tokyo) 118(6):1205-10 1995 Dec
A novel lectin was isolated from the leaf skin of "Kidachi Aloe" (Aloe arborescens Miller var. natalensis Berger) by sequential chromatographies on Sephadex G-25 gel filtration, DEAE ion exchange, and Superdex 75 gel filtration columns. The native lectin exhibited a molecular mass of about 35 kDa on both gel filtration on a Superdex 75 column and native-PAGE under nonreducing conditions. SDS-PAGE in the presence or absence of beta-mercaptoethanol revealed two distinct peptides with molecular masses of about 5.5 and 2.3 kDa, respectively, in addition to a major 9.2 kDa subunit, indicating the presence of a partially processed subunit. The N-terminal amino acid sequence of the intact subunit showed homology with that of snowdrop lectin. The native lectin showed hemagglutinating activity toward rabbit but not human and sheep erythrocytes, and specifically bound to mannose like snowdrop lectin did, indicating that the Aloe and snowdrop lectins are structurally and functionally similar proteins. In addition, the native lectin showed strong mitogenic activity toward mouse lymphocytes.

06) J Biochem (Tokyo) 85(1):163-71 1979 Jan
Purification & Characterization Of Two Lectins from Aloe Arborescens Miller.
Suzuki I; Saito H; Inoue S; Migita S; Takahashi T.
Two lectins have been isolated from leaves of Aloe arborescens Mill by salt precipitation, pH-dependent fractionation and gel filtration. One lectin (P-2) has a molecular weight of approximately 18,000, consists of two subunits (alphabeta) and contains more than 18% by weight of neutral carbohydrate. The smaller subunit (alpha) has a molecular weight of approximately 7,500 and the larger subunit (beta) a molecular weight of approximately 10,500. The other lectin (S-1) has a molecular weight of approximately 24,000, consists of two subunits (gamma2) with a molecular weight of approximately 12,000 and contains more than 50% by weight of neutral carbohydrate. An interesting feature of the amino acid compositions of these lectins is the high proportion of acidic amino acids, such as aspartic acid and glutamic acid, and the low proportion of methionine and histidine. S-1 has a strong hemagglutinating activity. On the other hand, P-2 has not only hemagglutinating activity but also mitogenic activity on lymphocytes, precipitate-forming reactivity with serum proteins, one of which is alpha2-macroglobulin, and complement C3 activating activity via the alternate pathway.

07) Phytother Res. 2001 Dec;15(8):705-11.
Inhibition of azoxymethane-induced aberrant crypt foci formation in rat colorectum by whole leaf Aloe arborescens Miller var. natalensis Berger.
Shimpo K, Chihara T, Beppu H, Ida C, Kaneko T, Nagatsu T, Kuzuya H.
Fujita Memorial Institute of Pharmacognosy, Fujita Health University, Hisai, Mie 514-1296, Japan. We examined the modifying effect of whole-leaf Aloe arborescens Miller var. natalensis Berger (designated as 'ALOE') on azoxymethane (AOM)-induced aberrant crypt foci (ACF), putative preneoplastic lesions, in the rat colorectum. Male F344 rats (4 weeks old) were fed the basal diet, or experimental diets containing 1% or 5% ALOE for 5 weeks. One week later, all rats except those in the vehicle-treated groups were injected s.c. with AOM (15 mg/kg, once weekly for 3 weeks). At 9 weeks of age, all the rats were killed, and the colorectum and liver were evaluated for ACF and cytosolic quinone reductase (QR; a phase 2 enzyme), respectively. In rats given AOM and ALOE (1% or 5% in diet) the numbers of ACF/colorectum, aberrant crypts/colorectum, aberrant crypts/focus and large ACF/colorectum were significantly decreased compared with those of rats given AOM alone (all p < 0.01). No ACF were found in rats treated without AOM. In addition, ALOE significantly increased cytosolic QR activity in the liver (p < 0.01). These results indicated that ALOE inhibited the development of AOM-induced ACF in the rat colorectum, with increased QR activity in the liver, and therefore suggested that ALOE might have a chemopreventive effect against colon carcinogenesis at least in the initiation stage. Copyright 2001 John Wiley & Sons, Ltd.
PMID: 11746864 [PubMed - indexed for MEDLINE]

08) Z Naturforsch [C]. 1977 Sep-Oct;32(9-10):731-4.
Biologically active constituents of leaves and roots of Aloe arborescens var. natalensis.
Hirata T, Suga T.
Several biologically active substances, such as aloenin (1), magnesium lactate, aloe-emodin (4), barbaloin (5), and succinic acid, were found to be contained in the leaf juice of Aloe arborescens Mill. var. natalensis Berger, which has widely been used in domestic medicines. Aloenin (1) and magnesium lactate were elucidated to exhibit an inhibitory action on the gastric juice secretion of rats. Various constituents other than the above bioactive substances were found in the leaves and the roots of the plant.
PMID: 145111 [PubMed - indexed for MEDLINE]

09) Antimicrob Agents Chemother. 1978 Jul;14(1):132-6.
Effect of leaf extracts of Aloe arborescens Mill subsp. natalensis Berger on growth of Trichophyton mentagrophytes.
Fujita K, Yamada Y, Azuma K, Hirozawa S.
PMID: 686703 [PubMed - indexed for MEDLINE]

10) Chem Pharm Bull (Tokyo). 1990 Jan;38(1):197-200.
Studies of aloe. III. Mechanism of cathartic effect. (2).
Ishii Y, Tanizawa H, Takino Y.
School of Pharmaceutical Sciences, University of Shizuoka, Japan.
The mechanism of action of aloe-emodin-9-anthrone, a decomposition product of barbaloin, in causing a significant increase in the water content of the rat large intestine, was investigated. Aloe-emodin-9-anthrone inhibited rat colonic Na+, K(+)-adenosine triphosphatase (ATPase) in vitro, and increased the paracellular permeability across the rat colonic mucosa in vivo. Therefore, it seemed that the increase in water content of the rat large intestine produced by aloe-emodin-9-anthrone was due to both inhibition of absorption and stimulation of secretion without stimulation of peristalsis. Furthermore, pretreatment with loperamide, an antidiarrheal agent, completely prevented the increase of paracellular permeability induced by aloe-emodin-9-anthrone but did not completely reduce the concomitant increase in residual fluid volume. These findings suggest that aloe-emodin-9-anthrone has multiple mechanisms of action involved in the increase of water content in the rat large intestine.
PMID: 2159853 [PubMed - indexed for MEDLINE]

11) Chem Pharm Bull (Tokyo). 1974 Jul;22(7):1565-70.
Studies on the constituents of Aloe arborescens Mill. var. natalensis Berger. II. The structures of two new aloesin esters.
Makino K, Yagi A, Nishioka I.
PMID: 4434578 [PubMed - indexed for MEDLINE]

12) Planta Med. 1977 Feb;31(1):17-20.
Aloe mannan, ploysaccharide, from Aloe arborescens var. natalensis.
Yagi A, Makino K, Nishioka I, Kuchino Y.
PMID: 840922 [PubMed - indexed for MEDLINE]

13) Experientia. 1985 May 15;41(5):669-71.
Effect of aloe lectin on deoxyribonucleic acid synthesis in baby hamster kidney cells.
Yagi A, Machii K, Nishimura H, Shida T, Nishioka I.
A homogeneous glycoprotein (mol. wt 40,000) containing 34% carbohydrate was isolated from Aloe arborescens var. natalensis. At a concentration of 5 micrograms/ml, this glycoprotein was shown to stimulate deoxyribonucleic acid (DNA) synthesis in baby hamster kidney (BHK) cells and to have the properties of a lectin which reacts with sheep blood cells. The chemical and physical properties of the glycoprotein (aloe lectin) are also discussed.
PMID: 3996544 [PubMed - indexed for MEDLINE]

14) J Ethnopharmacol. 2003 Nov; 89 (1):37-45.
Radical-scavenging effects of Aloe arborescens Miller on prevention of pancreatic islet B-cell destruction in rats.
Beppu H, Koike T, Shimpo K, Chihara T, Hoshino M, Ida C, Kuzuya H.
Fujita Memorial Institute of Pharmacognosy, Fujita Health University, 1865 Isshiki-cho, Hisai, Mie 514-1296, Japan. hbeppu@fujita-hu.ac.jp
We evaluated the possible scavenging effects of Aloe arborescens Miller var. natalensis Berger (Kidachi aloe in Japanese) on free radicals generated by streptozotocin (Sz) or alloxan (Ax). The components of Kidachi aloe were added to a reaction system in which .OH radicals derived from Sz or Ax as pancreatic islet B-cell toxins and hypoxanthine-xanthine oxidase (HX-XO)-derived O(2) radicals destroy isolated islet B-cells, and we observed its preventive effects. The Kidachi aloe components inhibited the destruction of rat pancreatic islet B-cells by Sz, Ax or HX-XO. These components were prepared in the form of a freeze-dried powder of the boiled leaf skin of Kidachi aloe, and measurement of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity showed higher radical-scavenging activity in this boiled leaf skin powder than the non-boiled leaf skin powder.Furthermore, HPLC chromatograms of the "Boiled leaf skin powder" were similar to those of commercially available aloin (barbaloin content: approximately 20%). Therefore, the main component may be a phenol compound. In addition, the phenolic fraction of the Boiled leaf skin contained large amounts of 2'-O-p-coumaroylaloesin and 2'-O-feruloylaloesin, which have higher DPPH radical-scavenging activity than barbaloin.These results suggest that the action mechanism of Kidachi aloe Boiled leaf skin components, which prevent destruction of the pancreatic islets by specific pancreatic islet toxins such as Sz, Ax, and HX-XO, involves inhibition of free radical-scavenging effects, and may be associated with a thermostable low molecular component. The co-existence of Kidachi aloe-derived 2'-O-p-coumaroylaloesin, 2'-O-feruloylaloesin, and aloin may result in the potentiation of radical-scavenging activity.
PMID: 14522430 [PubMed - indexed for MEDLINE]

15) Acta Pol Pharm. 2002 May-Jun;59(3):181-6.
Biopharmaceutical assessment of eye drops containing aloe (Aloe arborescens Mill.) and neomycin sulphate.
Kodym A, Grzeskowiak E, Partyka D, Marcinkowski A, Kaczynska-Dyba E.
Department of Drug Form Technology, Karol Marcinkowski Medical Academy in Poznan.
The subject of the studies was eye drops made of aloe, containing the group of aloe chemical substances of anti-inflammatory use and neomycin sulphate. The aim of the studies was to evaluate the permeability of biologically active aloe substances, determined as aloenin, through synthetic lipophilic and hydrophilic membranes in a standard perfusion apparatus and in vitro verification of the transport possibilities of these substances through the isolated cornea of pig's eye. The permeability process of biologically active aloe substances determined as aloenin, through synthetic lipophilic and hydrophilic membranes, was analyzed using the first-order kinetics. Estimated quotas of permeability rate constant show that the investigated chemical compounds of aloe, included in the eye drops, diffused through the applied membranes. The studies of permeability through isolated pig's cornea proved that biologically active aloe substances could not overcome this biological barrier. On the basis of biopharmaceutical studies it can be concluded that the eye drops containing aloe and neomycin sulphate, due to the lack of permeating abilities through the eye cornea, should be particularly useful in the treatment of inflammations and infections of external parts of the eye, such as conjuctiva, eyelid edges, lacrimal sac and cornea.
PMID: 12230244 [PubMed - indexed for MEDLINE]

16) Phytother Res. 2002 Aug;16(5):491-3.
Aloe arborescens extract inhibits TPA-induced ear oedema, putrescine increase and tumour promotion in mouse skin.
Shimpo K, Ida C, Chihara T, Beppu H, Kaneko T, Kuzuya H.
Fujita Memorial Institute of Pharmacognosy, Fujita Health University, Hisai, Mie 514-1296, Japan. shimpo@fujita-hu.ac.jp
The ethyl acetate extract of the acetone-soluble Aloe arborescens fraction was found to inhibit 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ear oedema, putrescine increase and tumour promotion in mouse skin. Chromatographic analyses of this extract revealed that phenolic compounds such as aloenin, barbaloin and isobarbaloin could be useful as cancer chemopreventive agents against tumour promotion. Copyright 2002 John Wiley & Sons, Ltd.
PMID: 12203274 [PubMed - indexed for MEDLINE]

17) Phytother Res. 1999 Aug;13(5):401-7.
Antifungal effects of different plant extracts and their major components of selected aloe species.
Ali MI, Shalaby NM, Elgamal MH, Mousa AS.
Botany Department, Faculty of Science, Cairo University, Giza 12613, Egypt.
Different extracts of both fresh and dry leaves of Aloe eru A. Berger, A. vera L. Webb & Berth and A. arborescens Mill. were screened for their antifungal activity against Aspergillus niger, Cladosporium herbarum and Fusarium moniliforme. The toxicity of the isolated pure components were evaluated on the tested fungi. A comparative chromatographic study was performed to differentiate between natural components existing in various fractions and extracts of Aloe species and specific spray reagents were used for the detection of anthraquinones in the isolated components. Copyright 1999 John Wiley & Sons, Ltd.
PMID: 10441780 [PubMed - indexed for MEDLINE]

18) Pharmazie. 2002 Dec;57(12):834-7.
Physicochemical and microbiological properties as well as stability of ointments containing aloe extract (Aloe arborescens Mill.) or aloe extract associated to neomycin sulphate.
Kodym A, Bujak T.
Department of Drug Form Technology, Karol Marcinkowski Medical Academy, Poznan.
The aim of the study was to work out methods of quality assessment of ointments containing dry extract from fresh leaves of Aloe arborescens Mill. (Lilliaceae) and also of ointments containing both of dry extract and neomycin sulphate. The stability of the ointments, stored at 20 degrees C, was studied and the following criteria were considered: chromatographic analysis (TLC), pH of the ointments, the content of the substances in the dry extract converted to aloenin, the content of aloenin and aloin, anti-microbial activity of neomycin in the ointments, the size of the particles of the dry extract and of neomycin sulphate in the ointment suspension and the sterility of the ointments. After two years of storage at 20 degrees C, the ointments prepared with the anhydrous lipophilic base, did not change their physicochemical characteristics and neomycin in those ointments retained almost 100% of starting anti-microbial activity. Water or propylene glycol significantly decreased the stability of the biologically active substances of the dry extract in the ointments. Besides, in the ointments containing the dry extract and neomycin sulphate, the presence of water or propylene glycol induced degradation of the biologically active substances of the dry extract and a decrease in the anti-microbial activity of neomycin in the ointments. Considering the physicochemical and microbiological stability, the most advisable base for the ointments with aloe and neomycin sulphate was composed of white vaseline, liquid paraffin, solid paraffin, cholesterol. PMID: 12561247 [PubMed - indexed for MEDLINE]

19) Chem Pharm Bull (Tokyo). 1989 Jan;37(1):155-9.
Effect of water extracts of aloe and some herbs in decreasing blood ethanol concentration in rats. II.
Sakai K, Saitoh Y, Ikawa C, Nishihata T.
Oral administration of ethanol to rats at a dose of 3 g/kg decreased alcohol dehydrogenase (ADH) activity and metabolism of lactate to pyruvate in the liver. The effects of water extracts of Aloe and some other herbs on blood ethanol concentration and on ADH activity in liver cytosol were examined. The water extracts of these herbs caused a faster elimination of ethanol from blood of normal rats when administered orally 30 min before oral administration of ethanol. The rapid elimination of ethanol seems to be due to a protection of ADH activity and the supply of nicotinamide dinucleotide, both of which are reduced by high ethanol concentration. The effects of ethanol in decreasing the enzyme activities relating to its own metabolism occur when high concentrations of ethanol pass through the liver, and thus may primarily appear during the absorption of alcohol from the gastrointestinal tract, when portal concentration of ethanol are very high.
PMID: 2720844 [PubMed - indexed for MEDLINE]

20) Biochem Syst Ecol. 2000 Nov 1;28(9):825-838.
The distribution of the phenolic metabolites barbaloin, aloeresin and aloenin as a peripheral defense strategy in the succulent leaf parts of Aloe arborescens.
Gutterman Y, Chauser-Volfson E.
Jacob Blaustein Institute for Desert Research and Dept. of Life Sciences, Ben-Gurion University of the Negev, Sede Boker Campus 84990, Israel
Aloe arborescens is a large, multi-stemmed shrub. It is used as hedge plants to protect agricultural fields or stock and as horticultural plants in gardens. In natural habitats it is one of the very common Aloe species along the Indian Ocean coast of southern Africa, from the Cape, in the south, to Zimbabwe and Malawi in the north. Secondary phenolic metabolites such as barbaloin (Rf 0.31-0.35), aloeresin (Rf 0.25-0.3) and aloenin (Rf 0.51-0.55) have been found to be distributed in the succulent leaves of Aloe arborescens in a peripheral defense strategy. The youngest leaves have the highest content. The terminal third of each leaf has the highest content and the basal third, the lowest. Along the leaf margins, on the top third and adaxial side, the content is the highest and in the base third, the lowest along the leaf center on the abaxial side. Similar relative amounts of these three secondary phenolic metabolites were found in the different leaf locations. The leaf orientation may affect the total content of these three phenols but not their relative amounts in the different parts of the leaves. It is possible that the more often the plant parts are damaged by consumption by animals such as elephants, kudu or insects, the greater the increase of their phenolic metabolites. This increase may reduce or prevent further consumption when the content of the metabolites reaches a certain level. The plants then have a chance to renew themselves.
PMID: 10913844 [PubMed - as supplied by publisher]

21) Asian Pac J Cancer Prev. 2000;1(4):283-288.
Inhibition of N-ethyl-N'-nitro-N-nitrosoguanidine-induced Duodenal Tumorigenesis in Mice by Whole-leaf Aloe arborescens Miller var. natalensis Berger.
Shimpo K, Chikako T, Shinzato M, Beppu H, Kaneko T, Ida C, Kawai K, Hirono I, Shamoto M, Nagatsu T, Kuzuya H.
Fujita Memorial Institute of Pharmacognosy, Fujita Health University, Hisai, Mie 514-1296, Japan. shimpo@fujita-hu.ac.jp
We examined the modifying effects of freeze-dried whole-leaf Aloe arborescens Miller var. natalensis Berger (designated as 'ALOE') on N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG)-induced duodenal tumorigenesis in C57BL/6 mice. Experiment 1: Male mice were given ENNG in drinking water for the first 4 weeks, and then 10% ALOE in basal diet for 16 weeks. Experiment 2: Female mice were given ENNG for 5 weeks, and then 5%, 1% or 0.2% ALOE in the diet were given for 15 weeks. In Experiment 1, the tumor incidence and tumor multiplicity (tumors per mouse) of the duodenum in the ENNG + 10% ALOE group were significantly decreased compared with that in the ENNG alone group. Erythrocyte polyamine levels in the ENNG + 10% ALOE group were also significantly decreased. In Experiment 2, the incidence of duodenal tumors in the ENNG + 5% ALOE group were significantly decreased compared with that in the ENNG alone group. These results indicated that ALOE, especially at 10% in the diet, inhibits ENNG-induced duodenal tumorigenesis in mice.
PMID: 12716301 [PubMed - as supplied by publisher]

22) Biol Pharm Bull. 1998 Nov; 21(11):1226-7.
Studies of aloe. VI. Cathartic effect of isobarbaloin.
Ishii Y, Takino Y, Toyo'oka T, Tanizawa H.
School of Pharmaceutical Sciences, University of Shizuoka, Japan.
The cathartic effect of isobarbaloin, a stereoisomer of barbaloin (compound principally responsible for the cathartic activity of Aloe), was examined in male rats by oral administration. Individual differences in sensitivity in the laxative activity of isobarbaloin and barbaloin was not found. The cathartic activity (ED50) of isobarbaloin in barbaloin positive rats was 19.2 mg/kg, nearly equal to that of barbaloin (19.5 mg/kg). Also, isobarbaloin administered orally was demonstrated to decompose to aloe-emodin-9-anthrone (active metabolite of barbaloin) as well as to barbaloin. Therefore, it is considered that the mechanism underlying the cathartic effect of isobarbaloin is the same as that of barbaloin.
PMID: 9853419 [PubMed - indexed for MEDLINE]

23) Biol Pharm Bull. 1994 May;17(5):651-3.
Studies of aloe. V. Mechanism of cathartic effect. (4).
Ishii Y, Tanizawa H, Takino Y.
School of Pharmaceutical Sciences, University of Shizuoka, Japan.
Aloe-emodin-9-anthrone(AE-anthrone), produced from barbaloin in the rat large intestine, caused not only an increase in the intestinal water content but also stimulated mucus secretion. This might play an important role in the occurrence of diarrhea. It was demonstrated that the amount of AE-anthrone produced in the rat large intestine(maximal amount: 568 micrograms/rat at 4 h after injection) was enough to cause both of these effects, which were observed following intracecal administration of barbaloin (31.1 mg/kg). These results together with our previous data, which showed a relationship between increase in the intestinal water content and the stimulation of peristalsis, confirm that AE-anthrone is the principal agent responsible for the cathartic effect of barbaloin. We also propose that the increase in water content is a more important factor than stimulation of peristalsis in the induction of diarrhea by barbaloin.
PMID: 7920425 [PubMed - indexed for MEDLINE]

24) Experientia. 1981 Dec 15;37(12):1252-3.
Biotransformation of aloenin, a bitter glucoside constituent of Aloe arborescens, by rats.
Hirata T, Sakano S, Suga T.
Aloenin has been established to be 4-methoxy-6-(2-beta-D-glucopyranosyloxy-4-hydroxy-6-methylphenyl)-2-pyrone; it shows an inhibitory activity for gastric juice secretion. Rats metabolized it to 4-methoxy-6-(2,4-dihydroxy-6-methylphenyl)-2-pyrone, 2,5-dimethyl-7-hydroxychromone and glucose, which were excreted in the feces and the urine. The distribution of the radioactivity originating from 14C-labeled aloenin was studied. The tracer found in the kidney and the liver reached 60% of the amount administered 24 h after feeding and decreased rapidly in the next 24 hs.
PMID: 7035211 [PubMed - indexed for MEDLINE]

25) Gene. 2000 Feb 8;243(1-2):85-92.
An isozyme of the NADP-malic enzyme of a CAM plant, Aloe arborescens, with variation on conservative amino acid residues.
Honda H, Akagi H, Shimada H.
Life Sciences Laboratory, Mitsui Chemicals, Inc., 1144 Togo, Mobara, Japan.
In Aloe arborescens, an obligate CAM plant, Western analysis detected three major isoforms of NADP-malic enzyme (NADP-ME), 72kDa with a pI of 6.0, 65kDa with a pI of 5.6 and 65kDa with a pI of 5.5. Among them, the 65kDa protein with a pI of 5.5 was leaf-specific, and the 65kDa protein with a pI of 5.6 was found only in roots, whereas the 72kDa protein was uniformly detected in both organs. Activity staining indicated enzyme activity of both 65kDa NADP-MEs but little activity of the 72kDa protein. A cDNA clone encoding a leaf-abundant NADP-ME, AME1, was isolated. Deduced amino acid sequence of AME1 showed a high degree of homology to known NADP-MEs, but it was also found that AME1 contained substitutions on five conservative amino- acid residues, some of which have been predicted to be important for their enzyme activity. Transgenic rice carrying the aloe AME1 gene efficiently produced an additional 65kDa protein with a pI of 5.5 as an active NADP-ME. These results indicate that AME1 corresponds to the leaf-specific 65kDa NADP-ME, which may be involved in CAM photosynthesis. It was also shown that substitutions of these conservative amino acid residues identified in AME1 still allowed it to give enzyme activity.
PMID: 10675616 [PubMed - indexed for MEDLINE]

26) Yakugaku Zasshi. 1989 May;109(5):335-9.
Effects of aloe extracts, aloctin A, on gastric secretion and on experimental gastric lesions in rats. [Article in Japanese]
Saito H, Imanishi K, Okabe S.
Effect of aloctin A, glycoprotein isolated from leaves of Aloe arborescens MILL, on gastric secretion and on acute gastric lesions in rats were examined. Aloctin A given intravenously dose-dependently inhibited the volume of gastric juice, acid and pepsin output in pylorus-ligated rats. Aloctin A given intravenously significantly inhibited the development of Shay ulcers and indomethacin-induced gastric lesions in rats. It also inhibited water-immersion stress lesions induced in pylorus-ligated rats.
PMID: 2625663 [PubMed - indexed for MEDLINE]

27) Plant Cell Physiol. 1996 Sep;37(6):881-8.
Isolation of a cDNA for a phosphoenolpyruvate carboxylase from a monocot CAM-plant, Aloe arborescens: structure and its gene expression.
Honda H, Okamoto T, Shimada H.
Life Science Institute, Mitsui Toatsu Chemicals, Inc., Mobara, Japan.
A phosphoenolpyruvate carboxylase (PEPCase) cDNA was isolated from Aloe arborescens, a monocot CAM plant. Northern analysis of the PEPCase transcript indicated that it is specifically expressed in green leaves, strongly suggesting its involvement in CAM photosynthesis. No diurnal change in expression level was evident. Western blot analysis also showed no alteration of the amount of the PEPCase protein. These results suggest that circadian rhythm in PEPCase activity may be regulated post-translationally. The representative cDNA clone contained an ORF encoding 964 amino acid residues. Deduced amino acid sequence of the aloe PEPCase is highly conserved as compared with other PEPCases. The phosphorylation site which may be modified by PEPC-kinase was conserved. An evolutional map with known PEPCases suggested that CAM-type PEPCases were located between C4 and housekeeping PEPCases. PMID: 8888625 [PubMed - indexed for MEDLINE]

28) Acta Diabetol Lat. 1987 Jan-Mar;24(1):37-41.
Studies on the activity of individual plants of an antidiabetic plant mixture.
Al-Awadi FM, Gumaa KA.
A blood glucose lowering extract of a mixture of five plants in use by Kuwaiti diabetics was studied for the identification of its active component(s). Only the extracts of myrrh and aloe gums effectively increased glucose tolerance in both normal and diabetic rats. The remaining components, gum olibanum, Nigella sativa seeds and gum assafoetida were without effect.

29) Jpn J Pharmacol. 1982 Feb;32(1):139-42.
Pharmacological studies on a plant lectin aloctin A. II. Inhibitory effect of aloctin A on experimental models of inflammation in rats.
Saito H, Ishiguro T, Imanishi K, Suzuki I.
A glycoprotein, Aloctin A, which was isolated from Aloe arborescens Mill, markedly inhibits adjuvant arthritis in rats and carrageenin-induced edema in rats.
PMID: 7087254 [PubMed - indexed for MEDLINE]

30) J Assoc Off Anal Chem. 1985 May-Jun;68(3):493-4.
Liquid chromatographic determination of barbaloin (aloin) in foods.
Yamamoto M, Ishikawa M, Masui T, Nakazawa H, Kabasawa Y.
A simple and rapid liquid chromatographic method is described for the determination of barbaloin (aloin, 10-D-glucopyranosyl-1,8-dihydroxy-3-(hydroxymethyl)-9(10H)-anthraceno ne) in foods. Barbaloin is extracted with water from foods containing aloe and the extract is cleaned up on a disposable cartridge by using methanol-water (55 + 45) as eluant. The eluted barbaloin is separated by liquid chromatography on a YMC A-302 column with methanol-water (50 + 50) mobile phase, and detected at 293 nm. Recoveries of barbaloin added to foods at the levels of 0.05 and 0.50 mg/g were 94.4-100%. Assay results for commercial food samples indicated that the present method is applicable to a variety of foods supplemented with aloe.
PMID: 4019374 [PubMed - indexed for MEDLINE)

31) Cancer Lett. 2002 Apr 25;178(2):117-22.
Chemopreventive effects of Aloe arborescens on N-nitrosobis(2-oxopropyl)amine-induced pancreatic carcinogenesis in hamsters.
Furukawa F, Nishikawa A, Chihara T, Shimpo K, Beppu H, Kuzuya H, Lee IS, Hirose M.
Division of Pathology, Biological Safety Research Center, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
The modification effects of freeze-dried aloe (Aloe arborescens) whole leaf powder during the initiation phase of carcinogenesis were investigated in hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). Female Syrian hamsters were given four weekly subcutaneous injections of BOP at a dose of 10mg/kg and then given 0, 1 or 5% aloe in their diet for 5 weeks. At week 54 of the experiment, all surviving animals were sacrificed and development of neoplastic and preneoplastic lesions was assessed histopathologically. The incidences of pancreatic adenocarcinomas, atypical hyperplasias or total atypical hyperplasias plus adenocarcinomas were significantly (P<0.05) decreased with BOP+5% aloe, and that of adenocarcinomas were also significantly (P<0.05) reduced in the BOP+1% aloe as compared to the BOP alone group. Multiplicities of pancreatic adenocarcinomas, atypical hyperplasias or total lesions were also significantly (P<0.01 or P<0.05) lower in the BOP+5% aloe group than with the BOP alone. Quantitative data for neoplastic lesions in the lung, liver, gall bladder, kidney and urinary bladder of hamsters were not significantly different among the three groups. In a satellite experiment, pretreatment with aloe significantly (P<0.01) reduced the formation of O6-methyldeoxyguanosine in epithelial cells of pancreatic ducts as compared to the BOP alone value. Our results thus indicate that aloe prevents BOP-induced pancreatic neoplasia in hamsters in relation to decreased DNA adduct formation in the target tissue.
PMID: 11867195 [PubMed - indexed for MEDLINE]

32) J Chromatogr A. 1995 Dec 1;718(1):99-106.
High-performance liquid chromatographic profiles of aloe constituents and determination of aloin in beverages, with reference to the EEC regulation for flavouring substances.
Zonta F, Bogoni P, Masotti P, Micali G.
Istituto di Statistica e Ricerca Operativa, Universita di Trento, Italy.
Characteristic HPLC profiles of fresh and aged aloe solutions, detected at 360 and 220 nm, are presented and compared. Several aloe constituents (aloesin, aloeresin A, hydroxyaloin, aloin A and B and aloinoside A and B) were simultaneously separated and identified. The determination of aloin is described (detection limit 0.15 ppm) and discussed. In aloe-based alcoholic beverages, the aloins could not be detected, owing to their instability and degradation in solution; this is discussed in relation to the EEC Council Directive 88/388, which fixed the values of maximum allowable concentrations for aloin in food and beverages. Instead of aloin, other aloe compounds (e.g., aloeresin A or aloesin) should perhaps be used as an index of the presence of aloe in alcoholic beverages.
PMID: 8556168 [PubMed - indexed for MEDLINE]

33) Zhong Yao Cai. 2000 Feb;23(2):63-5.
Tissue culture and rapid propagation of Aloe arborescens
[Article in Chinese]
Zeng S, Peng X.
South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510520.
Tissue culture and rapid propagation of Aloe arborescens have been studied. The main results are as follows: the optimum medium for cluster shoots induction is MS + 6-BA 3.0 mg/L + NAA 0.2 mg/L; for cluster shoots propagation is MS + 6-BA 2.0 mg/L + NAA 0.2 mg/L; for roots induction is 1/2 MS + NAA 0.5 mg/L. The survival rate of the tube plantlets is 100% in the transplanting. Cutting down the cost of medium in large scale of production have been studied also.
PMID: 12575139 [PubMed - indexed for MEDLINE]

34) Asian Pac J Cancer Prev. 2003 Jul-Sep;4(3):247-51.
Inhibition of azoxymethane-induced DNA adduct formation by Aloe arborescens var. natalensis.
Shimpo K, Chihara T, Beppu H, Ida C, Kaneko T, Hoshino M, Kuzuya H.
Fujita Memorial Institute of Pharmacognosy, Fujita Health University , Hisai, Mie 514-1296, Japan . shimpo@fujita-hu.ac.jp
To clarify the possible mechanisms of inhibition of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in the rat colorectum by freeze-dried whole leaves of Aloe arborescens var. natalensis (Kidachi aloe) (hereinafter referred to as ALOE) and commercial crude aloin (Sigma A-0451; from Curacao aloe) (hereinafter ALOIN), we studied the effects of ALOE and ALOIN on the formation of AOM-induced DNA adducts (O6-methylguanine; O6-MeG) in rats. Male F344 rats (4 weeks old) were fed a basal diet, or experimental diets containing 5%ALOE or 0.25%ALOIN for 5 weeks. All rats were injected s.c. twice with 15 mg/kg AOM, once at the end of week 1, and once at the end of week 2. The animals were sacrificed 6 hours after the second injection to analyze DNA adducts (O6-MeG) in the colorectum. Dietary administration of ALOE significantly inhibited the O6-MeG levels (50% reduction) compared with controls, whereas the O6-MeG levels in the ALOIN-fed rats showed a tendency to decrease (by 30%), although not significantly. In this study, we also measured the enzyme activity and mRNA level of cytochrome (CYP) 2E1, known to be responsible for the activation of AOM, in rat liver. ALOE-fed rats showed significantly reduced CYP2E1 enzymatic activity (27% reduction) compared with controls. On the other hand, the activity in ALOIN-fed rats tended to decrease by 11%, although not significantly. The CYP2E1 mRNA levels in ALOE- and ALOIN-fed rats were slightly reduced (9.7% and 5.2%, respectively). These results may explain, at least in part, the previously observed inhibitory effects of ALOE and ALOIN, especially ALOE on AOM-induced ACF formation in the rat colorectum.
PMID: 14507246 [PubMed - indexed for MEDLINE]