Dietary Aloe Vera Gel Powder and Extract Inhibit AzoxymethaneinducedColorectal Aberrant Crypt Foci in Mice Fed a Highfat Diet

Aloe vera gel exhibits protective effects against insulin resistance as well as lipid-lowering and anti-diabeticeffects. The anti-diabetic compounds in this gel were identified as Aloe-sterols. Aloe vera gel extract (AVGE)containing Aloe-sterols has recently been produced using a new procedure. We previously reported that AVGEreduced large-sized intestinal polyps in Apc-deficient Min mice fed a high fat diet (HFD), suggesting that Aloevera gel may protect against colorectal cancer. In the present study, we examined the effects of Aloe vera gelpowder (AVGP) and AVGE on azoxymethane-induced colorectal preneoplastic aberrant crypt foci (ACF) in micefed a HFD. Male C57BL/6J mice were given a normal diet (ND), HFD, HFD containing 0.5% carboxymethylcellulose solution, which was used as a solvent for AVGE (HFDC), HFD containing 3% or 1% AVGP, and HFDCcontaining 0.0125% (H-) or 0.00375% (L-) AVGE. The number of ACF was significantly lower in mice given3% AVGP and H-AVGE than in those given HFD or HFDC alone. Moreover, 3% AVGP, H-AVGE and L-AVGEsignificantly decreased the mean Ki-67 labeling index, assessed as a measure of cell proliferation in the colonicmucosa. In addition, hepatic phase II enzyme glutathione S-transferase mRNA levels were higher in the H-AVGEgroup than in the HFDC group. These results suggest that both AVGP and AVGE may have chemopreventiveeffects on colorectal carcinogenesis under the HFD condition. Furthermore, the concentration of Aloe-sterolswas similar between 3% AVGP and H-AVGE, suggesting that Aloe-sterols were the main active ingredients inthis experiment.