Clear Evidence of Carcinogenic Activity by a Whole-Leaf Extract of Aloe barbadensis Miller (Aloe vera) in F344/N Rats

Abstract

Aloe barbadensis Miller (Aloe vera) is an herbal remedy promoted to treat a variety of illnesses; however, only limited data are available on the safety of this dietary supplement. Drinking water exposure of F344/N rats and B6C3F1 mice to an Aloe vera whole-leaf extract (1, 2, and 3%) for 13 weeks resulted in goblet cell hyperplasia of the large intestine in both species. Based upon this observation, 2-year drinking water studies were conducted to assess the carcinogenic potential of an Aloe vera whole-leaf extract when administered to F344/N rats (48 per sex per group) at 0.5, 1, and 1.5%, and B6C3F1 mice (48 per sex per group) at 1, 2, and 3%. Compared with controls, survival was decreased in the 1.5% dose group of female rats. Treatment-related neoplasms and nonneoplastic lesions in both species were confined primarily to the large intestine. Incidences of adenomas and/or carcinomas of the ileo-cecal and cecal-colic junction, cecum, and ascending and transverse colon were significantly higher than controls in male and female rats in the 1 and 1.5% dose groups. There were no neoplasms of the large intestine in mice or in the 0 or 0.5% dose groups of rats. Increased incidences of mucosa hyperplasia of the large intestine were observed in F344/N rats, and increased incidences of goblet cell hyperplasia of the large intestine occurred in B6C3F1 mice. These results indicate that Aloe vera whole-leaf extract is an intestinal irritant in F344/N rats and B6C3F1 mice and a carcinogen of the large intestine in F344/N rats.

Estonian folk traditional experiences on natural anticancer remedies: From past to the future

“…Among them, Aloe vera (L.) Burm.f. (Aloaceae) (aloe) is a genus of medicinal plants with a history of medical use for several thousand years (Boudreau et al, 2013;Harlev et al, 2012). Its antineoplastic property is due to at least three different mechanisms based on antiproliferative, immunostimulatory, and antioxidant effects, whereas the antiproliferative action is determined mainly by the anthraquinonic molecules, such as aloin and emodin (Harlev et al, 2012).…”

“…However, only limited data are available on the safety of Aloe vera supplements leaving this issue controversial and uncertain. Few reports have even shown that aloe leaf extract can itself exert some carcinogenic activity (Ahlawat & Khatkar, 2011;Boudreau et al, 2013). Aloin and aloe emodin were found in roots and petioles of Rheum rhaponticum L. (Polygonaceae) (dietary rhubarb) cultivated in Estonia, but not mentioned in folk medicine as the anticancer herbal remedy (Püssa et al, 2009).…”

Long-Term (24 Months) Carcinogenicity Study of D-004, a Lipid Extract From Roystonea regia Fruits, in Sprague Dawley Rats

“…In such regard, the conduct of long-term carcinogenicity/toxicity studies of natural products should not be minimized as proven by the recent demonstration of the carcinogenic effects of kava and aloe vera extracts for increasing hepatocellular and lower bowel (adenomas and carcinomas) tumors, respectively, in rats. [61][62][63][64] We believe, therefore, that the conduct of long-term carcinogenicity/toxicity studies of natural products, mainly those used for years, should be encouraged.…”

The Efficacy and Safety of 4 Natural Products for the Management of IBS

“…44 Aloe vera latex extracted from the outer leaf pulp contains anthraquinones, mainly as aloins, which have been shown to produce a laxative effect, 39 but are carcinogenic in animal models. 45 Because of such safety concerns, since 2002, the FDA has banned the use of Aloe vera latex in over-the-counter laxative products. 46 The Natural Medicines Comprehensive Database warns against the oral ingestion of Aloe vera latex because it is likely unsafe for use by adults and children.…”