Chemoprevention of LA7-Induced Mammary Tumor Growth by SM6Met, a Well-Characterized Cyclopia Extract.

Breast cancer (BC) is the leading cause of cancer-related deaths in women. Chemoprevention of BC by using plant extracts is gaining attention. SM6Met, a well-characterized extract of Cyclopia subternata with reported selective estrogen receptor subtype activity, has shown tumor suppressive effects in a chemically induced BC model in rats, which is known to be estrogen responsive. However, there is no information on the estrogen sensitivity of the relatively new orthotopic model of LA7 cell-induced mammary tumors. In the present study, the potential chemopreventative and side-effect profile of SM6Met on LA7 cell-induced tumor growth was evaluated, as was the effects of 17ß-estradiol and standard-of-care (SOC) endocrine therapies, such as tamoxifen (TAM), letrozole (LET), and fulvestrant (FUL). Tumor growth was observed in the tumor-vehicle control group until day 10 post tumor induction, which declined afterward on days 12-14. SM6Met suppressed tumor growth to the same extent as TAM, while LET, but not FUL, also showed substantial anti-tumor effects. Short-term 17ß-estradiol treatment reduced tumor volume on days prior to day 10, whereas tumor promoting effects were observed during long-term treatment, which was especially evident at later time points. Marked elevation in serum markers of liver injury, which was further supported by histological evaluation, was observed in the vehicle-treated tumor control, TAM, LET, and long-term 17ß-estradiol treatment groups. Alterations in the lipid profiles were also observed in the 17ß-estradiol treatment groups. In contrast, SM6Met did not augment the increase in serum levels of liver injury biomarkers caused by tumor induction and no effect was observed on lipid profiles. In summary, the results from the current study demonstrate the chemopreventative effect of SM6Met on mammary tumor growth, which was comparable to that of TAM, without eliciting the negative side-effects observed with this SOC endocrine therapy. Furthermore, the results of this study also showed some responsiveness of LA7-induced tumors to estrogen and SOC endocrine therapies. Thus, this model may be useful in evaluating potential endocrine therapies for hormone responsive BC.

Hoodia gordonii extract targets both adipose and muscle tissue to achieve weight loss in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Hoodia gordonii (Masson) Sweet ex Decne (family Apocynaceae) is consumed globally as a natural appetite suppressant. While this effect-and its subsequent effect of weight loss-has been reported in the scientific literature, no information is available on the specific tissue types affected that accounts for the significant weight loss reported after consumption of the plant. Furthermore, most studies are performed on lean animals, so that the response of overweight or obese individuals to this plant supplement remains largely unknown. MATERIALS AND METHODS: Twelve lean and twelve obese male Wistar rats were supplemented with different doses of Hoodia gordonii extract (80 or 160 mg/kg body mass twice daily) in a placebo-controlled study, for a period of 14 days. RESULTS: All supplemented rats exhibited significant weight loss (P<0.001). This could be ascribed to decrease in both adipose cell size and skeletal muscle fibre size. CONCLUSIONS: We conclude that the weight loss seen after consumption of Hoodia gordonii is due to loss of both adipose and muscle mass.

Hoodia gordonii: to eat, or not to eat.

ETHNOPHARMACOLOGICAL RELEVANCE: Hoodia gordonii (family Apocynaceae) has become known globally for its claimed effect of appetite suppression. Despite a relatively large body of evidence of the plant׳s chemical make-up, peer-reviewed studies to provide scientific information on physiological effects of Hoodia gordonii are relatively sparse. The role of the pregnane glycoside P57-commonly accepted to be responsible for appetite suppression-has been questioned recently. Furthermore, a variety of physiological side-effects associated with consumption of the plant in extracted form questions its suitability for consumption. Although adverse effects have been described before, the relative abundance of non-peer-reviewed data originating from patent documents and lay publication for advertising, which specifically only focus on beneficial outcomes, skews the view of the risk-benefit-balance. Here we provide a review of peer-reviewed studies on the plant׳s physiological effects. Novel data from an in vivo rodent study further elucidate the benefit-to-risk ratio associated with consumption. CONCLUSIONS: we conclude that although Hoodia gordonii seems to have a desired effect on appetite and weight loss, this effect may at least in part be a secondary symptom of the serious adverse effects that are associated with consumption of the high doses required to achieve therapeutic clinical effect.