Maricela Gómez-Sánchez

Mexican medicinal plants used for cancer treatment: Pharmacological, phytochemical and ethnobotanical studies

AIM OF THE STUDY This review provides a summary of Mexican medicinal flora in terms of ethnobotanical, pharmacology, and chemistry of natural products related to anticancer activity. MATERIALS AND METHODS Bibliographic investigation was carried out by analyzing recognized books and peer-reviewed papers, consulting worldwide accepted scientific databases from the last five decades. Mexican plants with attributed anti-cancer properties were classified into six groups: (a) plant extracts that have been evaluated for cytotoxic effects, (b) plant extracts that have documented anti-tumoral effects, (c) plants with active compounds tested on cancer cell lines, (d) plants with novel active compounds found only in Mexican species, (e) plants with active compounds that have been assayed on animal models and (f) plants with anti-cancer ethnopharmacological references but without scientific studies. RESULTS Three hundred plant species belonging to 90 botanical families used for cancer treatment have been recorded, of which only 181 have been experimentally analyzed. The remaining 119 plant species are in use in empirical treatment of diseases consistent with cancer symptomatology. Only 88 of the plant extracts experimentally studied in in vitro cellular models have demonstrated active cytotoxic effects in at least one cancer cell line, and 14 out of the 88 have also been tested in vivo with the results that one of them demonstrated anti-neoplasic effects. A total of 187 compounds, belonging to 19 types of plant secondary metabolites, have been isolated from 51 plant extracts with active cytotoxic effects, but only 77 of these compounds (41%) have demonstrated cytoxicity. Seventeen of these active principles have not been reported in other plant species. However, only 5 compounds have been evaluated in vivo, and 3 of them could be considered as active. CONCLUSION Clearly, this review indicates that it is time to increase the number of experimental studies and to begin to conduct clinical trials with those Mexican plants and its active compounds selected by in vitro and in vivo activities. Also, the mechanisms of action by which plant extracts and their active compounds exert anti-cancer effects remain to be studied.

The antidiabetic plants Tecoma stans (L.) Juss. ex Kunth (Bignoniaceae) and Teucrium cubense Jacq (Lamiaceae) induce the incorporation of glucose in insulin-sensitive and insulin-resistant murine and human adipocytes

AIM OF THE STUDY Tecoma stans (L.) Juss. ex Kunth (Bignoniaceae) and Teucrium cubense Jacq (Lamiaceae) are plants extensively used for the empirical treatment of diabetes mellitus, but their antidiabetic mechanisms remain to be clarified. In this study, the effect of aqueous extracts of Tecoma stans (TSE) and Teucrium cubense (TCE) on the glucose uptake in adipose cells was evaluated. MATERIALS AND METHODS Non-toxic concentrations of TSE and TCE were assayed on the adipogenesis and 2-NBDglucose uptake in insulin-sensitive and insulin-resistant murine 3T3-F442A and human subcutaneous adipocytes. RESULTS Both extracts stimulated 2-NBDG uptake by insulin-sensitive and insulin-resistant adipocytes in a concentration-dependent manner. In insulin-sensitive cells, TSE 70 microg/ml stimulated 2-NBDG uptake by 193% (murine) and by 115% (human), whereas the same concentration of TCE induced the 2-NBDG uptake by 112% (murine) and 54% (human). In insulin-resistant adipocytes, TSE induced the 2-NBDG uptake by 94% (murine) and 70% (human), compared with the incorporation shown by insulin-sensitive adipocytes stimulated by the hormone, whereas TCE induced the incorporation of 2-NBDG by 69% (murine) and 31% (human). On the other hand, TSE and TCE exerted only minimal or null proadipogenic effects on murine and human preadipocytes. CONCLUSION Tecoma stans and Teucrium cubense exert their antidiabetic effects stimulating glucose uptake in both insulin-sensitive and insulin-resistant murine and human adipocytes without significant proadipogenic or antiadipogenic side effects.

Ibervillea sonorae (Cucurbitaceae) induces the glucose uptake in human adipocytes by activating a PI3K-independent pathway.

ETHNOPHARMACOLOGICAL RELEVANCE Ibervillea sonorae (S. Watson) Greene (Cucurbitaceae), a plant used for the empirical treatment of type 2 diabetes in México, exerts antidiabetic effects on animal models but its mechanism of action remains unknown. The aim of this study is to investigate the antidiabetic mechanism of an Ibervillea sonorae aqueous extract (ISE). MATERIALS AND METHODS Non-toxic ISE concentrations were assayed on the glucose uptake by insulin-sensitive and insulin-resistant murine and human cultured adipocytes, both in the absence or the presence of insulin signaling pathway inhibitors, and on murine and human adipogenesis. Chemical composition of ISE was examined by spectrophotometric and HPLC techniques. RESULTS ISE stimulated the 2-NBDGlucose uptake by mature adipocytes in a concentration-dependent manner. ISE 50 µg/ml induced the 2-NBDG uptake in insulin-sensitive 3T3-F442A, 3T3-L1 and human adipocytes by 100%, 63% and 33%, compared to insulin control. Inhibitors for the insulin receptor, PI3K, AKT and GLUT4 blocked the 2-NBDG uptake in murine cells, but human adipocytes were insensitive to the PI3K inhibitor Wortmannin. ISE 50 µg/ml also stimulated the 2-NBDG uptake in insulin-resistant adipocytes by 117% (3T3-F442A), 83% (3T3-L1) and 48% (human). ISE induced 3T3-F442A adipogenesis but lacked proadipogenic effects on 3T3-L1 and human preadipocytes. Chemical analyses showed the presence of phenolics in ISE, mainly an appreciable concentration of gallic acid. CONCLUSION Ibervillea sonorae exerts its antidiabetic properties by means of hydrosoluble compounds stimulating the glucose uptake in human preadipocytes by a PI3K-independent pathway and without proadipogenic effects.

Carex vizarronensis (Cyperaceae), a New Species of Carex Section Schiedeanae from Central Mexico

Abstract— Carex vizarronensis, a new species from Cadereyta de Montes in the Mexican state of Queretaro, is described and illustrated. The new species is distinguished from C. schiedeana by its densely papillose culms, leaves and inflorescence bracts, and, perigynia with a corky stipe.

Floristic analysis of the Cañada, Queretaro, Mexico

Resumen es: Resumen: La localidad La Canada, pese a su cercania con la ciudad de Queretaro, es una area con bosque tropical caducifolio y matorral xerofilo medianam...