Cytotoxic Acetogenins from the Roots of Annona purpurea.

Annona purpurea, known in Mexico as "cabeza de negro" or "ilama", belongs to the Annonaceae family. Its roots are employed in folk medicine in several regions of Mexico. Taking that information into account, a chemical and biological analysis of the components present in the roots of this species was proposed. Our results demonstrated that the dichloromethane (DCM) extract was exclusively constituted by a mixture of five new acetogenins named annopurpuricins A-E (1-5). These compounds have an aliphatic chain of 37 carbons with a terminal α,ß unsaturated γ-lactone. Compounds 1 and 2 belong to the adjacent bis-THF (tetrahydrofuran) α-monohydroxylated type, while compounds 3 and 4 belong to the adjacent bis-THF α,α'-dihydroxylated type; only compound 5 possesses a bis-epoxide system. Complete structure analysis was carried out by spectroscopy and chemical methods. All compounds were evaluated for their antiproliferative activity on three human tumor cell lines (MSTO-211H, HeLa and HepG2). Compounds 1-4 inhibited significantly the growth of HeLa and HepG2 cells, showing GI50 values in the low/subnanomolar range, while 5 was completely ineffective under the tested conditions. The investigation of the mechanism of action responsible for cytotoxicity revealed for the most interesting compound 1 the ability to block the complex I activity on isolated rat liver mitochondria (RLM).

Age-dependent vasorelaxation of Casimiroa edulis and Casimiroa pubescens extracts in rat caudal artery in vitro.

ETHNOPHARMACOLOGICAL RELEVANCE: Leaf and seed decoctions of Casimiroa spp. are used in Mexican traditional medicine to treat high blood pressure. Previous researches showed as Casimiroa extracts are able to induce relaxation of rat aortic and caudal arteries. To study the influence of the aging, we determined the vascular effect induced by extracts of Casimiroa edulis and Casimiroa pubescens in arterial tissues from young and old rats. MATERIALS AND METHODS: The activity of Casimiroa edulis extracts: hexanic-leaf (Ce5), methanolic-leaf (Ce6), hexanic-seed (Ce7) and methanolic-seed (Ce8), and Casimiroa pubescens: hexanic-leaf (Cp9), methanolic-leaf (Cp10), hexanic-seed (Cp11) and methanolic-seed (Cp12) were investigated in precontracted caudal arteries of young (4 months) and old (20 months) rats. RESULTS: The Casimiroa extracts tested at 20 µg/ml induced vasorelaxation in phenylephrine-precontracted arterial tissues both in young and old arterial tissues. Methanolic seed extracts of Casimiroa edulis (Ce8) and Casimiroa pubescens (Cp12) caused a higher relaxation in young than in old arterial tissues. Nifedipine (0.01 µM) did not change the vasorelaxation induced by Casimiroa edulis extract either in young and old rat arterial tissues. CONCLUSIONS: The vasorelaxation induced by Casimiroa edulis and Casimiroa pubescens extracts is decreased from aging since the effects were higher in young than in old rat arterial tissues. However, the methanolic-seed extracts of both plant species induced a relevant vasorelaxation also in old arterial tissues. Thus the results support the traditional use of Casimiroa decoctions as antihypertensive, also in elderly.

Veriaciones cuantitativas de la melanina durante la muda de pelaje del conejo de los volcanes (Romerologus diazi) / Quantitative variations of metanin during the moulting of atypical fur in the volcano rabbit (Romerolagus diazi)

Se establecen las diferencias cuantitativas de melanina en los diversos estadios del proceso de la muda atípica de pelaje del conejo de los volcanes. La intensidad del color de la piel de los conejos estudiados tuvo relación directa con su contenido de melanina. Las pieles con lunares temporales tuvieron mayor cantidad de melanoide que las normales, y éstas, a su vez, más que las pieles alopécicas