Chemical composition and cytotoxic activity of Lepechinia speciosa (St. Hill) Epling

The cell viability of Lepechinia speciosa (St. Hill) Epling fractions was measured by cell membrane integrity (lactate dehydrogenase assay) on rat basophilic leukemia cells (RBL-2H3). All fractions and extract tested (100 μg/ml) increased the release of lactate dehydrogenase (LDH), being the ethyl acetate and dichloromethane fractions with LDH release of 94.5% and 91.2%, respectively. As these fractions showed decrease of cell viability, the antiproliferative activity on human breast adenocarcinoma cells (MCF-7) through sulphorhodamine B (SRB) assay was performed with them. The dichloromethane fraction (50 μg/ml) displayed the maximum activity (95% of inhibition) (IC50 = 1.99 ± 0.06 μg/ml). From this fraction was obtained a mixture containing two triterpenes (ursolic and oleanolic acids) and one fatty acid (palmitic acid), which were identified by gas chromatography coupled to mass spectrometry (GC-MS) and had their structures confirmed by 13C NMR. Rosmarinic acid and verbascoside were isolated from the ethyl acetate fraction and had their structures confirmed by 1H NMR.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Evaluation of the antioxidant and phototoxic potentials of Bauhinia microstachya var. massambabensis Vaz leaf extracts

Four different leaf extracts of B. microstachya var. massambabensis were studied to evaluate their antioxidant capacity by using three in vitro methods, with Ginkgo biloba and Trolox® as the standards. With the DPPH and ABTS·+ methods, the antioxidant activity of the extracts was in the following order, from maximum to minimum: AcEt > WAc > raw EtOH > EtOH CA > EGb, while with the ORAC method, it was as follows: EtOH CA > raw EtOH > AcEt > WAc > EGb. Phototoxic analysis was performed in yeast cultures of Saccharomyces cerevisiae. From the ethyl acetate extract, 2 flavonoids kaempferol-3-O-rhamnoside and astragalin-2”,6”-O-digallate were isolated and identified by HPLC and 1H- and 13C-NMR; to our knowledge, this is the first report of the occurrence of astragalin-2”,6”-O-digallate in the Bauhinia genus.Colegio de Farmacéuticos de la Provincia de Buenos Aire