Lobophora variegata, a brown alga collected from the coast of the Yucatan peninsula, Mexico, was studied for antiprotozoal activity against Giardia intestinalis, Entamoeba histolytica and Trichomonas vaginalis. The whole extract showed the highest activity against T. vaginalis, with an IC₅₀ value of 3.2 mg/mL. For the fractions, the best antiprotozoal activity was found in non-polar fractions. The chloroform fraction of the extract contained a major sulfoquinovosyldiacylglycerol (SQDG), identified as 1-O-palmitoyl-2-O-myristoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol (1), together with small amounts of 1,2-di-O-palmitoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol (2) and a new compound identified as 1-O-palmitoyl-2-O-oleoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol (3). Their structures were elucidated on the basis of chemical and enzymatic hydrolysis and careful analysis of FAB-MS and NMR spectroscopic data. This is the first report on the isolation of SQDGs from L. variegata. The mixture of 1–3 showed good activity against E. histolytica and moderate activity against T. vaginalis with IC_50s of 3.9 and 8.0 mg/mL, respectively, however, the activity of 1–3 is not as effective as metronidazole. These results afford ground information for the potential use of the whole extract and fractions of this species in protozoal infections.

The plant Aeschynomene fascicularis (Fabaceae) has been used in Mayan traditional medicine in the Yucatan peninsula. However, the compounds present in the plant responsible for its curative properties have not yet been investigated. Aeschynomene fascicularis root bark was extracted with 100% methanol to obtain a crude extract. The methanol extract was partitioned successively with solvents with increasing polarity to obtain the corresponding hexane (Hx), dichloromethane (DCM) and ethyl acetate fractions (EtOAc), as well as a residual water-alcoholic fraction. These fractions were tested for their cytotoxic activities using an MTT assay against Hep-2 cancer cell lines. The Hx fraction led to the isolation of spinochalcone C (1), spinochalcone A (2), isocordoin (3) and secundiflorol G (4). Their structures were identified based on spectroscopic evidence and chemical properties. All compounds were subjected to cytotoxicity and antiproliferative assays against a panel of seven cell lines, including one normal-type cell line. Spinochalcone A (2) exhibited cytotoxic activity against DU-145 cell line and antiproliferative activity against the KB cell line. Secundiflorol G (4) showed strong cytotoxic activity towards KB and Hep-2 cell lines. In addition, isocordoin (3) showed moderate activity on KB, Hep-2 and DU-145 cell lines. The active Compounds 2, 3 and 4 are potential therapeutic entities against cancer.

Several studies have shown the hepatoprotective effect of the consumption of coffee and tea, which is mainly attributed to caffeine. Many experimental studies have demonstrated this effect; however, these studies used high caffeine doses that are not related to human consumption. The aim of this study was to evaluate the hepatoprotective effect of low doses of caffeine on carbon tetrachloride (CCl₄)-treated rats. Low doses of caffeine (CAFF) 5 and 10 mg/kg (CAFF5 and CAFF10) were evaluated in chronic liver damage induced by CCl₄ (0.75 mL/kg) in rats. CAFF treatment was administered once a day and CCl₄ administration was twice weekly for 10 weeks. Liver function tests (biochemical markers) and functional (sleeping time) and histological (hematoxylin-eosin and Masson trichrome stains) parameters were carried out at the end of damage treatment. Daily treatments of CAFF5 and CAFF10 exhibited a hepatoprotective effect supported by a decrease of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (AP) serum activities and bilirubin serum levels compared with control and also restored serum albumin levels and liver glutathione (GSH). Moreover, CAFF prevented CCl₄-induced prolongation in pentobarbital sleeping time and a decrease of liver fibrosis and cell death. Our results demonstrated that low doses of CAFF exert a hepatoprotective effect against CCl₄ -induced liver damage in rats.