Antimicrobial, anti-inflammatory, antiparasitic, and cytotoxic activities of Galium mexicanum

Ethnopharmacological relevance: To study the potential benefit of the traditional Mexican medicinal plant Galium mexicanum Kunth (Rubiaceae). Hexane, chloroform, and methanol extracts as well as various fractions from these extracts were tested to determine antibacterial, antifungal, antiparasitic or anti-inflammatory activities in vitro. Materials and methods: Aerial parts of the plant were extracted with various solvents and fractionated accordingly. Their antibacterial and antifungal activities were assessed on nine bacterial and four fungal strains. Leishmania donovani was used as a protozoan strain for antiparasitic activity. The anti-inflammatory activity of the compounds was investigated by measuring the secretion of interleukin-6 when macrophages were exposed to lipopolysaccharide. Results: Various extracts and fractions obtained from this plant exhibit antibacterial, antifungal, antiparasitic, and anti-inflammatory activities. Of special interest was the hexane fraction HE 14b, which show antibacterial (ranging between 67 and 666 μg/ml) and antifungal (at concentrations of 333 μg/ml) activities. Also the hexane fraction HE 5 exhibited antiparasitic activity (at concentrations of 260 μg/ml), whereas the methanol fraction ME 13-15 showed a potent anti-inflammatory activity when compared to dexamethasone. Chemical analyses of the chloroform extract show the presence of triterpenes, saponins, flavonoids, sesquiterpene lactones, and glucosides, but no tannins were detected in the assayed extract. Conclusions: The benefit of Galium mexicanum as a traditional medicinal plant was confirmed using antibacterial and antifungal assays in vitro. We also report for the first time, and to the best of our knowledge, antiparasitic and anti-inflammatory activities of this plant.