Ana María García

Variation in the hexanic extract composition of Lippia graveolens in an arid zone from Mexico: environmental influence or true chemotypes?

The hexanic extract composition of two populations of Lippia graveolens growing in an arid zone in the Tehuacan-Cuicatlan Valley (Zapotitlan Salinas, Puebla), Central Mexico, in different seasons of the year, and in contrast- ing conditions of ecological disturbance has been studied by GC and GC-MS. Regarding to the composition of these extracts, qualitative differences among the two populations were found. Thus, 9 compounds were identified from the extracts of the Zone A (the less disturbed) and 10 from the ones of Zone B (the most disturbed). Thymol was detected as the major compound in most of the individuals sampled, while at the season level, September was the more productive month for zone B (higher content of identified compounds) and the only one that presents antibacterial activity. Lippia graveolens displays quantitative and qualitative variations both within and between natural plant populations.

Chemical composition and biological activity of Laennecia schiedeana.

The chemical study of Laennecia schiedeana afforded three sterols, five diterpenes, five flavonoids, three caffeoyl derivatives of quinic acid, and two triterpenes. Evaluation of the cytotoxic activity of the extracts and isolated metabolites showed that 15-methoxy-16-oxo- 15,16H-strictic acid was the most active compound [(15.05 ± 2.2) μg/mL against U-251 cells]. In antibacterial assays the acetonic extract of leaves was the only active extract exhibiting its highest effect against the multiresistant Staphylococcus epidermidis (MIC 0.25 mg/mL). The anti-inflammatory activity observed was mild in the extracts and not relevant in the isolated compounds