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.