Chromatographic (GC/flame ionization detection, GC/MS) and statistical analyses were applied to the study of essential oils and extracts obtained from flowers, leaves, and stems of Lippia origanoides plants, growing wild in different Colombian regions. Retention indices, mass spectra, and standard substances were used in the identification of 139 substances detected in these essential oils and extracts. Principal component analysis allowed L. origanoides classification into three chemotypes, characterized according to their essential oil major components. Alpha- and beta-phellandrenes, p-cymene, and limonene distinguished chemotype A; carvacrol and thymol were the distinctive major components of chemotypes B and C, respectively. Pinocembrin (5,7-dihydroxyflavanone) was found in L. origanoides chemotype A supercritical fluid (CO(2)) extract at a concentration of 0.83+/-0.03 mg/g of dry plant material, which makes this plant an interesting source of an important bioactive flavanone with diverse potential applications in cosmetic, food, and pharmaceutical products.

Microwave-assisted hydrodistillation, simultaneous distillation-solvent extraction, and supercritical fluid extraction, were used to isolate secondary metabolites from two Lippia origanoides chemotypes growing wild in Colombia. Compound identification was based on chromatographic and spectroscopic criteria. The main components identified in the essential oil of one chemotype were carvacrol (44.4-51.8%) and p-cymene (8.8-10.1%). Those of the other chemotype were p-cymene (11.3-15.7%) and 1,8-cineole (6.8-10.9%). The last one constitutes a new chemotype, characterized by its low thymol and carvacrol contents and very low antioxidant activity. The radical scavenging activity of the essential oil of the first chemotype was higher than that of butylated hydroxytoluene (BHT) and similar to that of α-tocopherol.

The results suggest the importance that recent transmission of TB may be having among young adults, IDU and prison inmates in particular, and calls for a review of control strategies.

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