A validated HPLC method for the analysis of herbal teas from three chemotypes of Brazilian Lippia alba

Infusions and decoctions of three chemotypes of Lippia alba (Mill.) N. E. Brown (Verbenaceae) were investigated for their quantitative profiles by HPLC-DAD-ESI-MS analyses. An RP-HPLC method was developed which permitted the quality control of the preparations. The correct choice of the column allowed the detailed characterization of the constituents in a total analysis time of 35 min. The HPLC method was accordingly validated for linearity range, LOD, LOQ, accuracy and precision. For the quantitative analysis the three major phytochemical groups were taken into consideration, namely iridoids, phenylpropanoids and flavonoids. Comparative quantitative analyses revealed significant differences among the chemotypes that should be taken into account in the uses of the herbal teas. The developed HPLC-UV assay proved to be an efficient and alternative method for the discrimination of the three chemotypes. This is the first report of detailed analysis of the chemical composition of the constituents of L. alba chemotypes' teas.

HPLC/DAD/ESI-MS Analysis of Non-volatile Constituents of Three Brazilian Chemotypes of Lippia alba (Mill.) N. E. Brown

Aqueous preparations and ethanolic extracts of three Brazilian chemotypes of Lippia alba (Mill.) N.E. Brown (Verbenaceae) were investigated for the chemical variability of their non volatile constituents by HPLC/DAD/ESI-MS analysis. The main class of compounds in all the extracts investigated was phenylpropanoids, mainly verbascoside, followed by the flavonoids tricin-7- O-diglucuronide (present in Lippia alba chemotypes 2 and 3), luteolin-7- O-glucuronide (present in L. alba chemotype 1) and mono-and di- O-glucuronic derivatives of apigenin and tricin. Four iridoids, geniposidic acid, theveside, 8- epi-loganin and mussaenoside were also identified.

Composition and Antioxidant Activity of Essential Oils of Lippia Origanoides H.B.K. grown in Colombia

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.

Ethnopharmacology of Lippia alba

INTRODUCTION

Chemical, ethnopharmacological and pharmacological research on Lippia alba (Mill.) N.E. Brown and the evidence that exists for its various usages have been looked for, focusing on high quality studies.

ETHNOPHARMACOLOGICAL INVESTIGATION

The species is mainly used against digestive and respiratory ailments, and as a sedative and antihypertensive remedy.

CHEMICAL CONSTITUENTS

Seven chemotypes exist for the essential oil, the non-volatile compounds are iridioids, phenylethanoids, flavone glycosides and biflavonoids.

BIOLOGICAL ACTIVITIES AND ETHNOPHARMACOLOGICAL APPRAISAL

Some positive, although partial, results have been obtained on sedative and anxiolytic activities. Real effects in other traditional uses can mainly be explained by anti-infectious and analgesic properties, at the moment.

CONCLUSION

Well conducted biological studies are still needed for several indications of this species. Its use as a sedative deserves a clinical investigation. The chemical variability of the species seems important both in the essential oil and in non-volatile compounds, so future research on the pharmacological properties of these extracts should provide more chemical data which will increase their validity.