Lippia Alba Mill, investigação etnobotânica e caracterização da composição química do seu óleo essencial por cromatografia.

Abstract

The study of the relationship between humans and plants and how these vegetables resources are used by the population is called ethnobotany, and is a multidisciplinary scientific area that encompasses several areas including: history , sociology , medicine , economics, herbal medicine , commerce , pharmacology , etc. Lippia alba is a native plant, known as "erva-cidreira " used in folk medicine for the treatment of different diseases. Considering the variation in the composition of essential oils of Lippia alba, the present study aimed to contribute to the ethnobotanical study of this species and the determination of the chemical composition of the essential oil of nine samples extracted from fresh leaves by hydrodistillation method, the samples were collected at Cuité in the state of Paraíba, Brazil, during the year 2013. A voucher specimen of the plant material is deposited in the herbarium of the Centro de Educação e Saúde, Federal University of Campina Grande, campus Cuité under number HCES 0032. The volatile content in the oil was analyzed by Gas Chromatography coupled to Mass Spectrometry -CG/EM the material obtained in the rainy and dry seasons. Their components were identified by comparing retention indices observed experimentally with the literature data, as well as comparison of the mass spectra data base of equipment. The yields of the oils ranged from 0.070 to 0.628 %, the best performance was observed in the samples of the dry season. The essential oil consists of monoterpenoids and sesquiterpenoids compounds and the identified constituents in higher concentration were D -Limonene, β - myrcene, citral, geraniol, carvone, geraniol and acetate being such that monoterpenes present in all samples. Citral ( 42,32 - 80,69 % ) and geraniol (3,85 - 16,65% ) were the major constituents in eight of the nine samples analyzed , with respect to, the time of collection that provided a higher relative content of citral was at 14 hours , with 80,69%, the sample A1T- ES and also this same sample D- limonene was the second largest constituent with 5.46 %. Due to the high variability in the chemical composition of the essential oil of Lippia alba, genotypes are grouped into chemotypes (chemical type), separated by its major elements. According to the results, the variation in the content of compounds of the samples may have resulted from the origin of accesses, since in this experiment were all grown in the same environment. Based on the composition was noting that it is a kind of citral chemotype - geraniol.