ABSTRACT
Several Lippia species have been used in folk medicine mainly for gastrointestinal and respiratory diseases. Their biological properties have been partially associated to the terpenoids found in their essential oils. According to the World Health Organization, cancer is the leading cause of death worldwide and is described as a complex group of diseases with several hallmarks. One of its acceptable defining features is the cell proliferation beyond their boundaries forming the tumors. Importantly, some drugs currently available were discovered by the investigation of plant secondary metabolites. Thus, this study aimed to evaluate in vitro cytotoxic effect of the essential oils extracted from five Lippia species against tumor cell lines. The results indicated that mouse colon carcinoma CT26.WT cell line viability was significantly reduced showing an IC50 of 19.05, 30.20 and 36.30 µg/ml when treated with the essential oils of L. sidoides, L. salviifolia and L. rotundifolia, respectively. Human lung carcinoma A549 cell line also had a compromised viability to the action of L. alba carvone chemotype essential oil. The tested essential oils did not compromise viability of the normal cell line CHO. These finds suggest that the studied Lippia essential oils might be good candidates for further in-depth studies.
ABSTRACT
The aim of this work was to analyze terpene oil production and terpene synthases (TPS) gene expression from leaves at different developmental stages of different chemotypes of Lippia alba (Mill.) N.E. Br. ex Britton & P. Wilson, Verbenaceae. Hydro-distilled essential oil were used for chemical analysis and gene expression of three monoterpene synthase genes called LaTPS12, LaTPS23 and LaTPS25 were used for analyses of gene expression associated to oil production. The putative genes were associated to TPS-b gene class. Semi-quantitative PCR and quantitative PCR (qPCR) analysis were used to investigate the expression profile of those three putative genes in different leaf stages and different chemotypes. Additionally, total oil production and gene expression of putative TPS genes cloned from L. alba chemotype linalool were evaluated at different stages of leaf development. The expression level of those three genes was higher when the highest oil production was observed, mainly in young leaves at the fourth nodal segment for all evaluated chemotypes. Total oil production was higher at leaves that had unopened trichomes. We also observed that the 1mM of MeJA treatment increased the gene expression in all chemotypes after 24 h elicitation.