Two new sesquiterpene lactones, (4S,6R,7S,8S,10R,11S,16R)-1-oxo-3(10),8(16)-diepoxy-16-methylprop-1Z-enyl-16-methoxygermacra-2-en-6(12)-olide (1) and (4S,6R,7S,8S,10R,11S)-1-oxo-3,10-epoxy-8-angeloyloxygermacra-2-en-6(12)-olide (2), were isolated from Lychnophora ericoides. Their structures, including absolute configuration, were established by spectroscopic methods, including single-crystal X-ray analysis. Monitoring the furanoheliangolide metabolism of L. ericoides revealed an increase in biosynthesis during the plant flowering period.

Recebido em 7/5/12; aceito em 18/9/12; publicado na web em 26/10/12The species Eremanthus mattogrossensis, known as "veludo do cerrado" (cerrado velvet), is native to the Brazilian Cerrado.Because the amount of metabolites present in plants may be influenced by biological and environmental factors, here we conducted an HPLC-DAD-MS/MS investigation of the metabolite concentrations found in the MeOH/H 2 O extract of the leaves of this species. The main compounds were identified and quantified, and the metabolites were grouped by chemical class (caffeoylquinic acids, flavonoids, and sesquiterpene lactone). Statistical analysis indicated a straight correlation between the quantity of metabolites and seasonality, suggesting that environmental properties elicit important metabolic responses.

Eremanthus seidelii MacLeish & Schumacher tem ocorrência restrita ao cerrado, em torno do reservatório de Furnas (MG), em habitats que vêm sendo seriamente deteriorados pela ação humana. A presente investigação fitoquímica mostrou, como metabólitos secundários majoritários das folhas de E. seidelii, as lactonas sesquiterpênicas (LS) 4β,5-diidro-2',3'-diidroxi-15-desoxigoiazensolídeo (1) e 4β,5-diidro-1',2'-epoxi-eremantolídeo-C (2); uma metodologia foi desenvolvida em CLAE para sua análise quantitativa. A análise por CLAE mostrou que não há variações sazonais significativas nas concentrações de ambas LS. Não foram encontradas diferenças qualitativas nos perfis de LS nos indivíduos amostrados. Entretanto, há diferenças no perfil quantitativo entre os indivíduos analisados, apontando para a existência de três quimiotipos quantitativos desta espécie, com diferenças possivelmente originadas na atividade enzimática das enzimas que ciclizam uma LS tipo goiazensolídeo (1) em uma LS tipo eremantolídeo (2).Eremanthus seidelii MacLeish & Schumacher has a restricted occurrence to the Brazilian "cerrado" surrounding the Furnas (MG) reservoir, in environments that have been seriously damaged by human activity. The present phytochemical investigation reveals that the sesquiterpene lactones (SL) 4β,5-dihydro-2',3'-dihydroxy-15-desoxy-goyazensolide (1) and 4β,5-dihydro-1',2'-epoxy-eremantholide-C (2) are the major secondary metabolites in E. seidelii leaves, and an HPLC method was developed for their quantitative analysis. HPLC analysis showed no significant seasonal variation in the concentrations of both SL. No qualitative differences were found in the SL patterns of all individuals sampled. However, there is a different SL quantitative pattern among the plants analyzed, pointing to the existence of three quantitative chemotypes of this species, with differences possibly originating from the activity of the enzymes that cyclize the goyazensolide type SL (1) to a eremantholide type SL (2). Keywords: HPLC, sesquiterpene lactones, chemotypes, populational variation, Eremanthus seidelii IntroductionThe genus Eremanthus Less (Asteraceae: Vernonieae) comprises 22 species that are restricted to the Brazilian "cerrado". 1,2 Previous phytochemical investigations with this genus led to the isolation of flavonoids, triterpenes, poliacetylenes and revealed sesquiterpene lactones (SL) as the main secondary metabolites. 3-9 Some of the SL isolated from the Eremanthus genus posses important biological activities, 3,[6][7][8]10 like the antiproliferative effects on some cancer cell lines 11 and the modulation of the inflammatory process in vitro, by inhibiting the NF-κβ transcriptor factor. 12 Seasonal, 13-16 circadian [17][18][19] and populational 20-24 variations in the content of almost all classes of secondary metabolites, including SL, [25][26][27][28][29] were reported. The recognition of variations in secondary metabolite production can be helpful in chemotaxonomic studies, 1397 Quantitative HPLC Analysis of Sesquiterpene Lactones V...