Estudo fitoquímico de Leptohyptis macrostachys (Benth.) Harley & J.F.B.Pastore e Mesosphaerum sidifolium (L'Hérit.) Harley & J.F. B. Pastore da subtribo Hyptidinae (Lamiaceae)

Abstract

Hyptidinae is a subtribe of the Ocimeae tribe (Lamiaceae), distributed from the southern United States to Argentina, occurring in the Caribbean. The Lamiaceae family consists of 295 genera and about 7775 species with a cosmopolitan distribution. In Brazil, it is estimated that this family is represented by 36 genera and 490 species. Thus, the objective of this work was to carry out a phytochemical study of two species of the subtribe Hyptidinae (Lamiaceae) found in the semi-arid region of Paraíba, Leptohyptis macrostachys (Benth.) Harley & J.F.B.Pastore and Mesosphaerum sidifolium (L'Hérit.) Harley & J.F.Pastore. The leaves and stems of the species under study were subjected to extraction, filtration, and chromatography processes of their respective extracts. Subsequently, the chemical structures of the isolated substances were identified by spectroscopic methods. From the gross ethanolic extract (BSE) of L. macrostachys, the hexane, dichloromethane and ethyl acetate phases were obtained. In the study with the ethyl acetate phase of L. macrostachys, three substances were isolated using conventional chromatographic methods, two of which are triterpenes: 3-β-hydroxy-olean-12-en-28-oico (oleanolic acid), which was encoded as Lm-1 and 3-β-acetoxy-olean-12-en-28-oico (oleanolic acid acetate) encoded as Lm-2, and also a caurane diterpene: ent-3β-acetoxy-caur15-eno-17-oico, encoded as Lm-3 which is being reported for the first time in the genus Leptohyptis, as well as the 13C NMR signaling was done for the first time. The M. sidifolium BSE was subjected to medium pressure chromatography and the resulting fractions were monitored, providing three unique Abietan diterpenes in the Mesosphaerum genus: pomiferin E (Ms-1), 2α-hydroxysugiol (Ms-2) and a derivative esterified pormiferin D (Ms-3). The 13C NMR assignment of Ms-1 and Ms-2 was performed for the first time. From this M. sidifolium species, two phenolic compounds were also isolated: caffeic acid (Ms-4) and rosmarinic acid (Ms-5). These results contributed to the phytochemical study of the species from the semi-arid region of Paraíba, L. macrostachys and M. sidifolium, through the structural identification of eight substances.