Croton blanchetianus Baill: variação intraespecífica da composição química volátil e não-volátil.

Abstract

Croton blanchetianus Baill. (Synonym: Croton sonderianus Müll. Arg.), commonly known as “marmeleiro preto”, is an endemic plant in Brazil, found mainly in the Northeast region. The general objective of this work is to contribute to the phytochemical knowledge of the species by studying the chemical composition of the essential oils from the aerial parts (leaves and inflorescences) and the hexane extract from the roots of individual C. blanchetianus specimens. The analysis by 1H NMR of the essential oils obtained from the aerial parts of eight individual specimens of C. blanchetianus, collected in the same geographic location, in the town of Acarape, CE, permitted to the determine the spectroscopic profile of each specimen, and then to classify them into four groups according to the characteristic of their major compounds. Based on the chemical profiles of the essential oils, three individual specimens (specimens 1, 4 and 8) were selected for a further phytochemical analysis of the hexane extract from their roots. Column chromatography (CC) and high performance liquid chromatography (HPLC) were the procedures used to isolate 10 compounds. A sesquiterpene isolated for the first time for the Croton genus, and nine diterpenes, four of them still unpublished in the literature: 3,4-seco-beieren-3-oic acid (CB-A), methyl 3,4-seco-sonderianoate (CB-B) and 12-oxo-hardwickiic acid (CB-H) were obtained from specimen 1. The compounds methyl 3,4-seco-sonderianoate (CB-B), isocapnel-9-en-8-one (CB-D), methyl blanchetianoate (CB-E), methyl 2-epi-blanchetionate (CB-F), and E-11,12-dehydro-elongatolide B (CB-C), were obtained from specimen 4, and sonderianol (CB-G), ent-3,4-seco-atisan-4(18),16-dien-3-oic acid (CB-I), and 3,4-seco-sonderianoic acid (CB-J) from specimen 8. Methyl 3,4-seco-sonderianoate (CB-B) was common to all three specimens studied. High resolution mass spectrometry (LC/MS Q-TOF), Fourier Transform Infrared Spectroscopy (FTIR), and uni and bidimentional NMR pulse sequences were used to determine the structure of all secondary metabolites. The compounds 3,4-seco-beieren-3-oic acid (CB-A), methyl 3,4-seco sonderianoate (CB-B) and ent-3,4-seco-atisan-4(18),16-dien-3-oic acid (CB-I) showed antimicrobial activity against Streptococcus mutans and S. parasanguinis, very common bacteria in oral biofilms, and the last two compounds also showed activity in inhibiting the formation of biofilms and pre-formed biofilms caused by those oral bacteria.