Ethnobotany, Pharmacology and Phytochemical Investigations of the Seeds of Pentaclethra macrophylla Benth (Mimosaceae)

Abstract

Phytochemical investigation of the seeds of Pentaclethra macrophylla led to the isolation of a mixture of two new aromatic monoterpene glycosides, pentamacrophylloside A (1a) and pentamacrophylloside B (1b), together with six known secondary metabolites: Comososide (2), secopentaclethroside (3), caffeoylputrescine (4), β-sitosterol-3-O-β-D-glucopyranoside (5), 2-hydroxymethyl-5-(2-hydroxypropan-2-yl)phenol (6), and sucrose (7). Their structures were elucidated mainly by extensive spectroscopic analysis (1D and 2D NMR), high-resolution mass spectrometry and by comparison of their spectral data with those of related compounds. The extracts and compounds 3 and 4 were screened for their antimicrobial activity. The n-BuOH fraction showed a weak effect against three microbial strains: Candida albicans (MIC: 256 μg/mL), Enterococcus faecalis (MIC: 512 μg/mL), and Proteus mirabilis (MIC: 512 μg/mL) while no significant inhibition was observed for pure compounds when compared to ketoconazole and ciprofloxacin used as references. Furthermore, the ethnobotany and pharmacology of this plant are reviewed, and the chemophenetic significance of the isolation of the above secondary metabolites is discussed. This is the first report on the isolation of aromatic monoterpenoids from a plant of the genus Pentaclethra.