Chromatographic separation of fruits and flowers of the Thai medicinal plant, Miliusa velutina, resulted in the isolation of five new rare homogentisic acid derivatives, miliusanal (1) and miliusanones A-D (2-5), together with fifteen known secondary metabolites (6-20). Their structures were determined through the use of extensive spectroscopic data. The absolute configurations of homogentisic acid derivatives 2-7 were identified using NOESY data and a comparison of experimental and calculated ECD spectral data. Compounds 2, 3, 6, and 7 showed antimalarial activity with IC50 values in the range of 3.3-5.2 μg/mL. Compound 6 also showed activity against Mycobacterium tuberculosis with an MIC value of 50 μg/mL. Compounds 1-3, 6 and 7 exhibited cytotoxicity againt KB, MCF-7, NCI-H187 and Vero cell lines with IC50 values in the range of 5.8-40.4 μg/mL. In addition, compounds 1, 2 and 6 showed moderate antibacterial activities against three Gram-positive bacteria (Bacillus cereus, Staphylococcus aureus, and Methicillin resistant S. aureus) with MICs in the range of 32-64 μg/mL.
Keywords: Antibacterial; Antimalarial; Cytotoxicity; Homogentisic acid derivative; Miliusa velutina.
Copyright © 2019 Elsevier B.V. All rights reserved.