Four p-terphenyl derivatives named curtisians I - L (1 - 4) were isolated from the MeOH extract of the fruit bodies of Paxillus curtisii. Their structures were elucidated by 2D NMR, MS, IR and UV spectroscopy and chemical reaction. The absolute configurations of curtisians were determined by GC-MS on a chiral column of the hydrolyzed products with authentic samples. Their antioxidative activities were also estimated by examination of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging effect.
From the methanolic extract of Xylaria sp. collected in Vietnam, a fluorescent constituent, ergosta-4,6,8(14),22-tetraen-3-one (1) was isolated and elucidated by the combination of 2D NMR, high resolution MS, IR and UV spectroscopy. Its inhibitory activity of nitric oxide production in RAW 264.7 cells stimulated by lipopolysaccharide was examined and showed a potential activity with the IC50 value of 28.96 µM.
Investigation of the methanolic extract of Vietnamese inedible Xylariaceous mushroom Xylaria intracolorata resulted in the isolation of two new compounds named coloratin A [3,5-dimethoxy-2-(6-oxo-5-pentyl-6H-pyran-3-carbonyl)-benzoic acid] (1) and coloratin B (2-carbomethoxyl-3,5-dimethoxybenzoic acid) (2). Their structures were elucidated by 2D-NMR, MS, IR, and UV spectroscopy. Coloratin A (1) showed strong antimicrobial activity.
A new chalcone named as balanochalcone (1) together with eight known compounds, methyl caffeate (2), β-hydroxydihydrochalcone (3), methyl gallate (4), dimethyl-6,9,10-trihydroxybenzo[kl]xanthene-1,2-dicarboxylate (5), p-coumaric acid (6), quercetin (7), scopoletin (8) and pinoresinol (9) have been isolated from the ethyl acetate extract of Vietnamese Balanophora laxiflora Hemsl. Their structures were characterised by IR, UV, HR-ESI-MS, 1D and 2D NMR and CD spectroscopies. Compounds 2 and 5 showed moderate cytotoxicity against four cancer cell lines, KB (a human epidermal carcinoma), MCF7 (human breast carcinoma), SK-LU-1 (human lung carcinoma) and HepG2 (hepatocellular carcinoma). In addition, compounds 1 and 5 showed moderate antioxidant activity.