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.
Keywords: Balanophora laxiflora; antioxidant; chalcone; cytotoxicity.