Two novel polyketones, along with four known compounds, were isolated from the leaves and twigs of Clerodendrum trichotomum. Their structures were determined to be clerodendruketone A (1), clerodendruketone B (2), ecdysanols E (3), ecdysanols D (4), 5,5'-dimethoxy-7-oxolariciresinol (5), and (-)-(7'S,8S,8'R)-4,4'-dihydroxy-3,3',5,5'-tetramethoxy-7',9-epoxy-lignan-9'-ol-7-one (6) through the methods of NMR, HRESIMS and ECD data analyses. The antioxidant effects against free radical were tested by DPPH assay. The antibacterial activity against Escherichia coli and Staphylococcus aureus were tested by turbidimetry assay. The results demonstrated that compounds 1 and 2 had significative antibacterial activity, and compound 3 had moderate antioxidant activity.
Keywords: Clerodendrum trichotomum; DPPH scavenging; Lamiaceae; antibacterial activity; antioxidant activity; polyketones.