3, 3′-Neolignans from Pithecellobium clypearia Benth and their anti-inflammatory activity

The twigs and leaves of Pithecellobium clypearia Benth have been used as a folk medicine for the treatment of diseases related to inflammation in southern China for many years. To search for novel bioactive constituents as lead structures for anti-inflammatory drug development, seven new 3, 3′-neolignans (1–7), together with four known ones (8–11) were isolated from the 70% EtOH extract of the twigs and leaves of P. clypearia. Their structures were determined by spectroscopic analyses, especially the 1D, 2D NMR and CD spectra. The antioxidant and anti-inflammatory activities of all the isolated compounds were investigated. Among them, compound 11 showed promising activity against nitric oxide (NO) and considerable antioxidant activity. These findings will help in the effective use of P. clypearia as a valuable source of novel compounds for the prevention and treatment of inflammation-related disorders. [Display omitted]