Objective To investigate the chemical composition of the rhizome of Dalbergia pinnata. Methods Separation and purification were performed using silica gel, RP-C₁₈, MCI, Sephadex LH-20 column chromatography, semi-preparative high-performance liquid chromatography and recrystallization; compound structures were identified based on spectroscopic techniques, including NMR spectroscopy; and the anti-complement activity of selected isolated monomeric compounds was screened using an in vitro erythrocyte hemolysis assay. Results Fifteen compounds were isolated and identified from the ethyl acetate fraction of D. pinnata, including 5,7,4′-trihydroxy-6,2′,5′-trimethoxyisoflavone (1), 7,3 ¢-dihydroxy-8,4 ¢-dimethoxyisoflavone (2), (&8722;)-vestitol (3), 3-O-acetyloleanolic acid (4), (&8722;)-hydroxymedioresinol (5), (&8722;)-episyringaresinol (6), (&8722;)-liquiritigenin (7), butein (8), (&8722;)- isolariciresinol (9), (＋)-lyoniresinol (10), (2R)-3-(3 ¢,4¢-dimethoxyphenyl)-1,2-propanediol (11), (2R)-3-(3 ¢,4 ¢,5 ¢-trimethoxyphenyl)-1,2-propanediol (12), 3,3 ¢,4,4 ¢-tetrahydroxybiphenyl (13), vanillicvanillyric acid (14), cinnamtannin B1 (15). In vitro anti-complement activity assays demonstrated that compounds 1, 3, 7 and 8 exhibited distinct in vitro complement inhibitory activities, with their half-maximal hemolysis-inhibitory concentrations (CH₅₀) measuring (1.21 ± 0.07), (0.57 ± 0.03), (0.12 ± 0.13) and (0.17 ± 0.04) mg/mL respectively. Conclusion Compound 1 is a new compound, designated as dalbergiaisoflavone A, obtained from D. pinnata; compounds 2—6 and 8—15 were obtained from this species for the first time, and compound 7 exhibits significant in vitro anti-complement activity.

Dalbergia pinnata (Lour.) Prain  /  dalbergiaisoflavone A  /  3 ¢  /  ,7-dihydroxy-8,4 ¢  /  -dimethoxyisoflavone  /  (-)-liquiritigenin  /  (-)-isolariciresinol  /  anti-complement activity