Acasiane A and B and farnesirane A and B, diterpene derivatives from the roots of Acacia farnesiana

Four new diterpenes, acasiane A (1), acasiane B (2), farnesirane A (3), and farnesirane B (4), along with three known diterpenes (5-7), two triterpenes (8 and 9), and eight flavonoids (10-17) were isolated from the roots of Acacia farnesiana. The structures and relative configurations of these compounds were determined by various spectroscopic and x-ray analyses. All isolated compounds were evaluated for their in vitro cytotoxic activities against six human cancer cell lines (Hep G2, Hep 3B, MDA-MB-231, MCF-7, A549, and Ca9-22) with the MTT method. Betulinic acid (8) displayed moderate cytotoxicity (1.70-5.74 μg/mL) towards five human cancer cell lines and the flavonoids had slight effects. In addition, 8, diosmetin (13), and 3′,4′,5-trihydroxy-7-methoxyflavone (15) slightly inhibited superoxide anion generation or elastase release by human neutrophils, indicating moderate anti-inflammatory activities.