Naphthalenone derivatives from Berrya ammonilla with inhibitory activity on superoxide generation and elastase release by neutrophils
Berrya ammonilla Roxb. (Tiliaceae) is a large tree, distributed in southern India, Ceylon, Philippines, and Taiwan . The plants of the family Tiliaceae are rich in flavonoids with flavones, flavanones, flavans, and biflavans as the major
constituents, some of which have demonstrated cytotoxic and antiplatelet aggregation activities. In our studies on constituents of Formosan plants for in vitro inhibitory activity on neutrophil proinflammatory responses, B. ammonilla has been found to be an active species. Five new naphthalenone derivatives, berryammone A (1), berryammone B (2), berryammone C (3), 6-O-methylberryammone C (4), and 4-O-methylberryammone C (5) and eleven known compounds (6–16) have been isolated and identified from the stem of B. ammonilla. The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1, 2, 3, 5, (+)-pinoresinol (6), and 3-epi-betulinic acid (12) exhibited inhibition (IC50 ≤1.58µg/mL) of superoxide anion generation by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB). Compounds 1, 2, and 5 also inhibited fMLP/CB induced elastase release with IC50 values ≤1.21µg/mL.
Acknowledgements: This work was supported by grant from the National Science Council of the Republic of China.
References: 1. Robson, N.K.B. Tiliaceae in Flora of Taiwan. 2nd edition. Editorial Committee of the Flora of Taiwan, Taipei, Taiwan: 1996; Vol. 3: 694–714.