A new ferulic acid ester, a new ellagic acid derivative, and other constituents from Pachycentria formosana: Effects on neutrophil pro-inflammatory responses
Pachycentria formosana Hayata (Melastomataceae) is an endemic creeping shrub distributed in 300–2100m forests throughout Taiwan . Various tannins, flavonoids, and triterpenoids are widely distributed in plants of the family Melastomataceae. Many of these compounds exhibit antioxidant, anti-inflammatory, cytotoxic, antifungal, antiprotozoal, and antimicrobial activities.
In our studies of Formosan plants for in vitro anti-inflammatory activity, P. formosana was found to be an active species. Investigation on the CH2Cl2-soluble fraction of the leaves and twigs of P. formosana led to the isolation of a new ferulic acid ester, 1,24-tetracosandiol di-(Z)-ferulate (1) and a new ellagic acid derivative, 3,4,3',4'-dimethylenedioxyellagic acid (2), along with eight known compounds. Among the isolated compounds, oleanolic acid (6), ursolic acid acetate (7), and 3-epi-betulinic acid (9) exhibited potent inhibition (IC50 values <21.8µM) of O2 ·- generation by human nutrophils in response to N-formyl-L- methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB). In addition, oleanolic acid (6), 3-O-(E)-feruloylursolic acid (8), 3-epi-betulinic acid (9), and lawsonic acid (10) also inhibited fMLP/CB-induced elastase release with IC50 values <18.6µM.
Acknowledgement: This research was supported by grants from the National Science Council of the Republic of China (NSC 95–2320-B-127–001-MY3 and NSC 98–2320-B-127–001- MY3), awarded to Prof. J.-J. Chen.
References: 1. Huang SF, Huang TC (1993) 'Melastomataceae', in 'Flora of Taiwan', 2nd edn., Editorial Committee of the Flora of Taiwan, Taipei, Taiwan, Vol. 3, p.905.