Anti-inflammatory effects of (+)-catechin isolated from the bark of Byrsonima crassifolia

Inflammation is a defence mechanism which is generally self-limiting, but there is an on-going search for anti-inflammatory drugs to treat chronic inflammatory conditions where the inflammatory response is inappropriate and harmful. Ever since the medicinal use of plants containing salicylates were first reported in Egyptian times, the search has continued to identify secondary metabolites in plants with immunomodulatory, anti-oxidant or anti-inflammatory activities. Initial screening of a number of plants collected in Venezuela led to the identification of Byrsonima crassifolia (Malpighiaceae) as an inhibitor of inflammatory mediators in its crude bark extract form. This plant has been traditionally as an antiemetic, diuretic, febrifuge, and to treat diarrhoea, gastritis and ulcers. Bioactivity-guided fractionation of the crude extract using solvents of different polarities, followed by HPLC, led to the isolation of a flavonoid which showed the greatest activity in several bioassays, nitric oxide (NO – 50% inhibition at 37 µg/ml) and prostaglandin E2 (40% inhibition at 100 µg/ml) production by LPS-stimulated Raw 264.7 cells, serum NO in LPS-challenged mice (56% inhibition at 40 mg/Kg) and paw oedema in the mouse carrageenan model (80% inhibition at 40 mg/Kg). The flavonoid did not significantly inhibit either TNF or IL-6 production in vitro or in vivo. MS and NMR analysis of the flavonoid identified it as (+)-catechin, for which anti-oxidant activities have been reported. However, as far we are aware, this is the first report of its activity against the inflammatory processes described here.

Fig. 1