Chiang Mai Journal of Science

Senna garrettiana (F. Caesalpiniaceae) is a Thai medicinal plant. Its heartwood is a rich source of piceatannol. In the present study, piceatannol-rich extract (PRE) from S. garrettiana containing 39.2% w/w piceatannol was investigated on inflammatory models in rodents. Topical application (2-8 mg/ear) of the PRE inhibited croton oil-induced mouse ear swelling with a maximal suppression of 45.85% and reduced myeloperoxidase activity by 30.21%. Oral administration of the PRE (10-40 mg/kg) dose-dependently produced a significant suppression of rat paw swelling with 75.81% maximal inhibition at 4 h. The PRE (40 mg/kg) decreased the granuloma weight and attenuated joint swelling at day 13 by 27.93% and 69.25%, respectively. The PRE (40 mg/kg) also suppressed the production of PGE2, TNF-a and IL-1b in the Complete Freund’s adjuvant-injected paw to levels comparable with indomethacin (5 mg/kg). These results demonstrated that the PRE possessed anti-inflammatory effect, and its action might be attributed to inhibition of leukocyte infiltration, as well as modulating the production of PGE2 and pro-inflammatory cytokines, TNF-a and IL-1b.