Aim of the study: To determine the anti-inflammatory, analgesic and antioxidant activities of the leaves of Memecylon edule Roxb. used traditionally in Thailand.
Materials and methods: Hexane, (Hex), ethyl acetate (EtOAc), methanol (MeOH) and 50% methanol (MeOH50) fractions of the dry leaves were tested in vitro for their interleukin-10 production; the most active fraction was further studied in vivo for its anti-inflammatory and analgesic activities using the ethylphenylpropiolate (EPP)-induced mouse ear edema and the writhing test with mice. All fractions except Hex were tested for their radical scavenging activity towards 1'-diphenyl-2-picrylhydrazyl radical (DPPH).
Results: The EtOAc showed the highest stimulation for interleukin-10 production. In the EPP test, this fraction was significantly active 30 min after topical application at all doses used (0.5, 1.0, 2.0mg/ear); after 4h and at 1.0mg/ear EtOAc was slightly less active (inhibition 47.8%) than the reference, indomethacin, at the same dose (62.4%). At 200mg/kg orally, the EtOAc caused a significant inhibition of the writhing response by 56.6% which was like indomethacin at 10mg/kg. EtOAc, MeOH and MeOH50 exhibited radical scavenging activity. The order of IC(50) values was: ascorbic acid (9.1 microg/mL)>trolox (11.6 microg/mL)>MeOH (46.9 microg/mL)>MeOH50 (152.1 microg/mL)>EtOAc (1742.2 microg/mL).
Conclusion: The results provide support for the traditional use of Memecylon edule leaves in relieving inflammation and pain.