Anti-inflammatory activity of Trichosanthes cucumerina Linn. in rats

Trichosanthes cucumerina Linn. (Family: Cucurbitaceae) is one of the medicinal plants that is often used in Sri Lankan traditional systems of medicine. One of its uses is the treatment of inflammatory conditions. However, validity of the anti-inflammatory activity has not been scientifically investigated so far. Therefore, the aim of this study was to investigate the anti-inflammatory potential of Trichosanthes cucumerina hot water extract (HWE) and its fractions.

The anti-inflammatory activity of Trichosanthes cucumerina was evaluated by use of the carrageenan-induced paw oedema model in Wistar rats. In addition, the mechanism/s by which Trichosanthes cucumerina is mediated the anti-inflammatory activity was assessed by determining its effects on (a) membrane stabilizing activity and (b) nitric oxide inhibitory activity.

Apart from the lowest dose of the HWE, other tested doses (500, 750, 1000 mg/kg) produced a significant (P ≤ 0.05) inhibition of the inflammation, most pronounced at 5h after the injection of carrageenan. The anti-inflammatory effect induced by 750 mg/kg, was comparable to that of the reference drug, indomethacin at 4 and 5h. Inhibition of nitric oxide (NO) production and membrane stabilization activities are probable mechanisms by which Trichosanthes cucumerina mediates its anti-inflammatory actions. Among the tested fractions, methanol fraction (MEF) and aqueous fraction (AQF) at a dose of 75 mg/kg exhibited marked inhibition against carrageenan-induced hind paw oedema. The anti-inflammatory effect induced by MEF, was comparable to that of the reference drug, indomethacin and as well as to the 750 mg/kg of HWE at 4 and 5h.

(a) These findings rationalize the traditional usage of this plant as an anti-inflammatory agent and (b) membrane stabilizing properties and NO inhibitory activity are possible mechanisms through which Trichosanthes cucumerina mediates its anti-inflammatory action.