Cucurbitacin R reduces delayed-type hypersensitivity reaction induced by dinitrofluorobenzene and sheep red blood cells in mice

The roots of Cayaponia tayuya (Vell.) Cogn. (Cucurbitaceae) are used in folk medicine as an anti-inflammatory and anti-allergic crude drug [1]. We previously reported its anti-inflammatory effect [2] and the anti-arthritic properties [3] of two cucurbitacins isolated from the chloroform extract. Now we tested the effects of cucurbitacin R (CCR) on different experimental models of systemic delayed-type hypersensitivity (DTH) in mice [3, 4].

CCR showed anti-allergic effects in two of the three models assayed. In the dinitrofluorobenzene (DNFB) model inhibited the ear oedema with a DI₅₀ of 0.56mg/ear at 48h. In the sheep red blood cells (SRBC) model, the inhibition reached 64% (18h), 58% (24h) and 62% (48h). In the oxazolone-induced DTH there was not significant effect. In the histological studies of the DNFB-induced contact dermatitis, the CCR-treated group inhibited the oedema formation and the inflammatory cell infiltration, along with a reduction of the tissue damage. In the DTH-induced by SRBC, when compared with the non-treated group, the paws of the CCR-treated group (12.5mg/kg) present a mild inflammatory lesion and scarce mixture of inflammatory cells, and a reduction of tissue damage. In addition, CCR abolished the production of TNF-α and IL-1β in the paws of the CCR-treated group giving a 100% (TNF-α) and 90% (IL-1β) of inhibition.

Acknowledgements: J.M.E. is recipient of a grant from the Generalitat Valenciana. This work was supported by the Spanish Government (SAF2002–00723)

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