Plaunol A isolated from Croton stellatopilosus suppress inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2)

A cyclic diterpene, namely plaunotol from Croton stellatopilosus Ohba or plaunoi (Thai name) has long been used in the treatment of gastric ulcer and it has been manufactured in a gelatin capsule under the trade name as Kelnac® (Sankyo Daiichi, Japan) [1]. Other cyclic diterpenes have also isolated from plaunoi including labdane-, kaurene-, clerodane-type diterpenes[2], [3]. Previously, plaunotol, plaunol E and plaunol F been reportedanti-inflammatory activity in lipopolysaccharide (LPS)-induced murine macrophage RAW264.7 cells [4]. In the present study, plaunol A, isolated from the stem, was assessed for an anti-inflammatory activity in the LPS-induced RAW264.7 cells model. The result showed that plaunol A exhibited an inhibitory effect on nitric oxide (NO) production with an IC₅₀ of 11.69 µM and cytotoxicity at the concentration more than30 µM. In addition, the transcription profile analysis of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) genes in the RAW264.7 cells using qRT-PCR technique that plaunol A inhibited the NO production by suppressing the iNOS and COX-2 mRNAs. In conclusion, plaunol A possessed an anti-inflammatory effect by suppressing the iNOS and COX-2 in the macrophage RAW cells.

• References

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