Anti inflammatory potential of Decalepis hamiltonii (Wight and Arn) as evidenced by down regulation of pro inflammatory cytokines—TNF-α and IL-2

Ethnopharmacological relevanceAncient tribes in the Western Ghats of India use the roots of Decalepis hamiltonii Wight and Arn (Asclepiadaceae) for several medicinal purposes particularly inflammation.AimTo investigate whether the pure compounds obtained from the Decalepis hamiltonii have anti inflammatory activity.Materials and methodsThe bioactive lead molecules from the roots of Decalepis hamiltonii were extracted into dichloromethane/methanol and purified by silica gel column chromatography. Structural elucidation of the purified compounds was performed with 1H and 13C NMR and mass spectrometry. The in vitro anti inflammatory activity of the pure compounds was studied in mitogen induced peripheral blood mononuclear cells (PBMCs) employing [3H] thymidine uptake assay and their effect on cytokine expression by reverse transcriptase polymerase chain reaction (RT-PCR). The inhibition of nuclear factor κB (NF-κB) activity in the presence of pure compounds was determined in J774 A.1 cells. The cytotoxicity of the compounds was tested using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay kit.Results and discussionLupeol acetate (Compound 1) and (2S)-5,7,4′-trihydroxy flavanone 4′-O-β-d-glucoside (Compound 2) isolated from Decalepis hamiltonii roots inhibited the proliferation of mitogen induced PBMCs with an IC50 value of 8 and 0.5 μg/ml respectively. MTT assay revealed the compounds to be non-cytotoxic. Though, both the compounds down regulated the synthesis of mRNA of the pro inflammatory cytokines, interleukin-2 (IL-2) and tumour necrosis factor-alpha (TNF-α), the anti inflammatory cytokine interleukin-10 (IL-10), was found to be up regulated. NF-κB activation in J774 A.1 cells were also inhibited by both the compounds.ConclusionLupeol acetate and (2S)-5,7,4′-trihydroxy flavanone 4′-O-β-d-glucoside isolated from Decalepis hamiltonii roots showed anti inflammatory activities by down regulating TNF-α and IL-2 specific mRNA, besides up regulating the synthesis of mRNA of IL-10.

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