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

Ethnopharmacological relevance: Ancient tribes in the Western Ghats of India use the roots of Decalepis hamiltonii Wight and Arn (Asclepiadaceae) for several medicinal purposes particularly inflammation. Aim: To investigate whether the pure compounds obtained from the Decalepis hamiltonii have anti inflammatory activity. Materials and methods: The 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 H-1 and C-13 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 [H-3] thymidine uptake assay and their effect on cytokine expression by reverse transcriptase polymerase chain reaction (RT-PCR). The inhibition of nuclear factor kappa B (NF-kappa B) 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 discussion: Lupeol acetate (Compound 1) and (2S)-5,7,4'-trihydroxy flavanone 4'-O-beta-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 mu g/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-alpha), the anti inflammatory cytokine interleukin-10 (IL-10), was found to be up regulated. NF-kappa B activation in J774 A.1 cells were also inhibited by both the compounds. Conclusion: Lupeol acetate and (2S)-5,7,4'-trihydroxy flavanone 4'-O-beta-D-glucoside isolated from Decalepis hamiltonii roots showed anti inflammatory activities by down regulating TNF-alpha and IL-2 specific mRNA, besides up regulating the synthesis of mRNA of IL-10. (C) 2010 Elsevier Ireland Ltd. All rights reserved.