N. Prakash Babu, S. Saravanan, P. Pandikumar, K. Bala Krishna, M. Karunai Raj, S. Ignacimuthu
Introduction: The leaves of Clerodendrum phlomidis L.f. have been used in the Indian traditional system of medicine to treat several inflammatory diseases and arthritis. The aim of the present study was to assess the anti-inflammatory and anti-arthritic activities of the leaves of C. phlomidis and to isolate the active principle by bioactivity guided fractionation.
Materials and methods: To find the anti-inflammatory constituents from this plant, fractionations were performed with concurrent bioassays. Carrageenan-induced inflammation and Freund complete adjuvant (FCA)-induced arthritic rat models were used. The anti-inflammatory and anti-arthritic activities of the isolated compound were studied by assessing the histology of the joints, levels of lysosomal enzymes, protein-bound carbohydrates, acute phase protein, etc., in plasma, as well as by estimating the levels and expression of pro-inflammatory cytokines in the joints.
Results: Repeated fractionations and bioassays yielded a novel bioactive compound: 3-hydroxy, 2-methoxy-sodium butanoate. Treatment with this compound reduced the paw edema induced by carrageenan and FCA dose dependently. The levels of lysosomal enzymes and protein-bound carbohydrates decreased significantly upon treatment with the compound. The level of plasma acute phase protein was also decreased compared with control animals. Protein levels and mRNA expression of pro-inflammatory cytokines TNF, IL-1 and IL-6 in the joints were decreased significantly in a dose-dependent manner and the histopathological data also added evidence of the anti-arthritic property of the compound.
Conclusion: The 3-hydroxy,2-methoxy sodium butanoate isolated from plant leaves displays considerable potency in anti-inflammatory action and has a prominent anti-arthritic effect. This is the first report of this natural compound with bioactivity.