Cartilage protective effect of Sida cordifolia L. and Piper longum L. is through modulation of MMPs and TIMP

Context: Sida cordifolia L. (SC) and Piper longum L. (PL) has been used traditionally for the treatment of osteoarthritis (OA). However the underlying mechanism of their beneficial action is not known. Objective: To investigate in vitro free radical scavenging potential and in vivo anti-osteoarthritic activity of SC and PL. Materials and Methods: SC and PL were studied for free radical scavenging potential along with phenolic content. Anti-osteoarthritic effect of both plants was assessed using collagenase induced OA (CIOA) rat model and further molecular study of isolated synovium was carried out. Statistical analysis was carried out by one-way analysis of variance followed by Fisher’s Least Significant Difference test. Results: SC and PL showed free radical scavenging potential, which could be attributed to their phenolic content, which is 10.360±1.165 and 0.633±0.018 mg/gm dry mass, respectively. OA was induced in rats by intra-articular injection of collagenase II. Rats were divided into 5 groups: Healthy control, osteoarthritic control (CIOA), indomethacin, S. cordifolia (SC) and P. longum (PL). Treatment was administered for 20 days. SC and PL have up-regulated superoxide dismutase (p=0.0442, 0.0538), glutathione peroxidase (p=0.9214, 0.9127), catalase (p=0.8329, 0.7598), paraoxonase-1 (p=0.7883, 0.9901), TIMP1 (p=0.0934, 0.0300) and down-regulated MMP3 (p=0.0929, 0.0361) and MMP9 (p=0.4231, 0.1759) in knee synovium compared to CIOA, respectively. Discussion and conclusion: SC and PL clearly attenuated OA-augmented expression of MMP and restored OA-reduced expression of TIMP in the synovium. This finding provides the first evidence that S. cordifolia and P. longum effectively operates through inhibition of cartilage matrix degradation in OA.