Toxicologic Profile and Anti-Nociceptive Effect of Two Semi-Synthetic Triterpene Derivatives from Combretum Leprosum in Mice

Abstract

Abstract Background and aim: Combretum leprosum Mart. serves as a medicinal plant in traditional Brazilian medicine. The beneficial effects of C. leprosum Mart. are attributed to the triterpene, 3β,6β,16β-trihydroxylup-20(29)-ene (CL-1). Herein we evaluate the toxicity of two semi-synthetic derivatives from CL-1 (CL-P2 and CL-P2A) in vitro and in vivo, and determine the efficacy in zymosan-induced writhing response and the putative mechanism of action. Experimental procedure: Toxicity prediction was assessed using the PROTOX-II and ADMETlab 2.0 prediction tools, and SMILES codes for structure identification. In vitro cytotoxicity of the derivatives was tested using the sulforhodamine B assay in L929 and HaCaT cells at 24, 48, and 72 h. Mice received (oral gavage) CL-P2 or CL-P2A (10 mg/kg/d) for 14 days in in vivo toxicity assays. Blood samples and organs (stomach, liver, and kidneys) were collected for AST/ALT level determination and H&E staining, respectively. The anti-nociceptive effect of CL-P2 and CL-P2A (0.1, 1, or 10 mg/kg) was evaluated in the zymosan-induced writhing response. The peritoneal exudate was collected to determine myeloperoxidase (MPO) and superoxide dismutase (SOD) activity, and nitrite concentration. Results: CL-P-2 and CL-P2A derivatives exhibited low cytotoxicity and did not change body mass, AST/ALT levels, or organ weight. The histopathologic analysis did not reveal significant changes in organs. Both derivatives inhibited the writhing response in a dose-dependent manner. In addition, both derivatives failed to reduce MPO activity. However, CL-P2A increased SOD activity and CL-P2 decreased nitrite/nitrate levels. Conclusion: CL-P2 and CL-P2A were shown to exhibit anti-nociceptive effects without toxicity. Our data suggest that CL-P2 and CL-P2A efficacy is mediated, at least in part, via antioxidant activity by modulating nitrite/nitrate levels and SOD activity, respectively.