Evaluation of Terminalia macroptera (Combretaceae) Guill. & Perr stem bark extract incorporated into an emulgel for the potential management of rheumatoid arthritis

Abstract

Background: Rheumatoid Arthritis (RA) is a chronic disease which causes inflammation and damage to the joint. The goals of treatment are to stop inflammation, relieve symptoms, improve physical function and overall well-being. The purpose of this study was to evaluate Terminalia macroptera stem bark (TMB) ethanol extract and formulate it into an herbal emulgel (TME) for the potential management of RA. Methods: Phytochemical analysis and anti-inflammatory activity of TMB were first evaluated using standard analytical methods and complete Freund’s adjuvant (CFA) induced arthritis model in rats respectively. Post-formulation, physical characterization of the carbopol 940 based herbal emulgels (TME) and the reduction in the induced rat paw sizes by the herbal emulgels were evaluated using diclofenac emulgel as the positive control. Results: Phytochemical screening revealed the presence of flavonoids, tannins, terpenoids, saponins, and alkaloids. Inflammatory activity of the extract gave the highest percentage inhibition with TMB (50 mg/kg). The formulated herbal emulgels had good spreadability, extrudability, pH ranging from 4.5±0.2 to 6.9±0.4 and viscosity ranging from 0.36 ± 0.20 to 8.37 ± 0.65 Pas at 6 rpm and 0.26 ± 0.01 to 10.67±0.96 Pas at 12 rpm. TME emulgel significantly (p < 0.05) reduced oedema formation and arthritic index induced by complete Freund’s adjuvant in rats. TME showed dose-dependent anti-inflammatory activity comparable with commercial diclofenac emulgel. Conclusion: TMB showed an excellent inhibitory activity on the induced paw of the test