Abstract
A simple, sensitive, and stability-indicating thin-layer chromatographic (TLC)-densitometric method was developed for the assay of biomarker bergenin in the methanol extract of aerial parts of Flueggea virosa (FVME). Chromatography was performed on glass-backed silica gel 60 F 254 high-performance thin-layer chromatographic (HPTLC) plates with dichloromethane-methanol (8.5:1.5, v/v) as the mobile phase. Scanning and quantification were done at 220 nm. The system was found to give compact spot for bergenin at R-F = 0.29 +/- 0.01. The linear regression analysis data for the calibration plots showed good linear relationship with r(2) = 0.998 with respect to area in the concentration range of 100-800 ng. The regression equation of bergenin was found to be Y = 8.708X + 51.017. The limit of detection (LOD) and limit of quantification (LOQ) for bergenin were found to be 17.5 and 53 ng band(-1), respectively. The percentage of bergenin was found to be 15.5% w/w in the FVME. Bergenin was subjected to acid and alkali hydrolysis, peroxide oxidation, photodegradation, dry heat, moist heat, and ultraviolet (UV) treatment for its stability studies. Treatment of bergenin with acid showed 21.25% degradation resulting in the formation of three degraded products at R-F 0.01, 0.11, and 0.48, respectively. Bergenin showed 100% degradation with the formation of one degraded product appearing at R-F 0.03 under alkali hydrolysis. Under hydrogen peroxide treatment, bergenin showed 17.76% degradation and the resultant degraded products appeared at R-F 0.01 and 0.07. On treatment with dry heat, moist heat, photochemical, and UV (254 nm) light, bergenin showed no degradation products which suggested its stability under these conditions. The degraded products were found to be well separated from the pure drug. In this study, we report for the first time the quantification of bergenin in F. virosa by a validated HPTLC method. The stability study performed in this experiment may help in selecting or rejecting the in-process procedural conditions for making the formulation more efficacious and safe.