Authors:Mohamed AlAjmi, Perwez Alam, and Faiyaz Shakeel
A simple and sensitive high-performance thin-layer chromatographic (HPTLC)-densitometric method was developed and validated for quantification of β-amyrin in the crude extracts of two species of Maytenus (Maytenus obscura and Maytenus parviflora) grown in Saudi Arabia. HPTLC-densitometry was performed on glass-backed silica gel 60 F254 TLC plates with the binary mobile phase hexane-ethyl acetate (3:1, v/v). The developed plate was derivatized with p-anisaldehyde, then scanned and quantified densitometrically at 550 nm. The system was found to give a compact spot for β-amyrin at RF value of 0.38 ± 0.01. The method was found to be satisfactory in terms of sensitivity, accuracy, precision, and recovery. The content of β-amyrin was estimated as 0.42% ± 0.01% and 0.88% ± 0.01% w/w in M. obscura and M. parviflora, respectively. The developed HPTLC technique can be very useful for the quantification of β-amyrin present in various medicinal plants.
A densitometric high-performance thin-layer chromatographic (HPTLC) method for analysis of hydroquinone has been developed and validated. Chromatography was performed on aluminum foilbacked silica gel 60 F254 plates with chloroform-methanol 85:15 (% v/v) as mobile phase. This system furnished a compact band for hydroquinone at RF 0.51. Hydroquinone was quantified densitometrically at 289 nm. The limits of detection (LOD) and quantification (LOQ) were 38.50 and 115.50 ng per band, respectively. High precision and accuracy were achieved. The method was used for both qualitative and quantitative analysis of hydroquinone in commercial formulations. Because the method can effectively separate the hydroquinone in the presence of its degradation products, it can be used as a stability-indicating method.
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 F254 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 RF = 0.29 ± 0.01. The linear regression analysis data for the calibration plots showed good linear relationship with r2 = 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 RF 0.01, 0.11, and 0.48, respectively. Bergenin showed 100% degradation with the formation of one degraded product appearing at RF 0.03 under alkali hydrolysis. Under hydrogen peroxide treatment, bergenin showed 17.76% degradation and the resultant degraded products appeared at RF 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.