Isolation, development and validation of HPTLC method for the estimation of β-carotene from Gymnosporia senegalensis (Lam.) Loes.

The present study is aimed to isolate terpenoids from Gymnosporia senegalensis through analytical and preparative thin-layer chromatography (TLC) and to determine their antioxidant activity using the 2, 2-diphenyl-1- picrylhydrazyl (DPPH) assay and to find out the presence of β-carotene through high-performance thin-layer chromatography (HPTLC). The validation included linearity, limit of detection (LOD), limit of quantification (LOQ), specificity, precision, recovery, and robustness. All the isolated compounds from TLC exhibited significant antioxidant activity. Among all, isolated compounds from leaf showed highest IC values. The highest total terpenoid content (TTC) was found 51.6 ± 0.06 in stem, then 49.02 ± 0.01 in bark, and 46.27 ± 0.01 in leaf. DPPH results indicated that leaf-isolated compound 1 (LIC1) showed the highest IC at 7.55 ± 0.02 and stem-isolated compound 2 (SIC2) showed the lowest IC at 0.616 ± 0.01 among all the isolated compounds of G. senegalensis. HPTLC separation was carried out on aluminium plates pre-coated with silica gel 60 F254 as the stationary phase and n-hexane: ethyl acetate (6:4, v/v) as the mobile phase. Quantification was achieved based on a densitometric analysis of β-carotene in the concentration range of 100-500 ng/band at 254 nm. For the calibration plots, linear regression produced r = 0.96450 and Rf = 0.27. The LOD and LOQ were 10.15 and 30.76 ng/mL for HPTLC and relative standard deviation were 137.26 ± 2.03 and 160.43 ± 2.95 (intra-day) and 127.88 ± 2.14 and 157.27 ± 1.90 (inter-day) for 200 and 400 ng/band, respectively. The present study shows the presence of various types of terpenoids through TLC whereas the HPTLC results indicated that the developed methods were accurate and precise. It also shows that the approach is appropriate for its intended use in routine quality control testing of commercially available tablet formulations and drug assay to assist both industries and researchers in making important decisions at a reasonable cost. Moreover, due to the use of a safer and more environmentally friendly mobile phase in comparison to the toxic mobile phases used in recent analytical techniques to estimate β-carotene, this methodology is also secure and sustainable.