Development of a validated high-performance thin-layer chromatography method for the simultaneous estimation of caffeic acid, ferulic acid, β-sitosterol, and lupeol in Convolvulus pluricaulis Choisy and its adulterants/substitutes

Abstract

The present paper reports a validated high-performance thin-layer chromatography (HPTLC)—densitometric method for the simultaneous quantification of phenolic (ferulic acid and caffeic acid) and terpenoid (β-sitosterol and lupeol) markers in Convolvulus pluricaulis Choisy. According to Ayurveda, it is commonly known as ‘Shankhpushpi’ due to its ‘Conch’ or ‘Shankh’-shape flower. The plant species, viz., Clitoria ternatea L., Evolvulus alsinoides (L.) L., and Tephrosia purpurea (L.) Pers., also having similar flowers are reported as its adulterants/substitutes. This creates a problem in its quality and efficacy in the commercial drug market of India. Therefore, a HPTLCmethod was performed on a pre-coated silica gel 60 F254 plate with the aforesaid markers. The solvent system toluene—ethyl acetate—formic acid (8.5:1.5:0.1) was determined to be the best system for the simultaneous separation of caffeic acid, ferulic acid, β-sitosterol, and lupeol at RF values of 0.14, 0.29, 0.48, and 0.63, respectively. A densitometric scanning profile of all the samples at 580 nm showed peaks for all the four markers of varying heights in the samples, except the absence of caffeic acid in Tephrosia purpurea. The developed method was standardized and validated for the quantification of active principal-based quality-control markers in terms of precision, accuracy, linearity, recovery, and repeatability. It will help to maintain batch-to-batch consistency and identification of adulterants/substitutes in raw materials during production of drug in the pharmaceutical units.