Development of pharmacognostical parameters and estimation of beta-sitosterol using HPTLC in roots of Gmelina arborea Roxb.
This paper deals with the detailed pharmacognostical evaluation of roots of Gmelina arborea Roxb. (Verbenaceae), a highly valued plant in Ayurveda as a bitter tonic, stomachic, laxative and useful in fever, indigestion, anasarca and skin problems. It has been used as an ingredient in many preparations like Dashmoola, Panchmoola di kwatha and Chyawanprasha. Chemical constituents of G. arborea roots have been studied extensively which include lignans, flavonoids, alkaloids and various phenyl propanoid glycosides but pharmacognosy of roots has not been reported. The main objective of the present work is to develop detailed pharmacognostical and physicochemical parameters recommended by World Health Organization (WHO) and various pharmacopoeias for the roots, as this has not been reported so far for the roots of the plant. Preliminary analysis showed the presence of phenolics and flavonoids, which led us to estimate total phenolics in roots. The present study also focuses on development of high-performance thinlayer chromatographic (HPTLC) method for the quantitative analysis of roots using β-sitosterol as a chemical marker. Major microscopic features of roots are lignified cork, presence of oil globules, scattered stone cell islets in secondary cortex and pitted wood elements. Phytochemical screening reveals the presence of flavonoids, lignans, sterols, tannins, carbohydrate, coumarins and alkaloids. Total phenolics were found 1.89% w/w in roots and β-sitosterol was found 0.120±0.018% in methanolic extract of the roots by the developed HPTLC method. These findings will aid in the standardization of one of the major roots used in a well known Ayurvedic formulation, Dashmoola. Validated HPTLC method developed can be used as a tool for standardization of roots in different formulations using β-sitosterol as a marker.