Phytochemical and Microscopic Analysis of Tubers of Ipomoea mauritiana Jacq. (Convolvulaceae)

Tubers of Ipomoea mauritiana that are used as Vidari in Ayurveda are important ingredients in popular Ayurvedic nutraceutical products such as Chyavanprash. The objective of the current study was to develop distinct phytochemical and microscopy protocols and standards that can be used in quality control of the crude drug. Chromatographic analyses of methanol extracts of the tuber gave typical fingerprints, where Scopoletin, a standard reference marker, resolved at Rf 0.56 under TLC and at Rt 21.5 min under HPLC conditions. Three bright blue fluorescent bands at Rf 0.70, 0.56 and 0.45 under the TLC conditions were characteristic of the raw drug. Scopoletin was quantified to be 0.029-0.034 % using the HPTLC and HPLC methods. Powder microscopic features of authentic tubers of Ipomoea mauritiana were characterized by the presence of cluster crystals, simple and compound starch grains with a range of 10-50 µm and orangish-brown cell fragments of laticiferous elements. Longitudinal sections showed the laticifers (latex cells) of articulated anastomosing type and the transverse section of the tubers were mostly characterized by the specific successive cortical cambial activity.