Comparative pharmacognostic evaluation of Tecomella undulata and Rhododendron arboreum as two different sources of Rohitaka

Abstract

Background: Tecomella undulata (Sm.) Seem. is considered as a genuine source of Rohitaka which is mentioned in Ayurveda
classics for Yakrit Pliha Roga (liver and spleen diseases). In different parts of India, various other species are used as substitute
of Rohitaka due to non-availability of the genuine source. In Nepal, folklore traditional practitioners use Rhododendron
arboreum Sm. for the treatment of jaundice and it is marketed by the name of Rohitaka. Objective: The present study
outlines the concept of substitution. The stem bark of T. undulata (Sm.) Seem. and R. arboreum Sm. is compared on the basis
of macroscopic/organoleptic evaluation, microscopic evaluation, physicochemical analysis, phytochemical analysis, and
high-performance thin-layer chromatography (HPTLC). Materials and Methods: Macroscopic/organoleptic evaluation,
microscopic evaluation, and physicochemical and preliminary phytochemical screening were carried out using standard
methods. Semi-automatic applicator was used for HPTLC profiling. Results: Macroscopic/organoleptic evaluation showed
longitudinally fissured and fibrous fracture in T. undulata with bitter taste, while longitudinally furrowed, laminated bark
with bitter taste in R. arboreum. Powder microscopy revealed the presence of parenchyma with starch, parenchyma with
cell content, and cork cells in both drugs. On physiochemical analysis, T. undulata showed greater water and alcoholic
extractive value than R. arboreum. Carbohydrates, alkaloids, tannins, and phenols were the chemical constituents found in
both the drugs. HPTLC study revealed that there are 18 active phytoconstituents in R. arboreum barks and 24 in T. undulata
on the basis of peaks observed. Conclusion: The present study revealed few common phytoconstituents found in both
T. undulata and R. arboreum.