Pharmacognostical Standardization of Stem Bark of Rhododendron arboreum Sm.(Pullas)

Aims: To evaluate the Pharmacognostical and Phytochemical characteristics of the stem bark of Rhododendron arboreum Sm.(Pullas)

Place and Duration of Study: Pharmacognostical and phytochemical laboratory, PG Department of Dravyaguna Vigyana, National Institute of Ayurveda, Jaipur-302002 and Ayushraj Laboratory, Jaipur. During the period of October 2017 to December 2017.

Methodology: Rhododendron arboreum Sm. was collected from Godawari Botanical Garden of Nepal, Ministry of forest, Govt. of Nepal, during the month of September 2017. The samples were Identified and authenticated by the same institution. Then the materials were subjected to evaluate the Macroscopic study, Microscopic study, Physicochemical study, Phytochemical screening, Heavy Metals Analysis, Determination of Aflatoxins and Pesticide residue analysis as per the standard available guideline.

Results: The microscopic feature of stem bark Rhododendron arborieum Sm. after treatment of different reagents (safranin, fecl3, iodine etc.) showed various cellular and chemical structures like scaliform vessels, calcium oxalate, starch grain, fragment of cork cells and pitted vessel. Physicochemical analysis showed Moisture content-7.55%, Total ash-2.11%, Acid insoluble ash-3.47%, Water soluble ash-0.91%, Aqueous extractive value-3.45%, Ether extractive value-3.17%, Petroleum ether extractive value-1.83, Ph-4.6. Analysis of heavy metal and aflatoxin analysis showed parameters were the within limit as per API standard. HPTLC screening of ethanol extract of the test sample showed four unknown chemical constituent with Rf value 0.12, 0.25, 0.47, 0.71 ; where the mobile solution was used Toluene: Ethyl acetate: Formic acid (5: 4: 1).

Conclusion: Result of the study may act as future standard for authentication of the genuine plant, Rhododendron arboreum Sm.(Pullas) which is used as a source of famous Ayurveda plant Rohitaka (the plant used for liver and spleen disorders) in Nepal. There is a scope of further scientific research to explore this important medicinal in future.