Validation of the Best Procurement Season of Arjuna Bark [Terminalia arjuna (Roxb. ex DC.) Wight & Arn.] by Comparative HPLC and Pharmacognostical Studies

Abstract

Aim: The present study was undertaken to establish the best procurement time for Arjuna (Terminalia arjuna (Roxb. ex DC.) Wight & Arn.) by analyzing the seasonal variation in bioactive secondary metabolite in the bark with quantitative high performance liquid chromatography (HPLC) as well as comparative pharmacognosy by taking consideration of Ayurvedic literature. In Ayurveda, it is mentioned that for all the herbs, the best-suited procurement time is Sharad Ritu, especially for bark.1,2 Therefore, to validate the time of collection, the present study has been planned. Materials and methods: Arjuna bark from the same habitat in all six seasons described in Ayurveda, i.e., Shishir (January–February), Vasant (March–April), Grishma (May-June), Varsha (July–August), Sharad (September–October), and Hemant (November–December), has been collected. Authentication of the source of the collected plant material was done and the accession number was given by the herbarium of NVARI, Jhansi. Identification and comparative pharmacognosy in each season at the macroscopic and microscopic levels along with powder microscopy of the useful part of the plant per the standard procedures was done at NVARI Jhansi. The extraction of the economically important plant bark and the quantitative HPLC analysis of the extracted material in all six seasons and comparison of HPLC analysis of different seasons were carried out at Captain Srinivasa Murthy Research Institute of Ayurveda and Siddha Drug Development (CSMRIASDD), Chennai, Tamil Nadu, India. Results: The present study showed that internal microscopical features remained the same throughout the year. A selected marker compound, ellagic acid, was quantified in each season by HPLC. The extractive value was found to be maximum, e.g., 1.7698 g of hydro-alcoholic extract in the Sharad Ritu sample. HPLC estimation showed that the abundance of ellagic acid is more in the Sharad Ritu sample, e.g., 0.0826 to 0.1103. Results indicated that a maximum concentration of bioactive secondary metabolite, i.e., ellagic acid, is in the Sharad Ritu sample. Conclusion: Findings suggest that if Arjuna [Terminalia arjuna (Roxb. ex DC.) Wight & Arn.] barks are collected in Sharad Ritu, then it will provide better therapeutic results.