Pharmacognostic Standardization and Antileishmanial Activity of Selected Himalayan Plants

Abstract

newline x newlineABSTRACT newlineAim: Pharmacognostic standardization and antileishmanial activity of selected Himalayan plants newlineMethods: Visceral leishmaniasis is endemic to Himachal Pradesh, a northern Indian state located in lower Himalayas. Available treatments are inadequate and unsatisfactory due to limited efficacy and adverse and toxic side effects. Also, they are expensive. Therefore, there is need for new effective and more affordable drugs. Ten plants from the unique Himalayan flora were selected on the basis of literature and screened for antileishmanial activity against L. donovani. Plants were collected from various parts of Himachal Pradesh and were taxonomically identified and authenticated. Further, plant materials were standardized as per the quality control methods for medicinal plant materials designed by World Health Organization. Plants were analysed for morphological, microscopical features (transverse section and powder) and physicochemical constants (foreign matter, foaming index, swelling index, ash value, extractable matter, moisture content). Air dried coarse powders of plants were first defatted using petroleum ether, and then extracted with ethanol using Soxhlet apparatus, followed by fractionation using successive solvents with increasing polarity (Chloroform, ethyl acetate and n-butanol). Preliminary phytochemical screening of fractions was carried out to assess the presence of plant secondary metabolites. Extracts and fractions were standardised using HPTLC. Further in vitro antileishmanial activity of plant fractions was performed on promastigotes stage of parasite using the colorimetric MTT reduction assay and active fractions were quantified by using bioactive standards with the help of HPTLC. newlineResults: Ten plants were selected from Himalayan region on the basis of, either the plant species showing antileishmanial activity against another leishmania species or antileishmanial activity of plants from same genera or reports of phytochemical class with antileishmanial activity. Voucher specimen numbers were obtained corresponding to each authentified plants. Pharmacognostic characters of the collected plants matched with diagnostic characters those described in literature for the selected species respectively. Physicochemical parameters were in the range specified for each plant in Ayurvedic Pharmacopoeia of India respectively thus were of acceptable quality. Plant extracts were successfully standardized using appropriate chemical newlinexi newlineagents and solvent systems. A. bracteosa, A. officinalis, C. arvensis were standardized using chlorogenic acid, R. parviflora and R. cinerea using quercetin and C. carandas, G. arborea, M. esculenta, P. lanceolata and S. alba using lupeol, catechin, gallic acid, aucubin and p-coumaric acid, respectively. Petroleum ether fraction of A. bracteosa and n-butanol fraction of A. officinalis found to be most active with IC50 value 13.9 and 21.2 and#956;g/mL with respect to miltefosine; IC50 value 10.1and#956;g/mL. The PE fraction of A. bracteosa and n-butanol fraction of A. officinalis were standardized using withaferin A and diosgenin, respectively, the compounds with antileishmanial activity as per literature. newlineConclusion: Plants were of acceptable quality confirmed by WHO standardization parameters for physicochemical and pharmacognostical characteristics. Out of forty fractions screened for ten different plants, ten showed antileishmanial activity with two showing activity in range similar to standard drug. Active fractions, PE fraction of A. bracteosa and n-butanol fraction of A. officinalis were standardized using bioactive compounds, withaferin and diosgenin. Compounds from the active fractions should be isolated and explored for antileishmanial activity. newlineKeywords: Pharmacognostic standardization, visceral leishmaniasis, MTT reduction assay, Himachal Pradesh, miltefosine, physicochemical.