Evaluation of the antimicrobial potential of methanolic extract and a dihydrostilbene isolated from tubers of Habenaria pectinata Kaur Charanjit1,2,**, Chandermohan3,* 1IKG Punjab Technical University, Kapurthala, (Punjab) - 144603, India 2Department of Pharmaceutical Chemistry, Khalsa College of Pharmacy, Amritsar, (Punjab) - 143001, India 3Rayat Bahra Institute of Pharmacy, Hoshiarpur, (Punjab) - 146001, India **Corresponding Author E-mail: charanjitkaur13@gmail.com
*chandermohan@rayatbahra.com
Online published on 20 February, 2023. Abstract Habenaria pectinata is a terrestrial plant from the Orchid family, found in the mountain forests of India, Yunnan, and Nepal. The antimicrobial potential of the genus Habenaria has been reported in the literature. This study aimed to evaluate the antimicrobial potential of methanolic extract, and its fractions; and to isolate an antimicrobial compound from H. pectinata. Antimicrobial potential of tubers of Habenaria pectinata was assessed by using methanol extract against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Aspergillus flavus, Candida albicans, and Aspergillus niger using agar well diffusion method. Column chromatography was used for the isolation of compounds from the most active ethyl acetate fraction of methanolic extract. Structure elucidation was done using 1D and 2D NMR spectroscopy and mass spectrometry. The methanolic extract and ethyl acetate fraction expressed a significant zone of inhibition. The compound isolated from ethyl acetate fraction was identified as 2-(2-hydroxy-6-methoxyphenethyl)-5-methoxybenzene-1,3-diol(Combretastatin B4/Stillbene) using spectroscopic data. Minimum inhibitory concentration (MIC value) of the isolated compound against S. aureus and A. niger was found to be 40 and 120μg/ml, respectively followed by E. coli (125μg/ml) and P. aeruginosa (150μg/ml) which makes it a potent antimicrobial molecule. This is the first report of the isolation of 2-(2-hydroxy-6-methoxyphenethyl)-5-methoxybenzene-1,3-diol from H.pectinata and its antimicrobial potential. This study represents the potential of alcoholic extract of this plant as a probable source of antimicrobials for future use. Top Keywords Habenaria, Stilbene, Antimicrobial activity, Zone of inhibition, Orchid, Fraction. Top |