Methanolic Extract of Angelica glauca Edgew Root and Stem: A Possible Component of Herbal Medicines against Respiratory Infections

Plants are identified to produce a variety of compounds to protect themselves against a diversity of pathogens. This study assessed the antibacterial, antioxidant potential and phytochemical screening of medicinal plant Angelica glauca (Choru) root and stem extracts against respiratory tract pathogens i.e., Staphylococcus aureus MTCC 1144, Streptococcus pneumoniae MTCC 655, Streptococcus pyogenes MTCC 442, Pseudomonas aeruginosa MTCC 2474 and Klebsiella pneumoniae MTCC 4030. The plant material was collected from Tungnath 3,800m amsl of Garhwal Himalaya. Root and stem of the plants were washed, shade dried, grinded into fine powder and extracted in the organic solvents of different polarity (petroleum ether, chloroform, methanol and water). Antibacterial activities of prepared extracts were assayed using agar well diffusion and two-fold serial dilution method of MIC determination. Antioxidant potential was determined using DPPH assay and phytochemical analysis was performed using qualitative methods for different phytochemicals. Experimental outcomes revealed maximum antibacterial and antioxidant activity of methanol extract; also the maximum groups of phytochemicals were present in the methanolic extract. The methanol extract produced ZOIs of 11.0±0.54mm to 30.3±1.58mm diameters and MICs ranges were recorded between 3.12 mg/ml to 25 mg/ml against all the tested bacteria. Alkaloids, flavonoids, glycosides, tannins, steroids and saponins were present in the extracts of A. glauca. This study favors a good response towards using A. glauca as natural antioxidant in herbal medicines, either in pure form or as supplement with other herbal formulations already available in the market, to enhance their potential against respiratory tract diseases. In the present COVID-19 pandemic situation, use of A. glauca can be beneficial, as it’s methanolic extract showed promising antibacterial activity against bacterial pathogens of human respiratory tract.