Evaluation of bacteriostatic and antioxidant activities of various extracts from aerial part of Piper nigrum grown in Gulf countries traditionally used for the treatment of various infectious diseases

Abstract

AbstractPiper nigrum (P. nigrum) is a tropical medicinal plant widely available in Southeast Asian countries including Oman. In Asian It has a long history of usage in places such as Oman for treating of rheumatism, colds, and various infections. Based on the medicinal uses, the purpose of this research is to create diverse fractions using increasing solvent polarity from the aerial part of the collected plant species and evaluate their antibacterial and antioxidant activities by using established bioassays. The aerial part was collected from the Southern part of Oman and processed using the standard method. The processed materials were recovered using the maceration method using methanol, and the methanol raw extracts was further fractionated with water extraction, butanol, ethyl acetate (ETA), hexane, and dichloromethane are produced using different liquid polarities. Each of the six plant extracts was tested for antioxidant and antibacterial potential at different concentrations against DPPH (1, 1-diphenyl-2-picrylhydrazyl) and agar diffusion methods. All of the fractions at varied concentrations shown promising antioxidant activity with DPPH against the gallic acid. The maximum activity was observed in hexane extract, while the smallest potential was noticed in butanol extract, in the following order: hexane > chloroform > water > methanol > ethyl acetate > butanol extract. The antibacterial efficacy of six different polarities extracts gives moderate activity against two Gram-positive bacteria strains namely S. saprophyticus and S. aureus and three Gram-negative namely P. vulgaris, K. senegalensis and E. coli. Among the six extracts, hexane extract had the most antibacterial activity, whereas butanol extract had the smallest activity. The remaining four extracts, chloroform, ethyl acetate, methanol, and water, all had comparable activity. In conclusion, the extracts with the greatest activity from the chosen plant types might be employed as natural antioxidants to treat infectious disorders.