In Vitro and In Silico Screening and Characterization of Antimicrobial Napin Bioactive Protein in Brassica juncea and Moringa oleifera.

Sangeeta Chandrashekar,Ghazala Sultan,Raman Vijayakumar,Deog-Hwan Oh,Su-Jung Yeon,Fazle Elahi,Momna Rubab,Eric Banan-Mwine Daliri,Inamul Hasan Madar,Ramachandran Chelliah

doi:10.3390/molecules26072080

Abstract

The study aimed to investigate the antibacterial activity of Mustard (Brassica juncea) and Moringa (Moringa oleifera) leaf extracts and coagulant protein for their potential application in water treatment. Bacterial cell aggregation and growth kinetics studies were employed for thirteen bacterial strains with different concentrations of leaf extracts and coagulant protein. Moringa oleifera leaf extract (MOS) and coagulant protein showed cell aggregation against ten bacterial strains, whereas leaf extract alone showed growth inhibition of five bacterial strains for up to 6 h and five bacterial strains for up to 3 h. Brassica juncea leaf extract (BJS) showed growth inhibition for up to 6 h, and three bacterial strains showed inhibition for up to 3 h. The highest inhibition concentration with 2.5 mg/mL was 19 mm, and furthermore, the minimum inhibitory concentration (MIC) (0.5 mg/mL) and MBC (1.5 mg/mL) were determined to have a higher antibacterial effect for <3 KDa peptides. Based on LCMS analysis, napin was identified in both MOS and BJS; furthermore, the mode of action of napin peptide was determined on lipoprotein X complex (LpxC) and four-chained structured binding protein of bacterial type II topoisomerase (4PLB). The docking analysis has exhibited moderate to potent inhibition with a range of dock score −912.9 Kcal/mol. Thus, it possesses antibacterial-coagulant potential bioactive peptides present in the Moringa oleifera purified protein (MOP) and Brassica juncea purified protein (BJP) that could act as an effective antimicrobial agent to replace currently available antibiotics. The result implies that MOP and Brassica juncea purified coagulant (BJP) proteins may perform a wide degree of antibacterial functions against different pathogens.

Highlights

Water scarcity has been predicted globally and in India by 2020 [1]
The current study aimed to investigate the antibacterial effect of Moringa and Mustard leaf extracts and antimicrobial-coagulant protein against thirteen different clinical pathogens isolated from patients samples in India
Microbial Strains Applied in the Study Clinical isolates of thirteen bacterial strains—Escherichia coli (E.coli), Salmonella paratyphi B (S. paratyphi B), Enterobacter species (E. species), Shigella flexneri (S. flexneri), Salmonella typhimurium (S. typhimurium), Salmonella typhi (S. typhi), Salmonella paratyphi A (S. paratyphi A), Klebsiella pneumonia (K. pneumonia), Staphylococcus aureus (S. aureus), Serratia marcescens (S. marcescens), Shigella dysentriae (S. dysentriae), Proteus mirbalis (P. mirbalis), and Enterococcus faecalis (E. faecalis)—were obtained from Department of Microbiology, Ramachandra Hospital in Chennai, India

Summary

Introduction

The major problem is poor water quality, and it is estimated that waterborne diseases affect about 37.7 million Indians annually and 1.5 million children under the age of five die due to diarrhea each year [2]. Increased pressure on the resources due to the alarmingly growing population and other factors such as industrial discharge, agricultural run-off, and poor sanitation practices put the long-term availability and quality of the potable water at stake. In most developing countries, including India, farming by-products, crop residues, and grazing along with some protein and energy supplements are the main source of livestock feed for ruminant animals. Common protein supplements for ruminants are oilseed cakes obtained as oil industry by-products. Microbial contamination through fecal contamination in water is the major reason for the poor water quality in developing countries, transmitting a large number of diseases. The common pathogens present in the drinking water include Shigella species, Salmonella species, Klebsiella species, Escherichia coli, Enterobacter species, and parasites such as Giardia lamblia and Entamaebahistolytica [4,5]

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