In vitro Antimicrobial Potential and Phytochemical Screening of Albizzia lebbeck Benth. Bark against Respiratory Tract Pathogens

Abstract

This study investigates the antimicrobial activity of Albizzia lebbeck bark extracts against key respiratory pathogens, including Staphylococcus aureus MTCC 1144, Streptococcus pyogenes MTCC 442, and Streptococcus pneumoniae MTCC 655. Phytochemical studies have identified a wide array of bioactive compounds in A. lebbeck, including glycosides, alkaloids, terpenoids, steroids, saponins, anthraquinones, and other phenolics. Respiratory tract infections remain one of the leading causes of morbidity and mortality, especially in light of the recent Covid-19 pandemic, which highlighted the urgent need for effective antimicrobial solutions. The Bark samples were collected from the Botanical Garden of MIET College, Meerut, Uttar Pradesh, and processed using petroleum ether, acetone, methanol, and water in Soxhlet extraction. The antimicrobial efficacy of the extracts was evaluated using the agar well diffusion method, and the methanolic extract demonstrated the highest activity. The results showed that these phytoconstituents were also active against all test pathogens at 50 mg/ml concentration (Table 3). Tannins/phenols were most effective against S. aureus (13.55±0.41mm) followed by S. pyogenes (12.21±0.15mm) and alkoids against S. pneumoniae (12.26±0.03mm). Among the phytoconstituents, tannins/phenols were the most active constituents. Chromatographic separation and phytochemical analysis of the methanolic extract revealed the presence of alkaloids, flavonoids, tannins, phenolics, saponins, glycosides, amino acids, and steroids, compounds associated with antimicrobial properties. Among the tested pathogens, S. aureus was most susceptible to the methanolic extract. These findings support the traditional use of A. lebbeck in managing respiratory diseases and underscore its potential as a natural antimicrobial agent.