Phytochemistry and Antibacterial Potentiality of Selected Mangrove Plants from Coringa Wild Life Sanctuary, Andhra Pradesh, India

Mangrove plants are well known for their resilience in saline and stressful environments, leading to the biosynthesis of a variety of secondary metabolites with significant pharmacological potential. The objective of this study is to explore phytochemical composition, total phenolic content (TPC), functional group characterization and antibacterial potentialities from four different mangrove species— Aegiceros corniculatum, Bruguiera gymnorrhiza, Ceriops decandra, and Sonneratia apetala leaf and stem in different solvents. Preliminary phytochemical screening revealed that B. gymnorrhiza plant exhibited diversity of secondary metabolites, including flavonoids, alkaloids, tannins, saponins, steroids and terpenoids whereas Aegiceros corniculatum and Sonneratia apetala also exhibited the presence of all metabolites except alkaloids and quinones, and C. decandra is devoid of tannins. Quantification of total phenolic content further confirmed that the richest phenolic contents in A. corniculatum and B. gymnorrhiza and S. apetala non polar solvents (120 mg, 73 mg and 76 mg GAE/g dry weight respectively) whereas C. decandra polar extract exhibited highest phenolic concentration (79 mg GAE/g). FTIR spectroscopy identified key functional groups such as hydroxyl (-OH), carbonyl (C=O), alkenes (C=C), alkanes (CH), amine salts (NH) and aromatic rings supporting the presence of polyphenolic compounds such as flavonoids, tannins, terpenoids, saponins more from non-polar extracts than polar solvents responsible for antimicrobial effects. All plants screened for antibacterial efficacy against multi drug resistant (MDR) Escherichia coli, Salmonella typhimurium, Shigella flexineri, Klebsiella pneumonia, Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, Vibrio parahaemolyticus. Of the four plant extracts B. gymnorrhiza ethyl acetate and chloroform had the highest inhibitory effects against Gram negative bacteria than the Gram-positive bacteria tested. These findings highlight the potential of non-polar extracts of mangrove species, particularly B. gymnorrhiza, as propitious source of natural antibacterial agents for pharmaceutical applications.