Objective: The present study investigates the antimicrobial activities of eight different mangrove plants and also the development of their intra-relationship through cluster analysis.
Methods: The dried and powdered leaves of different mangrove species were extracted by cold maceration process with water, methanol, and chloroform. The antimicrobial activity was done using the agar well diffusion method. The cluster analysis of the mangrove plants was analyzed by MINITAB Release 13.1.
Results: The order of extraction yield for each mangrove species was methanol > chloroform > water. The methanol extract of Suaeda maritima, Avicennia marina, Avicennia officinalis, and chloroform extract of Sonneratia apetala gave the highest inhibition zones of 19 mm, 19 mm, 19.33 mm, and 19.33 mm, respectively, against Bacillus subtilis. The methanol extract of Ceriops decandra, Xylocarpus granatum, and Bruguiera gymnorrhiza found the highest inhibition zones of 21.67 mm, 22 mm, and 20.3 mm, respectively, against Escherichia coli, Shigella flexneri, and Staphylococcus aureus, respectively. The endangered and endemic species Heritiera fomes gave the highest result (18 mm) against both for Micrococcus luteus and B. subtilis in methanolic extract. The maximum zone of inhibition of fungal strains was found against Botrytis cinerea (15 mm), Fusarium oxysporum (16.33 mm), and Rhizopus oryzae (13.33 mm) with the methanol extract of X. granatum, S. apetala, and C. decandra, respectively. Cluster analysis of 8 mangrove species based on different bacterial pathogens was also shown where it demonstrated their intra-relationship against some bacterial pathogens.
Conclusion: From this study, it may be concluded that mangrove plants can be used to discover bioactive natural products.