Two novel antifungals, acornine 1 and acornine 2, from the bark of mangrove plant Aegiceras corniculatum (Linn.) Blanco from Sundarban Estuary

Background: Microbes have been implicated in a wide variety of human diseases many of which are of life‑threatening nature. New antimicrobials are urgently needed not only for combating these organisms but also to counter the menace of the harmful microbes developing resistance against drugs at alarming rates. Mangrove plants are rich sources of secondary metabolites having many beneficial biological activities including antimicrobial ones. True to this fact, this report describes identification, isolation and partial characterization of two novel antifungal compounds from Aegiceras corniculatum, a mangrove plant from Indian Sundarban estuary. Materials and Methods: Two compounds, named as Acornine 1 and Acornine 2, having antifungal activities were isolated from the bark of A. corniculatum, a mangrove plant, by using standard techniques. The compounds were characterized using routine microbiological and physicochemical methods. Results: Partial structural characterization of the two compounds indicated they are oleanane triterpenoids with linked sugar moieties. While both the compounds exhibited growth inhibition in tested Gram positive bacteria, Acornine 2 in particular demonstrated strong antifungal activities against several pathogenic fungi tested. Results also indicated that various environmental factors may govern the secondary metabolite profiles of the same mangrove plants growing in different geographical areas. Conclusion: Tissue extracts of Aegiceras corniculatum, a mangrove plant from Indian Sundarban estuary, exhibited the presence of remarkable antifungal activities. The isolated compounds responsible for such activities, named as Acornine 1 and Acornine 2, appear to have potential in food processing and health care industry. They need to be studied further.