Antibacterial potential of some Cameroonian ornamental plants and their isolated endophytic fungi

Abstract

Bacterial resistance to antibiotics is a real challenge for health practitioners and society in general today, bringing a constant need for the search for new molecules. The present study is focused on the antibacterial effect of extracts of three ornamental plants and their endophytes. The endophytic fungi isolated from the ornamental plants included Sansevieria trifasciata leaves, Monstera deliciosa fruits, Monstera deliciosa and Cordyline fruticosa roots. The morphocultural features were studied, the antibacterial activities of the endophytes as well as those of their host plant extracts were determined through the agar diffusion and broth microdilution methods. The plant extracts were obtained by ethanol maceration, while those from the endophytes were obtained by ethyl acetate depletion. Phytochemical screening of the different extracts was done using standard methods. Four endophytes were isolated from the three plants: Geotrichum sp. from the leaves of Sansevieria trifasciata; Colletotrichum sp. and Rhizopus sp. from the roots of Cordyline fruticosa and Monstera deliciosa respectively and Phoma sp. from the fruits of Monstera deliciosa. Endophyte isolates inhibited the growth of almost all the tested bacterial with inhibition diameters ranging from 5 to 40 mm. The host endophytic plant extracts were less active than endophytic extracts, with inhibition diameters ranging from 0 to 20 mm. Some endophytic fungal secretions and plant extracts exhibited antibacterial activities in liquid media, with MICs ranging from 512 to 2048 µg/ml. Finally, endophytic extracts were more active than plant extracts. There was no concordance between the activities of endophytes and those of plant extracts, reflecting their independence.