Abstract
Research on endophytes diversity has a long history. They are viewed as biological agents that are outstanding source of secondary metabolites that serves as bioactive antimicrobial natural products. Calotropis procera is a well-known medicinal plant that has been used to cure various health ailments traditionally. This study was aimed at evaluating the antibacterial potential of endophytic fungi isolated from leaves of C. procera from Aliero Local Government. Leave (150) were collected during winter and were subjected to surface sterilization. Samples were processed using standard microbiological methods. Endophytic fungi were identified phenotypically and confirmed using DNA sequencing method targeting internal transcribed spacer (ITS1 and ITS4) regions of the rRNA gene. Pure culture of endophytic fungal isolates were subjected to fermentation and end product were extracted using ethyl acetate to obtain the crude extract. The ethyl acetate crude extract of the 7 endophytic fungi were tested for antibacterial activities using agar well diffusion method against five pathogenic bacteria (S. aureus, E. coli, S. typhimurium, S. epidermidis and P. aurogenosa). The overall colonization rate was 58.7%. A total of 88 isolates were obtained out of which 7 distinct fungal species were recovered viz Penicillium sclerotigenum, Penicillium chrysogenum, Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus Fusarium solani and Fusarium proliferatum. The dominant endophytic fungus was found to be Penicillium sclerotigenum (31.82%), and the least was Fusarium proliferatum (05.68%). The highest activity of the fungal endophytes ethyl acetate crude extract was observed with P. sclerotigenum against S. aureus (27mm) followed by P. chrysogenum against S. aureus also (22mm) then A. niger and F. solani (19mm) against S. typhi and S. aureus respectively, F. proliferatum (16mm) against S. aureus and the least were A. flavus and A. fumigatus (15mm) against S. aureus and S. typhi respectively. This study indicates that the leaves of Calotropis procera harbored diverse species of endophytic fungi which showed promising antibacterial activity. Therefore, this may serve as an alternative way to source for novel antimicrobial agents.

Key words: Endophytic fungi, Calotropis procera, Antibacterial Activity, Pathogenic bacteria, Aliero