Exploring medicinal plant associated fungal endophytes

Abstract

Fungal endophytes play a vital ecological role in terms of plant defense from different environmental stresses. Fungal communities in the healthy leaves of kown Philippine medicinal plants, Ocimum sanctum and Plectranthus amboinicus were isolated and identified morphologically through agar-block method. Active mycochemical properties were also determined qualitatively subjecting each isolate to mycelial mat production and ethanolic extraction. Presence of lapachol, a natural napthoquinone was also evaluated. Fungal isolates positive for lapachol were subjected to antibacterial assay using standard microbiological procedures. Eight endophytic fungal species belonging to four different families were isolated and identified from O. sanctum leaves namely Lasiodiplodia sp., Cladosporium cladosporioides, Aspergillus terreus, Aspergillus ustus, Alternaria alternata, Fusarium vertillioides, Penicillium chrysogenum, and Mycelia sterilia. On the other hand, five species and the sterile mycelia were isolated and identified from P. amboinicus leaves including Aspergillus tamarii, Aspergillus terreus, Aspergillus niger, Penicllium oxalicum, and Mycelia sterila. Qualitative mycochemical analyses exhibited that ethanolic extracts of each fungal isolates contain active biochemical compounds like anthraquinone, tannins, saponins, flavonoids, glycosides, alkaloids, terpenes, and sterols which can further be utilized for therapeutic and cosmeceutical development. It was recorded that the mycochemical properties exhibited by A. terreus differed from each plant species. Lapachol was detected positive among A. alternata, A. niger and A. terreus both from O. sanctum and P. amboinicus. Antibacterial assay showed potential inhibitory activities against E. coli and S. aureus. This current study shows the potential of these endophytic fungi for pharmacologic evaluations.