Abstract
In the present study, we isolated endophytic fungi from the medicinal plant Rhazya stricta from Saudi Arabia. Twenty-eight fungal isolates representing five species were isolated from 21 leaves (10 young and 11 old) of R. stricta. These fungi include two species of Alternaria, Aspergillus sp., Nothophoma sp. and one species producing sterile mycelia. Based on morphology and phylogenetic analyses of LSU rDNA, we describe Nothophoma (E-2-5) as a new species to science. Nothophoma multilocularis is characterized by its large multiloculate pycnidia and its larger conidial dimensions than the six described Nothophoma species. A table (Table 3) comparing the morphology and the host of the seven Nothophoma species is provided, along with a key for their identification. The culture filtrates of the isolated endophytic fungi were extracted using ethyl acetate and were tested against pathogenic microbes. Fifty-five bioactive chemical compounds were identified from the crude extracts of Nothophoma multilocularis using GC-MS. Ten major bioactive compounds were recorded namely: Di-n-octyl phthalate representing 53.98 % of the crude extract, 2-Allyl-3,4-dimethoxybenzaldehyde (10.26 %), Maltol (9.45 %), Cetene (2.73 %), 1-Tetradecene (2.07 %), E-15-Heptadecenal (2.06 %), 2,5-Cyclohexadien-1-one (1.88 %), 1-Octadecene (1.36 %), Diethyldithiophosphinic acid (1.17 %) and Phenol, 2,4-di-t-butyl-6-nitrophenol (1.07 %). These compounds showed strong antimicrobial activity in combination.