University of Khartoum

Endophytic Fungal Communities Associated With Three Ethno-Medicinal Plants from Sudan and Their Antimicrobial and Antioxidant Prospective

Endophytic Fungal Communities Associated With Three Ethno-Medicinal Plants from Sudan and Their Antimicrobial and Antioxidant Prospective

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Title: Endophytic Fungal Communities Associated With Three Ethno-Medicinal Plants from Sudan and Their Antimicrobial and Antioxidant Prospective
Author: Madani, Tawsol Mohammed Mahadi
Abstract: Endophytes are microorganisms colonizing healthy plants tissue without causing any apparent symptoms and noticeable injury to the host. Both fungi and bacteria are the most common microbes existing as endophytes and are to be found in virtually every plant on earth. The investigation was carried out to isolate and characterize the endophytic fungi associated with selected medicinal plants growing in Sudan and to evaluate their bioactive potential. The endophytic fungal population was explored from leaves and stems of Datura stramonium (family Solanaceae), Moringa oleifera (family Moringaceae) and Prosopis chilensis (family Fabaceae). Seventeen isolates were recorded where, 10 isolates were identified to species level and 7 to genus one. The endophytic fungal communities of D. stramonium comprised of fungi belonging to genera Aspergillus and Curvularia. The tissue of M. oleifera was found colonized with endophytic fungi of the genera Emericella, Aspergillus and Curvularia whereas, those of P. chilensis were colonized with Emericella, Aspergillus and Chaetomium. The dominant genus associated with the three plant species in this study was Aspergillus and consisted of 4 different species in D. stramonium and 3 different species in M. oleifera and P. chilensis. The crude ethyl acetate extracts obtained from the isolated fungal endophytes were screened for evaluation of their secondary metabolites profile, antimicrobial activity and antioxidant capacity. Preliminary screening of extracts, using thin layer technique, revealed that the isolated endophytic fungi were rich in secondary metabolites. Some spots were comparable to those of host plants extracts indicating the possibility of presence of similar secondary metabolites whereas, others were different in their polarity and colour characteristic indicative of their distinct type of chemical constituents. The antimicrobial activity at concentration 10 mg/mL of extracts was determined against the Gram negative bacteria Escherichia coli, Klepsella pneumoniae, Pseudomonas aeruginosa and Salmonella typhi and the Gram positive Staphylococccus aureus and two fungi; Aspergillus niger and Candida albicans using the disc diffusion method. Endophytic fungi crude extracts isolated from of P. chilensis showed the highest antibacterial activity compared to other isolates. They all inhibited E. coli, K. pneumoniae, P. aeruginosa, S. typhi and S. aureus with minimum inhibitory concentration and minimum bacterial concentration value of 25 and 12.5 μg/mL respectively. All endophytic fungi extracts were inactive against the tested fungi. The antioxidant activity was determined using the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay and total phenolic contents of endophytic fungi extracts were also evaluated. A remarkable scavenging activity was obtained from endophytic fungi Aspergillus sp. (D-4) and Emericella bicolor (M-6) isolated from D. stramonium and M. oleifera respectively where they possessed activity higher than that obtained from the standard control ascorbic acid. Moreover, a positive correlation between the phenolic content of the extracts with their antioxidant activity was also observed suggesting that polyphenols contributed largely for the antioxidant activities of endophytic fungi extracts under study. In conclusion, the endophytic flora associated within these widely used medicinal plants could be a potential source of novel products of great importance in medicine, agriculture and industry.
URI: http://khartoumspace.uofk.edu/123456789/17006
Date: 2015-11-12


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