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العنوان
Characterization of Secondary Metabolites of Endophytic Fungi Isolated from Some Egyptian Medicinal Plants /
الناشر
Tarek Abd Elrazik Abd Elrazik Abd Elrazik Kardosha,
المؤلف
Kardosha, Tarek Abd Elrazik Abd Elrazik Abd Elrazik.
هيئة الاعداد
باحث / Tarek Abd Elrazik Abd Elrazik Abd Elrazik Kardosha
مناقش / Zakaria Awad M. Baka
مشرف / Mamdouh Salem Serag
مشرف / Reda Mohammed Shehata
الموضوع
النباتات الطبية - مصر.
تاريخ النشر
2018.
عدد الصفحات
197 p. :
اللغة
الإنجليزية
الدرجة
الدكتوراه
التخصص
علوم النبات
تاريخ الإجازة
25/11/2018
مكان الإجازة
جامعة دمياط - كلية العلوم - Botany & Microbiology
الفهرس
Only 14 pages are availabe for public view

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from 237

Abstract

Seventy-three fungal isolates were isolated from thirty five medicinal plants. The preliminary identification of these isolates was affiliated to 9 main genera, namely Alternaria, Aspergillus, Cunninghamella, Curvularia, Emericella, Fusarium, Penicillium, Rhizopus, and Ulocladium. Then, 100 ml of each culture broth of 73 tested fungi and also, their fungal mat, were extracted, concentrated, and applied on a thin-layer chromatography (TLC) silica gel plate and optimized for the best developing solvent system for separation of the secondary metabolites into individual fractions.
Seventy-three intracellular and extracellular endophytic fungal extracts were tested for antioxidant activity. Many of the studied fungi were found to have antioxidant activity against 1, 1- diphenyl-2-picryl hydrazyl (DPPH) free radical in vitro. In general, extracellular metabolites showed a promising antioxidant activity when compared with intracellular metabolites of the studied fungi. Four internal extracts and seventeen external extracts of the isolated fungi showed a strong activity as antioxidants. In addition, four internal extracts and 12 external extracts of isolated fungi showed a significant activity. While eight of the internal extracts and five of the external extracts of the isolated fungi showed a weak activity.
Antimicrobial activity was also tested for extracts of seventy-three isolated fungi against a number of pathogenic bacteria and fungi. Tests showed that many isolated fungi produce substances that have inhibitory activity against one or more of the following pathogenic microbes, bacteria: Staphylococcus aureus, Escherichia coli, Pseudomonas aerugonosa, Salmonella typhimurium, Bacillus subtilis and fungi: Candida albicans, Penicillium aurantiogriseum, Aspergillus niger, Aspergillus fumigatus. In contrast to antioxidants, there were many fungi that did not have anti-microbial activity. In general, the extracellular metabolites of the isolated fungi showed higher activity as an antimicrobial when compared to the intracellular metabolites of the isolated fungi.
All isolates were subjected to chemical screening by TLC. Accordingly, together with the data obtained from antimicrobial and antioxidant, the isolates of Emericella quadrilineata (C3), Scytalidium dimidiatum (C5), Aspergillus flavus (D3), Alternaria alternata (F2), Aspergillus parasiticus (J1), Penicillium aurantiogriseum (T1) and Aspergillus parasiticus (32) were considered to be the most promising and were selected for further study. These isolates were identified according to its International Reference Key and confirmed by the Regional Center of Mycology and Biotechnolgy (RCMB) Database Management System for fungal identification at Al-Azhar University, Egypt. The main distinguishing features are given and the data are expressed as the mean of multiple measurements. These isolates were identified as Aspergillus flavus, Aspergillus parasiticus, Alternaria alternata, Scytalidium dimidiatum and Emericella quadrilineata.
Large-scale production of the active metabolites from the most potent endophytic isolates (C3, C5, D3, F2, J1, T1 and 32) were done for further tests. The antimicrobial tests of extracts from isolates C3, C5, D3, F2, J1,T1 and 32 have been carried out using the agar well diffusion method against wide range of pathogenic microbes including Gram +ve and Gram -ve bacteria, yeast, and fungi. The extracts from isolates 32, C5, F2, D3 and J1 showed a significant growth inhibition against Gram +ve (Staphylococcus aureus, Bacillus subtilis) and Gram -ve bacteria (Salmonella typhimurium, Escherichia coli). The extracts from C3, C5, D3, F2, J1, T1 and 32 showed a significant growth inhibition against Croptococcus neoformas. The extracts from isolates C3, C5, D3, J1 and 32 showed a significant growth inhibition against Candida albicans.
Also, the most potent fungal extracts showed a promising antioxidant activity on DPPH free radical, where the IC50 values equal 87.5 µg/ml for the extract of Aspergillus flavus (D3), 17.6 µg/ml for the extract of Aspergillus parasiticus (J1), 19.8 µg/ml for the extract of Alternaria alternata (F2), 15.5 µg/ml for thye extract of Aspergillus parasiticus (32), 5.5 µg /ml for the extract of Scytalidium-dimidiatum (C5), 10.1 µg /ml for the extract of Emericella quadrilineata (C3) and 61 µg /ml for the extract of Penicillium aurantiogriseum (T1).
As well as, the most potent fungal extracts exhibited antitumor activity, which decreased the survival of liver carcinoma cells (HepG2) revealing promising activity with IC50 =110 µg/ml for Aspergillus parasiticus(J1) extract, IC50=16.7µg/ml for Aspergillus flavus(D3) extract, IC5 =59.5 µg/ml for Aspergillus parasiticus(32) extract, IC50 =89.4 µg/ml for Penicillium aurantiogriseum(T1) extract, IC50=116 µg/ml for Scytalidium dimidiatum (C5) extract, IC50=46.8 µg/ml for Alternaria alternate(F2) extract and IC50=94.4 µg/ml for Emericella quadrilineata(C3) extract.
As well as, the most potent fungal extracts decreased the survival of colon carcinoma cells (HCT-116) revealing a promising activity with IC50 =155 µg/ml for Aspergillus parasiticus(J1) extract, IC50=25.8 µg/ml for Aspergillus flavus (D3) extract, IC50=120µg/ml for Aspergillus parasiticus(32) extract, IC50=124 µg/ml for Penicillium aurantiogriseum(T1) extract, IC50=218 µg/ml for Scytalidium dimidiatum (C5) extract, IC50 =95.5µg/ml for Alternaria alternata (F2) extract and IC50=167.8 µg/ml for Emericella quadrilineata (C3) extract.
The secondary metabolites produced by the most potent seven fungi were separated and studied using different chromatographic techniques, including TLC scanner system and the gas chromatographic separation system. The qualitative analysis of the fungal extracts showed a variation in the chemical structure of the separated metabolites, as well as many of them, have phenolic nature, which is characterized by their biological properties.
Twelve compounds from extracellular fungal extracts of the most potent fungi were separated and purified by TLC and Column chromatography. Three of these were identified and available in good quantities. Quantitation of kojic acid in the active fungal cultures was conducted, which indicated the ability of four of them to produce it in suitable quantities. The study also examined the biological and economic importance of this acid, which is included in the installation of many personal care products.