Abstract
Indigenous plants in Northern border region of Saudi Arabia are still virgins; the majority of them are still not markedly investigated for their phytoconstituents and/or their endophytic metabolites. The present work deals with the isolation, identification of endophytic fungal strains and investigation of their antimicrobial and cytotoxic activities from two indigenous plants, Polygonum aviculare and Achillea fragrantissima, three fungal strains have been isolated and identified as Pseudeurotium oval, Aspergillus sydowii, and Trichoderma longibrachiatum. These fungal strains were cultivated on solid nutrient media (rice media), their secondary metabolites were extracted and fractionated. The antimicrobial and Cytotoxic activities of these fractions were evaluated. Sub-fractions of both A. sydowii, and T. longibrachiatum showed a comparable antimicrobial activities while those of P. oval were inactive. In addition, Sub-fractions of both A. sydowii, and T. longibrachiatum showed a promising cytotoxic activities against three Mammalian cancer cell lines: MCF-7 cells (human breast cancer cell line), HepG-2 cells (human Hepatocellular carcinoma) and HCT-116 (colon carcinoma) while the most promising results obtained from T. longibrachiatum sub-fractions.