Production and Evaluation of Bioactive Metabolites from Newly Isolated Endophytic Fungal Isolates

Abstract

The aim of this study is the production and evaluation of bioactive metabolites produced by the endophytic fungi of medicinal plant Taxus fuana inhabited in the Himalayan region of Pakistan. A total of 07 endophytic fungal isolates encoded (NFW1, NFW3, NFW6, NFW7, NFW9, NFW11, and NF3L2) obtained as pure culture from MRL QAU, were screened for the production of antimicrobial metabolites and also qualitatively screened for the production of extracellular enzymes (amylase, protease, lipase, and cellulase). All the fungal isolates were positive against at least one test organism. Two out of 07 were negative against all the test bacterial strains (E. coli, B. spizizenii, S. aureus, S. typhi and S. epidermidis). Three isolates shows activity against both Gram positive and Gram negative bacteria. Five isolates exhibit antibacterial effect against Gram positive while 04 isolates possess antibacterial effect against Gram negative bacteria. All the fungal isolates showed antifungal activity against at least one test fungal strain (A. niger, A.fumigatus and Mucor sp.). Three fungal isolates produce at least one extracellular enzyme. Two fungal isolates NFW9 and NFW3 producing relatively better antimicrobial metabolites were studied for the optimization of operational parameters such as (Incubation time, media, pH value and temperature). SDB medium, pH range 6.5 to 7, incubation time of 14 days and 15°C temperature was optimum for both of the isolates. On the basis of initial screening and optimization studies NFW9 showing better results was further studied for organic extraction of both extracellular and intracellular bioactive metabolites and their preliminary study by TLC, FTIR, protein precipitation and bioautography. TLC analysis showed the production of a wide range of organic metabolites and staining of TLC plates indicate the presence of terpenes and sesquiterpenes which showed inhibitory effect against test bacterial strains in bioautography. The FTIR analysis of organic extracts indicates the presence of functional groups like phenols, amines, Alkenes, alkanes and ketones which may attribute to the antimicrobial activity against test microbial strains.