Screening of endophytic actinomycetes of medicinal plants of Pakistan for their antifungal and cytotoxic potential

Many diseases in humans and animals are caused by toxins produced by fungus. The most common disease of the respiratory tract is caused by many fungal species and Aspergillus fumigatus is the most prominent and primary pathogen among them. Due to the emergence of multiple drug resistance in the last years, the treatment of pathogenic fungi has become quite difficult. Therefore, the need to find out new biologically active and novel compounds has become a necessity. Medicinal plants of Pakistan such as Ocimum tenuiflorum (Tulsi) and Azadirachta indica (Neem) are well known for their medicinal uses. Endophytic actinomycetes are known for producing a variety of bioactive metabolites that are beneficial for plant health. The purpose of our study was to check the antifungal potential and to carry out the cytotoxicity profiling of endophytic actinomycetes residing within these plants. Agar plug method was used for preliminary screening and 2 isolates with antifungal activity were observed. Further minimum inhibitory concentration (MIC) was done of their concentrated broth and they were observed to be potent against A. fumigatus strains with a MIC value of 16µg/ml. Interestingly, cytotoxicity profiling of endophytic actinomycetes on baby hamster kidney (BHK-21) cell line showed that the concentrated broth of endophytic actinomycetes was most potent at a concentration of 100mg/ml. Our study concludes that endophytic actinomycetes, inhabiting tulsi, and neem plants, have potent antifungal activity against A. fumigatus along with cytotoxic activity.