Antibacterial activity of isolated endophytic fungi from Rauvolfia serpentina (L.) Benth. Ex Kurz

Abstract

Objective: The aim of the present study was to isolate the endophytic fungi from medicinal plant Rauvolfia serpentina (L.) Benth. ex Kurz. (Family Apocynaceae) and observed their antibacterial activity against bacteria as well as the molecular characterization of most potent fungal strain. Methods: Collection and isolation of endophytic fungi from different parts (root, shoot, leaves) of Rauvolfia serpentina plant. Screening of endophytic fungi for antibacterial activity was scrutinised against six bacteria viz. Bacillus subtilis, Enterococcus sp., Klebsiella pneumoniae, Escherichia coli, Salmonella typhimurium and Streptococcus pyogenes by using Agar well diffusion method. For molecular sequencing of potent fungi, the DNA was extracted, quantified and amplified by using two oligonucleotide primers ITS4 and ITS6 in PCR. Results: A total seven endophytic fungi Aspergillus niger, Penicillium citrinum, Cladosporium sp., Curvularia lunata, Aspergillus sp., Alternaria sp. and Aspergillus fumigatus were isolated from different parts of Rauvolfia serpentina and fungal strain Penicillium citrinum was shown the maximum zone of inhibition against Bacillus subtilis (23.0±0.12 mm), Escherichia coli (19.9±0.16 mm), Streptococcus pyrogens (19.2±0.59 mm), Enterococcus sp., (17.2±0.08 mm), Klebsiella pneumoniae (18.9±0.16 mm) and Salmonella typhimurium (15.1±0.16 mm). The molecular sequencing of the potent fungi was done by primers (ITS4 and ITS6) which showed strong specificity with fungal DNA and the percentages of identical matches of ITS4 and ITS6 DNA sequences in the GeneBank database (NCBI) were determined to 98 %. Conclusion: In the present study, the endophytic fungal strain Penicillium citrinum showed the potential source of antibacterial bioactive compounds and molecular sequencing of this fungus helps in future to determine the various metabolic pathways that are responsible for the production of such type of novel compounds.