Isolation characterization and antioxidant potential  of endophytic fungi of Ocimum sanctum Linn.  (Lamiaceae)

Robin Sharma; B.S. Vijaya Kumar

Volume : III, Issue : VII, July - 2013

Isolation characterization and antioxidant potential of endophytic fungi of Ocimum sanctum Linn. (Lamiaceae)

Robin Sharma, B. S. Vijaya Kumar

Abstract :

Endophytic fungi of medicinal plants have gained tremendous importance with emerging evidence of their immense ecological and biotechnological relevance. In the present study an attempt has been made to isolate, characterize and screen endophytes associated with leaves of Ocimum sanctum Linn. (Lamiaceae) for their antioxidant potential. A total of 147 endophytic fungal strains, with high colonization rate of 73.5% were isolated from the host plant. Using multiple assay system ethyl acetate extracts of representative endophytes grown in improved Czapex Dox oth were subjected to free radical scavenging activities against 2,2–Diphenyl–1–picrylhydrazyl (DPPH), reducing power assay (RP) and ferric reducing antioxidant power (FRAP). Total phenolic content (TPC) and total flavonoid content (TFC) were also evaluated. The total phenolic and flavonoid content ranged from 1.6±0.13 to 18.13±0.09 mgGAE/100mL culture and, 1.7±0.03 to 5.33±0.21 mgRE/100mL culture respectively. Endophytic fungi, Mycelia sterilia was found to be the most potent free radical scavenger with highest phenolics and flavonoid content, and was therefore subjected to molecular characterization based on rDNA sequencing of internal transcriber sequence (ITS) region. The results obtained indicate a significant positive correlation between antioxidant capacity and total phenolic and flavonoid content thereby suggesting that the antioxidant activity of these endophytes may be attributed to its high phenolic and flavonoid content. Therefore, fungal endophytes isolated from O. sanctum represent a potential antioxidant resource.