Isolation and identification of endophytic bacteria from fresh Gastrodia elata and preliminary study on its functional activity

Abstract

Objective: This study aimed to elucidate the activities of endophytic bacteria and their metabolites of Gastrodia elata BI, and to provide theoretical reference for the development of new natural food antibacterial agents and antioxidants. Methods: The endophyte of fresh G. elata in Qinba area was isolated and purified by tissue homogenization and streaking method. The antibacterial, antioxidant and anti-tumor activities of the extract were determined. Furthermore, molecular biology identification was applied for the highly active strains. Results: In this study, four strains were isolated from the inside of fresh G. elata, among which, endophytic bacteria B1 and B2 have good antibacterial activity against Escherichia coli and Staphylococcus aureus. The inhibition zone diameter of endophytic bacteria B2 against S. aureus was 26.33 mm. The four strains all have good antioxidant activities, among which, the percentage of scavenging DPPH scavenges for endophytic bacteria B2 was as high as 69.13%. Endophytic bacteria strain B2, endophytic bacteria B3, and endophytic bacteria B4 have a potential inhibitory effect on HEK293T cells. Among them, endophytic bacteria B2 showed the highest inhibition rate which was 40.40%. The results of molecular biological identification showed that the endophytic bacteria strain B1 and B2 all belonged to Bacillus velezensis, while, endophytic bacteria B3 was Lelliottia sp., and endophytic bacteria B4 was Rahnella aquatilis. Conclusion: The endophyte of fresh G. elata in Qinba area was isolated and purified had antibacterial activity and antioxidant activity.

Keywords

• gastrodia elata
• endophyte
• antibacterial activity
• antioxidant activity
• antitumor activity