Antibacterial and Anticancer Activity and Untargeted Secondary Metabolite Profiling of Crude Bacterial Endophyte Extracts from Crinum macowanii Baker Leaves.

Tendani E Sebola,Vuyo Mavumengwana,Ezekiel Green,Lukhanyo Mekuto,Maya Mellisa Makatini,Nkemdinma C Uche-Okereafor

doi:10.1155/2020/8839490

Abstract

This study isolated and identified endophytic bacteria from the leaves of Crinum macowanii and investigated the potential of the bacterial endophyte extracts as antibacterial and anticancer agents and their subsequent secondary metabolites. Ethyl acetate extracts from the endophytes and the leaves (methanol: dichloromethane (1 : 1)) were used for antibacterial activity against selected pathogenic bacterial strains by using the broth microdilution method. The anticancer activity against the U87MG glioblastoma and A549 lung carcinoma cells was determined by the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. Bacterial endophytes that were successfully isolated from C. macowanii leaves include Raoultella ornithinolytica, Acinetobacter guillouiae, Pseudomonas sp., Pseudomonas palleroniana, Pseudomonas putida, Bacillus safensis, Enterobacter asburiae, Pseudomonas cichorii, and Arthrobacter pascens. Pseudomonas cichorii exhibited broad antibacterial activity against both Gram-negative and Gram-positive pathogenic bacteria while Arthrobacter pascens displayed the least MIC of 0.0625 mg/mL. Bacillus safensis crude extracts were the only sample that showed notable cell reduction of 50% against A549 lung carcinoma cells at a concentration of 100 μg/mL. Metabolite profiling of Bacillus safensis, Pseudomonas cichorii, and Arthrobacter pascens crude extracts revealed the presence of known antibacterial and/or anticancer agents such as lycorine (1), angustine (2), crinamidine (3), vasicinol (4), and powelline. It can be concluded that the crude bacterial endophyte extracts obtained from C. macowanii leaves can biosynthesize bioactive compounds and can be bioprospected for medical application into antibacterial and anticancer agents.

Highlights

Academic Editor: Karl Drlica is study isolated and identified endophytic bacteria from the leaves of Crinum macowanii and investigated the potential of the bacterial endophyte extracts as antibacterial and anticancer agents and their subsequent secondary metabolites
Ethyl acetate extracts from the endophytes and the leaves (methanol: dichloromethane (1 :1)) were used for antibacterial activity against selected pathogenic bacterial strains by using the broth microdilution method. e anticancer activity against the U87MG glioblastoma and A549 lung carcinoma cells was determined by the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay
Bacterial endophytes that were successfully isolated from C. macowanii leaves include Raoultella ornithinolytica, Acinetobacter guillouiae, Pseudomonas sp., Pseudomonas palleroniana, Pseudomonas putida, Bacillus safensis, Enterobacter asburiae, Pseudomonas cichorii, and Arthrobacter pascens

Summary

Materials and Methods

Bacterial endophytes were isolated from the leaves of the plant by a method described by Jasim et al [27] and Sebola et al [25] with minor modifications. Tween 20 was removed by rinsing several times with sterile distilled water, followed by disinfection with 50 mL of 70% ethanol for 1 minute. E sample was treated with 1% sodium hypochlorite (NaClO) for 10 minutes and again rinsed five times with sterile distilled water. E effectiveness of the sterilization was monitored on the wash control plate, with growth indicating poor sterilization. Under such circumstances, the plates for the plant part were discarded and the sterilization was repeated. Glycerol in a ratio of 500 μL glycerol : 500 μL overnight broth culture and kept at −80°C

Morphological Identification of Endophytic Bacteria

Molecular Identification

2.10. LC-QTOF-MS Analysis

Results and Discussion