Isolation of endophytic bacteria from the leaves of Anredera cordifolia CIX1 for metabolites and their biological activities

Abstract

Background Endophytes, especially those that are found from ethnopharmacologically noteworthy medicinal plants have attracted attention due to their diverse bioactive metabolites of pharmacological importance. Methods This study aimed at isolating endophytic bacterium from the leaves of Anredera cordifolia CIX1 for its bioactive metabolites. The endophytic isolates were identified by 16S rRNA sequence and investigated for antibiotic sensitivity using different antibiotics. The secondary metabolites were evaluated for antibacterial activity against four bacterial strains. The 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2′-azinobis (3- ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods were used to assess their scavenging activities. The chemical components were analysed by gas chromatography-mass spectrometry (GC-MS). Results Out of 13 isolates, Isolate 1 was identified as Pseudomonas aeruginosa CP043328.1. It was resistant to clindamycin, ertapenem, penicillin G, amoxicillin, cephalothin and kanamycin but sensitive to imipenem, meropenem, and gentamycin. Its extract demonstrated antibacterial activity with minimum inhibitory concentration value of 0.098 against Bacillus cereus (ATCC 10102) and Staphylococcus aureus (ATCC 25925) and 0.391 mg/ml against Escherichia coli (ATCC 25922) and Proteus mirabilis (ATCC 25933). The extract revealed DPPH and ABTS scavenging activities with half maximal inhibitory concentration value of 0.650 mg/ml and 0.15 mg/ml, respectively. The GC-MS revealed a total of 15 compounds with diisooctyl phthalate (50.51%) and [1, 2, 4] oxadiazole, 5-benzyl-3 (10.44%) as major components. Conclusions P. aeruginosa CP043328.1 produced secondary metabolites with antibacterial and antioxidant activities.

Antibacterial Effect and Mode of Action of Secondary Metabolites from Fungal Endophyte Associated with Aloe ferox Mill

“…The fragments were rinsed five times in autoclaved distilled water and dried under a laminar airflow chamber. Thereafter, the gel was extracted aseptically using a sterile knife into a sterile beaker and ground by a sterile mortar [18].…”

Production and Functionalities of Specialized Metabolites from Different Organic Sources

“…In an attempt to identify endophytic bacteria and their biological compounds, 13 isolates from the leaves of Anredera cordifolia were examined [51]. These isolates, which belong to Pseudomonas sp., particularly Pseudomonas aeruginosa, produced specialized metabolites that expressed effectiveness against bacteria and showed antioxidant activities.…”

“…has been identified as a major endophytic bacteria frequently isolated from medicinal plants [52][53][54]. The biological compounds produced by P. aeruginosa, as identified by Nxumalo and colleagues, included xanthoxylin, trans-2-decenoic acid, [1,2,4] oxadiazole, 5-benzyl-(thiophen-2-yl), dodecenoic acid, 3-nonynoic, pyrrolo [1,2-a] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl), pentadecanoic acid, and diisooctyl phthalate, which are recognized for antimicrobial activity while cis-9-Octadecenoic acid, 2-dodecenoic acid and 9-octadecenamide possess antioxidant properties [51]. Other bacteria species that have been identified as contributing to specialized metabolites in plants are Bacillus amyloliquefaciens [55] and Bacillus cereus [56] (Table 1).…”

Applications of bacterial endophytes and their advanced identification methodologies

“…Freshly collected leaves were washed under slow running tap water for 10-15 minutes followed by washing in Tween 20 for 1 minute and rinsed with sterile distilled water for 3 times in the laminar airflow cabinet. Sterilizing agents like Sodium hypochlorite: 1%-2% for 4-10 minutes [17], ethanol: 70% for 30 seconds-4 minutes [18], hydrogen peroxide [15] and mercuric chloride 0.05%-0.2% for 2-5 minutes are commonly followed for sterilization [19,20]. The validation of the above said sterilization procedure was carried out by imprinting the plant tissue onto nutrient media and fumigationbased process prevents microbial contamination [21,22].…”