A novel antibacterial and antifungal phenolic compound from the endophytic fungusPestalotiopsis mangiferae

Abstract

A novel phenolic compound, 4-(2,4,7-trioxa-bicyclo[4.1.0]heptan-3-yl) phenol (1), was isolated from Pestalotiopsis mangiferae, an endophytic fungus associated with Mangifera indica Linn. The structure of the compound was elucidated on the basis of comprehensive spectral analysis (UV, IR, ¹H-, ¹³C- and 2D-NMR, as well as HRESI-MS). Compound (1) shows potent antibacterial and antifungal activity against Bacillus subtilis, Klebsiella pneumoniae, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa and Candida albicans. The transmission electron microscope study for the mode of inhibition of compound (1) on bacterial pathogens revealed the destruction of bacterial cells by cytoplasm agglutination with the formation of pores in cell wall membranes.

Exploitation of endophytic fungus, Guignardia mangiferae for extracellular synthesis of silver nanoparticles and their in vitro biological activities

“…13 Based on the particle stability and antibacterial activity, pH 7 was found to be optimum. At pH 7, 14 silver nanoparticles exhibited remarkable antibacterial activity against P. mirabilis, 15 K. pneumoniae, P. aeruginosa and S. aureus with a clear inhibition zone of 16 mm at the 16 concentration of 1 mg/ mL. Whereas moderate activity (13 mm) was observed for E. coli, 17 S. epidermidis and B. subtilis whilst the ZOI was found to be as low as 6 mm against E. faecalis.…”

“…However, there has only a limited data exist for the cytotoxic effects of 20 A microorganism, which usually tends to live whole or part of its life cycle colonizing either 21 inter-or intra cellularly inside the living tissues of the host plant and causing no apparent disease 22 symptoms, is called endophyte (Tan and Zou, 2001). The fungal endophytes have often 23 considered as an exceptionally interesting source of novel bioactive secondary metabolites 24 having impressive biological activities (Kamalraj and Muthumary, 2012; Subban et al, 2013). 25 To the best of our knowledge, only a few endophytic fungi have been reported to synthesize 14 The collected leaf samples were washed thoroughly with running tap water.…”

“…The fungal endophytes have often 23 considered as an exceptionally interesting source of novel bioactive secondary metabolites 24 having impressive biological activities (Kamalraj and Muthumary, 2012; Subban et al, 2013). 25 To the best of our knowledge, only a few endophytic fungi have been reported to synthesize 14 The collected leaf samples were washed thoroughly with running tap water. The leaves were 15 then cut into small segments (5×5 mm) aseptically and isolation of endophytic fungi was carried 16 out using a modified procedure described by Kamalraj and Muthumary (2012) and Schulz et al…”

“…The part of ribosomal RNA straddling the 3' end of the 18S rDNA, the 13 internal transcriber spacer, the 5.8S rDNA and a part of the 5' end of 28S rDNA was amplified. 14 The purified PCR products were sequenced using ABI 3730xl Genetic Analyzer by BigDye 15 terminator method (Applied Biosystems, USA). The 18S rDNA sequence of fungus under study 16 was aligned with reference sequences showing sequence homology from the NCBI database 17 using multiple sequence alignment programme.…”

“…After treatment, the cells were incubated for 24 h and washed with phosphate 12 buffered saline (PBS, pH 7.4). Following this, 10 µL of MTT (5 mg/ mL) was added and the 13 plates were incubated for another 4 h (at 37 °C) and then 100 µL of dimethyl sulfoxide (DMSO) 14 was added. Optical density of the formazan product was read at 495 nm using scanning multi 15 well spectrophotometer.…”