Chemical characterization and biological activity of Curvularia Lunata, an endophytic fungus isolated from lemongrass (Cymbopogon citratus)

Abstract

Exploration of medicinal plants for bioactive-producing endophytic fungi is a relatively unmapped source of pharmaceutically important compounds. In this study, the endophytic fungus Curvularia lunata AREF029 isolated from the medicinal plant Cymbopogon citratus (known as lemongrass) was assessed for its biological activity. The methanolic extract of AREF029 had minimum inhibition concentration (MIC) ranging from 38 to 174 µg/ml against phytopathogenic fungi Alteranria solani, Fusarium oxysporum and Rhizoctonia solani. Furthermore, the AREF029 methanolic extract displayed a broad-spectrum MIC of 25 µg/ml in the case of Staphylococcus aureus, Salmonella typhimurium and MRSA (methicillin-resistant S. aureus). In vitro cytotoxicity analysis with murine macrophage cell line RAW 264.7 determined 56% nitric oxide inhibition activity at 200 µg/ml concentration of the extract and more than 99% cell viability. Gas chromatography-mass spectrometry (GC-MS) and Liquid chromatography-high resolution mass spectrometry (LC-HRMS) analyses showed the presence of methoxy-5-methyl-4-oxo-2,5-hexadienoic acid (penicillic acid), phthalic acid, bis (7-methyloctyl) ester, 8-hydroxyquinoline, tetroquinone, curvulamine, Curvuleremophilane B/D, Chromonilinc acid A/C and other putative bioactive compounds in the extract. The current investigation supports the significance of the endophytic fungus C. lunata as a source of potent antibacterial, antifungal and anti-inflammatory compounds.

Keywords: Curvularia lunata; Antibacterial; Antifungal; Bioactives; Endophytes.

Fig. 1

Total ion chromatogram (TIC) of AREF029