Biological activities and GC–MS based chemical profiling of polymolecular methanol extract of Alternaria alternata KUDB15

Abstract

Objectives: The ecological niche of soil for microorganisms that produce beneficial naturally occurring and biologically active products suitable for pharmaceutical industries is widely recognized. The purpose of the current study is to isolate fungus from soil samples of Dandeli, Karnataka and its metabolic profiling and investigating biological activities. Methods: Soil fungal isolates were screened for their antimicrobial potency against pathogens. The selected fungal isolate was morphologically characterized and ascertained by 18S rRNA gene sequencing, and the extract was investigated by gas chromatography-mass spectrometry (GC–MS) to identify the bio-molecules. Later the fungal extract was evaluated for antioxidant, antimicrobial, anti-mycobacterial and anti-proliferative activity against Human acute leukemia (K562) cell line. Results: The potential fungal isolate, Alternaria sp. KUDB15 showed a number of bioactive compounds through GC–MS analysis. A significant antioxidant activity (IC50 = 37.60 µg/ml) was also reported for this organism. A significant inhibitory activity against tested pathogens was shown by Alternaria sp. KUDB15 along with a strong anti-mycobacterial activity with an IC50 value of 3.12 μg/ml. During anticancer assay, this organism showed a concentration dependent reduction in cell viability having IC50 of 112.09 µg/ml. Further purification of the crude extract with column chromatography and thin layer chromatography (TLC) recorded several bands and the particular band having antibacterial activity was determined by bioautography. Conclusions: In the present research, the in vitro evaluation of biological activities of the fungal extract suggested that it might serve as a useful foundation for the discovery of compounds that have potential for medical applications. Additional research is required to identify and understand the structure of bio-molecules.

Keywords

• Alternaria alternata
• 18S rRNA gene sequencing
• Anti-mycobacterial
• GC–MS
• Bioautography
• Anti-proliferative