Antioxidant compounds extracted from Diaporthe schini using supercritical CO₂ plus cosolvent

Area of Science:

• Biotechnology
• Natural Product Chemistry
• Mycology

Background:

• Endophytic fungi are prolific sources of secondary metabolites with diverse bioactivities.
• Antioxidant compounds are crucial for combating oxidative stress and related diseases.
• Diaporthe schini is an endophytic fungus with potential for bioactive compound production.

Purpose of the Study:

• To extract antioxidant compounds from Diaporthe schini biomass.
• To optimize supercritical carbon dioxide (CO2) extraction parameters using ethanol as a cosolvent.
• To evaluate the extraction yield, antioxidant activity, and chemical composition of the extracts.

Main Methods:

• Biomass of Diaporthe schini was produced via submerged fermentation.
• Supercritical carbon dioxide (CO2) extraction was performed with and without ethanol cosolvent.
• Extraction parameters varied: pressure (150-250 bar), temperature (40-60 °C), and cosolvent ratio (1:0, 1:0.75, 1:1.5 w/v).
• Extraction yield, antioxidant activity (DPPH assay), and chemical composition (GC/MS) were analyzed.

Main Results:

• The highest extraction yield (3.24 wt.%) was achieved at 40 °C, 250 bar, and a 1:1.5 (w/v) biomass:cosolvent ratio.
• Maximum antioxidant activity (96.62% DPPH radical scavenging) was obtained under the same optimal conditions.
• GC/MS analysis identified 1,4-diaza-2,5-dioxo-3-isobutyl bicyclo[4.3.0]nonane and benzeneethanol as potential antioxidant contributors.

Conclusions:

• Supercritical CO2 extraction with ethanol is effective for isolating antioxidant compounds from Diaporthe schini.
• Optimized extraction conditions significantly enhance both yield and antioxidant potency.
• Identified compounds suggest a basis for the observed antioxidant properties, warranting further investigation.