Improving phenolic antioxidants in Illicium griffithii fruit through optimizing subcritical water extraction method

Area of Science:

• Phytochemistry and Natural Product Extraction
• Green Chemistry and Sustainable Processes
• Pharmacognosy and Ethnomedicine

Background:

• Illicium griffithii, a plant from Northeast India, is recognized for its medicinal and aromatic properties.
• The fruit of Illicium griffithii is traditionally used in ethnomedicine and possesses significant economic value.
• Phenolic antioxidants are crucial bioactive compounds with potential health benefits.

Purpose of the Study:

• To optimize subcritical water extraction (SWE) conditions for maximizing phenolic antioxidant recovery from Illicium griffithii fruit.
• To evaluate the impact of temperature, pressure, and time on extraction yield and antioxidant activity.
• To characterize the phenolic profile and identify major antioxidant compounds.

Main Methods:

• Box-Behnken Design (BBD) was employed to systematically study the effects of temperature (100-220°C), pressure (30-90 bar), and time (10-50 min).
• Quantification of total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity using DPPH and ABTS assays.
• High-performance liquid chromatography (HPLC) was used for phenolic profiling, and ATR-FTIR spectroscopy confirmed compound presence.

Main Results:

• Optimal extraction conditions were determined as 161.32°C, 45 bar, and 30 min, yielding TPC of 30.91 mg GAE/g dw and TFC of 2.07 mg QE/g dw.
• Antioxidant scavenging activities correlated with phytochemical content, with DPPH at 23.27 µg AAE/g dw and ABTS at 17.82 µg AAE/g dw under optimal conditions.
• Gallic acid (9.77 mg/g), catechin (8.84 mg/g), and p-hydroxybenzoic acid (4.06 mg/g) were identified as predominant phenolic compounds.

Conclusions:

• Subcritical water extraction is a highly effective method for recovering phenolic antioxidants from Illicium griffithii fruit, offering higher yield and bioactivity compared to other methods.
• Temperature was identified as the most significant parameter influencing phenolic antioxidant recovery.
• The study demonstrates the potential of Illicium griffithii fruit as a source of valuable phenolic compounds for various applications.