A Comparative Study of Polyphenolic Composition and In-vitro Antioxidant Activity of Illicium verum Extracted by Microwave and Soxhlet Extraction Techniques

Abstract:

Star anise (Illicium verum) was extracted with ethanol using microwave - assisted extraction and soxhlet extraction. Total phenolic content of microwave – assisted extract (MSA) and conventional extract of star anise (SSA) reached 271.2 mg/g and 289 mg/g dry weight, respectively, expressed as gallic acid equivalents, which were quantified using Folin–Ciocalteau reagent. Subsequently, total flavonoids content of MSA and SSA extracts were found to be 14.64 mg/g and 13.98 mg/g dry weight, respectively, expressed as catechin equivalents (P < 0.05). Antioxidant properties of two extracts were investigated employing various established systems in vitro including 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, ABTS assay, total antioxidant activity, hydroxyl radical assay, nitric oxide radical scavenging and total reducing power. MSA and SSA showed excellent antioxidant in all test systems compared to standard ascorbic acid and the antioxidant activities of MSA were all superior to those of SSA. The results obtained in this study clearly indicate that star anise has a significant potential to use as a natural anti-oxidant agent.

Keywords: Illicium verum; microwave assisted extract; antioxidant activity; total flavonoids content; total phenolic content.