Glycyrrhiza glabra or licorice has long been known as a commonly used Ayurvedic herb. This study aims to investigate the effect of extraction methods on the chemical composition and biologically active properties of Glycyrrhiza glabra extract samples. The highest yield of the Glycyrrhiza glabra extract (21.31 ± 0.64 wt.%) was produced using the Soxhlet extraction method with methanol. The highest concentrations of biologically active substances (3,4-dihydroxybenzoic acid, n-coumaric acid, luteolin-7-glucoside, acacetin, apigenin-7-O-glucoside, chicoric acid, and hesperetin) were found in these samples of Glycyrrhiza glabra extracts. When applying the maceration method using a mixture of solvents methanol-NaOH, rosmarinic acid was identified, and catechin was found in large quantities with a mixture of methanol-trifluoroacetic acid (TFA). Growth inhibition zones were determined for Escherichia coli (13.6 ± 0.41 mm), Pseudomonas aeruginosa (10.8 ± 0.32 mm), Bacillus subtilis (16.1 ± 0.48 mm), and Candida albicans (13.2 ± 0.39 mm) when exposed to samples of Glycyrrhiza glabra extracts obtained by the Soxhlet method with methanol. The antioxidant activity of Glycyrrhiza glabra extract samples obtained by the Soxhlet method was 117.62 ± 7.91 µmol Trolox equivalent/g, using the ABTS method (highest value), and 23.91 ± 1.12 µmol Trolox equivalent/g according to the FRAP method (smallest). The antioxidant activity of the extract samples according to the DPPH method was an intermediate value of 58.16 ± 3.90 µmol Trolox equivalent/g. Antibacterial and antioxidant activities are manifested by the polyphenolic compounds and flavonoids contained in the samples of the methanol extract of Glycyrrhiza glabra produced using the Soxhlet method. These Glycyrrhiza glabra extract samples have the potential to become a natural alternative to existing therapies for the elimination of bacterial infections or the prevention of premature aging caused by free radicals and oxidative stress in the human body.
Keywords: Glycyrrhiza glabra; Soxhlet methanol extraction; antibacterial; antioxidant activity; biologically active substances; chemical composition.