Bioactive characterization of ultrasonicated ginger (Zingiber officinale) and licorice (Glycyrrhiza Glabra) freeze dried extracts

Ginger (Zingiber officinale) and Licorice (Glycyrrhiza glabra L.) are one of the most popular spices having a wide range of bioactive compounds that have varied biological and pharmacological properties. The study was aimed to extract polyphenols from Himalayan medicinal herbs ginger and licorice in different solvents using ultra-sonication technique. The extraction efficiency (EE) was determined, and the extracts were characterized for physical properties (particle size, colour values), total phenolics, flavonoids, antioxidant properties, and structural and morphological features. Ultra-sonicated ginger in aqueous phase had the highest EE of polyphenols (15.27%) as compared to other solvents. Similar trend was observed in licorice with EE of 30.52 % in aqueous phase followed by ethanol: water (50: 50), and methanol: water (50:50) with 28.52% and 26.39%, respectively. The preliminary screening showed the presence of tannins, phenolics, flavonoids, saponins and carbohydrates, steroids and alkaloids in all the extracts. The phenolic and flavonoid content of dried ginger was found higher in ethanolic extracts compared to fresh ones as revealed by HPLC. Similarly, for licorice, the ethanolic fractions had the highest polyphenolic content. The representative samples of ginger (ethanol: water 75:25 and ethylacetate: water 75:25) and licorice (ethanol: water 70:30 and methanol: water 50:50) were studied for FESEM and particle size. The results showed the agglomerated extract micro-particles with a diameter of 0.5–10 µm and increased particle size (ginger: 547 and 766 nm), and (licorice: 450 and 566 nm). The findings could be beneficial for the advancement of ginger and licorice processing, for the comprehension of these herbs as a source of natural antioxidants in different food formulations.