Effects of Extraction Media and Techniques on the Antioxidant Properties and Recovery of Phenolics from Roots of Glycyrrhiza Glabra

Objective: Medicinal herbs have been widely explored due to their ability to scavenge free radicals and protect from the reactive oxygen species those are involved in several kinds of degenerative diseases. Glycyrrhiza glabra is a perennial herb, its extensive soft and fibrous root system is good source of nutrients and antioxidants applicable in different types of diseases and wide range of pharmacological activities including expectorant, antitussive, emollient, anti-inflammatory, antipyretic activities. This study aimed to determine the best combination of extraction media and techniques for the extraction of phenolic compounds from its roots for best utilization in medicinal applications. Methods: The extractions were carried out in methanol, chloroform and ether by using soxhlet, ambient and orbital shaker extraction techniques. The antioxidant activity of these extracts was also evaluated by determining crucial parameters, such as total phenolic contents, total flavonoid contents, DPPH radical scavenging activity and estimation of antioxidant activity in linoliec acid system. Results: We have found that all extraction techniques exhibited a wide range of total phenolic, 9.689 ± 1.015 to 56.7 ± 5.935 mg/g of gallic acid equivalents and total flavonoid content, 9.6153 ± 0.985 to 53.77 ± 4.29 mg/g of quercitin equivalents. In addition, these extraction techniques also inhibited oxidation of linoleic acid by 45.113 ± 2.567 % to 88.516 ± 2.188 % , while DPPH radical scavenging activity in the range of to 7.706 ± 0.258 % to 92.627 ± 3.0 %. Moreover, soxhlet extraction technique showed the highest recovery of TPC and maximum AA content, while orbital shaker extraction technique showed the highest DPPH scavenging activity. The extraction efficiency of antioxidant compounds was highest in methanol. Conclusions: Analysis of the TPC, TFC and free radical scavenging activity of Glycyrrhiza glabra extracts showed differences depending on extraction method and solvent used. Among the tested parameters, more polar solvent with soxhlet extraction is recommended for the extraction of antioxidants from roots of Glycyrrhiza glabra.