In vitro antioxidant and alpha-glucosidase inhibitory activities of coriander (Coriandrum sativum L.) root extracts

Abstract

Background: Coriander (Coriandrum sativum L.) is a versatile culinary herb known for its edible leaves, seeds, stems, and roots. It is widely utilized in traditional medicine across the globe and is reputed for its diverse biological properties, including significant antioxidant and antidiabetic effects. Nonetheless, the majority of research has primarily concentrated on the seeds, leaves, and stems, leaving the roots comparatively underexplored. Objective: This research delved into the antioxidative capabilities and alpha-glucosidase inhibitory properties of coriander root extracts and assessed their phytochemical makeup.  Methods: The coriander roots were lyophilized, pulverized to powder, and extracted using two methods:  boiling and maceration with water, 50% ethanol, or 100% ethanol. The extracts underwent assessment for antioxidant activity through ABTS and DPPH radical scavenging methods, total phenolic and flavonoid concentrations, and inhibition of the alpha-glucosidase enzyme. In addition, their phytochemical profiles were identified and quantified by HPLC.  Results: Among all the extracts, the 100% ethanol extract demonstrated the greatest levels of total flavonoids and phenolics, exhibited the strongest antioxidant activity against ABTS and DPPH radicals, and showed the most potent alpha-glucosidase inhibition. Notably, the boiling extract, although containing the lowest total phenolic and flavonoid contents, exhibited ABTS radical scavenging capacity comparable to the 100% ethanol extract. This suggested that the boiling extract might contain non-phenolic antioxidant compounds and should be further studied. Additionally, HPLC analysis unveiled the novel identification of benzoic acid and ferulic acid within the coriander root extracts for the first time. The highest contents of these compounds were also found in the 100% ethanol extract.   Conclusion: Coriander roots, a common culinary ingredient, exhibited antioxidant and alpha-glucosidase inhibitory activities, suggesting potential as a functional food for preventing age- and lifestyle-related diseases, such as diabetes and certain cancers. Keywords: Coriander roots, Antioxidants, Antidiabetics, Benzoic acid, Ferulic acid, HPLC analysis