Amelioration of oxidative stress induced by oxidative mutagens and COX-2 inhibitory activity of umbelliferone isolated from Glycyrrhiza glabra L.

Abstract: Objective: To evaluate antigenotoxic, antioxidant and COX-2 inhibitory potential of ‘GG-1’ fraction isolated by Medium Pressure Liquid Chromatography (MPLC) from ethyl acetate extract of Glycyrrhiza glabra (G. glabra) L rhizomes. Methods: The antigenotoxic activity was tested in human blood lymphocytes using comet assay and SOS chromotest using PQ37 strain of Escherichia coli (E. coli) against the diagnostic mutagens viz. 4-NQO and H₂O₂. Antioxidant activity was determined by DPPH radical scavenging assay. It was also investigated for the COX-2 inhibitory activity using Cayman COX (ovine) inhibitory screening assay. Results: The spectroscopic data of ‘GG-1’ fraction revealed it to be 7-hydroxycoumarin (Umbelliferone). In SOS chromotest, at the concentration of 616.75 μM, umbelliferone exhibited moderate response by reducing the induction factor of hydrogen peroxide by 68.99% (IC₅₀ 223.44 μM) and that of 4NQO by 59.71% (IC₅₀ 280.74 μM). In comet assay, exhibited a good activity by inhibiting the genotoxicity of both hydrogen peroxide and 4NQO by 61.64% (IC₅₀ 330.02 μM) and 50.66% (IC₅₀ 577.83 μM) respectively. The umbelliferone exhibited free radical scavenging potential of 43.88% at 616.75 μM. Umbelliferone possessed 95.68% inhibition of COX-2 at 10 μM concentration with IC₅₀<1. Conclusions: The antigenotoxic, antioxidant and COX-2 inhibitory properties showed by the umbelliferone suggests that it may have several applications in nutraceuticals and human health care. [Copyright &y& Elsevier]