In vitro antioxidant activity and effect of ethanolic extract of Curcuma leucorhhiza Roxb. on in vivo antioxidant status of diabetic rats

Hypoglycemic effect of Curcuma leucorhiza extract in diabetic rats

Abstract

Medicinal plants possess secondary metabolites such as flavonoids, phenolic acids, and tannins, which exhibit significant antioxidant activity by scavenging free radicals. Curcuma leucorrhiza Roxb. is a medicinal plant known for its antiseptic, anti-inflammatory and antioxidant properties. This study evaluates the in vitro antioxidant potential of its rhizome extracts and assesses the effect of its ethanolic extract on in vivo antioxidant status in streptozotocin (STZ) induced diabetic rats. Extracts prepared using chloroform, ethanol, methanol, petroleum ether, aqueous and 50% ethanol were tested via DPPH radical scavenging, FRAP and total phenolic content (TPC) assays. The methanol extract exhibited the highest activity, followed by ethanol. For in vivo studies, 30 male Wistar rats were divided into five groups (n=6) viz. normal control (Group-I), diabetic untreated (Group-II), metformin treated (5 mg/kg bw, Group-III) and ethanolic extract (absolute) treated (100 and 200 mg/kg bw, Groups IV and V). Treatment with 200 mg/kg ethanolic extract significantly restored antioxidant markers in diabetic rats, comparable to metformin treatment, reducing malondialdehyde (P<0.01) and increasing catalase (P<0.05), superoxide dismutase (P<0.01) and glutathione peroxidase (P<0.05) levels. These findings support the ethnomedicinal use of Curcuma leucorrhiza Roxb. and indicate its potential as a natural antioxidant therapy for diabetes associated oxidative stress. Further research is warranted to isolate active compounds, DNA sequence based molecular characterization and evaluate long-term efficacy.