Antihepatotoxic, nephroprotective, and antioxidant activities of phenolic compounds from Satureja macrostema leaves against carbon tetrachloride-induced hepatic damage in mice

Satureja macrostema (SM) is used with culinary and medicinal purposes. Methanol extract from SM was investigated for its phenolic content, antioxidant, hepatoprotective, and kidney protective activities. Liver and kidney damage were induced in rats with CCl₄. Hepatoprotective efficacy was measured by the activity of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total bilirubin, cholesterol, high density lipoprotein and total protein, and lipid peroxidation. Kidney function was evaluated by measuring plasma urea and creatinine. Antioxidant activity was evaluated by measuring blood glutathione content, superoxide dismutase and catalase activities, and malondialdehyde equivalent; their activity was comparable to that of silymarin, a well-known hepatoprotective agent. Methanol extracts of S. macrostema showed potent antioxidant, kidney protective, and hepatoprotective activities; in-depth chromatographic investigation resulted in the identification of six new flavonoid glycosides: 5-hydroxy-3,6,4′-trimethoxyflavonol-7-C-α-l-rhamnopyranosyl-(1 → 3)-β-d-glucopyranoside (2), 4′-methoxy-5,7,3′,5′-tetra-hydroxyflavanone-3-O-β-d-rhamnopyranosyl-(1 → 2)-β-d-rhamnopyranoside (3), 5,4′-dimethoxy-7,3′,5′-trihydroxyflavanone-3-O-β-d-rhamnopyranoside (4), 5,3′,4′,5′-tetrahydroxyflavanone-7-O-β-d-rhamnopyranoside (5), 5,3′,4′,5′-tetramethoxyflavanone-7-O-β-d-rhamnopyranoside (6), and 5,4′-dimethoxy-3′-hydroxyflavone-7-β-d-rhamnopyranoside (8) along with three known compounds: 5-hydroxy-7,4′-dimethoxyflavone (1), prunin (7), and diosmin (9) that were isolated. Structural elucidation of the new compounds was established based on the spectral data. The present study revealed that S. macrostema leaves have a significant radical scavenging and hepatoprotective activity.