Effect of aroma and magnum hops extracts and paracetamol on antioxidant liver parameters in mice.

Hop varieties that are mainly grown in Serbia are Magnum (German variety) and Aroma, which is grown only in the Vojvodina region. About the use of hops extracts as an auxiliary remedy there are divergent opinions. Our findings indicate that extracts of Magnum and Aroma varieties, among the others, enhance and prolong the analgesic action of paracetamol. For this reason we undertook a study of the effects of these extracts alone and in combination with paracetamol, along with the action of paracetamol alone, on the activity of the antioxidant enzymes GSHPx, CAT, Px, XOD, GSHR, glutathione content, LPx intensity, as well as activities of AST and ALT. Paracetamol in the dose applied exerted no influence on the investigated parameters and neither did ethanolic extract of Magnum variety. On the other hand, ethanolic extract of Aroma hops caused a significant reduction of GSH content. In combination with paracetamol, extracts of both Magnum and Aroma varieties reduced significantly the LPx intensity, activities of CAT and GSHPx, as well as GSH content in the liver homogenate. A significant increase in the AST value with respect to control was also observed. These findings indicate the disturbance in the functioning of hepatocytes, probably by decelarating metabolism and elimination of paracetamol.

Effect of aroma and magnum hops extracts and paracetamol on antioxidant liver parameters in mice.

Hop varieties that are mainly grown in Serbia are Magnum (German variety) and Aroma, which is grown only in the Vojvodina region. About the use of hops extracts as an auxiliary remedy there are divergent opinions. Our findings indicate that extracts of Magnum and Aroma varieties, among the others, enhance and prolong the analgesic action of paracetamol. For this reason we undertook a study of the effects of these extracts alone and in combination with paracetamol, along with the action of paracetamol alone, on the activity of the antioxidant enzymes GSHPx, CAT, Px, XOD, GSHR, glutathione content, LPx intensity, as well as activities of AST and ALT. Paracetamol in the dose applied exerted no influence on the investigated parameters and neither did ethanolic extract of Magnum variety. On the other hand, ethanolic extract of Aroma hops caused a significant reduction of GSH content. In combination with paracetamol, extracts of both Magnum and Aroma varieties reduced significantly the LPx intensity, activities of CAT and GSHPx, as well as GSH content in the liver homogenate. A significant increase in the AST value with respect to control was also observed. These findings indicate the disturbance in the functioning of hepatocytes, probably by decelarating metabolism and elimination of paracetamol.

Interaction of alcoholic extracts of hops with pentobarbital and diazepam in mice.

The interaction of alcoholic extracts of Magnum, Aroma and wild genotype hops with drugs that lower the activity of the central nervous system (CNS) was studied in mice. Hops drying and preparation of extracts were performed according to standard pharmacological procedures for preparing total alcoholic extracts of medicinal plants, i.e. in a ratio of one part dry herbs to two parts of 70% alcohol, with evaporation to dryness so that the extracts no longer contained any alcohol. The mice received four doses intraperitoneally (i.p.) of 0.5% aqueous solutions of the above-mentioned extracts, which were dissolved in warm physiological solution to make up a 0.5% aqueous solution, 24, 16, 4 and 0.5 hours before pentobarbital (40 mg/kg) or diazepam (3 mg/kg) administration. The hypnotic action of pentobarbital and the effect of diazepam on the coordination of movements (rotating rod method) were measured. It was found that hops extracts influenced the action of the investigated drugs, and that the extracts of the Magnum and Aroma genotypes suppressed the hypnotic action of pentobarbital and diazepam. Tert-butanolic extracts also suppressed the action of these two drugs but to a lesser extent, whereas wild hops extracts did not exert any significant effects compared to controls.

Interaction of alcoholic extracts of hops with pentobarbital and diazepam in mice.

The interaction of alcoholic extracts of Magnum, Aroma and wild genotype hops with drugs that lower the activity of the central nervous system (CNS) was studied in mice. Hops drying and preparation of extracts were performed according to standard pharmacological procedures for preparing total alcoholic extracts of medicinal plants, i.e. in a ratio of one part dry herbs to two parts of 70% alcohol, with evaporation to dryness so that the extracts no longer contained any alcohol. The mice received four doses intraperitoneally (i.p.) of 0.5% aqueous solutions of the above-mentioned extracts, which were dissolved in warm physiological solution to make up a 0.5% aqueous solution, 24, 16, 4 and 0.5 hours before pentobarbital (40 mg/kg) or diazepam (3 mg/kg) administration. The hypnotic action of pentobarbital and the effect of diazepam on the coordination of movements (rotating rod method) were measured. It was found that hops extracts influenced the action of the investigated drugs, and that the extracts of the Magnum and Aroma genotypes suppressed the hypnotic action of pentobarbital and diazepam. Tert-butanolic extracts also suppressed the action of these two drugs but to a lesser extent, whereas wild hops extracts did not exert any significant effects compared to controls.

Electrochemical versus spectrophotometric assessment of antioxidant activity of hop (Humulus lupulus L.) products and individual compounds.

Antioxidant (AO) activity of extracts of hop cones (Serbian domestic varieties) and commercial hop products (Saaz, Spalter, Spalter select, and Magnum pellets) was determined by parallel application of recently developed direct current (DC) polarographic and widely used DPPH assay. Correlations between 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging and total phenolics (TPC) determined by the Folin-Ciocalteu assay (FC) (0.99), and between H2O2 scavenging (HPS) and humulone content (H) determined by conductometric method (0.94), total resins (TR) (0.85), and hop storage index (HIS) (-0.90), were found statistically significant at p < 0.05 level while complete lack of HPS correlation with TPC and DPPH was observed. To obtain an insight into differences between results of AO assays applied, activity of individual compounds, prevalent hop phenolics, and bitter acids was determined. By far superior HPS activity of humulone was followed by catechin, quercetin, xanthohumol, lupulone, and rutin. In contrast, DPPH scavenging activity of phenolics (quercetin > catechin > rutin > xantohumol) was found substantially higher than activity of bitter acids. According to ferric reducing antioxidant power (FRAP) and scavenging of 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), higher AO activity was ascribed to phenolics, while almost neglecting humulone. Besides reliability, low cost, and an easy-to-handle procedure, an ability to recognize humulone as the major contributor of hop AO activity could allow DC polarographic assay to be applied in analysis of various hop-derived products.