Chemical composition, antioxidant and alpha-Glucosidase-Inhibiting activities of the aqueous and hydroethanolic extracts of Vaccinium myrtillus Leaves

Vaccinium myrtillus (bilberry) leaf is traditionally used in southeastern Europe for the treatment of diabetes. In the present study, the ability of bilberry leaf extracts to inhibit carbohydrate-hydrolyzing enzymes and restore glutathione concentration in Hep G2 cells subjected to glucose-induced oxidative stress was investigated. A comprehensive analysis of the antioxidant activity of two bilberry leaf extracts was performed. The aqueous extract showed excellent total antioxidant and chelating activity. Its antioxidant activity in the beta-carotene-linoleic acid assay was very good, reaching the activity of the antioxidant standard BHA (93.4 +/- 2.3% vs. 95.1 +/- 2.4%, respectively). The hydroethanolic extract (ethanol/H2O, 8:2, v/v), on the other hand, was a better radical scavenger and Fe2+ reducing agent. Furthermore, the aqueous extract was able to efficiently increase glutathione concentration in Hep G2 cells subjected to glucose-induced oxidative stress and restore it to the levels observed in non-hyperglycaemic cells. The hydroethanolic extract strongly inhibited alpha-glucosidase, with the IC50 statistically equal to the antidiabetic drug acarbose (0.29 +/- 0.02 mg/mL vs. 0.50 +/- 0.01 mg/mL, respectively). Phytochemical analysis revealed the presence of quercetin and kaemferol derivatives, as well as chlorogenic and p-coumaric acid. The study results indicate that V. myrtillus leaf may have promising properties as a supporting therapy for diabetes.University of Zagrebinfo:eu-repo/semantics/publishedVersio

Paraoksonaza/arilesteraza u serumu ispitanika s dijabetesom tipa II

The aim of this study was to determine whether the paraoxonase (PON1) status, i.e. PON1 activities and phenotypes (AA, AB and BB), and its relationship with lipid status are different in patients with type II diabetes as compared to healthy population. Diabetic group comprised 175 patients with type II diabetes mellitus (94 men and 81 women) who came to their regular control examination and took the oral glucose tolerance test. Patients with type II diabetes mellitus diagnosis for 12 years on average were on peroral antidiabetics, or insulin or diet, and 3 patients had no therapy prescribed yet. Control group comprised 114 apparently healthy individuals (28 men and 86 women) who were not on any medication. The paraoxonase activity was measured with 2.0 mmol L-1 paraoxon in the absence and in the presence of 1.0 mol L-1 NaCl, and with 2.0 mmol L-1 phenylacetate. Both activities were measured spectrophotometrically at 37 oC in 0.1 mol L-1 Tris-HCl buffer, pH = 8.0, containing 2.0 mmol L-1 CaCl2. Sera of diabetic and control subjects were assigned to the paraoxonase phenotypes on the basis of the basal paraoxonase activity distribution. We assigned 45% sera of male and 49% sera of female diabetic patients, and 64% sera of both genders of the control group to the AA low activity phenotype. There were no differences in paraoxonase activities between the gender- and phenotype-matched diabetic and control groups. Enzyme activity against the phenylacetate was higher and phenotype-dependent only in diabetic patients. In contrast to AA phenotype individuals, total cholesterol and LDL-cholesterol in the female diabetic group and triglyceride concentration in the male diabetic group assigned to pooled AB and BB phenotypes were higher than in the corresponding controls. It follows from PON1 phenotype distribution that less antiatherogenic paraoxonase B allele is more frequent in type II diabetes mellitus than in the healthy population. Their lipid status is more atherogenic, which could indicate a risk of premature atherosclerosis.Cilj rada je usporediti katalitičku aktivnost paraoksonaze (PON1) te učestalost fenotipova AA, AB i BB paraoksonaze i njihovu povezanost s lipidnim statusom u serumu ispitanika s dijabetesom tipa II i kontrolnoj skupini. U skupini ispitanika s dijabetesom tipa II bilo je 175 osoba (81 žena i 94 muškaraca), s prosječnim trajanjem bolesti od 12 godina, koji su bili na peroralnoj terapiji antidijabeticima ili inzulinom ili na dijeti, dok trojici pacijenata još nije predložena terapija. Aktivnost paraoksonaze mjerena je s paraoksonom (O,O-dietil-O-p-nitrofenilfosfat). Koncentracije reagensa u reakcijskoj smjesi za određivanje bazalne aktivnosti paraoksonaze bile su: 2.0 mmol L-1 paraokson i 2.0 mmol L-1 CaCl2 u 0.1 mol L-1 Tris-HCl puferu, pH=8.0. Reakcijska smjesa za određivanje NaCl-stimulirane aktivnosti paraoksonaze sadržavala je još 1.0 mol L-1 NaCl. Arilesterazna aktivnost enzima mjerena je s fenilacetatom. Reakcijska smjesa je sadržavala 2.0 mmol L-1 fenilacetata i 2.0 mmol L-1 CaCl2 u 0.1 mol L-1 Tris-HCl puferu, pH=8.0. Broj ispitanika s AA fenotipom odnosno skupno AB i BB fenotipom paraoksonaze određen je iz raspodjelne krivulje bazalnih aktivnosti (bez prisutnosti 1.0 mol L-1 NaCl) paraoksonaze u serumu. U serumima 45% žena i 49% muškaraca skupine ispitanika s dijabetesom tipa II te u 64% seruma oba spola u skupini zdravih ispitanika potvrđen je AA homozigotni fenotip paraoksonaze. Katalitičke aktivnosti enzima prema paraoksonu nisu se značajno razlikovale ovisno o spolu i fenotipu izmedu dijabetične i kontrolne skupine, dok su aktivnosti enzima prema fenilacetatu bile veće i ovisne o fenotipu samo u dijabetičnoj skupini ispitanika. Značajno veće koncentracije ukupnog kolesterola i LDL-kolesterola izmjerene su u serumima žena te veće koncentracije triglicerida u serumima muškaraca s dijabetesom tipa II koji su razvrstani u zajedničku skupinu AB+BB fenotipova što bi ukazivalo da su AB i BB fenotipovi uglavnom povezani s lipidnim statusom većeg rizika za razvoj ateroskleroze u ispitanika s dijabetesom tipa II

Paraoksonaza/arilesteraza u serumu ispitanika s dijabetesom tipa II

The aim of this study was to determine whether the paraoxonase (PON1) status, i.e. PON1 activities and phenotypes (AA, AB and BB), and its relationship with lipid status are different in patients with type II diabetes as compared to healthy population. Diabetic group comprised 175 patients with type II diabetes mellitus (94 men and 81 women) who came to their regular control examination and took the oral glucose tolerance test. Patients with type II diabetes mellitus diagnosis for 12 years on average were on peroral antidiabetics, or insulin or diet, and 3 patients had no therapy prescribed yet. Control group comprised 114 apparently healthy individuals (28 men and 86 women) who were not on any medication. The paraoxonase activity was measured with 2.0 mmol L-1 paraoxon in the absence and in the presence of 1.0 mol L-1 NaCl, and with 2.0 mmol L-1 phenylacetate. Both activities were measured spectrophotometrically at 37 oC in 0.1 mol L-1 Tris-HCl buffer, pH = 8.0, containing 2.0 mmol L-1 CaCl2. Sera of diabetic and control subjects were assigned to the paraoxonase phenotypes on the basis of the basal paraoxonase activity distribution. We assigned 45% sera of male and 49% sera of female diabetic patients, and 64% sera of both genders of the control group to the AA low activity phenotype. There were no differences in paraoxonase activities between the gender- and phenotype-matched diabetic and control groups. Enzyme activity against the phenylacetate was higher and phenotype-dependent only in diabetic patients. In contrast to AA phenotype individuals, total cholesterol and LDL-cholesterol in the female diabetic group and triglyceride concentration in the male diabetic group assigned to pooled AB and BB phenotypes were higher than in the corresponding controls. It follows from PON1 phenotype distribution that less antiatherogenic paraoxonase B allele is more frequent in type II diabetes mellitus than in the healthy population. Their lipid status is more atherogenic, which could indicate a risk of premature atherosclerosis.Cilj rada je usporediti katalitičku aktivnost paraoksonaze (PON1) te učestalost fenotipova AA, AB i BB paraoksonaze i njihovu povezanost s lipidnim statusom u serumu ispitanika s dijabetesom tipa II i kontrolnoj skupini. U skupini ispitanika s dijabetesom tipa II bilo je 175 osoba (81 žena i 94 muškaraca), s prosječnim trajanjem bolesti od 12 godina, koji su bili na peroralnoj terapiji antidijabeticima ili inzulinom ili na dijeti, dok trojici pacijenata još nije predložena terapija. Aktivnost paraoksonaze mjerena je s paraoksonom (O,O-dietil-O-p-nitrofenilfosfat). Koncentracije reagensa u reakcijskoj smjesi za određivanje bazalne aktivnosti paraoksonaze bile su: 2.0 mmol L-1 paraokson i 2.0 mmol L-1 CaCl2 u 0.1 mol L-1 Tris-HCl puferu, pH=8.0. Reakcijska smjesa za određivanje NaCl-stimulirane aktivnosti paraoksonaze sadržavala je još 1.0 mol L-1 NaCl. Arilesterazna aktivnost enzima mjerena je s fenilacetatom. Reakcijska smjesa je sadržavala 2.0 mmol L-1 fenilacetata i 2.0 mmol L-1 CaCl2 u 0.1 mol L-1 Tris-HCl puferu, pH=8.0. Broj ispitanika s AA fenotipom odnosno skupno AB i BB fenotipom paraoksonaze određen je iz raspodjelne krivulje bazalnih aktivnosti (bez prisutnosti 1.0 mol L-1 NaCl) paraoksonaze u serumu. U serumima 45% žena i 49% muškaraca skupine ispitanika s dijabetesom tipa II te u 64% seruma oba spola u skupini zdravih ispitanika potvrđen je AA homozigotni fenotip paraoksonaze. Katalitičke aktivnosti enzima prema paraoksonu nisu se značajno razlikovale ovisno o spolu i fenotipu izmedu dijabetične i kontrolne skupine, dok su aktivnosti enzima prema fenilacetatu bile veće i ovisne o fenotipu samo u dijabetičnoj skupini ispitanika. Značajno veće koncentracije ukupnog kolesterola i LDL-kolesterola izmjerene su u serumima žena te veće koncentracije triglicerida u serumima muškaraca s dijabetesom tipa II koji su razvrstani u zajedničku skupinu AB+BB fenotipova što bi ukazivalo da su AB i BB fenotipovi uglavnom povezani s lipidnim statusom većeg rizika za razvoj ateroskleroze u ispitanika s dijabetesom tipa II

Effect of Betula pendula leaf extract on alpha-glucosidase and glutathione level in glucose-induced oxidative stress

B. pendula leaf is a common ingredient in traditional herbal combinations for treatment of diabetes in southeastern Europe. Present study investigated B. pendula ethanolic and aqueous extract as inhibitors of carbohydrate hydrolyzing enzymes, as well as their ability to restore glutathione concentration in Hep G2 cells subjected to glucose-induced oxidative stress. Phytochemical analysis revealed presence of rutin and other quercetin derivatives, as well as chlorogenic acid. In general, ethanolic extract was richer in phenolic substances than the aqueous extract. Furthermore, a comprehensive analysis of antioxidant activity of two extracts (determined by DPPH and ABTS radical scavenging activity, total antioxidant activity, and chelating activity as well as ferric-reducing antioxidant power) has shown that ethanolic extract was better radical scavenger and metal ion reductant. In addition, ethanolic extract effectively increased cellular glutathione levels caused by hyperglycemia and inhibited alpha-glucosidase with the activity comparable to that of acarbose. Therefore, in vitro research using B. pendula plant extracts has confirmed their antidiabetic properties

Paraoxonase/arylesterase in serum of patients with type II diabetes mellitus

Cilj rada je usporediti katalitičku aktivnost paraoksonaze (PON1) te učestalost fenotipova AA, AB i BB paraoksonaze i njihovu povezanost s lipidnim statusom u serumu ispitanika s dijabetesom tipa II i kontrolnoj skupini. U skupini ispitanika s dijabetesom tipa II bilo je 175 osoba (81 žena i 94 muškaraca), s prosječnim trajanjem bolesti od 12 godina, koji su bili na peroralnoj terapiji antidijabeticima ili inzulinom ili na dijeti, dok trojici pacijenata još nije predložena terapija. Aktivnost paraoksonaze mjerena je s paraoksonom (O,O-dietil-O-p-nitrofenilfosfat). Koncentracije reagensa u reakcijskoj smjesi za određivanje bazalne aktivnosti paraoksonaze bile su: 2.0 mmol L-1 paraokson i 2.0 mmol L-1 CaCl2 u 0.1 mol L-1 Tris-HCl puferu, pH=8.0. Reakcijska smjesa za određivanje NaCl-stimulirane aktivnosti paraoksonaze sadržavala je još 1.0 mol L-1 NaCl. Arilesterazna aktivnost enzima mjerena je s fenilacetatom. Reakcijska smjesa je sadržavala 2.0 mmol L-1 fenilacetata i 2.0 mmol L-1 CaCl2 u 0.1 mol L-1 Tris-HCl puferu, pH=8.0. Broj ispitanika s AA fenotipom odnosno skupno AB i BB fenotipom paraoksonaze određen je iz raspodjelne krivulje bazalnih aktivnosti (bez prisutnosti 1.0 mol L-1 NaCl) paraoksonaze u serumu. U serumima 45% žena i 49% muškaraca skupine ispitanika s dijabetesom tipa II te u 64% seruma oba spola u skupini zdravih ispitanika potvrđen je AA homozigotni fenotip paraoksonaze. Katalitičke aktivnosti enzima prema paraoksonu nisu se značajno razlikovale ovisno o spolu i fenotipu izmedu dijabetične i kontrolne skupine, dok su aktivnosti enzima prema fenilacetatu bile veće i ovisne o fenotipu samo u dijabetičnoj skupini ispitanika. Značajno veće koncentracije ukupnog kolesterola i LDL-kolesterola izmjerene su u serumima žena te veće koncentracije triglicerida u serumima muškaraca s dijabetesom tipa II koji su razvrstani u zajedničku skupinu AB+BB fenotipova što bi ukazivalo da su AB i BB fenotipovi uglavnom povezani s lipidnim statusom većeg rizika za razvoj ateroskleroze u ispitanika s dijabetesom tipa II.The aim of this study was to determine whether the paraoxonase (PON1) status, i.e. PON1 activities and phenotypes (AA, AB and BB), and its relationship with lipid status are different in patients with type II diabetes as compared to healthy population. Diabetic group comprised 175 patients with type II diabetes mellitus (94 men and 81 women) who came to their regular control examination and took the oral glucose tolerance test. Patients with type II diabetes mellitus diagnosis for 12 years on average were on peroral antidiabetics, or insulin or diet, and 3 patients had no therapy prescribed yet. Control group comprised 114 apparently healthy individuals (28 men and 86 women) who were not on any medication. The paraoxonase activity was measured with 2.0 mmol L-1 paraoxon in the absence and in the presence of 1.0 mol L-1 NaCl, and with 2.0 mmol L-1 phenylacetate. Both activities were measured spectrophotometrically at 37 oC in 0.1 mol L-1 Tris-HCl buffer, pH = 8.0, containing 2.0 mmol L-1 CaCl2. Sera of diabetic and control subjects were assigned to the paraoxonase phenotypes on the basis of the basal paraoxonase activity distribution. We assigned 45% sera of male and 49% sera of female diabetic patients, and 64% sera of both genders of the control group to the AA low activity phenotype. There were no differences in paraoxonase activities between the gender- and phenotype-matched diabetic and control groups. Enzyme activity against the phenylacetate was higher and phenotype-dependent only in diabetic patients. In contrast to AA phenotype individuals, total cholesterol and LDL-cholesterol in the female diabetic group and triglyceride concentration in the male diabetic group assigned to pooled AB and BB phenotypes were higher than in the corresponding controls. It follows from PON1 phenotype distribution that less antiatherogenic paraoxonase B allele is more frequent in type II diabetes mellitus than in the healthy population. Their lipid status is more atherogenic, which could indicate a risk of premature atherosclerosis