Biosynthesis of Oligomeric Anthocyanins from Grape Skin Extracts.

We synthesized oligomeric anthocyanins from grape skin-derived monomeric anthocyanins such as anthocyanidin and proanthocyanidin by a fermentation technique using Aspergillus niger, crude enzymes and glucosidase. The biosyntheses of the oligomeric anthocyanins carried out by the conventional method using Aspergillus niger and crude enzymes were confirmed by ESI-MS. The molecular weight of the synthesized anthocyanin oligomers was determined using MALDI-MS. The yield of anthocyanin oligomers using crude enzymes was higher than that of the synthesis using Aspergillus fermentation. Several studies have been demonstrated that oligomeric anthocyanins have higher antioxidant activity than monomeric anthocyanins. Fermentation-based synthesis of oligomeric anthocyanins is an alternative way of producing useful anthocyanins that could support the food industry.

Antioxidant and Anti-Inflammatory Effects of Chaenomeles sinensis Leaf Extracts on LPS-Stimulated RAW 264.7 Cells.

The fruit of Chaenomeles sinensis has been traditionally used in ethnomedicine for the treatment of various human ailments, including pneumonia, bronchitis, and so on, but the pharmacological applications of the leaf part of the plant have not been studied. In this study, we evaluated the various radical scavenging activities and anti-inflammatory effects of different Chaenomeles sinensis leaf (CSL) extracts. The water extract showed a higher antioxidant and radical scavenging activities. However the ethanolic extracts showed higher NO scavenging activity than water extract, therefore the ethanolic extract of CSL was examined for anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The 70% ethanol extract of CSL (CSLE) has higher anti-inflammatory activity and significantly inhibited the production of nitric oxide (NO), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). In addition, CSLE suppressed LPS-stimulated inducible nitric oxide synthase (iNOS) and NO production, IL-1ß and phospho-STAT1 expression. In this study, we investigated the effect of CSLE on the production of inflammatory mediators through the inhibition of the TRIF-dependent pathways. Furthermore, we evaluated the role of CSLE on LPS-induced expression of pro-inflammatory cytokines, such as TNF-α, IL-1ß and IL-6. Our results suggest that CSLE attenuates the LPS-stimulated inflammatory responses in macrophages through regulating the key inflammatory mechanisms, providing scientific support for its traditional uses in treating various inflammatory diseases.

Characterization of the antioxidant fraction of Trapa japonica pericarp and its hepatic protective effects in vitro and in vivo.

The ethanolic extract of Trapa japonica pericarp (TJP) and its various fractions were evaluated for their antioxidant potential. The ethyl acetate fraction (EF) from TJP exhibited significant antioxidant and protective effects against tert-butylhydroperoxide (t-BHP)-induced oxidative damage in vitro and in vivo. In vitro experimental results showed that the EF suppressed t-BHP-induced damage in Chang cells by inhibiting reactive oxygen species generation and regulating the mitochondrial membrane potential. Furthermore, western blot analysis showed that the EF effectively inhibited t-BHP-induced apoptosis by suppressing caspase-3, caspase-7, caspase-8, and caspase-9. In the in vivo study, the EF significantly prevented serum increases in glutamate oxaloacetate transaminase and glutamate pyruvate transaminase and hepatic malondialdehyde levels caused by t-BHP. Furthermore, the EF markedly increased hepatic superoxide dismutase, catalase, and glutathione levels. Histopathological examinations further confirmed that the EF could protect the liver from t-BHP-induced oxidative injury. These findings indicate that the EF could be developed as a therapy or to prevent hepatic injury.

Anticancer Effect of Thymol on AGS Human Gastric Carcinoma Cells.

Numerous plants have been documented to contain phenolic compounds. Thymol is one among these phenolic compounds that possess a repertoire of pharmacological activities, including anti-inflammatory, anticancer, antioxidant, antibacterial, and antimicrobial effects. Despite of the plethora of affects elicited by thymol, its activity profile on gastric cancer cells is not explored. In this study, we discovered that thymol exerts anticancer effects by suppressing cell growth, inducing apoptosis, producing intracellular reactive oxygen species, depolarizing mitochondrial membrane potential, and activating the proapoptotic mitochondrial proteins Bax, cysteine aspartases (caspases), and poly ADP ribose polymerase in human gastric AGS cells. The outcomes of this study displayed that thymol, via an intrinsic mitochondrial pathway, was responsible for inducing apoptosis in gastric AGS cells. Hence, thymol might serve as a tentative agent in the future to treat cancer.

6,6'-Bieckol protects insulinoma cells against high glucose-induced glucotoxicity by reducing oxidative stress and apoptosis.

Pancreatic ß cells are highly sensitive to oxidative stress, which might play an important role in ß cell death in diabetes. The protective effect of 6,6'-bieckol, a phlorotannin polyphenol compound purified from Ecklonia cava, against high glucose-induced glucotoxicity was investigated in rat insulinoma cells. High glucose (30 mM) treatment induced the death of rat insulinoma cells, but treatment with 10 or 50 µg/mL 6,6'-bieckol significantly inhibited the high glucose-induced glucotoxicity. Furthermore, treatment with 6,6'-bieckol dose-dependently reduced the level of thiobarbituric acid reactive substances, generation of intracellular reactive oxygen species, and the level of nitric oxide, all of which were increased by high glucose concentration. In addition, 6,6'-bieckol protected rat insulinoma cells from apoptosis under high-glucose conditions. These effects were associated with increased expression of the anti-apoptotic protein Bcl-2 and reduced expression of the pro-apoptotic protein Bax. These findings indicate that 6,6'-bieckol could be used as a potential nutraceutical agent offering protection against the glucotoxicity caused by hyperglycemia-induced oxidative stress associated with diabetes.

Growth Period Effects on the Protective Properties of Aloe vera Against t-BHP-Induced Oxidative Stress in Chang Cells.

Aloe vera has been used in traditional medicine for the therapy of a variety of disorders, such as wounds and burns. However, few studies have examined the antioxidant capacities of A. vera plants during different growth periods. In order to investigate the effects of growth on antioxidant activity, A. vera was prepared from 2-, 4-, 6-, 8-, and 12-month-old aloe. The extracts from 6-month-old A. vera showed the highest contents of flavonoids (9.750 mg catechin equivalent/g extract) and polyphenols (23.375 mg gallic acid equivalent/g extract) and the highest ferric reducing antioxidant power (0.047 mM ferrous sulfate equivalent/mg extract). The extract from 6-month-old A. vera exhibited the highest free radical scavenging potential, and the lowest IC50 values were found for 2,2-diphenyl-1-picrylhydrazyl (0.26 mg/ml) and alkyl radicals (0.50 mg/ml). In addition, the extract from 6-month-old A. vera showed the greatest effects on cell viability in normal liver cells. Based on these findings, the extract from 6-month-old A. vera was examined further in order to determine its protective potential against tert-butyl hydroperoxide (t-BHP)-induced oxidative stress. The extract from 6-monthold A. vera at a concentration of 0.25 mg/ml showed the highest protective activity against t-BHP-induced reactive oxygen species production. These findings suggested that harvesting regimens were critical in the regulation of effects of the bioactive potential of A. vera on antioxidant activity.

Antioxidant activity and protective effect of extract of Celosia cristata L. flower on tert-butyl hydroperoxide-induced oxidative hepatotoxicity.

This study was undertaken to evaluate the antioxidant potential and protective effects of Celosia cristata L. (Family: Amaranthaceae) flower (CCF) extracts on tert-butyl-hydroperoxide (t-BHP)-induced oxidative damage in the hepatocytes of Chang cells and rat livers. In vitro, CCF extracts exhibited protective effect through their radical scavenging ability to enhance cell viability, prevent reactive oxygen species (ROS) generation, and inhibit mitochondrial membrane depolarisation in t-BHP-induced hepatotoxicity in Chang cells. In vivo, oral feeding of CCF (100mg and 500mg/kg of body weight) to rats for five consecutive days before a single dose of t-BHP (2mmol/kg, i.p.) showed a significant (p<0.05) protective effect by lowering serum levels of glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT). The extract decreased the hepatic levels of lipid peroxidation (MDA) and serum level of triglyceride (TG) against t-BHP-induced oxidative stress. These results indicate that CCF extract prevented oxidative stress-induced liver injury by enhancing hepatocyte antioxidant abilities.

Thymol from Thymus quinquecostatus Celak. protects against tert-butyl hydroperoxide-induced oxidative stress in Chang cells.

The present work describes the protective effects of thymol isolated from Thymus quinquecostatus Celak. against tert-butyl hydroperoxide (t-BHP)-induced oxidative damage through various experiments with Chang liver cells. Thymol significantly protected hepatocytes against t-BHP-induced cell cytotoxicity as demonstrated by increased viability. Furthermore, observation of Hoechst staining, annexin V/PI staining, and expression of Bcl-2 and Bax indicated that thymol inhibited t-BHP-induced Chang cell damage. Further, thymol inhibited the loss of mitochondrial membrane potential in t-BHP-treated Chang cells and prevented oxidative stress-triggered reactive oxygen species (ROS) and lipid peroxidation (malondialdehyde, MDA). Thymol restored the antioxidant capability of hepatocytes including glutathione (GSH) levels which were reduced by t-BHP. These results indicated that thymol prevents oxidative stress-induced damage to liver cells through suppression of ROS and MDA levels and increase of GSH level.

Antioxidant activity and protective effects of Trapa japonica pericarp extracts against tert-butylhydroperoxide-induced oxidative damage in Chang cells.

In this study, the antioxidant properties of Trapa japonica pericarp extracts were evaluated through several biochemical assays: 2,2-diphenyl-1-picrylhydrazyl (DPPH), alkyl radical scavenging activity, hydroxyl radical scavenging, ferric reducing antioxidant power (FRAP) assay, ABTS radical scavenging activity and oxygen radical absorbance capacity (ORAC). The antioxidant activities were compared with other natural and synthetic antioxidants. The results showed that higher radical scavenging activity and antioxidant capacity in FRAP than those of vitamin C as a positive control. T. japonica pericarp extracts have antioxidant properties through its ability to prevent tert-butylhydroperoxide (t-BHP)-induced toxicity which enhance the cell viability, reduce reactive oxygen species (ROS) production, inhibits of oxidative damage and mitochondria dysfunction in Chang liver cells. Therefore, based on these finding, it seems reasonable to suggest that T. japonica pericarp extracts has the potential to protect liver against t-BHP-induced cell damage and should be considered as a potential functional food.

Isolation and identification of an antioxidant flavonoid compound from citrus-processing by-product.

BACKGROUND: Large amounts of citrus by-products are released from juice-processing plants every year. Most bioactive compounds are found in the peel and inner white pulp. Flavonoids are a widely distributed group of bioactive compounds. The methanolic extract of citrus peel powder has been shown to possess strong antioxidant activity. Therefore the aim of this study was to isolate the major antioxidant flavonoid compound from Citrus unshiu (satsuma) peel as citrus by-product and evaluate its antioxidant activity. RESULTS: The major flavonoid isolated from C. unshiu peel was identified as quercetagetin. The structure of the compound was determined by tandem mass spectrometry and ultraviolet spectroscopy. Its antioxidant activity was assessed by assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, hydroxyl radical and intracellular reactive oxygen species (ROS) scavenging and DNA damage inhibition. Quercetagetin showed strong DPPH radical-scavenging activity (IC50 7.89 µmol L⁻¹) but much lower hydroxyl radical-scavenging activity (IC50 203.82 µmol L⁻¹). Furthermore, it significantly reduced ROS in Vero cells and showed a strong protective effect against hydrogen peroxide-induced DNA damage. CONCLUSION: The results of this study suggest that quercetagetin could be used in the functional food, cosmetic and pharmaceutical industries.

Antioxidant activity of enzymatic extracts from Stellaria dichotoma.

The antioxidant properties of enzymatic extracts from Stellaria dichotoma were evaluated using seven carbohydrases (Promozyme, Celluclast, Maltogenase, Viscozyme, Termamyl, Dextrozyme, and AMG 300L) and five proteases (Protamex, Flavourzyme, Neutrase, pancreatic trypsin, and Alcalase) (all from Novo Co., Novozyme Nordisk, Bagsvaerd, Denmark) for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical, and alkyl radical scavenging activity using an electron spin resonance spectrometer. The DPPH radical scavenging activities of pancreatic trypsin and Celluclast extracts from S. dichotoma were the highest among various protease and carbohydrate extracts, and the 50% inhibitory concentration (IC(50)) values were 10.45 and 13.80 microg/mL, respectively. The Flavourzyme and Promozyme extracts of S. dichotoma showed the highest hydroxyl radical scavenging activities among the tested protease and carbohydrase extracts, with IC(50) values of 1.51 and 1.23 microg/mL, respectively. The S. dichotoma enzymatic extracts also exhibited alkyl radical scavenging activity in a dose-dependent manner. In addition, the ability of the enzymatic extracts to inhibit the oxidative damage of DNA was assessed in vitro by measuring the conversion of supercoiled pBR322 plasmid DNA to the open circular form. It was found that the enzymatic extracts could significantly and dose-dependently protect against hydroxyl radical-induced DNA damage. These results indicate that enzymatic extracts of S. dichotoma possess potent antioxidant activity.