Synergistic Effect Of Ascorbic Acid Research Articles

Synthesis of new 4-aminobenzoic acid (PABA) hydrazide-hydrazone/sulfonate hybrids and antimicrobial evaluation with ascorbic acid/salicylic acid/N-acetyl cysteine combinations

One of the most serious threats to human health is the increasing prevalence of drug-resistant pathogens. The development of new antibiotics capable of combating drug resistance is critical. In various bacteria and plant species, 4-aminobenzoic acid (PABA) is produced and used as a substrate for folate generation. In this study, a new series of PABA analogs were synthesized and evaluated for their antimicrobial activity. Thirteen novel compounds were prepared by linking PABA hydrazide to sulfonate esters via a hydrazone bridge (4a–m). The structures of these compounds were characterized by 1H and 13C NMR and FT-IR spectroscopy as well as by LC-MS. Following structural characterization, all compounds were tested for their antimicrobial activity against Staphylococcus aureus (ATCC 29213), Enterococcus faecium (ATCC 19434), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), and Candida albicans (ATCC 10231) strains. Four compounds were found to have moderate antimicrobial activity against the P. aeruginosa strain. These compounds, including 4e, 4f, 4g, and 4m, containing a hydrazide-hydrazone sulfonate functionality, showed the best MIC value of 64 μg/mL. In addition, synergistic effects of ascorbic acid, salicylic acid, and N-acetyl cysteine (NAC) with synthesized compounds were also investigated. It was observed that the combination of compounds 4f and 4g with NAC showed antipseudomonal activity with MIC values of 32 μg/mL and 16 μg/mL, respectively, against the P. aeuriginosa strain. The antimicrobial activity of 4f and 4g was enhanced by two folds in combination with NAC. Our findings in this study can be crucial for the development of new potent antimicrobial agents.

Thermal degradation and oxidation of glucosinolates in model systems and Brassica vegetable broth is mediated by redox-active compounds

Glucosinolates (GLSs) are secondary plant metabolites with health-promoting effects found in Brassica vegetables. Recently, next to non-enzymatic degradation yielding nitriles, 4-(methylthio)butyl GLS (4MTB-GLS) was shown to undergo side chain oxidation during thermal treatment, forming 4-(methylsulfinyl)butyl GLS (4MSOB-GLS). Here, we investigated natural plant components and artificial analogs on their capability of altering the thermal reactivity of 4MTB-GLS in vegetable broths and model systems using buffers. Addition of ascorbic acid and dehydroascorbic acid caused varying effects: in broth samples, it increased nitrile formation, while in buffer, 4MSOB-GLS was formed. In further experiments, the antioxidant compounds quercetin and Trolox triggered the side chain oxidation of 4MTB-GLS, while H2S terminated its degradation. A synergistic effect of ascorbic acid and Fe2+ was observed, degrading 98% of 4MTB-GLS to the nitrile after 60 min of boiling. Deepening the understanding of factors that influence the non-enzymatic degradation of GLSs will help to preserve their health-promoting effects.

Synergistic antimicrobial effect of ascorbic acid and nicotinamide with rifampicin and vancomycin against SCCmec type IV methicillin-resistant Staphylococcus aureus (MRSA).

Background. Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogenic bacteria involved in a wide spectrum of human diseases. Many virulence factors promote this widespread propagation. One important factor is acquiring antibiotic resistance genes, which leads to a reduction in the availability and efficacy of therapy options. Recently, research has suggested that the remarkable antimicrobial effect of antioxidants against superbugs such as MRSA shows synergistic effects when accompanied by antimicrobial therapy. This paper aims to examine the synergistic effects of ascorbic acid and nicotinamide with a panel of antibiotics used in antimicrobial therapy against MRSA. Material and Methods. Two SCCmec type IV MRSA reference strains (EMRSA-15 and USA300) and 10 MRSA clinical isolates feature in this paper. SCCmec typing was conducted on the 10 clinical isolates via multiplex PCR after identification. Synergy experiments on antioxidants and antibiotics were evaluated via checkerboard assay. The minimum inhibitory concentration (MIC) of each agent was determined in accordance with the Clinical and Laboratory Standards Institute (CLSI) M100 guidelines through twofold microdilution assay. Results and Discussion. Synergy (FIC <0.5) was demonstrated for ascorbic acid (1/2 to 1/4 MIC) with rifampicin (1/2 to 1/8 MIC), and also ascorbic acid (1/2 to 1/16 MIC) when associated with vancomycin (1/2 MIC). Similarly, nicotinamide (1/2 to 1/16 MIC) showed a synergistic effect when paired with low concentrations of rifampicin (1/2 to 1/16 MIC), and also (at 1/4 to 1/16 MIC) with vancomycin (1/2 MIC). All reduced MICs due to synergistic combinations demonstrated statistical significance (P<0.05). Conclusion. The synergistic activity demonstrated in associating antioxidants with antibiotics shows promise in managing superbugs. However, more research is required to better understand the mechanism of the synergy and for utilization in clinical care.

Multi-Analytical Approach to Study Fresh-Cut Apples Vacuum Impregnated with Different Solutions.

The aim of this study was to evaluate the effect of different solutions for vacuum impregnation (VI) of fresh-cut (FC) apples through an innovative multi-analytical approach. In particular, the individual and synergistic effects of ascorbic acid and calcium lactate on the preservation of freshness of FC apples was assessed through color, texture, microscopy, isothermal calorimetry, and time-domain nuclear magnetic resonance (TD-NMR) evaluations. The analysis was performed immediately after VI and after 24 h of refrigerated storage. The obtained results showed a good preservation of color and higher firmness in the impregnated samples. Concerning the metabolic heat production, a decrease following the VI treatment was observed, especially when the combined solution was used for the impregnation. The TD-NMR studies showed higher changes in terms of signal intensity and transversal relaxation time T2 after 24 h of storage, evidencing the meta-stability of the plant material for its dynamic tissue nature, and the dewatering/impregnation processes evolution until the achievement of dynamic equilibrium.

Ascorbic acid induced TET2 enzyme activation enhances cancer immunotherapy efficacy in renal cell carcinoma.

Exploring the regulatory mechanism of PD-L1 in renal cancer is one of the key strategies to improve the response of renal cancer patients to checkpoint blockade therapy. In this study, the synergistic effect of ascorbic acid (vitamin C) supplementation and the impact of TET2 depletion on anti-PD-L1 therapy were determined in xenograft model experiments. Lymphocyte infiltration and chemokine expression were determined using flow cytometry and qRT-PCR. To determine the downstream targets of TET2, we performed hMeDip-seq and RNA-seq analyses. The molecular mechanism was further confirmed by hMeDip-qPCR, MeDip-qPCR, bisulfite sequencing, Western blotting, qRT-PCR and xenograft model experiments in vitro and in vivo. The present study demonstrated that ascorbic acid enhanced the efficacy of immunotherapy and that the loss of TET2 function enabled renal cancer cells to evade antitumor immunity. Ascorbic acid treatment significantly increased the intratumoral infiltration of T cells and the expression of cytokines and chemokines, while the loss of TET2 impaired the infiltration of T cells and the expression of cytokines and chemokines. TET2 was recruited to IRF1 by IFN-γ-STAT1 signaling, thereby maintaining IRF1 demethylation and ultimately inducing PD-L1 expression. These results suggest a new strategy of stimulating TET activity to improve immunotherapy for renal cell carcinoma.

Synergistic effects of ascorbic acid, low methoxy pectin, and EDTA on stabilizing the natural red colors in acidified beverages

Betacyanins are one of the reddish to violet betalain pigments that are unstable under an oxygen atmosphere, greatly limiting their application and commercial potential. To improve the betacyanins color stability, we explored synergistic effects between ascorbic acid (AA), polysaccharides, and Ethylenediaminetetraacetic acid (EDTA) to improve the color stability of betacyanins in acidified conditions. We found that alginate and low methoxy pectin (LMP), among the thirteen studied polysaccharides, increased the red color stability of beetroot extract at pH 3.2 during thermal treatment. Our results proved that there is a synergistic effect between polysaccharides, AA, and EDTA, for enhancing the betacyanins color stability. Further, the red color in a model sports beverage recipe protected by the LMP, AA, and EDTA was stable for up to 45 days at room temperature and under natural light. The synergistic stabilization of betacyanins in acidified beverages was confirmed through ATR-FTIR and quartz crystal microbalance with dissipation analyses.

The Synergistic Effect of Ascorbic Acid and Selenium on Serum Testosterone in Restraint Stressed Rats

The Synergistic Effect of Ascorbic Acid and Selenium on Serum Testosterone in Restraint Stressed Rats

Synergistic effect of ascorbic acid and taurine in the treatment of a spinal cord injury-induced model in rats.

Spinal cord injury (SCI) results in severe damage, which causes functional alterations together with loss of autonomic functions, sensations, and muscle functioning. This injury leads to apoptosis of neurons and oligodendrocytes, which further leads to dysfunction of the spinal cord due to axonal degeneration and demyelination. Taurine is non-proteogenic and an essential amino acid, which plays a major role in the growth and development of brain cells. Ascorbic acid, also known as vitamin C, is found in various foods and is known to prevent scurvy. In this study, we have investigated the therapeutic effect of ascorbic acid and taurine against SCI-induced rats. The rats were divided into the following groups: sham, control, 100mg/kg of taurine, 100mg/kg of ascorbic acid, and 100mg/kg of taurine + 100mg/kg of ascorbic acid. Treatment was continued daily for 45 consecutive days. The combined treatment of taurine and ascorbic acid decreased caspase-3, bax, pro-NGF, and p53 mRNA expression by more than 30% compared to individual treatments. The combined treatment of taurine and ascorbic acid reduced caspase-3 and p53 expression by 33.7% and 44%, respectively, compared to individual treatments. The combined treatment of taurine and ascorbic acid decreased mRNA expression of interleukin-6 (IL-6), cyclooxygenase-2, tumor necrosis factor-alpha (TNF-α), and inducible nitric oxide synthase (iNOS) compared to the individual treatments of taurine and ascorbic acid. The combined treatment of taurine and ascorbic acid also significantly recovered altered antioxidant markers, and induced lipid peroxidation to near normal levels. In summary, apoptotic, inflammatory and oxidative stress markers were significantly decreased in SCI-induced rats treated with taurine and ascorbic acid.

Synergistic effects of ascorbic acid and plant-derived ceramide to enhance storability and boost antioxidant systems of postharvest strawberries.

Excessive reactive oxygen species (ROS) may attack biological macromolecules and induce oxidative stress. The inhibition by ascorbic acid (AsA) on oxidative damage has been reported in fruits, while the barrier effect of ceramide has also been proven. However, there are few reports about the effects of ceramide-AsA interactions to enhance storability and boost antioxidant systems in fruits during storage. This study was conducted to study the synergistic effects of AsA in combination with ceramide on the quality of postharvest strawberry (Fragaria anannasa cv. Tianbao). Treatment with 100 mg L-1 AsA plus 1.2mmol L-1 ceramide significantly delayed the rot of strawberries, reduced the water loss and the contents of ROS, malonaldehyde (MDA), and proline, however, increased the contents of total flavonoids, total phenols, and anthocyanins compared with other treatments. Also, treatment with 100 mg L-1 AsA plus 1.2mmol L-1 ceramide significantly increased the activities of peroxidase (POD) and superoxide dismutase (SOD) but inhibited the activity of polyphenol oxidase (PPO). It is suggested that treatment with 100 mg L-1 AsA plus 1.2mmol L-1 ceramide could significantly reduce the oxidative damage and maintain the storage quality of strawberries during storage by enhancing the antioxidant systems. © 2019 Society of Chemical Industry.

Synergistic effect of ascorbic acid on the synthesis of mesoporous rGO-MoS2(100) nanocomposites and promotion of hydrogen evolution reaction

Abstract We report a new method for the preparation of MoS2 (100)-reduced graphene oxide (rGO) nanocomposites for enhancement of HER. Ascorbic acid synergistically is applied to reduce graphene oxide and controls the sulfur content of MoS2 resulted in texturing of MoS2 (100) by up taking sulfur and proposing Mo(VI) oxidation state. Variety of characterization were performed to support this hypothesis including XRD, FESEM, TEM, EDX elemental mapping, XPS, Raman, FT-IR and UV–Vis spectroscopies, TGA and BET-BJH analyses. By incorporating ascorbic acid in the synthesis process, the atomic ratio of S Mo is 0.02 for rGO-Mo(VI)S2 hybrid structure with quenched (002) Bragg diffraction peak. rGO-MoS2 shows a net 0.08 mA cm−2 polarized photocurrent in light off-on measurement. A Tafel slope of 44 mV.dec−1, an exchange current of 0.62 mA cm−2, over potential of 156 mV 10 mA cm−2 and onset potential of 25 mV was obtained. This report opens a new pass way in simple and cheap preparation of controlled defective MoS2-rGO structures with new crystal growth (100) of MoS2 for enhanced Hydrogen Evolution Reaction using ascorbic acid. Mechanisms for the role of ascorbic acid on the formation of such defective structure as well as the process of enhancement of HER have been suggested.

Investigation of Phytochemical Constituents, Phenolic Profiles and Antioxidant Activities of Ricegrass Juice compared to Wheatgrass Juice

Background: Cereal grass has been brought attention as a new functional food. Wheatgrass juice was known as a super food which provides lots of advantages for human health. However, the young stage of rice sprout has not been made widely known for consumption, though it is in the similar family to wheat (Poaeceae). Accordingly, ricegrass juice can and should be introduced, especially in Asian countries, as an economical functional drink. Nevertheless, currently there is none of the apparent evidences which confirm the nutritive values of ricegrass juice compared to wheatgrass juice.Objective: To investigate the chemical compositions, major phytochemical constituents, bioactive compounds content, specific phenolic profiles, and in vitro antioxidant activities of ricegrass juice compared to wheatgrass juice. Methods: Rice and wheat seeds were germinated and grown hydroponically for 8 days. Both fresh plants were determined for chemical compositions. Next, the grasses were extracted with water, centrifuged, and the supernatants were tested for chlorophyll, carotenoid, and ascorbic acid contents. The left-over supernatant were freeze-dried. The extracts were then screened for the main group of phytochemicals, total extractable phenolic and specific phenolic compounds. Lastly, the extracts were tested for the antioxidant activities using DPPH, ABTS, FRAP, FCA and HRSA. Results: Data revealed that wheatgrass contained higher levels of protein and fat. Both ricegrass and wheatgrass juice extract exhibited the group of phenol, tannin and saponin but not alkaloid, flavonoid, sterol, terpenoid, courmarin, and cardiac glycoside. Wheatgrass juice can be detected for higher level of ascorbic acid and chlorophyll. Both grass juices were found the similar phenolic acids analyzed by HPLC included pyrogallol, vanilic acid, syringic acid and ferulic acid, however, ricegrass juice contained larger amounts of all phenolic acids excluding syringic acid. Conversely, wheatgrass juice exposed higher antioxidant activities for all methods. This may propose from the synergistic effects of ascorbic acid, chlorophyll, and phenolic compounds in wheatgrass juice, while the main composites exhibited antioxidant activities in ricegrass were phenolic compounds.Conclusion: Ricegrass juice contained great level of phenolic acid molecules. Even if ricegrass juice gave less statistically ability on antioxidant activities, they still had comparable levels of antioxidant activities. With the reduction in cost of raw materials and contribution of high nutritional values, ricegrass juice could be introduced as an antioxidant boosting drink in competition to wheatgrass juice.Keywords: Antioxidant, Phytochemical, Phenolic compounds, Ricegrass, Wheatgrass

Synergistic effect of ascorbic acid and collagen addition on the increase in type 2 collagen accumulation in cartilage-like MSC sheet.

Aiming to increase the content of type 2 collagen in scaffold-free cartilage-like cell sheets prepared using human bone marrow mesenchymal stem cells, the effect of several kinds of additives in a chondrogenic medium was investigated. Addition of ascorbic acid 2 phosphate (VCP) at a high concentration (250µg/ml) and type 1 atelocollagen (5µg/ml) increased the accumulation of type 2 collagen by fourfold and twofold, respectively. On the other hand, an antioxidant, glutathione showed no such effect. The synergistic effect of VCP and type 1 atelocollagen resulted in an eightfold increase in the accumulation level of type 2 collagen. Furthermore, the gene expression level of type 2 collagen increased and that of matrix metalloproteinase-13 (MMP-13) decreased to approximately one-third of the control. The increase in type 2 collagen accumulation in the scaffold-free cartilage-like cell sheet might be due to not only the enhancement of the synthesis but also the suppression of the degradation of type 2 collagen by MMP-13.

Antidepressant-like effect of ascorbic acid is associated with the modulation of mammalian target of rapamycin pathway

The present study investigated the involvement of the PI3K, GSK-3β, heme oxygenase-1 (HO-1) and mTOR in the antidepressant-like effect of ascorbic acid in the tail suspension test (TST). Male Swiss mice were pretreated with ascorbic acid (1 mg/kg, p.o.) or vehicle and 45 min after, LY294002 (10 μg/site, i.c.v., reversible PI3K inhibitor), rapamycin (0.2 nmol/site, i.c.v., selective mTOR inhibitor), zinc protoporphyrin (ZnPP – 10 ng/site, i.c.v., HO-1 inhibitor) or vehicle was administered. We also investigated the synergistic effect of ascorbic acid (0.1 mg/kg, p.o., sub-effective dose in the TST) with lithium chloride (10 mg/kg, p.o., non-selective GSK-3β inhibitor), AR-A014418 (0.01 μg/site, i.c.v., selective GSK-3β inhibitor) or cobalt protoporphyrin (CoPP – 0.01 μg/site, i.c.v., HO-1 inducer) in the TST. The antidepressant-like effect of ascorbic acid (1 mg/kg, p.o.) was prevented by the treatment of mice with LY294002, rapamycin or ZnPP. In addition, sub-effective doses of lithium chloride, AR-A014418 or CoPP, combined with a sub-effective dose of ascorbic acid produced a synergistic antidepressant-like effect. We also demonstrated that 1 h after its administration, ascorbic acid increased the phosphorylation of p70S6K and the immunocontent of PSD-95 in the hippocampus of mice. These results indicate that the antidepressant-like effect of ascorbic acid in the TST might be dependent on the activation of PI3K and mTOR, inhibition of GSK-3β as well as induction of HO-1, reinforcing the notion that these are important targets for antidepressant activity and contributing to better elucidate the mechanisms underlying the antidepressant-like effect of ascorbic acid.

P24: Effects of iodide on nitrite reduction by ascorbate and implications on nitrosoamine formation

Background Under acidic conditions of the stomach with gastric juice pH ranging from 1.7 to 2.6, nitrite is reduced to nitric oxide. When a diet rich in nitrate is consumed, it is partially reduced to nitrite in the mouth by oral bacteria followed by ingestion and partial reduction of nitrite to nitric oxide (NO) in the stomach. When the dietary nitrate is consumed along with protein, secondary amines from protein react with nitrite via the formation of reactive nitrogen species to form nitrosamines, which are carcinogenic. Ascorbic acid, also obtained from diet, can react with nitrite to form NO in the acidic gastric juice, which does not react with amines. Ascorbate has a protective effect on the formation of carcinogenic compounds like nitrosamines by reducing nitrite faster and out competing nitrosamine formation by reactive oxygen species and amines. Iodide can also reduce nitrite to NO in acidic pH, which is the basis of a nitrite assay used in nitric oxide analyzers. Although it has been suggested that dietary iodide would lead to increased nitrosamine formation the enhanced formation of NO from nitrite due to iodide suggests iodide would be protective against nitrosamine formation. Thus, the combined effect of ascorbate and sodium iodide in the presence of nitrite and amines under acidic conditions on nitrosamine formation was studied. Methods In this study the effect of ascorbic acid and sodium nitrite on nitrite reduction and nitrosamine formation was determined in vitro. Nitrite reduction to NO was determined under anaerobic conditions by ozone chemiluminescence by the Nitric Oxide Analyzer (NOA 280i, Sievers, GE Analytical Instruments, Boulder, CO). Nitrosamine concentrations were measured using absorption spectroscopy according to a modification of method by Mirvish et al., Science 175 (1972) 65–68. Results Both Iodide and ascorbic acid are effective in reducing nitrite to NO at the pH range that includes the pH of stomach. There is a synergistic effect of ascorbic acid and iodide on the rates of nitrite reduction to NO. Very low levels of nitrite are reduced to NO by either ascorbic acid or iodide alone. Nitrosomorpholine formation is reduced by iodide and ascorbate combined compared to ascorbic acid alone at pH 2. Conclusions The results indicate that, due to the increased rate of nitrite reduction byascorbic acid in the presence of iodide, nitrosation of morpholine to nitrosomorpholine can be reduced. Given that both nitrate and iodide are taken up by salivary glands and concentrated in the oral cavity, their combined effects on nitrosamine formation could have substantial impact. Disclosure This work was supported by NIH Grant HL058091.

The synergistic effect of ribose, carnosine, and ascorbic acid on the sensory and physico-chemical characteristics of minced bison meat.

Ingredients such as ascorbic acid used to preserve redness of the raw meat, and carnosine and ribose used for flavor improvement have been incorporated into minced meats to increase consumer acceptance. The objective of this study was to investigate the possible synergistic effect of ascorbic acid, carnosine, and ribose on the sensory and physico-chemical characteristics of minced bison meat. Samples included control (Co) ±1% carnosine (C), 0.1% ascorbic acid (A), 2% ribose (R) (w/w), and combinations of RC, RA, RCA in the same concentrations as the single ingredient samples. A trained sensory panel (n = 7) measured the intensity of the aromas and flavors of salty, sour, beef, and liver of the bison patties. A consumer acceptance panel (n = 59) evaluated color, aroma, flavor, texture, and overall acceptability of the patties. Hunterlab colorimetry, shear force, cook loss, and drip loss percentage were measured on the cooked patties, and color and pH on the raw patties. The sample containing 2% ribose (R), 1% carnosine (C), and 0.1% ascorbic acid (A) in combination (RCA) showed a significantly higher consumer acceptance for aroma, which could possibly be attributed to the high beef aroma intensity measured by the descriptive analysis panel. RCA had the highest color acceptance which may be related to the high a* value for the cooked sample. RCA also had high overall acceptance corresponding to “like slightly.” Raw and cooked color values, shear force, pH, cook loss and drip loss percentages, and aroma and flavor attribute intensities for RCA were not significantly different from the control sample. The synergistic effect of ribose, carnosine, and ascorbic acid may positively affect the aroma and color of minced bison meat leading to higher overall acceptability without compromising sensory and physico-chemical quality.

Electrochemical modeling of antioxidants action and determination of their activity

The method of pulse voltammetry was applied to the investigation of the antioxidant activity of sulfur-containing biologically active substances. Three models were considered to characterize the substances in aqueous medium: First, the interaction of antioxidants with a ferrous ion to characterize the preventive activity on the initiation stage of free radical oxidation, second and third describing the interaction of an antioxidant with electrochemically generated hydroxy radicals and hydrogen peroxide, to characterize the inhibitory activity in the initial stages of propagation and branching of the chain of free radical oxidation. A synergistic effect of ascorbic acid and other studied compounds at their combined action on hydroxy radicals and hydrogen peroxide was revealed.

Synergistic effects of ascorbic acid and thiazolidinedione on secretion of high molecular weight adiponectin from human adipocytes

To test the hypothesis that ascorbic acid (AA) and thiazolidinedione (TZD) would have additive effects on HMW adiponectin secretion by virtue of different modes of action. We determined the effects of supplementation of AA and/or TZD on expression and secretion of total and HMW adiponectin from human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes in the absence or presence of the proinflammatory cytokine TNFα. AA supplementation significantly increased secretion of HMW adiponectin (1.7-fold) without altering adiponectin expression or total adiponectin secretion. TZD significantly increased expression (3-fold) and secretion of total (1.4-fold) but not HMW adiponectin. Combined supplementation resulted in a significant increase in expression (3-fold) and secretion of total (1.8-fold) and HMW (5-fold) adiponectin. Similar results were seen in cells co-treated with TNFα. These data show that AA and TZD have synergistic rather than simple additive effects on secretion of HMW adiponectin from human adipocytes and raise the possibility that differences in AA levels may contribute to the variability in adiponectin multimer profiles and efficacy of TZD in humans. Our results also provide a rationale for longitudinal clinical trials investigating the effects of AA supplementation with or without TZD on adiponectin and metabolic profiles.

南アフリカのハーブティーやブドウ種子抽出物の酸化防止活性の評価

Anti-oxidative activity in South African herbal tea, Rooibos (red bush in English, Asparathus linearis) tea extract (RTE) and grape seed extracts (Procidyn:Pro and Gravinol:Gra) was evaluated based on that in mixed tocopherol (Toc), epigallocatechin gallate (EGCG) and propyl gallate (PG). Polyphenol content in RTE, Pro, and Gra was determined to be 17, 90, and 49%, respectively in term of EGCG. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability of RTE, Pro, Gra, EGCG, PG, and Toc given as 3.29, 6.58, 2.86, 9.98, 4.26, and 1.00 per unit polyphenol content, respectively. Anti-oxidative ability in RTE, Pro, Gra, EGCG, PG, and Toc was determined by adding different amounts as 500ppm polyphenol to be present in the substrate of methyl linoleate in the non-aqueous and O/W emulsifying systems. Anti-oxidative activity was found to follow the order, Control<Toc<RTE<Pro<Gra<<EGCG=PG in the non-aqueous system and EGCG<Control<Gra=Pro<Toc<PG<RTE in the emulsifying system. Intensity of synergistic effects of ascorbic acid (AA), citric acid (CA) and phosphatidylethanolamine (PE) for RTE followed the order, Control<RTE=RTE+AA=RTE+CA<<RTE+PE in the two systms. Main component present in RTE was indicated by TLC and IR to be rutin.

Potentiation of Ethanol-Induced Loss of the Righting Reflex by Ascorbic Acid in Mice: Interaction With Dopamine Antagonists

WU, C. F., H. L. ZHANG AND W. LIU. Potentiation of ethanol-induced loss of the righting reflex by ascorbic acid in mice: Interaction with dopamine antagonists. PHARMACOL BIOCHEM BEHAV 66(2) 413–418, 2000.—The present investigation was carried out to determine the effect of ascorbic acid on ethanol-induced loss of the righting reflex (LORR) and the interactions between ascorbic acid and dopamine receptor antagonists in affecting this action of ethanol in mice. To test the effect of each drug on ethanol-induced LORR, ascorbic acid (31.25, 62.5, 125, 250, 500, 1000 mg/kg intraperitoneally [IP]) and dopamine receptor antagonists (haloperidol 0.5, 1.0 mg/kg; L-sulpiride 20, 40, 80 mg/kg; clozapine 0.625, 1.25, 2.5 mg/kg; SCH 23390 0.5, 1.0, 2.0 mg/kg subcutaneously [SC]) were administered, respectively, 30 min before ethanol (4.0 g/kg IP) administration. Ascorbic acid, at the dose of 1000 mg/kg, significantly potentiated ethanol-induced LORR in mice. Dopamine D 2 antagonists haloperidol (0.5, 1.0 mg/kg SC), and L-sulpiride (80 mg/kg SC) also significantly prolonged the duration of LORR induced by ethanol. Clozapine and SCH 23390, at the doses used, did not affect ethanol-induced LORR. In the interaction study, the synergistic effect of ascorbic acid (1000 mg/kg IP) on ethanol-induced LORR was significantly enhanced by dopamine D 2 antagonists haloperidol, L-sulpiride, and clozapine, and the highest dose of dopamine D 1 antagonist SCH 23390. These results suggest that ascorbic acid may potentiate ethanol-induced LORR partially via a mechanism mainly linked to blockade of dopamine D 2 receptors.

Antioxidative properties of methanolic extracts from peanut hulls

Antioxidative properties of methanolic extracts from peanut hulls (MEPH) have been investigated. MEPH had good thermal stability and showed an 85.2% inhibition of peroxidation of linoleic acid when heated at 185°C for 2 h. Only a slight decrease in antioxidative activity of MEPH occurred when the extract was stored at different temperatures (∓20, 5 and 30°C) under air or nitrogen (30°C) for 70 d. Antioxidative activity of MEPH decreased with an increase of pH from 3 to 9. No synergistic effect of ascorbic acid, citric acid, cysteine or α‐tocopherol was observed on the inhibitory effect of MEPH. The reducing power of MEPH increased with an increase in concentration and was significantly correlated (r=0.9793,P&lt;0.05) to the extent of antioxidative activity. MEPH also showed good inhibitory activity in lard oxidation when compared with butylated hydroxyanisole.