Influence of the interactions between tea (Camellia sinensis) extracts and ascorbic acid on their antioxidant activity: analysis with interaction indexes and isobolograms

Antioxidant interaction between α-tocopherol and γ-oryzanol in HepG2 cells

Minor constituents exhibit certain antioxidant interactions in vitro, and the effects in different media are different. However, it is not clear whether there are antioxidant interactions in cells after digestion and absorption. We utilized the cellular antioxidant evaluation model in HepG2 cells to study the antioxidant interaction between α-tocopherol and γ-oryzanol, and the interaction mechanism of a binary mixture was also illustrated. A cellular antioxidant assay (CAA) model and a combined index (CI) method were firstly used to explore the antioxidant activity and interaction of the binary mixture in HepG2 cells. The CAA value was positively correlated with the single addition concentration, while the results displayed a biphasic tendency with increasing concentrations of the binary mixture. The combination of TO11 (1 μg mL-1 α-tocopherol and 10 μg mL-1 γ-oryzanol) showed the greatest antioxidant activity and synergistic effect, and the maximum CAA value reached up to 94.84 ± 4.2. Then the mechanism of the synergistic antioxidant effect of the binary mixture was explained from three aspects including cellular uptake, intracellular reactive oxygen species (ROS) level and endogenous enzyme activity. The results demonstrated that the antioxidant interaction of the binary mixture in cells was related to cellular uptake of minor constituents, and the combination of TO11 exerted a synergistic effect by scavenging ROS and up-regulating glutathione peroxidase (GSH-Px) activity, resulting in the strongest cellular antioxidant activity. This study throws light on the nature of antioxidant interaction between minor constituents, which may contribute to the development of related functional foods and rational dietary collocation.

Biosorption of bioactive compounds in bacterial nanocellulose: Mechanisms and physical-chemical properties

Bacterial cellulose (BC) is a biomaterial produced by Gluconacetobacter xylinus, with wide applicability in different areas, such as biomedical, pharmaceutical, and food. BC production is usually carried out in a medium containing phenolic compounds (PC), such as teas, however, the purification process leads to the loss of such bioactive. Thus, the innovation of this research consists of the reincorporation of PC after the purification of the BC matrices through the biosorption process. In this context, the effects of the biosorption process in BC were evaluated to maximize the incorporation of phenolic compounds from a ternary mixture of hibiscus (Hibiscus sabdariffa), white tea (Camellia sinensis), and grape pomace (Vitis labrusca). The biosorbed membrane (BC-Bio) showed a great concentration of total phenolic compounds (TPC = 64.89 mg L^-1) and high antioxidant capacity through different assays (FRAP: 130.7 mg L^-1, DPPH: 83.4 mg L^-1, ABTS: 158.6 mg L^-1, TBARS: 234.2 mg L^-1). The physical tests also indicated that the biosorbed membrane presented high water absorption capacity, thermal stability, low permeability to water vapor and improved mechanical properties compared to BC-control. These results index that the biosorption of phenolic compounds in BC efficiently increases bioactive content and improves physical membrane characteristics. Also, PC release in a buffered solution suggests that BC-Bio can be used as a polyphenol delivery system. Therefore, BC-Bio is a polymer with wide application in different industrial segments.

Synergistic antioxidant activity of selected medicinal plants in Brunei Darussalam and its application in developing fortified pasta

BACKGROUND

Developing functional foods by utilizing plants can often lead to compromised sensory properties. Thus this study investigates the combination of plants to produce synergistic effects and to incorporate these plant powders into a pasta formulation without affecting its sensory acceptance. Six common Brunei medicinal plants were evaluated for their in vitro antioxidant activity determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (IC₅₀ ), ferric reducing antioxidant power (FRAP) assay and 2,2'-azino-bis(3-ethylbenziazoline-6-sulfonic acid) (ABTS) radical scavenging assay. Aqueous extracts of Amaranthus tricolor, Breynia androgyna, Manihot esculenta, Polygonum minus, Apium graveolens and Coriandrum sativum were prepared.

RESULTS

Breynia androgyna had the highest FRAP value of 74.3 ± 5.33 mg g^-1 ascorbic acid equivalents (AAE), with DPPH IC₅₀ antioxidant activity of 70.3 ± 3.14 μg mL^-1 and ABTS scavenging activity of 44.0 ± 2.80 mg g^-1 AAE. This correlates well with the total flavonoid, flavonol and phenolic content (50.5 mg g^-1 gallic acid equivalents (GAE), 50.6 mg g^-1 GAE and 24.3 mg g^-1 GAE, respectively). Plant species powders were combined in pairs and evaluated for their synergistic antioxidant properties. With potential synergistic plant mixtures, fortification of these mixtures into functional food can be developed to improve its overall antioxidant capacity. Based on the synergistic IC₅₀ results of these mixtures, three fortified pastas were formulated by incorporating selected plant powder combinations of Amaranthus tricolor + P. minus, Apium graveolens + P. minus, and P. minus + B. androgyna into wheat pasta at 1:100 (w/w).

CONCLUSION

Fortification of pasta with the plant powder blends resulted a significant increase in DPPH antioxidant activity, while successfully maintaining indistinguishable features from the control pasta, including minimal cooking loss, agreeable measure of cohesiveness, springiness and chewiness, with good overall sensory acceptability. © 2022 Society of Chemical Industry.

Antioxidative and Anti-Inflammatory Activity of Ascorbic Acid

Ascorbic acid, as a one of the basic exogenous vitamins, occurs in the body in the form of ascorbate, known for its strong antioxidant and anti-inflammatory properties. The presented review shows not only the importance of ascorbate as a free radical scavenger but also summarizes its antioxidant action based on other mechanisms, including the activation of intracellular antioxidant systems and its effect on the NFκB/TNFα pathway and apoptosis. Ascorbate interacts with small-molecule antioxidants, including tocopherol, glutathione, and thioredoxin; it can also stimulate biosynthesis and the activation of antioxidant enzymes, such as superoxide dismutase, catalase, or glutathione peroxidase. Moreover, ascorbate promotes the activity of transcription factors (Nrf2, Ref-1, AP-1), which enables the expression of genes encoding antioxidant proteins. Additionally, it supports the action of other exogenous antioxidants, mainly polyphenols. In this regard, both DNA, proteins, and lipids are protected against oxidation, leading to an inflammatory reaction and even cell death. Although ascorbate has strong antioxidant properties, it can also have pro-oxidant effects in the presence of free transition metals. However, its role in the prevention of DNA mutation, inflammation, and cell apoptosis, especially in relation to cancer cells, is controversial.

Extraction optimization for the antioxidants from Nigella sativa seeds using response surface methodology

Although many studies have explored the bioactive compound content of Nigella sativa (black seed – BS) essential oil, data on the phenolic compound content in the extracts of Nigella sativa seeds gives inconclusive results [1–3]. In this study, response surface methodology (RSM) with a central composite plan (CCP) was used for the experimental design and identification of the optimal conditions for maximizing the phenolic content and the antioxidant activity of BS extract. The independent variables were as followed: temperature (22.9–67.1ºC), time (31.7–208.2 min), and methanol concentration in water (5.9–94.1% v/v). Different response variables (total polyphenols – TPC, total flavonoids – TFC and the antioxidant activity – DPPH and TEAC) required different optimal conditions to maximize them. The multi-response optimization was performed to determine the extraction conditions, which would simultaneously ensure the highest phenolic content and the antioxidant activity. The optimal conditions derived from the multi-response desirability function were as followed: 120 min, 56 °C and 50% methanol, giving the TPC = 7.05 mg/g, TFC = 3.05 mg/g, DPPH = 9.04 µmol/g and TEAC = 33.24 µmol/g (with desirability function coefficient = 0.83). Solvent concentration was established as a crucial parameter for the extraction of antioxidants from BS. A quercetin derivative and two derivatives of kaempferol were determined by HPLC (high performance liquid chromatography) analysis of the BS extract at the optimal conditions. The accuracy of the models for all response variables was confirmed by a high correlation coefficient (r = 0.99) between the experimental values and those predicted under optimal conditions.

Identification of Epigallocatechin-3-Gallate (EGCG) from Green Tea Using Mass Spectrometry

In an era where humanity is reinstating its lost hope and expectation on natural products, green tea occupies quite a position for what it has proven to be, in its endeavors for human welfare and health. Epigallocatechin-3-gallate (EGCG) is the key to the vast biological activities of green tea. Green tea is no longer in the backdrop; it has emerged as the most viral, trending bioactive molecule when it comes to health benefits for human beings. This review focuses on the use of various analytical techniques for the analysis of EGCG. That which has been achieved so far, in terms of in vitro, pure component analysis, as well as those spikes in biological fluids and those in vivo in animal and human samples, was surveyed and presented. The use of MS-based techniques for the analysis of EGCG is elaborately reviewed and the need for improvising the applications is explained. The review emphasizes that there is plenty of room to explore matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) applications in this subject area.

Anti-Inflammatory, Anti-Diabetic, Anti-Oxidant and Cytotoxicity Assays of South African Herbal Teas and Bush Tea Blends

South Africa is home to a variety of herbal teas, such as bush tea (Athrixia phylicoides DC.), honeybush tea (Cyclopia intermedia E. Mey and C. subternata Vogel), special tea (Monsonia burkeana Planch. ex Harv.), and rooibos tea (Aspalathus linearis (Burm.f.) R. Dahlgren) that are known to possess anti-oxidant, anti-inflammatory and anti-diabetic properties. The objective of this study was to determine the in vitro anti-oxidant activity of selected tea blends using 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, as well as to assess their anti-inflammatory properties using the 15-lipoxygenase inhibitory assay. Furthermore, the study measured glucose utilisation in C2C12 myotubes. Lastly, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was used to test the safety of the tea extracts on Vero cells (African green monkey kidney cell line). Special tea and its blend with bush tea exhibited potent anti-oxidant and anti-inflammatory activity. The blending of bush tea with special tea at different ratios resulted in increased anti-oxidant activity. Although special tea had a level of cell toxicity, its toxicity was lowered during blending. All of the tea samples showed anti-diabetic effects, although with less potency as compared to insulin. The current investigation supports the use of blended herbal teas, and the positive anti-inflammatory effect of special tea warrants further research.

Indonesian Cinnamon (Cinnamomum burmannii): Extraction, Flavonoid Content, Antioxidant Activity, and Stability in the Presence of Ascorbic Acid

Cinnamon (Cinnamomum burmannii) is a potential source used in cosmetics to prevent skin aging due to its flavonoids and antioxidant properties. This research aims to determine the best solvent for extracting flavonoids, to conduct a large-scale isolation of flavonoids, and to evaluate the effect of ascorbic acid and temperature on the extract’s stability for 16 weeks. Various solvents for small-scale extraction were screened based on the polarity index, and one of the best for use in large-scale maceration was selected based on the AlCl3 colorimetric flavonoid content and DPPH antioxidant activity. The stability test was performed by treating cinnamon with and without ascorbic acid at selected temperatures. This test measured physical stability, evaluated flavonoid content and antioxidant activity, and analyzed volatile and non-volatile compounds using GC-MS and LC-MS. The most excellent solvent to extract flavonoids was ethanol due to its high yield (21.50%), flavonoid content (0.01749 ± 8.0 × 10−5 mg QE/g extract), and antioxidant activity (IC50 0.0162 + 7.5 × 10−4 mg/mL). The ascorbic acid addition at both temperatures affected the stability of the pH and chemical constituents. The vast majority of the extract’s flavonoid content and antioxidant activity continued to increase until the end of the observation week. This study revealed that ethanol was the best extraction solvent, and ascorbic acid can be recommended as a stabilizer of cinnamon extract for use in cosmetics for further application.

Interaction between Flavonoids and Carotenoids on Ameliorating Oxidative Stress and Cellular Uptake in Different Cells

Flavonoids (quercetin, luteolin) and carotenoids (lycopene, lutein) were combined at different molecular ratios in a total concentration of 8 μM to investigate their antioxidant interactions. Cellular uptake of carotenoids, the expression of carotenoid transporters, the ROS scavenging ability, and antioxidant enzymes activities were compared in HUVEC, Caco-2, and L-02 cells. Combinations with flavonoids in the majority showed stronger antioxidant activity. Lycopene combined with quercetin at ratio 1:5 showed stronger ROS scavenging activities, increased 18, 12, and 12 Cellular antioxidant activity (CAA) units in HUVEC, Caco-2, and L-02 cells, respectively, and promoted SOD and CAT activities than individual component. The cell uptake of carotenoids was enhanced by flavonoids in antioxidant synergistic groups, while dampened by flavonoids in antagonistic groups in HUVEC cells. The synergistic group (lycopene:quercetin = 1:5) increased lycopene uptake by 271%, while antagonistic group (lutein:quercetin = 5:1) decreased lutein uptake by 17%. Flavonoids modulated the effects of carotenoids on the expression of active transporters scavenger receptor class B type I (SR-BI) or Niemann-Pick C1-like 1 (NPC1L1). The synergistic group (lycopene:quercetin = 1:5) increased the expression of SR-BI compared to individual lycopene treatment in HUVEC and Caco-2 cells. Thus, a diet rich in both flavonoids and lycopene possesses a great antioxidant activity, especially if a higher amount of flavonoids is included.

Selected dried fruits as a source of nutrients

Dried fruits are an excellent alternative to unhealthy snacks. Twelve commercially available dried fruits were selected: dates, raisins, prunes, Goji berry, chokeberry, rose hip, sea buckthorn, berberis, physalis, haritaki, noni and juniper. The nutritional value in terms of moisture, ash, protein, fat, carbohydrate, dietary fiber, energy value, mineral composition, antioxidant activity and tannins was compared. It is a novelty in the literature in relation to the particular analytes (e.g., minerals, tannins) and/or fruits (e.g., berberis, noni, haritaki). Especially rich in protein were Goji berry (13.3%), sea buckthorn (9.3%), noni (8.9%) and physalis (8.0%); in fat − sea buckthorn (11.2%); in dietary fiber (4.4–53.0%) − most of analyzed products. High antioxidant capacity was noticed for haritaki, berberis, rose hip, Goji berry, and physalis. An important source of minerals was 100 g of: noni (345 mg of Ca; 251 mg of Mg), rose hip (844 mg of Ca; 207 mg of Mg), juniper (564 mg of Ca), sea buckthorn (58 mg of Fe), berberis (24 mg of Fe) and haritaki (14 mg of Fe). The nutritionally attractive dried fruits have the potential for wider application in food formulations.

Bioavailability and radical scavenging power of phenolic compounds of cocoa and coffee mixtures

Cocoa and coffee are natural sources of phenolic compounds, which are degraded during beans processing of both. For this reason, there is an interest in obtaining extracts of these bio compounds. The aim of this study was uncovering the radical scavenging activity (AC) of mixtures of cocoa and coffee extracts, and the bioavailability of their phenolic compounds, resorting to in vitro models: DPPH and ORAC antioxidant methods, and the characterization of the trans-epithelial transport of cocoa and coffee phenolics through Caco-2 cells monolayer model of the intestinal barrier. The cocoa displayed a higher AC than the coffee regarding both DPPH and ORAC assays, while the mixtures increased in parallel with the percentage of cocoa in the blends. The combination index was calculated to set up the type of interaction in the cocoa-coffee mixtures, obtaining that the mixture 25:75 was moderately antagonistic, 50:50 nearly additive, and 75:25 slightly synergistic. The absorption efficiency of the cocoa phenolic compounds was between 87.9%-97.4%, in the coffee compounds was 100%. The mixtures varied according to the proportion of cocoa and coffee. The results obtained allowed concluding that the phenolic compounds present in cocoa and coffee, respectively, are featured by high bioavailability and a valuable antioxidant capacity, while no pattern was found in the mixtures concerning the real benefit of using them combined.

A predictive approach to the antioxidant capacity assessment of green and black tea infusions

Contemporary consumers drink significant amounts of tea because of its health–benefits mainly associated to the presence of polyphenols with high antioxidant activity. Therefore, the information how to obtain tea infusion of the highest quality, i.e. with high antioxidant capacity is needed. In this study, the various models for the prediction of total polyphenols and antioxidant activity of green and black tea infusions were developed and compared. Three mathematical equations: Spiro’s, Peleg’s and logarithmic, and two data mining techniques: multivariate adaptive regression splines (MARS) and artificial neural networks (ANNs) were used to build the predictive models. The results obtained show that Spiro’s model could be used for the prediction of green tea quality expressed as total phenolic content or the antioxidant activity (determination coefficients above 0.99), whereas Peleg’s model is more suitable for black tea quality prediction (determination coefficients above 0.99). Data mining techniques (MARS and ANNs) enable to create models fast and of simple application with very good acceptability (determination coefficients above 0.99).

The synergistic and antagonistic antioxidant interactions of dietary phytochemical combinations

The frequent intake of whole foods and dietary food variety is recommended due to their health benefits, such as prevention of multiple chronic diseases, including cancer, Alzheimer's disease, cardiovascular diseases, and type 2 diabetes mellitus. Often, consuming whole fruits or vegetables showed the enhanced effects than consuming the individual dietary supplement from natural products, which is widely explained by the interactive effects of co-existing phytochemicals in whole foods. Although research relevant to interactive effects among the bioactive compounds mounted up, the mechanism of interaction is still not clear. Especially, biological influence factors such as bioavailability are often neglected. The present review summarizes the progress on the synergistic and antagonistic effects of dietary phytochemicals, the evaluating models for antioxidant interactions, and the possible interaction mechanisms both in vitro and in vivo, and with an emphasis on biological-related molecular mechanisms of phytochemicals. The research on the interaction mechanism is of value for guiding how to take advantage of synergistic effects and avoid antagonistic effects in daily diets or phytochemical-based treatments for preventing chronic diseases.

Simultaneous determination of vitamin B6 and catechins in dietary supplements by ZIC-HILIC chromatography and their antioxidant interactions

Hydrophilic interaction liquid chromatography coupled to mass spectrometry was employed for simultaneous determination of vitamin B6 and catechins in dietary supplements. The obtained results clearly shows the potential of the application of alcohol eluent (instead mainly used acetonitrile) as a component of an with zwitterionic stationary phase. The limits of detection on ZIC-HILIC column were 0.01 mg/L for catechins and vitamins B (only for pyridoxal phosphate was 0.10 mg/L). The investigations between green tea extract (GTE) and vitamin B were also evaluated using isobolographic analysis as well as the interaction indexes. Antioxidant activities of single components and their mixtures were determined by DPPH assay. It was found that the mixtures of GTE and vitamin B acted synergistically. In comparison to GTE alone, faster DPPH radical bleaching of the mixtures was observed in the presence of different forms of vitamin B6 (pyridoxine, pyridoxal, or pyridoxal phosphate), particularly for pyridoxal.

Effects of Infusion and Storage on Antioxidant Activity and Total Phenolic Content of Black Tea

This study determined antioxidant activity in terms of the 1,1-Diphenyl-2-picrylhydrazyl (DPPH) scavenging ability and total phenolic content of black tea under different infusion and storage conditions. High performance liquid chromatography analysis identified caffeine, (−)-epigallocatechin, (−)-epicatechin-3-gallate, (−)-epigallocatechin-3-gallate and (−)-gallocatechin-3-gallate in the tea sample. The water–tea leaves weight ratio did not affect the DPPH scavenging ability. However, infusion temperature affected the DPPH scavenging activity and the total phenolic content. In the present study, the 50% inhibitory concentrations (IC50) for DPPH of black tea infused at 60 to 100 °C ranged from 100.0 ± 13.7 to 28.4 ± 4.8 μg/mL. The total phenolic content of black tea steeped at 60 to 100 °C ranged from 50.4 ± 5.2 to 178.6 ± 16.4 mg gallic acid equivalent/g dry leaf. Black tea exhibited increased antioxidant activity when the infusion temperature was increased. Regarding short-term storage, the DPPH scavenging ability and total phenolic content of black tea did not significantly change within 15 days. This result was consistent for storage temperatures of 4, 9, and 25 °C.

Suppressive Effect of Huzhentongfeng on Experimental Gouty Arthritis: An In Vivo and In Vitro Study

Background

Huzhentongfeng (HZTF) is an extract from four Chinese medical herbs for treating gout. This study aims to evaluate its antigout activity and preliminary explore its mechanism in vivo and in vitro.

Methods

The rats were intragastrically administered with HZTF for 5 days and then injected 0.1 ml (10 mg) of MSU crystals to their joints for generating a gout model to analyze the paw volume and histopathology of joint synovial tissues of rats with different doses. We also investigated the antioxidant capacity of HZTF in vitro using indication including lipid peroxidation, DPPH^·, and ABTS⁺ radical-scavenging capacity; besides, we used qRT-PCR to measure the effect of HZTF on interleukin (IL)-1β, caspase-1, NLRP3, and NQO1 expression in hydrogen peroxide-stimulated RAW264.7 macrophages and IL-1β, IL-6, and tumor necrosis factor (TNF)-α in MSU crystal-induced THP-1 monocytes. Confocal microscopy analysis was used to observe the dimerization of ASC adapter proteins. In addition, we also established quality standard of HZTF by using the high-performance liquid chromatography (HPLC) method.

Results

HZTF could significantly suppress the paw swelling and neutrophil infiltration induced by MSU intra-articular injection in rats compared with the control group. HZTF also showed inhibition effects of inflammatory cytokines (IL-1β, IL-6, and TNF-α) secretion at 25.00 and 50.00 μg/ml in MSU-induced THP-1 cells but showed no effects of IL-1β, IL-6, and TNF-α mRNA expression in MSU-induced THP-1 cells. Furthermore, confocal microscopy analysis showed that HZTF could prevent the oligomerization of ASC. Moreover, HZTF also showed effects in cell-free and cell-base tests of antioxidant capacity.

Conclusion

The results prove that HZTF possessed the potential preventive effect against gout arthritis, and the effect may be attributed to its preventing effect on neutrophil infiltration and proinflammatory cytokines secretion such as IL-1β, IL-6, and TNF-α which were caused by the activation of inflammasome.

Characterization of Fulvic Acid Beverages by Mineral Profile and Antioxidant Capacity

The main purpose of the study was to investigate the quality of fulvic acid-based food products. The concentrations of Ca, K, Mg, Na, Cu, Fe, Mn, and Zn, and antioxidant capacities of fulvic acid concentrates and ready-to drink beverages available on the global market were determined. The concentrations of minerals were determined using microwave plasma-atomic emission spectrometry. Antioxidant capacity was expressed as total polyphenol (TP) and flavonoid (TF) contents, the trolox equivalent antioxidant capacity (TEAC) and ferric reducing ability of plasma (FRAP) values. The daily portion of eight out of 14 products realized 45–135% of recommended daily allowance (RDA) for Fe. One of ready-to-drink beverages was also a good source of Mg (about 40% of RDA), and another one of Mn (about 70% of RDA). The concentrations of TP and TF in ready-to-drink beverages varied from 6.5 to 187 µg/mL, whereas in concentrates, from 5886 to 19,844 µg/mL. Dietary supplements or food products with fulvic acids may be a good source of antioxidant polyphenolic compounds and some minerals.

The Effect of Thiamine Concentration on the Antioxidative Activity Indices in Tea Extracts

The aim of the study was to determine correlations between the concentration of thiamine in systems and indicators of the antioxidative activity of ethanol tea extracts in the presence of soybean oil. Variability of the thiamine form was assumed by comparison of the influence of thiamine hydrochloride or thiamine pyrophosphate and fermentation of ethanol tea extracts. The study provides practical knowledge about the antioxidative activity of ethanol tea extracts in products containing fat and thiamine. The study showed that all tea extracts exhibited higher antioxidative activity in the presence of thiamine amounts of 0.1 and 0.8 mg/100 g. The antioxidative activity of ethanol tea extracts was significantly reduced when the concentrations were higher than the natural level for foods (over 1.0 mg/100 g). The systems containing white tea extract were the most vulnerable, whereas those with black tea were the least vulnerable. The presence of thiamine pyrophosphate in the system was more strongly correlated with reduced activity of the extracts than the presence of thiamine hydrochloride.

Isobologram Analysis: A Comprehensive Review of Methodology and Current Research

Drug combination is a common method for clinical disease treatment. Whether the combination of drugs is reasonable often affects the result of the disease treatment. Many methods have been used to evaluate interaction between drugs to date. Isobologram analysis has been mathematically proven and widely used to evaluate drug interactions. In this paper, the principle of isobologram analysis and its application in drug interaction evaluation are summarized. The applications of the similar cotoxicity coefficient and fractional inhibitory concentration index in the evaluation of drug interaction are also reviewed. This work is expected to evaluate the effect of formulations scientifically and provide scientific judgment standards for the development of formulations and clinical drug compatibility.

Investigation of antioxidant activity of selenium compounds and their mixtures with tea polyphenols

The antioxidant interactions between selenium species and tea polyphenols were investigated using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals, cupric reducing antioxidant capacity (CUPRAC) and Folin-Ciocalteu (FC) assay. Se(IV) exhibited the lowest antioxidant properties in comparison to other selenium compounds in all assays. The highest reducing power was obtained for SeMet, while the highest ability to scavenging DPPH radicals for MeSeCys. The results obtained experimentally for the mixtures containing selenium species and green or black tea infusion were compared with theoretical values calculated by adding up the effects of both individual components analyzed separately. The results obtained from each assay clearly show that observed effect is not additive. In almost every case the theoretical value of antioxidant capacity was significantly higher from that obtained from the activity of the binary mixture of black tea infusion with selenium compound decreased in the order: SeMet > Se(IV) > Se(VI) > MeSeCys, while for similar mixtures with green tea infusion: MeSeCys > Se(VI) > SeMet ~ Se(IV).

Preliminary investigation on antioxidant interactions between bioactive components of Solanum anguivi and Capsicum annuum

Evaluation of antioxidative interaction between two fruits of contra-similar characteristics belonging to same botanical family Solanacea namely S. anguivi and Capsicum annuum was accomplished in this study. The relative reducing power (RRP) and radical scavenging activity (RSA) of the mixture (11:0, 10:1, 5:1, 2:1, 1:1, 1:2, 1:5,1:10, 0:11) with antioxidant interaction range of 0.6958-2.4244 and 0.724-1.648 was obtained for RRP and RSA respectively for acetone-hexane derived extract. Similarly antioxidant interaction range from 1.045-1.486 to 1.0969-1.3166 was obtained for RRP and RSA respectively for ethanolic extract samples.This study demonstrated enhanced activity of S. anguivi and C. annuum when used as a mixture in comparison to when used alone. These results suggested that application of S. anguivi and C. annuum as mixture decreased intensity of undesirable sensory properties of high intensity bitterness and hot pungency associated with S. anguivi and C. annuum respectively without the use of taste masking agents.

Green tea extract as an anti-browning agent for cloudy apple juice

BACKGROUND

Enzymatic browning of fruits and vegetables and their products is an important factor worsening their quality. The influence of five green tea extracts at the concentrations of 1 g L^-1 , 2 g L^-1 and 3 g L^-1 on polyphenol oxidase (PPO) activity in fresh cloudy apple juice was investigated. Moreover, PPO inhibition by tea extract and colour stability of juice during short-time refrigerated storage was studied. The changes of juice colour during storage was expressed as the total colour differences (ΔE*), browning index (BI), yellowness index (YI), and the absorbance at 420 nm (A₄₂₀ ).

RESULTS

All extracts inhibited PPO activity in fresh apple juice in concentration-dependent manner. PPO activity in pure apple juice decreased by 7% after 48 h, whereas PPO activity in samples with 1 g L^-1 , 2 g L^-1 and 3 g L^-1 tea extract decreased by 53%, 74%, and 96%, respectively. Browning of apple juice during storage decreased with increased concentration of green tea extract. After 48 h, extract at 1 g L^-1 , 2 g L^-1 and 3 g L^-1 inhibited browning of juice expressed as BI by 48%, 60%, and 86%, respectively, comparing to pure apple juice.

CONCLUSION

Green tea extract may be an effective anti-browning agent for short-time stored cloudy apple juices. © 2016 Society of Chemical Industry.