Immunomodulatory effects of feruloylated oligosaccharides from rice bran

Feruloylated oligosaccharides (FOs), the ferulic acid ester of oligosaccharides, can be released either by the enzymatic or mild acid hydrolysis of arabinoxylans present in cereal bran, and are usually considered as natural antioxidants. However, no related research is available to explain their immunomodulatory effects. This report elucidated their immunomodulatory effects through the variations of pro-inflammatory mediators in vitro. FOs were obtained from the mild acid hydrolysis of rice bran. We found that FOs (0.1–100 μg/ml) induced tumour necrosis factor alpha (TNF-α), IL-1β, IL-6, nitric oxide (NO) and PGE₂ production in unstimulated macrophages, RAW264.7 cells. Furthermore, pre- and post-treated FOs (0.1–100 μg/ml) dose-dependently suppressed TNF-α, IL-1β, IL-6 and NO production, and induced IL-10 production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells without exerting cytotoxicity. As a result anti-inflammatory and therapeutic activities were revealed. It is noteworthy that prostaglandin E₂ (PGE₂) production was significantly suppressed at an FO level of 100 μg/ml. The in vitro assessment of inflammatory mediators should be useful in further characterising the effects of FOs on immunomodulation. Moreover, it will create the economical value of rice bran, which has long been considered as conventional agricultural wastes.     

Antiproliferative effects of cherry juice and wine in Chinese hamster lung fibroblast cells and their phenolic constituents and antioxidant activities

Cherries are good sources of bioactive phenolic compounds that are widely considered to be potentially healthy. Here we investigated the protective activities of juice and wine products of tart and sweet cherries and their constituent anthocyanins (e.g., cyanidin 3-glucoside and cyanidin 3-rutinoside) against oxidative stress induced by hydrogen peroxide (H₂O₂) in Chinese hamster lung fibroblasts (V79-4). Total phenolics in the cherry juices and wines were 56.7–86.8 mg of gallic acid equivalents (GAE)/l and 79.4–149 mg GAE/l, respectively. Total anthocyanins in the cherry juices and wines were 7.9–50.1 mg of cyanidin 3-glucoside equivalents (CGE)/l and 29.6–63.4 mg CGE/l, respectively. Both cherry juices and wines exerted protective effects against oxidative stress induced by H₂O₂ on V79-4 cells and also enhanced the activities of antioxidative enzymes, such as superoxide dismutase and catalase, in a dose-dependent manner. The protection of V79-4 cells from oxidative stress by phenolics was mainly attributable to anthocyanins. The positive correlation between the protective effects against oxidative stress in V79-4 cells and the antioxidant enzyme activities was stronger for cyanidin 3-glucoside than for cyanidin 3-rutinoside.     

Protein glycation inhibitory activity of wheat bran feruloyl oligosaccharides

Protein glycation is believed to play an important role in the development of long-term disorders associated with diabetes. Water-soluble feruloyl oligosaccharides (FOs) from wheat bran, the ferulic acid esters of oligosaccharides, have been reported as natural antioxidants. The present work assesses the chelating activity of FOs and their inhibition of protein glycation in a bovine serum albumin (BSA)/glucose system, using fluorescence spectroscopy and sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE). FOs exhibited an effective ferrous ion chelating activity, and quenched the fluorescence intensity of glycated BSA in a dose-dependent manner with 64.0% of inhibition at 1.0 mg/ml. Further, the formation of advanced glycation end products in the tested system was significantly decreased by FOs, as shown by SDS–PAGE. These data indicate that FOs might be beneficial as glycation inhibitors under specified conditions.     

Wheat bran feruloyl oligosaccharides enhance the antioxidant activity of rat plasma

Wheat bran feruloyl oligosaccharides (FOs) possess in vitro antioxidative potential. The aim of this paper is to investigate the protective effect of FOs against oxidative stress in rat plasma. The levels of oxidative stress markers (oxidised glutathione and malondialdehyde) and the activities of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) in plasma from rats fed with a standard diet supplemented with 1% FOs were evaluated. The anti-radical capacity of rat plasma after ingestion of 0.5 mg FOs was measured using AAPH as the free radical inducer. Compared to the control group, the antioxidant enzyme activity was higher in plasma from rats fed with FOs, and oxidised glutathione and malondialdehyde levels were lower. Plasmas of rats after ingestion of FOs were more resistant to AAPH-induced hemolysis than was the control group (P < 0.01). These results suggest that FOs enhance the level of antioxidative activity in rat plasma in vivo.     

Nonthermal starch hydrolysis using ultra high pressure: I. Effects of acids and starch concentrations

Corn starches with 2 mol/l hydrochloric acid (HCl), 2 mol/l sulfuric acid (H₂SO₄) and 2 mol/l oxalic acid (C₂H₂O₄) were pressurized at 600 MPa for 30 min. Corn starch with C₂H₂O₄ formed a gel after ultra-high-pressure (UHP) treatment. Corn starch with HCl showed partial disintegration but starch with H₂SO₄ maintained its shape. Corn starch with HCl showed higher (0.42-0.47) degree of hydrolysis compared to starch with C₂H₂O₄ (about 0.14) and H₂SO₄ (0.13-0.14) regardless of increasing starch concentration up to 20 g/100 g sample. Main component of starch hydrolysate was maltose for HCl and oligosaccharides for H₂SO₄ and C₂H₂O₄. Crystallinity of starch with HCl decreased with decreasing starch concentration as observed by both differential scanning calorimetry (DSC) and X-ray diffraction. Therefore, UHP can be used for nonthermal starch hydrolysis and HCl would be a good catalyst for UHP starch hydrolysis compared to H₂SO₄ and C₂H₂O₄. This work provides a potential of nonthermal UHP processing for new starch hydrolysis method.     

Wheat bran lipophilic compounds with in vitro anticancer effects

Wheat bran has been widely recognised as a cancer preventive agent, although the mechanism of the protection is not yet fully understood. Some reports suggested that, for the protection, lipophilic phytochemicals from the bran were more important than the physiological function of bran fibre. Wheat bran lipophilic extracts were scrutinised using bioactivity-guided fractionation (HPLC) against the growth of human prostate adenocarcinoma (PC3) cells. The fractions containing unsaturated free fatty acid, phytosteroids and alkylresorcinols exerted high cytotoxic activity. Detailed research of the alkylresorcinol fraction isolated seven pure compounds, four of them with strong inhibitory properties against the growth of PC3 cells, including 5-heptadecylresorcinol (IC₅₀ = 22.5 μg/ml), 5-(16-heneicosenyl)resorcinol (trans) (IC₅₀ = 13.7 μg/ml), 5-(14-nonadecenyl)resorcinol (trans) (IC₅₀ = 42.2 μg/ml) and 5-(2-oxotricosanyl)resorcinol (IC₅₀ = 10.9 μg/ml). The alkylresorcinols in wheat bran were quantified using a Single Ion Monitoring (SIM) method developed on LC-MS. The active alkylresorcinols were found to be minor components in wheat bran, however, they exerted higher cytotoxic effects on cancer cells than the positive control chlorambucil (IC₅₀ = 58.7 μg/ml). This research suggested that alkylresorcinols are important for the cancer preventive activity of wheat bran. Other lipophilic compounds such as some free unsaturated fatty acids and phytosteroids may also contribute to the anticancer activity.     

Partial purification and preparation of bovine lactoperoxidase and characterization of kinetic properties of its immobilized form incorporated into cross-linked alginate films

Lactoperoxidase (LPS), purified directly from bovine rennet whey by Toyopearl-SP cation-exchange chromatography and lyophilized by using dextran as supporting material, maintained almost 70 and 60% of its activity after almost 2 and 5 months storage at −18 °C, respectively. Incorporation of the prepared LPS into alginate films between 0.08 and 0.69 mg/cm² (516–4325 U/cm²) caused the immobilization of most of the enzyme and gave films with LPS activity between 0.05 and 2.8 U/cm², determined in the presence of 8 μM H₂O₂. Between 2 and 24 μM H₂O₂ concentrations, a two-fold increase in H₂O₂ concentration caused 1.5–2.5-fold increase in LPS activity of films incorporated with 0.24–0.28 mg/cm² (1200 U/cm²) LPS. The Q₁₀ and E_a of immobilized enzyme activity between 4 and 16 °C were 1.69 and 34.6 kJ/mol, respectively. However, in the 16–30 °C range, the temperature change had almost no effect on LPS activity of films. The optimal activity of immobilized LPS was observed at pH 6.0, but the enzyme maintained 30–85% of its activity between pH 3.0 and 7.0. The immobilized LPS also had a high stability between pH 4.0 and 6.0. The results of this study showed the good potential of LPS-incorporated alginate films in forming a natural antimicrobial mechanism in different foods.     

Purification and characterisation of an antioxidative peptide from enzymatic hydrolysates of duck processing by-products

Duck processing by-products were hydrolysed using eight proteases to produce an antioxidative peptide. Of the various hydrolysates produced, the pepsin extract exhibited the highest hydroxyl radical scavenging activity. The derived peptide was purified using high-performance liquid chromatography (HPLC) to identify any potent radical scavenging activity. The sequence of the antioxidative peptide obtained was identified as Asp-Val-Cys-Gly-Arg-Asp-Val-Asn-Gly-Tyr, with a molecular weight of 1096 Da. The IC₅₀ value of purified peptide for hydroxyl radical scavenging activity was 75 μg/ml as the measurement by an electron spin resonance (ESR) spectrometer. In addition, the purified peptide exhibited a protective effect on H₂O₂-induced DNA damage. These results indicate that the purified peptide possesses a potent antioxidative activity and protective effect of DNA against H₂O₂-induced oxidative damage.     

Unraveling a mechanism of honey antibacterial action: Polyphenol/H2O2-induced oxidative effect on bacterial cell growth and on DNA degradation

Several compounds with antibacterial activities were identified in honey however, a mechanism by which they lead to bacterial growth inhibition and bacterial death remains still unknown. We recently found that honeys possess DNA degrading activity mediated by honey hydrogen peroxide and an unknown honey component(s). Here we provide evidence that active honeys (MIC₉₀ of 6.25–12.5% v/v) possessed significantly higher levels of phenolics (p < 0.02) of higher radical scavenging activities (p < 0.005) than honeys of average activity. Removal of H₂O₂ by catalase eliminated bacteriostatic activities caused by both phenolics and H₂O₂ suggesting that the growth inhibition resulted from the coupling chemistry between these compounds. Both phenolics and H₂O₂ were involved in DNA degradation by honeys. Treatment of plasmid DNA with H₂O₂ alone did not affect the DNA integrity but H₂O₂ removal from honey by catalase prevented DNA degradation. Polyphenols extracted from honeys degraded plasmid DNA in the presence of H₂O₂ and Cu(II) in the Fenton-type reaction. The extent of DNA degradation was inversely related to the polyphenol concentration in this system as well as in honeys. At low content, honey polyphenols exerted pro-oxidant activity damaging to DNA. In conclusion, honey phenolics with pro-oxidant activities were necessary intermediates that conferred oxidative action of H₂O₂. Phenolic/H₂O₂-induced oxidative stress constituted the mechanism of honey bacteriostatic and DNA damaging activities.     

Antioxidant activity of sugarcane molasses against 2,2′-azobis(2-amidinopropane) dihydrochloride-induced peroxyl radicals

Sugarcane molasses is a rich source of antioxidant materials with peroxyl radical scavenging effects. To explore the potent antioxidant activity of sugarcane molasses against 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced peroxyl radicals, 7 methanolic fractions of sugarcane molasses (F1–F7) were separated via bioassay-guided fractionation and evaluated by oxygen radical absorbance capacity (ORAC), cellular antioxidant activity (CAA), and oxidative DNA damage protective activity assays. The ORAC values of sugarcane molasses fractions ranged from 4399 to 6266 μmol TE/g, whilst the EC₅₀ values for CAA ranged from 3.7 to 5.9 μg/ml. Moreover, it was found that sugarcane molasses fractions, particularly F6 and F7, could protect against oxidative DNA damage caused by peroxyl radicals at an effective concentration of 100 μg/ml. Ten phenolic constituents were identified in the fractions, including known antioxidative compounds, viz., schaftoside, isoschaftoside, ferulic acid, p-coumaric acid, and p-hydroxybenzaldehyde.     

Protective effect of two edible mushrooms against oxidative cell damage and their phenolic composition

The aim of the study was to investigate phenolic composition, antioxidative, protective and cytotoxic effects of Pleurotus eryngii and Auricularia auricula-judae. Analysis of phenolic compounds in these edible mushrooms species has been carried out by high-performance liquid chromatography (HPLC). Protective effect of these mushrooms on H₂O₂ induced oxidative cell damage was determined by using MTT (3-(4,5-Dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole) assay. Antioxidant activities of the mushrooms extracts were evaluated by using complementary in vitro assays. In addition, the measurement of total antioxidant compounds in the extracts was carried out. All the extracts exhibited protective effect against H₂O₂ induced oxidative cell damage but the highest activity was observed for A. auricula-judae aqueous extract (89.5 ± 1.8% cell viability at 0.1 mg/ml). P. eryngii methanolic extract showed the highest ferrous iron chelating ability (IC₅₀ = 0.42 ± 0.03 mg/ml). A. auricula-judae extracts (at concentration of 0.025–0.100 mg/ml) were not toxic to baby hamster kidney fibroblast cell line (BHK 21). These results suggest that these mushrooms may be used as a potential source of natural antioxidants for food supplementation or in the development of nutraceuticals.     

发酵麦麸阿魏酰低聚糖的纯化工艺及其心脏保护作用研究

以发酵麦麸阿魏酰低聚糖( Feruloylated oligosaccharides, FOs)粗提液为原料,研究Amberlite XAD-2 大孔吸附树脂结合Sephadex LH-20 葡聚糖凝胶对发酵麦麸FOs的纯化工艺和效果,同时考察分离纯化后发酵麦麸 FOs对斑马鱼心脏损伤的保护作用。结果表明：Amberlite XAD-2 大孔吸附树脂分离发酵麦麸FOs的最佳吸附条件为：上样液浓度4.0 mg /mL,上样液pH 4.0,上样体积40 mL,在此条件下吸附率可达83.76%;最佳的解吸条件为：乙醇浓度50%、洗脱体积15 mL,在此条件下解吸率可达94.80%。Sephadex LH-20 葡聚糖凝胶进一步纯化发酵麦麸FOs的最佳条件为：洗脱剂乙醇浓度25%,上样量1.25 mL,洗脱流速 0.3 mL/min,在此条件下,分离出的组分最多;紫外光谱分析表明纯化发酵麦麸 FOs中有阿魏酸的存在;纯化后发酵麦麸 FOs含量由粗提液的（1107.796 ± 52.18）nmol/g提高到（2217.38 ± 25.36 ）nmol/g,提高了2倍,纯化效果较佳;此外,经分离纯化后发酵麦麸FOs能有效缓解特非那定诱导的斑马鱼心率和降低斑马鱼心脏SV-BA间距,表明分离纯化后发酵麦麸 FOs具有良好的心脏保护作用。     

Isolation and purification of a novel antioxidant protein from the water extract of Sundakai (Solanum torvum) seeds

Reactive oxygen species (ROS) at physiological concentrations may be required for normal cell function. Excessive production of ROS can be detrimental to cells, because ROS can cause oxidative damage to lipids, proteins, and DNA. Herein, we describe the isolation and purification of a novel antioxidant protein the water extract of dried, powdered Sundakai (Solanum torvum [Solanaceae]) seeds. Sundakai belongs to the Solanaceae family, a small shrub, which is distributed widely in India, Malaya, China, Phillipines and tropical America. Fifty percent of ammonium sulphate-precipitated crude water extract was fractionated on a Sephadex G100 column, which yielded two peaks, PI and PII. Peaks PI and PII inhibited lipid peroxidation up to 40% and 89%, respectively in linolenic acid micelles. Rechromatographing of peak PII on Sephadex G100 yielded a single peak, indicating the homogeneity of the purified protein. SDS–PAGE analysis indicated the molecular weight of the purified protein to be ∼28 kDa. The purified protein, at 0.8 μM, inhibited deoxyribose degradation induced by generation of hydroxyl radicals by 90% and scavenged DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals by 76%. The reducing power and chelating power of the purified protein, at 0.8 μM, were found to be 72% and 85%, respectively. The protein, at 0.8 μM, also offered significant protection to calf thymus DNA damage induced by H₂O₂ (1 mM). Therefore, the present study demonstrates, for the first time, a novel protein from the water extract of Sundakai seeds as an excellent antioxidant.     

Dietary spices protect against hydrogen peroxide-induced DNA damage and inhibit nicotine-induced cancer cell migration

Spices are rich sources of antioxidants due to the presence of phenols and flavonoids. In this study, the DNA protecting activity and inhibition of nicotine-induced cancer cell migration of 9 spices were analysed. Murine fibroblasts (3T3-L1) and human breast cancer (MCF-7) cells were pre-treated with spice extracts and then exposed to H₂O₂ and nicotine. The comet assay was used to analyse the DNA damage. Among the 9 spices, ginger, at 50 μg/ml protected against 68% of DNA damage in 3T3-L1 cells. Caraway, cumin and fennel showed statistically significant (p < 0.05) DNA protecting activity. Treatment of MCF-7 cells with nicotine induced cell migration, whereas pre-treatment with spices reduced this migration. Pepper, long pepper and ginger exhibited a high rate of inhibition of cell migration. The results of this study prove that spices protect DNA and inhibit cancer cell migration.     

Antioxidant properties and chemical composition of technical Cashew Nut Shell Liquid (tCNSL)

The present study analysed the antioxidant activity of the technical Cashew Nut Shell Liquid (tCNSL) using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay and the xanthine oxidase assay, as well as in vivo evaluation by Saccharomycescerevisiae assay. Also, the chemical composition of tCNSL was determined by gas chromatography–mass spectrometry (GC–MS), revealing the presence of cardanols (40.26%), cardols (29.95%), phytosterol (10.68%), triacontanes (4.66%) and anacardic acid (1.79%). The DPPH-based assay results showed that tCNSL 1000 μg/ml reduced the radical level by 88.9%, and the scavenging of hydroxyl radicals in the xanthine oxidase assay indicated significant antioxidant activity (IC₅₀ = 702 μg/ml). In addition, tCNSL exerts an important protective effect against oxidative stress in yeast when used in 100–500 μg/ml concentration range, when exposed to paraquat or H₂O₂, indicating an in vivo antioxidant effect.     

Honey flavonoids as protection agents against oxidative damage to human red blood cells

Honey phenol extracts separated on the base of their hydrophobicity were evaluated for the antioxidant content and for the ability to inhibit oxidative damage induced by radical species generated in the water phase or in the membrane of human erythrocytes. The water and ether fractions obtained from crude methanol extract of honey exhibited a phenolic content of 5.33 and 2.62 mg caffeic acid equivalents/100 g honey, respectively. These values correlate well with those of total antioxidant power, as assessed by FRAP assay (37.67 vs. 10.65 μmol/100 g honey). Flavonoid contents were 2.57 and 1.64 mg catechin equivalents/100 g honey for ether and water fractions, respectively. Although both honey fractions protect erythrocytes against 2,2′-azobis(2-amidinopropane)dihydrochloride-induced lysis, only the ether fraction was found to be active in inhibiting hemolysis but not methemoglobin and ferrylhemoglobin formation caused by H₂O₂. In addition, the ether fraction prevents tert-butylhydroperoxide-induced lipid peroxidation in whole erythrocytes and in isolated membranes. The significant antioxidant effect against damages induced by both water-soluble and hydrophobic exogenous oxidants suggests that the ether fraction, owing to its lipophilic character, can interact with red blood cell membrane, and the protective effect can be associated with the binding of the flavonoids to the membrane. On the other hand, the water fraction is more hydrophilic than ether fraction and it acts only from the outside of the membrane by scavenging the radicals before they attack the erythrocyte membrane.     

Interactions between dietary fibre-rich preparations and glycoconjugated bile acids in vitro

Binding in small intestine and excretion of bile acids constitute a major hypocholesterolemic pathway. Interactions between different types of commercial and laboratory-made dietary fibres and glycoconjugated bile acids were investigated in vitro at pH 5.0 and 6.5. The interactions were greater at the lower pH and with dihydroxy-bile acids. Digested cereal products (barley, oat, rye and wheat flour; oat bran), alcohol-insoluble substances from apples, strawberries, rowan berries, carrots, white cabbage, red beets and sugar beet pulp, as well as arabinoxylan, bound 1.21–1.77 μmol bile acids/100 mg of preparation at pH 5.0. Novelose bound approximately 0.65 μmol bile acids/100 mg. Carob fibre had the highest binding capacity (1.83–1.96 μmol bile acids/100 mg) whereas cellulose had no effect. Besides the source and chemical composition, the bile acid binding correlated especially well with the presence of three-dimensional cell wall structures of the tested preparations but less well with the proportions of soluble and insoluble dietary fibre.     

Napiergrass (Pennisetum purpureum S.) protects oxidative damage of biomolecules and modulates antioxidant enzyme activity

The effects of water extract of napiergrass (Pennisetum purpureum S.) (WEN) on oxidative damage of biomolecules and modulation of antioxidant enzyme activity were investigated. The results showed that WEN displayed marked free radical scavenging, reducing power, as well as ferrous ions chelating effects. WEN has a dose-dependent response for protective action on oxidation of phospholipid, deoxyribose and low-density lipoprotein (LDL) in the range of 0–0.5 mg/ml, indicating that WEN had in vitro protective action on oxidative damage of biomolecules. Oxidative stress induced by H₂O₂ significantly decreased the viability of BNL cells. However, addition of WEN in the medium protected cells from H₂O₂-induced cytotoxicity. Furthermore, treatment of cells with WEN in the range of 0–0.2 mg/ml displayed protective effect from H₂O₂ induced oxidation in a concentration dependent manner. With respect to the effect of WEN on antioxidant enzymes, the results showed the WEN at 0.2 mg/ml enhanced activities of glutathione peroxidase (GPX), glutathione reductase (GR), glutathione transferase (GST) and catalase (CAT) in BNL cells by 2.93-, 35.8-, 4.23-, and 2.78-fold, respectively, compared to the control; WEN increased the GSH content by 3.2-fold, implying that WEN may up-regulate the levels of GSH and antioxidant enzymes in BNL cells. WEN scavenged NO generated by a NO donor, sodium nitroprusside (SNP) and suppressed NO production in lipopolysaccharide (LPS)-activated macrophage RAW 264.7 cells. The determination of ascorbic acid and total anthocyanins as well as HPLC analysis revealed that ascorbic acid, rutin, epicatechin, anthocyanins, p-coumaric acid, quercetin and catechin were present in WEN, which function as in vitro antioxidants by virtue of their ability to scavenge ROS and RNS. Overall, the results obtained showed that WEN is rich in antioxidant components and they can serve as an excellent potential for use as a natural phytochemicals source.     

Lycopene-rich fractions derived from pink guava by-product and their potential activity towards hydrogen peroxide-induced cellular and DNA damage

Effects of solvent and supercritical carbon dioxide (SC-CO₂) extraction on antioxidant and cytotoxic activities of lycopene-rich fractions of decanted pink guava by-product (decanter) were determined with lycopene-equivalent antioxidant capacity, β-carotene bleaching and MTT (3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide) assays. Extraction with SC-CO₂ gave a higher yield than solvent extraction (3.15 vs. 0.68 mg/100 g dried decanter, corresponding to 42.99 and 33.63 mg of lycopene). No cytotoxicity was found in Chang liver cells supplemented with either extracts (6.25–200 μg/ml). Solvent extract at 25 μg/ml (2.32 μM lycopene) and SC-CO₂ extract at 200 μg/ml (5.09 μM lycopene) had protective effect against hydrogen peroxide-induced cytotoxicity. However, only high concentrations of solvent extract (200 μg/ml; lycopene = 18.65 μM) or lycopene standard (10 μM) protected cells against DNA damage. Supercritical fluid extraction demonstrated a higher yield in lycopene-rich fraction from decanter. These fractions have the potential to be developed as a functional ingredient to prevent oxidative stress and other related diseases.     

Determination of hydrogen peroxide scavenging activity of phenolic acids by employing gold nanoshells precursor composites as nanoprobes

A series of phenolic acids were tested for their ability to scavenge hydrogen peroxide (H₂O₂) by using a novel enzyme-free, spectrophotometry assay. Gold nanoshells (GNSs) precursor composites were selected as the optical nanoprobes. The approach was based on the H₂O₂-induced growth of GNSs, which combines nanoscience with food/health research as an innovative detection scheme. The addition of phenolic acids inhibits the formation of complete GNSs and the corresponding peak wavelength changes rationally, which could be used as an optical signature. Among the tested samples, caffeic acid is found to be the most efficient H₂O₂-scavenger with its H₂O₂-scavenging activity being 125 × 10⁻³ μM⁻¹, whereas trans-cinnamic acid exhibits the weakest activity (0.73 × 10⁻³ μM⁻¹). Results obtained were considered on the basis of structure–activity relationships. Additionally, several tea and herb extracts were also evaluated. The presented wavelength-based detection method shows superiority in evaluating coloured samples, which avoids background interference compared with the conventional absorbance-based optical methods.