Soymilk phenolic compounds,isoflavones and antioxidant activity as affected by in vitro gastrointestinal digestion

The aim of this research was to evaluate changes in the phenolic compounds, isoflavones and antioxidant activity of soymilk following in vitro gastrointestinal digestion (including dialysis). Gastric digestion significantly influenced the release of bioactive substances from the soymilk matrix, increasing the concentration of total phenolic components (35% as the sum of individuals and 14% by Folin–Ciocalteu [F–C] method), total isoflavone content (22%) and total antioxidant activity (76%). The concentration of all those compounds was reduced significantly in the duodenal fraction in comparison to gastric digestion and their lowest concentration was observed in the dialysed fraction, where phenolic acids were not detected. The bioaccessibility of soymilk phenolic compounds was 15% as the sum of individuals and 20% by F–C assay; isoflavones 36% and constituents with antioxidant activity 27%. Results suggest that most of these compounds were sufficiently available to be absorbed and could contribute health benefits.     

Antioxidant activities of malt extract from barley (Hordeum vulgare L.) toward various oxidative stress in vitro and in vivo

The antioxidant activities of malt extract from barley were evaluated by various methods in vitro and in vivo. Scavenging effects on the hydroxyl and superoxide radicals, and protection against reactive oxygen species induced lipid, protein and DNA damage were evaluated. The d-galactose induced mouse aging model was used to evaluate ability of malt extract to behave as an antioxidant in vivo. The extract exhibited high antioxidant activities both in vitro and in vivo, evidenced by its ability to scavenge hydroxyl- and superoxide-radicals, high reducing power, and protection against biological macromolecular oxidative damage. Furthermore, malt extract prevented the decrease of antioxidant enzyme activities, decreased liver and brain malondialodehyde levels and carbonyl content, and improved total antioxidant capability in d-galactose-treated mice. In conclusion, these results demonstrate potential antioxidant activities and antiaging effect of malt, providing scientific support for the empirical use of malt as an antioxidant for diseases caused by reactive oxygen species.     

The in vitro and in vivo antioxidant properties of seabuckthorn (Hippophae rhamnoides L.) seed oil

The antioxidant capacity of seabuckthorn (Hippophae rhamnoides L.) seed oil was investigated with a number of established in vitro assays and in an in vivo study of carbon tetrachloride (CCl₄)-induced oxidative stress in mice. The results showed that DPPH radical scavenging activity, ferrous ion chelating activity, reducing power and inhibition of lipid peroxidation activity all increased with increasing concentrations of seabuckthorn seed oil. Moreover, the EC₅₀ values of seabuckthorn seed oil from the hydrogen peroxide, superoxide radical, hydroxyl radical scavenging assays were 2.63, 2.16 and 0.77 mg/ml, respectively. In the in vivo study, seabuckthorn seed oil inhibited the toxicity of CCl₄, as seen from the significantly increased activities of the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. The GSH content in the liver was also increased, whereas hepatic malondialdehyde was reduced. Taken together, these results clearly indicate that seabuckthorn seed oil has significant potential as a natural antioxidant agent.     

Quantification of the polyphenolic fraction and in vitro antioxidant and in vivo anti-hyperlipemic activities of Hibiscus sabdariffa aqueous extract

In the present study the quantification of the polyphenolic fraction, anthocyanins and other polar compounds, the antioxidant capacity and the anti-hyperlipemic action of the aqueous extract of Hibiscus sabdariffa has been achieved. Seventeen compounds were successfully quantified either by HPLC-DAD or HPLC-ESI-TOF-MS. Six of them were directly quantified by their corresponding standards, whereas the rest were indirectly quantified as equivalents using standards of similar compounds. The antioxidant capacity have also been estimated by comparing different assays, i,e, Trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and measurement of thiobarbituric acid reacting substances (TBARS). H. sabdariffa showed high reducing capacity in FRAP assay and significant capability to scavenge peroxyl radicals in the ORAC assay. Nevertheless, the extract exhibited poor efficacy to inhibit peroxyl radicals in lipid systems. The plant extract also exhibited the capacity to decrease serum triglyceride concentration on hyperlipemic mouse model.     

A comparative study of tocopherols composition and antioxidant properties of in vivo and in vitro ectomycorrhizal fungi

In aerobic organisms, the free radicals are constantly being produced during the normal cellular metabolism. The antioxidant properties of many organisms and particularly of wild mushrooms with their content in antioxidant compounds such as tocopherols, can detoxify potentially damaging forms of activated oxygen. Herein, a comparative study of tocopherols composition and antioxidant properties of in vivo (fruiting bodies) and in vitro (mycelia) ectomycorrhizal fungi: Paxillus involutus and Pisolithus arhizus. Tocopherols were determined by high performance liquid chromatography (HPLC) coupled to a fluorescence detector. The antioxidant properties were studied in terms of DPPH radical-scavenging activity, reducing power and inhibition of β-carotene bleaching. Fruiting bodies revealed the highest antioxidant properties, including scavenging effects on free radicals (EC₅₀ = 0.61 and 0.56 mg/ml) and inhibition of lipid peroxidation capacity (EC₅₀ = 0.40 and 0.24 mg/ml for P. involutus and P. arhizus, respectively), than mycelia produced in vitro cultures. Nevertheless, mycelia revealed higher levels of total tocopherols than fruiting bodies, and particularly P. arhizus mycelium proved to be a powerful source of γ-tocopherol (154.39 μg/g dry weight).     

Antioxidant and hepatoprotective activity of ethanolic extract of leaves of Solidago microglossa containing polyphenolic compounds

The antioxidative and hepatoprotective potential of Solidago microglossa D.C, a widely used medicinal plant from Brazil was investigated. The leaf extract showed inhibition against thiobarbituric acid reactive species (TBARS) induced by different prooxidants (10 μM FeSO₄ and 5 μM sodium nitroprusside SNP) in rat liver, brain and phospholipid homogenates from egg yolk. Moreover, the free radical scavenging activities of the extract was evaluated by the scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC_50, 3.8 ± 0.5 μg/ml) and hydroxyl radical on benzoic acid hydroxylation (IC_50, 32.3 ± 1.3 μg/ml) and deoxyribose (IC_50, 39.1 ± 2.4 μg/ml) assays. The ethanolic extract showed significant hepatoprotective activity against paracetamol (250 mg/kg) induced liver damage in mice in a dose dependent manner. The phenolic composition and their quantification by high performance liquid chromatography (HPLC) resulted in the identification of gallic acid and flavonoids: quercetrin (quercetin-3-O-rhamnoside), rutin (quercetin-3-O-rutinoside) and quercetin.     

Profiling of in vitro neurobiological effects and phenolic acids of selected endemic Salvia species

The ethyl acetate and methanol extracts from 16 Salvia L. species were screened for their inhibitory activity against acetylcholinesterase, butyrylcholinesterase, lipoxygenase, and tyrosinase; the enzymes linked to neurodegeneration. Their antioxidant activity was also tested using DPPH radical scavenging, metal-chelation, and ferric-reducing antioxidant power (FRAP) assays. Total flavonoid content of the extracts was determined by AlCl₃ reagent, while HPLC technique was applied for analysis of various phenolic acids in the extracts. The extracts exerted weak cholinesterase and tyrosinase inhibition, and remarkable inhibition against lipoxygenase (13.07 ± 2.73-74.21 ± 5.61%) at 100 μg ml⁻¹. The methanol extracts showed higher antioxidant activity in DPPH radical scavenging and FRAP assays. The extracts were analyzed for their gallic, protocateuchic, p-hydroxy-benzoic, vanillic, caffeic, chlorogenic, syringic, o- and p-coumaric, ferulic, rosmarinic, and tr-cinnamic acid contents and the methanol extract of Salvia ekimiana (153.50 mg 100 g⁻¹) was revealed to be the richest in terms of rosmarinic acid.     

In vitro scavenging capacity of annatto seed extracts against reactive oxygen and nitrogen species

Bixa orellana L. (annatto), from Bixaceae family, is a native plant of tropical America, which accumulates several carotenoids (including bixin and norbixin), terpenoids, tocotrienols and flavonoids with potential antioxidant activity. In the present study, the in vitro scavenging capacity of annatto seed extracts against reactive oxygen species (ROS) and reactive nitrogen species (RNS) was evaluated and compared to the bixin standard. Annatto extracts were obtained using solvents with different polarities and their phenolic compounds and bixin levels were determined by high performance liquid chromatography coupled to diode array detector. All annatto extracts were able to scavenge all the reactive species tested at the low μg/mL range, with the exception of superoxide radical. The ethanol:ethyl acetate and ethyl acetate extracts of annatto seeds, which presented the highest levels of hypolaetin and bixin, respectively, were the extracts with the highest antioxidant capacity, although bixin standard presented the lowest IC₅₀ values.     

Phenolic profiles of in vivo and in vitro grown Coriandrum sativum L.

Coriandrum sativum L. is a source of a variety of polyphenols and other phytochemicals, related to its high antioxidant activity and to its use for indigestion, rheumatism, and prevention of lipid peroxidation damage. Plant cell cultures are a means to study or to produce some active metabolites, such as polyphenols. This technique was applied to the investigation of coriander, and a detailed analysis of individual polyphenols in vivo and in vitro grown samples was performed. The in vivo vegetative parts showed quercetin derivatives as the main flavonoids and quercetin-3-O-rutinoside (3296 mg/kg dw) was the main polyphenol found in this part of coriander. The fruits revealed only phenolic acids and derivatives, caffeoyl N-tryptophan hexoside (45.33 mg/kg dw) being the most abundant phenolic derivative. In vitro samples also gave a high diversity of polyphenols, being C-glycosylated apigenin (2983 mg/kg dw) the main compound. Anthocyanins were only found in clone A, which was certainly related to its purple pigmentation, and peonidin-3-O-feruloylglucoside-5-O-glucoside was the major anthocyanin found (1.70 μg/kg dw). In vitro culture can be used to explore new industrial, pharmaceutical, and medicinal potentialities, such as the production of secondary metabolites like flavonoids.     

In vivo and in vitro antidiabetic effects of aqueous cinnamon extract and cinnamon polyphenol-enhanced food matrix

Cinnamon has a long history of medicinal use and continues to be valued for its therapeutic potential for improving metabolic disorders such as type 2 diabetes. In this study, a phytochemically-enhanced functional food ingredient that captures water soluble polyphenols from aqueous cinnamon extract (CE) onto a protein rich matrix was developed. CE and cinnamon polyphenol-enriched defatted soy flour (CDSF) were effective in acutely lowering fasting blood glucose levels in diet induced obese hyperglycemic mice at 300 and 600 mg/kg, respectively. To determine mechanisms of action, rat hepatoma cells were treated with CE and eluates of CDSF at a range of 1–25 μg/ml. CE and eluates of CDSF demonstrated dose-dependent inhibition of hepatic glucose production with significant levels of inhibition at 25 μg/ml. Furthermore, CE decreased the gene expression of two major regulators of hepatic gluconeogenesis, phosphoenolpyruvate carboxykinase and glucose-6-phosphatase. The hypoglycemic and insulin-like effects of CE and CDSF may help to ameliorate type 2 diabetes conditions.     

Identification of phenolic compounds from pomegranate (Punica granatum L.) seed residues and investigation into their antioxidant capacities by HPLC-ABTS assay

In this study, phenolic compounds were extracted and isolated from pomegranate seed residue (PSR). Phytochemicals and antioxidant capacity of extracts from PSR were firstly investigated. Total phenolic (TP) and proanthocyanidin (PC) contents of the extracts were determined as 2427.90 and 505.63 mg catechin equivalent of 100 g dry weight respectively. To evaluate the antioxidant capacity of individual compounds, on line assay of coupling high performance liquid chromatographic separation with ABTS free radical reaction system (HPLC-ABTS⁺) was carried out. 17 compounds in PSR extracts were detected with antioxidant capacity, and HPLC associated with electrospray ionization mass spectrometry (HPLC-ESI-MS) was used to identify them. The main phenolics in PSR identified were flavol-3-ols, phenolic acids, flavonoid glycosides, and hydrolysable tannin. The results showed that PSR contained some amount of antioxidant compounds, and the HPLC-ABTS⁺ on line method was fast, sensitive and effective.     

Antioxidant activity and phenolic compounds of fractions from Portulaca oleracea L.

Portulaca oleracea fractions obtained from the crude extract of the plant by reversed-phase separation were investigated for their antioxidant activities and phenolic compounds content. Five fractions were classified based on optical absorption between the wavelength range of 200–400 nm. Fraction 3 displayed higher absorption than the other fractions. The total amount of quantified phenolics in this fraction was found to be quite high compared to that of crude extract. Chlorogenic, caffeic, p-coumaric, ferulic and rosmarinic acids were the free phenolic acids, and quercetin and kaempferol were the free flavonoids detected in Fraction 3. IC₅₀ value of crude extract was found to be 511.8 μg/ml whereas Fraction 3 exhibited an IC₅₀ value of 154.1 μg/ml. TEAC of Fraction 3 was found to be almost four times higher than that of the crude extract. Fraction 3 was also found to show the highest lipid peroxidation inhibiting capacity, determined by TBARS assay.     

Antioxidant activity and phenolic compounds of Holotrichia parallela Motschulsky extracts

Insects have been relatively unexplored as potential sources of natural antioxidants. We report the antioxidant activity of extracts of the adult large black chafer beetle Holotrichia parallela Motschulsky, a common crop pest in China. The antioxidant activity of the ethanolic extract (EE) and the water extract (WE) of adult H. parallela were evaluated by four different in vitro assays. EE showed potent metal-chelating activity and inhibition of lipid peroxidation. WE proved to be an excellent antioxidant in the scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and metal-chelating activity. Catechin was identified in the ethanolic extract and proteins were the main components in the water extracts. Both compounds could contribute to the antioxidant activity of the species. These results suggest that adult H. parallela might be used as a nutraceutical to alleviate oxidate-induced diseases and as a natural antioxidant additive in the food industry.     

In vivo antitumoural activity and composition of an oil extract of Brazilian propolis

The present study aimed to evaluate in vivo and in vitro the antitumoural activity of a propolis extract obtained with edible vegetable oil and its fractions and also to investigate its chemical composition by LC–MS and LC–MS/MS. To evaluate the toxicological aspects related to the propolis extract treatment, hematological, biochemical, histopathological and morphological analyses of treated animals were performed. All propolis extracts showed an in vivo antitumour activity in the experimental model with a moderate toxicity effect at experimental exposure levels. The oil extract was as effective as the ethanolic extract at inhibiting tumour growth. In vitro assays showed that the whole oil extract produced better inhibition of tumour cells than its fractions. LC–MS and LC–MS/MS identified four phenolic acids and three flavonoids. The anticancer potential of the oil extract of propolis has been demonstrated and the edible vegetable oil was shown as an attractive alternative solvent to extract bioactive natural propolis components.     

In vitro antioxidant activity of liquor and semi-purified fractions from fermented squid pen biowaste by Serratia ureilytica TKU013

Antioxidative activities were found in the culture supernatant of Serratia ureilytica TKU013 with squid pen as the sole carbon/nitrogen source. The 4th day supernatant showed the strongest antioxidant activities and the highest total phenolic content. The supernatant was further purified by liquid–liquid partition, and it was found that the ethyl acetate-soluble (EA) extract exhibited the strongest antioxidant activity in a DPPH radical-scavenging assay and this was compared with the positive control, α-tocopherol. This extract was further divided into eight fractions, designated as F1–F8, by silica gel liquid chromatography. In most cases, F4 and F8 were found to possess the strongest antioxidative activities. Significant associations between the antioxidant potency and the total phenolic content, as well as between the antioxidant potency and free amino groups, were found for the supernatant, extract, and fractions. With this method, squid pen waste can be utilized and has potential in the production of functional foods.     

A comparison between bark extracts from Pinus pinaster and Pinus radiata: Antioxidant activity and procyanidin composition

The composition and antiradical activity of procyanidins from the bark of two kinds of pine, Pinus pinaster and Pinus radiata, were compared. Both the total bark extract and the fraction soluble in both water and ethyl acetate (OW) were evaluated, because of their promising results in previous experiments.     

In vitro antioxidant activity and in vivo anti-fatigue effect of loach (Misgurnus anguillicaudatus) peptides prepared by papain digestion

The in vitro antioxidant activity and in vivo anti-fatigue activity of loach peptide (LP) were determined. Results showed that LP contained the amino acids, which were expected to contribute to its antioxidant and anti-fatigue activities. LP could scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC₅₀ 17.0 ± 0.54 mg/ml) and hydroxyl radicals (IC₅₀ 2.64 ± 0.29 mg/ml). It could chelate cupric ion and inhibit the lipid peroxidation in a linoleic acid emulsion system. It also prolonged the swimming time to exhaustion of mice by 20–28% compared to the control. It increased the levels of blood glucose (28–42% increase) and liver glycogen (2.3–3.0-fold increase). It decreased the levels of lactic acid and blood urea nitrogen by 10.9–27.5% and 8.6–17.5%, respectively. It also improved the endogenous cellular antioxidant enzymes in mice by increasing the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). Therefore, LP can increase an endurance capacity and facilitate recovery from fatigue.