Quality assessment of Red Yeast Rice by fingerprint and fingerprint-effect relationship combined with antioxidant activity

Red Yeast Rice (RYR) is an important functional food ingredient that plays a critical role in promoting dietary guidance and maintaining health. To ensure its quality, four key compounds were quantified, and both HPLC fingerprint and electrochemical fingerprint (ECFP) were applied to assess quality. Additionally, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+•) scavenging test and ECFP were applied to assay the total antioxidant activity, with ascorbic acid as the positive control. The results showed that the holistic quality of samples was divided into 4 grades based on HPLC fingerprint analysis by the comprehensive linear quantitative fingerprint method. Additionally, the area of the total peak (Atp) in ECFP was found to be linearly correlated with the antioxidant activity (R > 0.99). A further fingerprint-efficacy relationship analysis determined the significant contributions to the antioxidant activity of peaks 20-Daidzein, 21-Glycitein, and 24-Genistein. Overall, this study suggested a comprehensive and reliable approach to the quality assessment of RYR.

Involvement of the Keap1-Nrf2-ARE pathway in the antioxidant activity of sinomenine

Sinomenine is a pure alkaloid isolated from Sinomenium acutum. This study is aimed to investigate the critical role of the nuclear factor erythroid 2-related factor 2 (Nrf2)-kelch-like ECH-associated protein-1(Keap1)-antioxidant response element (ARE) antioxidative signaling pathway in protecting sinomenine against H2O2-induced oxidative injury. Cytotoxicity and antioxidant experiments to initially determine the protective effects of sinomenine show that sinomenine has no effect on the decreased cell viability and presents similar potency in scavenging all three free radicals. The binding affinity between sinomenine and Keap1 was determined via fluorescence polarization assay, with IC50 of 13.52 μM. Quantum chemical calculation and theoretical simulation illustrated that sinomenine located into the Nrf2-binding site of Keap1 via hydrophobic and hydrogen interactions, showing high stability and binding affinity. On the basis of the stable binding of sinomenine with Keap1, sinomenine efficiently induced nuclear translocation of Nrf2, and increased in ARE activity in a concentration-dependent manner. Quantitative polymerase chain reaction provided further evidences that sinomenine-induced protection upregulated ARE-dependent genes, such as NAD(P)H quinone oxidoreductase 1, hemeoxygenase-1, and glutamate-cysteine ligase modifier subunit. Western blot confirmed that sinomenine increased the expressions of these antioxidative enzymes. Taken together, in vitro and in silico evaluations demonstrate that sinomenine inhibits the binding of Keap1 to Nrf2, promotes the nuclear accumulation of Nrf2 and thus leads to the upregulated expressions of Nrf2-dependent antioxidative genes. Our findings also highlight the use of sinomenine for pharmacological or therapeutic regulation of the Nrf2-Keap1-ARE system, which is a novel strategy to prevent the progression of oxidative injury.

Green extraction, chemical composition, and in vitro antioxidant activity of theabrownins from Kangzhuan dark tea

Theabrownins (TBs) in dark tea have received increasing attention for their multiple health benefits. In this study, ultrasound assisted extraction with deep eutectic solvent (UAE-DES) was developed for the extraction of TBs from Kangzhuan dark tea (KZDT). The highest yield (12.59%) of TBs was obtained using UAE-choline (ChCl)/malic acid (MA) with a liquid to solid ratio of 20:1 (v/w), ultrasonic power of 577 W, ultrasonic time of 25 min, and water content of 30%. TBs were further eluded by silica gel to obtain six theabrownine fractions (TBFs), namely, TBFs1, TBFs2, TBFs3, TBFs4, TBFs5, and TBFs6. LC-MS/MS revealed that flavonoids, terpenes, phenolic acids, alkaloids, lipids, and amino acids are the leading components of TBFs. The TBFs4, with the DPPH, ABTS, and FRAP values of 45.08 ± 0.42 μM Ascorbic acid/g DW, 178.52 ± 0.29 μM Trolox/g DW, and 370.85 ± 6.00 μM Fe(II)/g DW, respectively, showed the highest antioxidant activity among all the TBFs. Overall, this study first provided the evidence that UAE-ChCl/MA combining with silica gel was effective to extract TBs from KZDT, and the 6,7-dihydroxycoumarin-6-glucoside and neohesperidin were found as the leading compounds in the TBFs, providing a guidance for the chemical research and further utilization of dark tea and its TBs.

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Yield of TBs of 12.59% from KZDT was achieved by UAE-ChCl/MA.

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Silica gel powder with methanol (100%–0%) as a mobile phase was used for TBs separation.

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The chemical component of TBFs was revealed.

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Flavonoids are among the leading compounds in the TBFs.

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TBFs4 displayed the highest in vitro antioxidant activity.

Chemical typicity of tropical tannat red wines from sub-middle São Francisco Valley, Brazil

Tannat is a Vitis vinifera cultivar with typically high phenolic compound contents, showing intense coloration, well-bodied, and great aging potential. However, even with this great potential, this variety is still commercially underexplored in the Sub-middle São Francisco Valley (SSFV). This work aimed to characterize the typicity of Tannat red wines from Sub-middle São Francisco Valley (SSFV), Brazil. In addition, the present work represents the first study featuring phenolic compounds quantification and antioxidant activity of Tannat in tropical climate wine-producing regions. Considering the condition of a short-applied maceration time during the winemaking, the tropical Tannat wine showed significant antioxidant activity and high phenolic contents. Trans-caftaric, malvidin-3-O-glucoside, and procyanidin B1 stood out among the phenolic compounds quantified, presenting Tannat with the potential to be an important grape variety to tropical wine-producing regions in Brazil, containing high contents of bioactive compounds. Previously results to compounds (-)-epigallocatechin gallate, procyanidin B2, quercetin-3-β-D-glucoside, pelargonidin-3-O-glucoside, chlorogenic acid, and piceatannol were not found in Tannat wines. Further studies are necessary to make the Tannat grape's adaptation better in tropical climate conditions, including investigating the phenolic profile and antioxidant activity of Tannat red wines with longer maceration times during the winemaking.

Graphical abstract

Isolation, characterization and in vitro antioxidant activity screening of pure compound from black pepper (Piper nigrum)

The present study's aims of isolation, characterization and in vitro antioxidant activity screening of pure compound from Black pepper (Piper nigrum) were investigated. Nowadays, scientific exploration of medicinal plants from natural sources has become the prime concern globally. All the crude drugs that have been isolated from natural plant origin (herbs, root, stem, bark, fruit and flower) have great significance in drug discovery as well as a lead compound to demonstrate great synergistic effect on pharmacology. For this research work, methanol was selected as a mother solvent, and the crude methanolic extract of black pepper was partitioned in between the solvent chloroform and di-ethyl-ether. A crystal fraction has been eradicated from the chloroform extract of black pepper (Piper nigrum). The crystal compound (C₁) was isolated and purified by using thin layer chromatography (TLC) and recrystallization technique. The purified crystal compound (C₁) isolated from black pepper possesses a strong in vitro antioxidant activity. The IC₅₀ value of crystal compound (C₁) was 4.1 µg/ml where the standard one had 3.2 µg/ml. Physical, phytochemical and chromatographical characterization of pure crystal compound (C₁) has been explored, and from the analysis of all characteristics, it was found that, crystal compound (C₁) might have resembling features of the standard Piperine of black pepper. The overall research work was really remarkable and introduced a convenient way of isolating pure compound from the natural source which will be a great referential resource in isolating crude drugs for future analysis.

Phytochemical screening, total polyphenol, flavonoid content, in vitro antioxidant and antibacterial activities of Sri Lankan varieties of Murraya koenigii and Micromelum minutum leaves

The use of plant materials in traditional medicine as a significant ingredient in synthesizing drugs in the form of decoctions had played a vital role due to their potential therapeutic action. The curry leaves, Murraya koenigii, and Micromelum minutum are two most common aromatic herbs widespread in Sri Lanka and many other Asian countries. They are rich in nutrition and exert several medicinal properties such as antidiabetic, antioxidant, antimicrobial, anti-inflammatory, and anti-carcinogenic due to various essential phytochemicals, minerals, and trace minerals. In this study, we determined the proximate composition, in vitro antioxidant activity, total phenol (TPC), flavonoid content (TFC), and antibacterial activity in both species using standard methods. Results showed that both species varied greatly in nutritional composition, antioxidant, and antibacterial activities. The nutrient composition in terms of ash, crude protein, and fat was significantly high in M. koenigii based on dry weight basis. In vitro antioxidant potential of M. koenigii and M. minutum was evaluated by means of the DPPH radical scavenging assay, and the IC₅₀ values of M. koenigii and M. minutum were 107 ± 2 μg/mL and 208 ± 4 μg/mL, respectively. The TPC and TFC of M. koenigii were 101 ± 1 mg GAE/g and 9.75 ± 0.05 mg QE/g, and M. minutum were 80 ± 2 mg GAE/g and 9.16 ± 0.02 mg QE/g respectively. The antibacterial study was assessed against three bacterial strains. The study showed the highest inhibitory activity for M. koenigii and M. minutum against Staphylococcus aureus and Escherichia coli, respectively at 1.0 mg/mL concentration. The study indicated that M. koenigii possessed a significantly high TPC, and TFC correlated with higher antibacterial and antioxidant activity than M. minutum.

Phytochemical screening and DPPH radical scavenging activity of three morphotypes of Mauritia flexuosa L.f. from Peru, and thermal stability of a milk-based beverage enriched with carotenoids from these fruits

Mauritia flexuosa L.f. is a palm tree which presents great morphological variability (morphotypes), represented mainly by the mesocarp color of its fruits. The objective of the study was to characterize the physicochemical and antioxidant properties of three morphotypes of Mauritia flexuosa L.f. (“Yellow”, “Colour” and “Shambo”) of greater economic importance in the Peruvian Amazon. “Shambo” showed a significantly high content of bioactive compounds (total phenolics, flavonoids and carotenoids) and DPPH radical scavenging activity compared to the “Yellow” and “Colour” morphotypes (p ≤ 0.05). There was a significant correlation between DPPH radical scavenging activity and total phenolics, flavonoids and carotenoids (p ≤ 0.01). Furthermore, milk-based beverages enriched with carotenoids of those morphotypes of Mauritia flexuosa L.f. have been shown to be a good source of bioactive compounds for use in the food industry. The milk-based beverages enriched with carotenoids of those morphotypes of Mauritia flexuosa L.f. showed higher lightness (L∗) and yellowness (b∗).

Inclusion complexes between chrysin and amino-appended β-cyclodextrins (ACDs): Binding behavior, water solubility, in vitro antioxidant activity and cytotoxicity

Solid inclusion complexes between chrysin and four amino-appended β-cyclodextrins (ACDs) were prepared by suspension method and characterized in solid and solution states by kinds of analytical methods. The scanning electron microscopy (SEM) showed distinct micro-morphologies of them. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis revealed their unique thermal properties, such as decomposition temperatures and endothermic points. Powder X-ray diffractometry (XRD) analysis disclosed their unique crystal patterns. Their nuclear magnetic resonance (NMR) analyses provided the variations of chemical shifts before and after the formation of inclusion complexes. Their binding stability constants (Ks) were 574, 842, 704, and 474 L·mol^-1, respectively, as determined by spectral titration. A 1:1 inclusion mode with self-assembly of their amino side chains inside the ACD cavity was proposed based on Job plot and 2D-ROESY experiments. Water solubility of chrysin was promoted up to 4411.98 μg·mL^-1 after formation of inclusion complexes with ACDs, better than that of β-CD and its derivatives, i.e., HP- and SBE-β-CD. In vitro antioxidant activity of chrysin was also improved after inclusion complexation by the DPPH scavenging assay. Furthermore, in vitro cytotoxicity of solid inclusion complexes towards three human cancer cell lines, A549, HT-29 and HCT116 were enhanced significantly.

In vitro and in vivo antioxidant potential of milks, yoghurts, fermented milks and cheeses: a narrative review of evidence

The antioxidant potential (AP) is an important nutritional property of foods, as increased oxidative stress is involved in most diet-related chronic diseases. In dairy products, the protein fraction contains antioxidant activity, especially casein. Other antioxidants include: antioxidant enzymes; lactoferrin; conjugated linoleic acid; coenzyme Q10; vitamins C, E, A and D3; equol; uric acid; carotenoids; and mineral activators of antioxidant enzymes. The AP of dairy products has been extensively studied in vitro, with few studies in animals and human subjects. Available in vivo studies greatly differ in their design and objectives. Overall, on a 100 g fresh weight-basis, AP of dairy products is close to that of grain-based foods and vegetable or fruit juices. Among dairy products, cheeses present the highest AP due to their higher protein content. AP of milk increases during digestion by up to 2·5 times because of released antioxidant peptides. AP of casein is linked to specific amino acids, whereas β-lactoglobulin thiol groups play a major role in the AP of whey. Thermal treatments such as ultra-high temperature processing have no clear effect on the AP of milk. Raw fat-rich milks have higher AP than less fat-rich milk, because of lipophilic antioxidants. Probiotic yoghurts and fermented milks have higher AP than conventional yoghurt and milk because proteolysis by probiotics releases antioxidant peptides. Among the probiotics, Lactobacillus casei/acidophilus leads to the highest AP. The data are insufficient for cheese, but fermentation-based changes appear to make a positive impact on AP. In conclusion, AP might participate in the reported dairy product-protective effects against some chronic diseases.

Phenolic profile and antioxidant activity from non-toxic Mexican Jatropha curcas L. shell methanolic extracts

Jatropha curcas seed shells are the by-product obtained during oil extraction process. Recently, its chemical composition has gained attention since its potential applications. The aim of this study was to identify phenolic compounds profile from a non-toxic J. curcas shell from Mexico, besides, evaluate J. curcas shell methanolic extract (JcSME) antioxidant activity. Free, conjugate and bound phenolics were fractionated and quantified (606.7, 193.32 and 909.59 μg/g shell, respectively) and 13 individual phenolic compounds were detected by HPLC. The radical-scavenging activity of JcSME was similar to Trolox and ascorbic acid by DPPH assay while by ABTS assay it was similar to BHT. Effective antioxidant capacity by ORAC was found (426.44 ± 53.39 μmol Trolox equivalents/g shell). The Mexican non-toxic J. curcas shell is rich in phenolic compounds with high antioxidant activity; hence, it could be considerate as a good source of natural antioxidants.

Phyto-mediated nanostructured carriers based on dual vegetable actives involved in the prevention of cellular damage

The growing scientific interest in exploitation of vegetable bioactives has raised a number of questions regarding their imminent presence in pharmaceutical formulations. This study intends to demonstrate that a dual combination between vegetable oil (e.g. thistle oil, safflower oil, sea buckthorn oil) and a carrot extract represents an optimal approach to formulate safe carrier systems that manifest cell regeneration effect and promising antioxidant and anti-inflammatory activity. Inclusion of both natural actives into lipid carriers imparted a strong negative charge on the nanocarrier surface (up to -45mV) and displayed average sizes of 70nm to 140nm. The entrapment efficiency of carrot extract into nanostructured carriers ranged between 78.3 and 88.3%. The in vitro release study has demonstrated that the entrapment of the extract represents a viable way for an equilibrated release of carotenoids. Besides the excellent antioxidant properties (e.g. scavenging up to 98% of the free oxygen radicals), the results of cellular integrity (e.g. cell viability of 133%) recommend these nanocarriers based on dual carrot extract-bioactive oil as a promising trend for the treatment of certain disorders in which oxidative stress plays a prominent role. In addition, the lipid nanocarriers based on safflower oil and sea buckthorn oil demonstrated an anti-inflammatory effect on LPS induced THP-1 macrophages, by inhibiting the secretion of two pro-inflammatory cytokines, IL-6 and TNF-α.

Improved in vitro digestion stability of (-)-epigallocatechin gallate through nanoliposome encapsulation

(-)-Epigallocatechin gallate (EGCG) is unstable and degraded in near-neutral or alkaline fluids. To overcome its limitation, EGCG nanoliposome (EN) was prepared by an ethanol injection method combined with dynamic high-pressure microfluidization. EN possessed good physicochemical characterizations (high entrapment efficiency=92.1%, small average particle size=71.7nm, low polydispersity index=0.286 and zeta potential=-10.81mv). EN exhibited a relative good sustained release property. Stability of EGCG in simulated intestinal fluid (SIF) was significantly improved by nanoliposome encapsulation. After 1.5h incubating in SIF without or with pancreatin, the residual EGCG of EN was 31.2% and 47.7% respectively, but the residual EGCG in EGCG solution was only 3.4% and 3.5% respectively. The degenerations of in vitro antioxidant activities of EGCG were effectively slowed by nanoliposome encapsulation. This study expects to provide theories and practice guides for further applications of EN.

Appraisal of in vitro and in vivo antioxidant activity potential of cornelian cherry leaves

The antioxidant activity of the 80% methanolic extract of Cornus mas L. leaves (CMM) was evaluated by various methods both in vitro and in vivo. In vitro screening tests indicated that CMM had high antioxidant activity in terms of free radical scavenging and metal reducing activity. In vivo antioxidant activity studies in normal healthy rats demonstrated that the total antioxidant capacity of liver homogenates were increased, although no changes were observed in the activities of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase or in the level of lipid peroxidation. Studies on CCl4-treated rats also showed that CMM restored the activities of antioxidant enzymes, lowered the level of lipid peroxidation and elevated the total antioxidant capacities of both the total blood and liver homogenates of the animals. Further activity-guided fractionation studies led to the isolation of gallic acid, a well-known antioxidant, as one of the active components.

In vitro antioxidant and anticancer activity studies on drosera indica L. (Droseraceae)

PURPOSE

The aim of present in vitro studies was performed to examine the antioxidant and anticancer activities of ethanol and aqueous extracts of Drosera indica L.

METHODS

Different concentrations (5 - 640mcg/ml) of the ethanol (EEDI) and aqueous (AEDI) extracts of D.indica L were used in various antioxidant assay methods such as hydroxyl radicals, DPPH, super oxide radical scavenging activity, chelating ability of ferrous ion, nitric oxide radical inhibition, ABTS and reducing power. Ascorbic acid (AA) was used as the standard antioxidant for the free radical scavenging assays. Dalton's Ascitic Lymphoma (DAL) and Ehrlich Ascitic Carcinoma (EAC) cell lines were used as the in vitro cancer models for the tryphan blue dye and LDH leakage assays, where 5 to 250mcg /ml of both EEDI and AEDI were tested.

RESULTS

EEDI showed antioxidant activities with the minimum IC50 values of 34.8±0.43 mcg/ml in scavenging of hydroxyl radical and moreover AEDI showed minimum IC50 values of 94.51±0.84 mcg/ml in Fe(2+)chelating assay. EEDI on the reducing power assay and ABTS showed higher IC50 than standard AA. IC50 values of AEDI on Fe(2+) chelating assay and super oxide radical assay was lesser than IC50 value of AA. Both extracts at 250mcg/ml dose showed remarkable increase in the percentage of dead cancer cells (90% by EEDI and 86% by AEDI in DAL model and 89% by EEDI and 80% by AEDI in EAC model).

CONCLUSION

It is concluded from this study that D.indica L exhibited excellent antioxidant activity against the different in vitro antioxidant models and anticancer activity against the two different cell lines tested.