•Discusses selection of optimal antioxidant/antibacterial assays.•Discusses strengths and weaknesses of many common antioxidant/antibacterial assays.•Highlights alternative assays.
Natural product ...research is an active branch of science, driven by the increased value placed on individual health and well-being. Many naturally-occurring phytochemicals in plants, fruits and vegetables have been reported to exhibit antioxidant and antibacterial activity; often touted as being beneficial for human health. In vitro screening is a common practice in many research laboratories as a means of rapidly assessing these properties. However, the methods used by many are not necessarily optimal; a result of poor standardization, redundant assays and/or outdated methodology. This review primarily aims to give a better understanding in the selection of in vitro assays, with emphasis placed on some common assays such as the total phenolic content assay, free radical scavenging activity, disc-diffusion and broth microdilution. This includes a discussion on the reasons for choosing a particular assay, its strengths and weaknesses, ways to improve the accuracy of results and alternative assays.
The effect of Argentine propolis extracts against enzymes related to metabolic syndrome and oxidative stress, as well as the botanical origin of raw propolis, were studied. Histological and chemical ...analyses of propolis samples revealed that the botanical origin is Zuccagnia punctata, an Argentine medicinal plant. The melissopalynological analysis showed both pollen grains of Z. punctata and the other plant species. This result indicates that the differences found in the botanical remains compared to the palynological studies may have been caused by the bees selecting resinous shrubs mainly of Z. punctata for the production of propolis and other plants with flowers for the production of honey.
The richness of propolis was remarkable in two flavonoid precursors (2´,4´‐dihydroxy‐3´‐methoxychalcone, 2´,4´‐dihydroxychalcone), the major chemical components of Z. punctata. The hydroalcoholic extracts of Argentine propolis and Z. punctata were able to inhibit enzymes associated with the metabolic syndrome, including α‐glucosidase, α‐amylase and lipase, with IC50 values between 7 to 14, 37 to 48, and 13 to 28 µg/mL, respectively. Biological activity was mainly attributed to chalcones. Oxygen and nitrogen reactive species scavenging activity was determined by the assays of superoxide radical (O2•−), hydroxyl radical (HO•), hydrogen peroxide (H2O2), nitric oxide (NO•), and cation radical (ABTS•+). Results showed SC50 values between 115 to 278, 12.50 to 46; 39 to 92; 50 to 104.50 and 23 to 33.75 µg/mL, respectively. This study suggests for the first time that propolis from Argentina is highly effective in inhibiting enzymes related to the metabolic syndrome and in free‐radical scavenging that would justify its use as a dietary supplement or as a functional ingredient in special food.
Practical Application
Propolis from Catamarca, Argentina, is traditionally used as medicine and food. Its botanical origin is Zuccagnia punctata, an endemic plant species popularly used as a medicine in Argentina. Propolis has the ability to regulate the activity of enzymes involved in the carbohydrate and lipid metabolism, and consequently in metabolic syndrome. Besides, its antioxidant capacity makes it a natural product that can be used as a dietary supplement or as a functional ingredient in special foods. It is important to highlight that in the Argentine Food Code, propolis was incorporated in 2008 as a dietary supplement and the present results give major added value to this product.
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•Sphingobium yanoikuyae BBL01 was isolated from marine habitat.•Strain able to produce a heteropolysaccharides i.e., 2.63 ± 0.02 g/L EPS.•Exopolysaccharide was composed of seven ...different monosaccharides units.•Exopolysaccharide was thermally stable up to 233 °C.•EPS showed emulsifying, flocculating, and metal chelating activity.
In the present study, an exopolysaccharide (EPS)-producing bacterial strain was isolated from the Eastern Sea (Sokcho Beach) of South Korea and identified as Sphingobium yanoikuyae BBL01. Media optimization was performed using response surface design, and a yield of 2.63 ± 0.02 g/L EPS was achieved. Purified EPS produced using lactose as the main carbon source was analyzed by GC–MS and found to be composed of α-D-xylopyranose (28.6 ± 2.0%), β-D-glucopyranose (21.0 ± 1.6%), α-D-mannopyranose (18.5 ± 1.2%), β-d-mannopyranose (13.1 ± 1.4%), β-D-xylopyranose (10.2 ± 2.1%), α-d-talopyranose (5.9 ± 1.1%), and β-d-galacturonic acid (2.43 ± 0.8%). Interestingly, different carbon sources (glucose, galactose, glycerol, lactose, sucrose, and xylose) showed no effect on EPS monomer composition, with a slight change in the mass percentage of various monosaccharides. Purified EPS was stable up to 233 °C, indicating its possible suitability as a thickening and gelling agent for food-related applications. EPS also showed considerable emulsifying, flocculating, free-radical scavenging, and metal-complexion activity, suggesting various biotechnological applications.
Unsymmetrical thiourea of general formula RR’CS where R ≠ R′, were prepared by treating phenyisothiocayanate with iso-butylamine and tert-butylamine and respective thiourea derivatives, ...isobutylphenylthiourea (1) and tert-butylphenylthiourea (2) were obtained. These ligands were treated with ZnCl2, CdCl2 and HgI2 and neutral complexes bis(isobutylphenylthiourea)dichlorozinc(II) 3, bis(tert-butylphenylthiourea)dichlorozinc(II) 4, bis(isobutylphenylthiourea)dichlorocadmium(II) 5, bis(tert-butylphenylthiourea)dichl-orocadmium(II) 6, bis(isobutylphenylthiourea)diiodomercurry(II) 7, bis(tert-butylphenyl-thiourea)diiodomercurry(II) 8 were obtained. All compounds were structurally characterized with the help of FT-IR and NMR (1H and 13C) spectroscopy. Compounds 2, 3, 5, 7 are crystalline and their structure was confirmed by SC-XRD. Complexes and their starting precursors were evaluated for their antioxidant and enzyme inhibition potentials. Some of the compounds exhibited excellent antioxidant potentials. Molecular docking studies were also carried out for compounds 1–8.
Unsymmetrical thiourea of general formula RR’CS where R ≠ R′, were used as ligands and complexes of general formula M(Tu)2Cl2 were obtained. All compounds were structurally characterized with the help of FT-IR, NMR (1H and 13C) spectroscopy and structure of a ligand and three complexes was confirmed by SC-XRD. All compounds were evaluated for their antioxidant and enzyme inhibition potentials. Some of the compounds exhibited excellent antioxidant potentials. Molecular docking studies were also carried out for compounds. Display omitted
•Asymmetrical thiourea of general formula RR’CS and their Zn/Cd/Hg metal complexes were synthesized.•Structure of compounds were elucidated from respective FT-IR, NMR spectroscopic data.•Structure of a ligand and three complexes were confirmed by single crystal X-ray diffraction.•Ligands and respective complexes were evaluated as antioxidant agents and AChE and BChE inhibitor.•Molecular docking studies were carried out for all compounds.
The applications of clove (Syzygium aromaticum) essential oil (CEO) are limited by instability, low solubility and high volatility. The present study aimed to improve the properties of CEO by ...microencapsulation with cyclodextrin metal organic frameworks (β-CD-MOFs) to enhance the preservation effects on Chinese bacon (preserved meat products). The microencapsulated CEO by β-CD-MOFs (CEO/β-CD-MOFs) not only did not inhibit the antioxidant activities of CEO, but also showed significant improvements on their ROS scavenging abilities and thermo-/pH-stabilities. The increases of superoxide anion and hydroxyl radical scavenging activities were 20.74% and 12.84%, respectively. In addition, less lipid oxidation, including malondialdehyde (MDA) contents and peroxide values (POV), of Chinese bacon was found after the CEO/β-CD-MOFs treatment than CEO and synthetic antioxidant (BHT) treatments. These results suggested the enhanced preservation effects of microencapsulated CEO on the processing of Chinese bacon and the great potential of β-CD-MOFs as carriers for essential oils in food industry applications.
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•Free radical scavenging activities of CEO in vitro were improved after microencapsulation by β-CD-MOFs.•Both the thermo- and pH-stabilities of CEO were also improved by microencapsulation.•The preservation effects of microencapsulated CEO on the processing of Chinese bacon were also enhanced.•β-CD-MOFs could expand the food applications of CEO as new and good carriers.
The functional properties of fibrillar protein make them an excellent novel food ingredient. However, for industrial applications, it is necessary to have an insight into their digestibility and ...bioactivity. Therefore, the objectives of this work were to study the enzymatic hydrolysis and bioactivity of nanofibrillated whey protein isolate (WPI), prepared at 90 °C under acidic condition, followed by pH adjustment to 2, 4, and 6. Fourier transform infrared spectroscopy (FTIR) showed that the secondary structure of protein changed and the intermolecular β-sheets structure was formed over fibrillization. The results showed that by increasing the rate of fibril formation at lower pH level monitored by Thioflavin T (ThT) fluorescence spectrophotometry, the degree of pepsin and trypsin hydrolysis in simulated gastrointestinal environments increased significantly. As the extent of fibrillar structure decreased at higher pH, Diphenyl-picryl hydrazinyl (DPPH) radical scavenging activity and Ferric reducing ⁄ antioxidant power (FRAP) of nanofibrillated WPI hydrolysates were reduced. Likewise, in all samples at different hydrolysis times, the antioxidant activities of pepsin-derived hydrolysates were higher than those of tryptic hydrolyzed samples, which probably was resulted from the increased hydrolyzed peptides with higher antioxidant activity. Overall, these findings may reinforce the applications of nanofibrillated proteins as functional food ingredients.
•Enzymatic hydrolysis of nanofibrillated whey protein is affected by fibril solution pH.•Degree of enzymatic hydrolysis increases by increasing the rate of fibril formation.•Antioxidant activity of nanofibrillated whey protein hydrolysates is reduced at higher pH.
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•GEO is a powerful natural additive in inhibiting formation of BaP.•Reducing ability of sulfide from GEO is dependent on S number and thioallyl group.•AMTS showed the strongest effect ...in inhibiting the formation of BaP.•Inhibiting BaP formation-mechanism is relevant to free radical scavenging reaction.
To addgarlic more conveniently, the substitute–garlic essential oil(GEO)is wildly applied in meat product for flavor improvement. However, the effects of GEOon chemical hazard formation, such as benzoapyrene (BaP), in meat processing have not been studied. This study focused on the inhibitory effect of garlic (0.05–0.15%, w/w), GEO (0.002–0.006%, w/w) and the active sulfide compounds (0.006%, w/w) on the formation of BaP in charcoal-grilled pork sausages. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity of the garlic, GEO and sulfide compounds was also determined. The results showed that the garlic was efficient in the decrease of DPPH free radicals (14.91–23.39%) and BaP content (37.2–62.3%). GEO was also efficient in scavenging DPPH free radicals (14.17–26.20%) and reducing BaP formation (29.1–57.1%). Gas chromatography-mass spectrometer (GC–MS) analysis identified a total of 41 compounds, of which six major sulfide compounds (allyl methyl sulfide, diallyl sulfide, allyl methyl disulfide, diallyl disulfide, allyl methyl trisulfide and diallyl trisulfide) were screened to assess their inhibition of BaP generation. The BaP inhibition of these sulfide compounds were dependent on the number of sulfur (-S-) and thioallyl group (–S–CH2–CH═CH2); and allyl methyl trisulfide (AMTS) showed the highest BaP inhibition (63.3%). A significant correlation was found between their BaP inhibition and DPPH scavenging activity (Spearman correlation = 0.91, P < 0.001), which indicates that the mechanism of sulfides influencing BaP formation in grilling sausage is related to free radical reaction. Our research gives an insight into the theoretical basis about application of GEO to inhibit BaP during food processing and supports use of GEO as a natural additive in meat products.
•Design of NME.•Docking.•ADMET predictions.•Synthesis.•Free radical scavenging activity.
In this research, we synthesised novel benzimidazole-1,3,4 oxadiazole derivatives and studied their ...antioxidant properties using the DPPH Radical Scavenging Assay. A significant class of substances with a broad range of biological activities is the 1,3,4-benzimidazole family. Furthermore, enabling for various biological activities are the five-membered heterocyclic moieties. Thus, a number of benzimidazole derivatives have been created, there in vitro antioxidant activity has been evaluated, and they have been characterized by FTIR and 1H NMR spectral studies. Compounds 1A, 2A and 3A have the highest G-score i.e., - 7.575 kcal/mol, -6.932 kcal/mol, -6.911 kcal/mol, as compared to standards propyl gallate and Ascorbic acid, which had glide scores of -4.757 kcal/mol and -4.50 kcal/mol respectively. The benzimidazole-1,3,4 oxadiazole containing compounds that were created demonstrated impressive antioxidant activity. When compared to the reference standard, ascorbic acid, (IC50-11.51±0.31 µg/ml) Compound 2A demonstrated the strongest antioxidant activity with an IC50 value (53.00±1.31 µg/ml) respectively.
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Compound 4-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl)-N-((3-substituted-2-hydrobenzo dthiazol-2-yl)methylene)thiazol-2-amine (3c) was shown great anti-inflammation, analgesic, Ulcerogenic, Acute ...toxicity and free radical scavenging action as compare to reference drugs in albino rats at a dose of 50 mg/kg p.o.
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•Oxazole substitutents were found to be less biologacally active.•Compound 3a-3d had more inhibition potential than 3a′-3d′.•Compound 3c was the most anti-inflammatory and analgesically active.•Chloro substituted derivatives were found to be more effective than other.
Non-Steroidal biologically active heterocyclic compounds 4-(2-(4-chlorophenyl) benzodthiazol-3(2H)-yl)-N-((3-substituted-2-hydrobenzodthiazol-2-yl)methylene) thiazol-2-amine (3a-3d), 4-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl)-N-((3-substituted − 2-hydrobenzo dthiazol-2-yl)methylene)oxazol-2-amine (3a′-3d′), (Z)-N'-(4-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl)thiaol-2-yl)-N-(4-substituted phenylimino)-3-substituted-2-hydrobenzodthiazole-2-carboxamidine (4a-4 h) and (Z)-N'-(4-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl)oxazol-2-yl)-N-(4-substituted phenylimino) − 3-substituted-2-hydrobenzodthiazole-2-carboxamidine (4a′-4h′) were synthesized starting from 2-chloro-1-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl) ethanone (1). The structure configuration of newly synthesized compounds has been determined by elemental analysis and various spectroscopic (IR, 1HNMR and GCMS) techniques. These compounds were tested for their anti-inflammation, analgesic, ulcerogenic, acute toxicity and free radical scavenging action and compared with reference drugs in albino rats. Compound 4-(2-(4-chlorophenyl)benzodthiazol-3(2H)-yl)-N-((3-substituted-2-hydrobenzo dthiazol-2-yl)methylene)thiazol-2-amine (3c) was the most active compound than reference drug at a dose of 50 mg/kg p.o.
Benzoapyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) that has been found in barbecued meat products and has shown carcinogenic properties in humans. The purpose of this study was to ...investigate the effect of vinegar (fermented vinegars and distilled vinegar) on the generation of BaP in barbecued pork sausages. The results showed that fermented vinegars and distilled vinegar could significantly (P < 0.05) inhibit the formation of BaP (26.8%–82.3%) in barbecued pork sausages. Furthermore, fermented vinegar could enhance the sensory evaluation of barbecued pork sausages(tenderness, flavor, juiciness and overall acceptability). Additionally, an intermediate of the Maillard reaction (hydroxymethylfurfural) (0.14–2.34 mg/kg), which is possibly associated with BaP generation, was inhibited because of the decrease in pH. The fermented vinegars, which were rich in phenols (1787.09–3089.60 mg GRE/L) and flavonoid (622.54–2167.97 mg RE/L) compounds, inhibited the formation of BaP by scavenging reactive oxide species (1,1-diphenyl-2-picrylhydrazine (DPPH) radical (85.50–96.73%) and hydroxy free radical (34.56–66.30%) scavenging activities) in pork sausages. Therefore, the vinegars inhibited the content of BaP in barbecued pork sausages by decreasing the pH and scavenging free radicals. In addition, ten phenolic compounds in sun vinegar were confirmed to be critical in inhibiting the content of BaP in barbecued pork sausages. This study provides a more affordable and feasible strategy for the inhibition of BaP in meat processing.
•Vinegars inhibited the generation of BaP in barbecued pork sausages.•Variation of Maillard reactions played a vital role in this mechanism.•Fermented vinegars rich in phenolic compounds had better inhibition of BaP.•More polyphenol hydroxyl groups have better inhibition of BaP.
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