DPPH Radical Scavenging Properties Research Articles

Stabilization of zein nanoparticles with tween-80 and fucoidan for encapsulation of eugenol via a nozzle simulation chip

Eugenol (EU), a natural bioactive compound found in various plants, offers numerous health benefits, but its application in the food and pharmaceutical industry is limited by its high volatility, instability, and low water solubility. Therefore, this study aimed to utilize the surface coating technique to develop zein-tween-80-fucoidan (Z-T-FD) composite nanoparticles for encapsulating eugenol using a nozzle simulation chip. The physicochemical characteristics of the composite nanoparticles were examined by varying the weight ratios of Z, T, and FD. Results showed that the Z-T-FD weight ratio of 5:1:15 exhibited excellent colloidal stability under a range of conditions, including pH (2–8), salt concentrations (10–500 mmol/L), heating (80 °C), and storage (30 days). Encapsulation of EU into Z-T-FD nanoparticles (0.5:5:1:15) resulted in an encapsulation efficiency of 49.29 ± 1.00%, loading capacity of 0.46 ± 0.05%, particle size of 205.01 ± 3.25 nm, PDI of 0.179 ± 0.006, and zeta-potential of 37.12 ± 1.87 mV. Spherical structures were formed through hydrophobic interaction and hydrogen bonding, as confirmed by Fourier transform infrared spectroscopy and molecular docking. Furthermore, the EU-Z-T-FD (0.5:5:1:15) nanoparticles displayed higher in vitro antioxidant properties (with DPPH and ABTS radical scavenging properties at 75.28 ± 0.16% and 39.13 ± 1.22%, respectively), in vitro bioaccessibility (64.78 ± 1.37%), and retention rates under thermal and storage conditions for EU compared to other formulations. These findings demonstrate that the Z-T-FD nanoparticle system can effectively encapsulate, protect, and deliver eugenol, making it a promising option for applications in the food and pharmaceutical industries.

Photoprotective effect of topical treatment with Lopezia racemosa extract against deleterious UVB irradiation effects in the skin of hairless mice.

Lopezia racemosa is known as a "mosquito flower or perlilla." It is commonly found in corn crops. In traditional Mexican medicine, this plant is used to treat stomach cancer and urinary tract infections. Likewise, compounds and extracts isolated from plants have shown cytotoxic and anti-inflammatory effects. Theobjective of this study was to evaluate the photochemoprotective effect of topical treatment with the methanolic extract of L. racemosa (MELR) as a photochemoprotective agent against the harmful effects of UV irradiation (UVR) on a bacterial model and hairless mice. The MELR components were separated and analyzed via HPLC-UV-ESI-MS. Antioxidant activity was evaluated by the ability of MERL to scavenge DPPH and ABTS free radicals and by its FRAP capacity. The toxicity of MELR was evaluated in keratinocyte cultures. The photoprotective capacity of MELR was assessed through challenge experiments using models with bacteria and hairless CD1 et/et mice; cytokines related to the damage caused by UVR were also measured. In the methanolic extract of L. racemosa, five metabolites were detected and identified: two isomers of quercetin 6-C glycoside, orientin, quercetin 3-(6″-acetylglycoside) and quercetin 3-(6″-galloylglycoside) 7-(2,3-dihydroxytetrahydro-2H-pyran-4-yl acetate). MELR exhibited DPPH and ABTS radical scavenging properties, in addition to Fe ion reducing activity. MELR showed a photoprotective effect against UVB radiation-induced death in Escherichia coli bacteria. At the histological level, topical treatment of CD-1 et/et mice with MERL reduced the damage caused by UVR. Quantification of interleukins in the blood of mice revealed that the expression of IL-12 was greater in the control group treated with ultraviolet radiation than in the group protected with MELR. The methanolic extract of L. racemosa has photochemoprotective properties.

Effects of Lactobacillus plantarum FM 17 fermentation on jackfruit polysaccharides: Physicochemical, structural, and bioactive properties

Fermentation is a novel technology for modifying polysaccharides in fruits and improving their bioactivities. In this work, we introduced Lactobacillus plantarum FM 17 to ferment jackfruit pulp and subsequently purified polysaccharides from unfermented (JP) and fermented jackfruit pulp (JP-F). Furthermore, the physicochemical, structural, and bioactive properties of JP and JP-F were investigated. Results showed fermentation dropped the glucuronic acid, molecular weight, and particle size of JP-F by 15.62 %, 23.92 %, and 39.43 %, respectively, compared with those of JP. JP-F showed higher solubility than JP but lower apparent viscosity and thermal stability. Additionally, FT-IR spectra and X-ray diffraction analysis showed that fermentation did not alter the different types of glycosidic bonds and the fundamental polysaccharide structure. Moreover, JP-F exhibited stronger DPPH and ABTS free radical scavenging properties than JP and stronger stimulation on macrophage secretion of NO and IL-6 in RAW 264.7 cells. Therefore, using L. plantarum FM 17 for fermentation can alter physical and chemical properties of jackfruit pulp polysaccharides, enhancing their bioactivities.

Synthesis and biological evaluation of selenopyrimidine derivatives bearing thiazolyl moiety

The aim of this study is to explain how new thiazole and selenophene moieties were obtained from 2-amino-4-(4-methylthiazol-2-yl)selenophene-3-carbonitrile (3) and to assess the antioxidant and cytotoxic properties of these new compounds. Compound 3 is prepared and subjected to react with each of CS2, malononitrile in EtOH/TEA, ECA, a mixture of HCl and AcOH, formamide, formic acid, malononitrile in the presence of EtONa to give their corresponding selenopyrimidine and selenopyridine derivatives 4–10. Moreover, compound 3 reacted with thiourea, hydrazine hydrate, CS2 in NaOH/DMF, and phenyl isothiocyanate to afford selenolo[2,3-d]pyrimidines 11–17 and related compounds. The recently synthesized compounds were tested for their DPPH radical scavenging and cytotoxic properties against the HePG-2 and MCF-7 cell lines. Compounds 5 and 11 demonstrated potential radical scavenging activity, but compounds 5 and 6 exhibited the strongest cytotoxic action against the examined cell lines. According to molecular docking data, the compounds under research are intriguing candidates for the development of new anticancer therapeutic targets.

In vitro antioxidant, anti-inflammatory and in vivo anti-hyperglycemia potentials of cookies made from sorghum, orange-flesh-sweet-potato and mushroom protein isolate flour blends fed to Wistar rats

Cookies were produced from a blend of sorghum, orange-flesh-sweet-potato and mushroom protein isolate flour at different ratios viz: MOS A (60:20:20), MOS B (40:30:30), MOS C (30:35:35), MOS D 30:40:30) and MOS E (100% wheat flour) as control. The cookies were investigated for their physicochemical properties, amino acid profile, in vitro antioxidant, in vitro anti-inflammatory, in vivo antihyperglycemia and consumer acceptability using standard methods. The protein and fiber contents of the cookies ranged from 14.76 to 35.20% and 8.17–9.63%, respectively. The improved bioactivities of the cookies could be due to its enhanced hydrophobic, aromatic, branch chained amino acids, BV (∼70–76%) and Arg/Lys-contents. All the cookie samples were classified under the medium glycemic load (18–25) classification. The cookie sample MOS D has the highest hydroxyl (91.33%), DPPH radical scavenging, iron chelation (67.67%) and ferric reducing (∼51%) properties. Moreso, the anti-inflammatory activities of sample MOS D revealed its membrane stabilization (23.40–27.06%), anti-proteinase (23.25–27.36%), albumin denaturation inhibition (23.14–32.35%), nitric oxide scavenging (23.07–32.21%), anti-lipoxygenase (23.31–32.08%) and anti-cyclooxygenase (11.37–23.57%) to be comparable with those of diclofenac, a standard NSAIDs. However, the MOS D sample was rated highest and most acceptable by the consumers when compared with the commercial wheat cookies.

Phytochemical and bioactivity evaluation of secondary metabolites and essential oils of Sedum rubens growing wild in Jordan

Sedum rubens L. (Crassulaceae family) is an interesting succulent medicinal plant that has never been investigated for its phytochemical constituents. Thus, the current study was designed to unveil its chemical constituents and bioactivity potentials. In the current study, the total phenol content (TPC), total flavonoid content (TFC) and DPPH radical scavenging properties of the hydroalcoholic (HA) and water extracts (W) were determined. Moreover, the presence of selected phenolic acids (gallic acid, chlorogenic acid, caffeic acid) and flavonoids (rutin, quercetin, hesperidin) was determined by HPLC-PDA. In addition, hydro-distilled essential oil (HDEO) composition of the plant at the pre-flowering (PF) and full-flowering (FF) stages was determined by GC/MS and GC/FID techniques. Results revealed that the FF hydroalcoholic extract had the highest TPC (136.9 mg gallic acid/g extract), TFC (234.7 mg quercetin/g extract) and DPPH• radical scavenging activity (7.10 × 10-2 ± 1.0 × 10-3 mg/mL). This extract was rich in gallic acid and caffeic acids (366, 243 mg/Kg dry plant, respectively). The study resulted in reporting four known compounds including α- & β-amyrin acetates, β-sitosterol and β-sitosterol glycoside for the first time from the plant. The HDEO at the PF and FF stages were dominated by oxygenated sesquiterpenes (21.92%) and aliphatic hydrocarbons (45.71%).

Antioxidant and gas chromatography-mass spectrometry characterization of methanol extract of Alchornea cordifolia

Antioxidant, phytochemical and GC-MS analyses of methanol extract of Alchornea cordifolia were determined by various methods to quantify each of the phytochemical constituent present in the sample. The quantitative phytochemical tests conducted include; alkaloids, saponins, phenols, flavonoids, flavonol and proanthocyanidin content estimation. The extract was subjected to antioxidant assay; total antioxidant, nitric oxide, DPPH radical scavenging and copper chelating properties of Alchornea cordifolia. Results: The quantitative phytochemical analysis revealed the different percentages of phytoconstituents in the extract. The results showed that the saponin content in extract was found to be 19±2.5% is present in high concentration as compared to the total alkaloid content (2.5±0.5%). The phenol, flavonoid, flavonol and proanthocyanidin contents were found to be 1.5±1.0 mgGAE/g, 16±0.2 mgQE/g, 8.6± 0.3mgRE/g and 10 ± 0.6mg TAE/g respectively. The NO, DPPH scavenging and copper chelating of Alchornea cordifolia at 1 mg/ml are 52.25±4.44%, 55.7±5.62% and 33.5±0.36% respectively. GC-MS results revealed the presence of many polar and nonpolar compounds in order of decreasing abundance Vitamin E > 1,2-dimethyl-cyclooctane >campesterol>stigmasterol> 1, 4-dimethoxy-2-methyl cyclohexane >Bicycle[4.4.0]dec-2-ene-4-ol > Pregn-4-en-17,21-diol-3,20-diene-9,11-epoxy > 2, 4,6-trimethyl-octane. Alchornea cordifolia is a medicinal plant found in Africa with many polar and nonpolar compounds that contributed to its traditional uses medically. In conclusion Alchornea cordifolia is endowed with phytochemicals of antioxidant and antiradical potentials.

Medical applications of Couroupita guianensis Abul plant and Covid-19 best Safety measure by using Mathematical Nano topological spaces

Lellis Thivagar and Richard introduced the idea of Nano topology as an extension of set theory for such study of intelligent systems with little or imperfect knowledge. The Nano open set consists of the components of a Nano topological space. It is derived from the Greek term 'Nanos,' which means 'dwarf,' in the current scientific meaning, a magnitude of one billionth. The topology is referred to as a Nano topology due to its small size, since it has no more than five components. Lellis Thivagar has carried out Nutrition Modeling Through Nanotopology directions, some of which were shown in his pioneering work. This article discusses the implementation of nanotopological structures to enable knowledge reduction in real-world scenarios. Couroupita guianensis's Ayurvedic usage of Immunobooster, antifungal, antibacterial, Skin infection, hypertension, tumor, snake bite, malaria. The chemical ingredient of C. guianensis, numerous studies have indicated that extracts derived from various sections of CG have a considerable antioxidant activity. Leaf, stem, as well as flower extracts demonstrated varied DPPH, hydrogen peroxide, nitric oxide, and hydroxyl radical scavenging properties. Almost every component of the tree has been Ayurvedic utilised to cure a variety of diseases. In mathematically using Nano topological spaces we can identify which parts the plant mostly cure antifungal, and antibacterial activities. After that one more applications of regarding Covid-19 virus. The WHO verified on 12 January 2020 that a new coronavirus was responsible for a cluster of respiratory illnesses in a cluster of persons in Wuhan, Hubei, China, which has been notified to the WHO on 31 December 2019. India announced its first incidence of COVID-19 at Thrissur, Kerala, on 30 January 2020, India is Cases: 43,018,032 and death cases 520,885 and Recovered: 42,480,436.After third wave of covid 19 now normal functioned happened. WHO and Indian government defined covid safety measures like Wear mask, Don't skip vaccinations, avoid touching his or her eyes, nose, and mouth, maintain a physical distance from the others, and vaccinations of all the people. Now using nano topological spaces which are main core component identified by nano topological spaces.

Functional Properties of Protein Hydrolyzate from Ribbon Fish (Lepturacanthus Savala) as Prepared by Enzymatic hydrolysis

ABSTRACT Fish protein hydrolyzates (FPH) are breakdown products of hydrolysis and are gaining importance in the field of nutraceuticals and functional foods due to their bioactive properties, high nutritional value, solubility, and digestibility. This study aimed to evaluate the effect of hydrolysis time (1–5 h) on the functional properties of FPH prepared from ribbon fish by using the alcalase enzyme. Results showed that the enzymatic hydrolysis time affected the protein content, degree of hydrolysis (DH) and properties of protein hydrolyzates. The protein content of hydrolyzates was significantly (P < .05) increased with an increase in time from 1 to 5 h. Similarly, a trend was observed in the case of DH% (P < .05) as well. Enzyme hydrolysis time had substantially changed the secondary structure of the protein that decreased the crystalline structure of protein hydrolyzate as reported in FT-IR results. On the other hand, a significant reduction in the hydrolyzates’ particle size was noticed with increased hydrolysis time. Furthermore, protein hydrolyzates (1–5 h) exhibited an enhanced solubility, oil-holding capacity, ACE-I inhibitory, and DPPH radical scavenging activity. Statistical results showed an inverse correlation between hydrolysis time and particle size (r = – 0.969), while other parameters such as DH% (r = 0.994), OHC (r = 0.984), ACE-I inhibitory (r = 0.948) and DPPH radical scavenging properties (r = 0.928) presented a positive correlation with hydrolysis time. Therefore, the present work reveals that protein hydrolyzates, when subjected to a greater enzymatic hydrolysis time, enhanced certain properties of the hydrolyzate, which may be beneficial for functional food development.

Eco-friendly natural extract loaded antioxidative chitosan/polyvinyl alcohol based active films for food packaging

Nowadays, biodegradable antimicrobial packaging materials draw substantial attention and are considered one of the preferred emerging technologies to be used in the food industry. In this study, we have reported developing a two-component, chitosan (CS) and polyvinyl alcohol (PVA) based films loaded with natural extract of Ocimum tenuiflorum via solvent casting technique. Experimental results showed that all the components were well dispersed, resulting in complete homogenous films. FTIR-ATR spectral analysis indicated strong interaction between the film matrix components, which also gets reflected by the films' physical properties. Transparent biodegradable films have resulted from the mixture and incorporation of the natural agent/extracts influenced light barrier, water resistance, moisture content (9.89–9.01%), and DPPH radical scavenging properties (antioxidant value ~41.1%) of the CS/PVA films. Therefore, this natural extract containing transparent CS/PVA-based films promises to be used in the food industry as packaging material to enhance food safety.

Antioxidant mediated protective effect of Bridelia tomentosa leaf extract against carbofuran induced oxidative hepatic toxicity.

Bridelia tomentosa (B. tomentosa) is a traditional medicinal plant for treating diverse ailments. Hence, we designed our study to scrutinize the protective effect of the methanol extract of B. tomentosa leaf (BTL) against carbofuran-induced oxidative stress-mediated hepato-toxicity in Sprague-Dawley rats for the first time, along with the identification and quantification of phenolic acids and flavonoids by high-performance liquid chromatography (HPLC) and evaluation of antioxidant and antiradical activities of this extract. HPLC analysis confirmed the existence of tannic acid, gallic acid, salicylic acid, and naringin in B. tomentosa leaf extract which showed in-vitro antioxidant potentialities with DPPH, nitric oxide, hydrogen peroxide, and hydroxyl radical scavenging properties. Co-administration of B. tomentosa leaf extract with carbofuran showed dose-dependent significant protective effects of hepatic toxicity on serum markers such as alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl-transferase, lactate dehydrogenase, total bilirubin, total protein, albumin, globulin, lipid profile, urea, uric acid, and creatinine. Carbofuran intoxication also revealed an upsurge in malondialdehyde (MDA) and a decline in cellular endogenous antioxidant enzyme levels in rats compared with the control group. However, B. tomentosa leaf extract co-treatment increased the levels of hepatic antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione peroxidase, and amended the MDA level. Similarly, histopathological evaluation further assured that BTL could keep the hepatocyte from carbofuran-induced damage. Therefore, all of our findings may conclude that the phenolic acids and flavonoids of B. tomentosa leaf extract are responsible to neutralize the toxic free radical-mediated oxidative hepatic damages.

The effects of active double-layered furcellaran/gelatin hydrolysate film system with Ala-Tyr peptide on fresh Atlantic mackerel stored at −18 °C

This is the first time that active double-layered furcellaran/gelatin hydrolysate films containing Ala-Tyr peptide were developed and characterised for their properties. Afterwards, films were used on Atlantic mackerel stored at −18 °C for 4 months and samples were analysed for changes in their microbiological quality, TVB-N, biogenic amine content, fatty acid composition and TBARS. Active films had higher TS (13.4 MPa) and lower WS (62.8%). The films showed no DPPH radical scavenging properties but high FRAP (6.6 mMol Trolox/mg). No significant effects on the oxidation of fish samples were observed with TBARS increasing from 12.04 to 22.50 mg/kg. Freezing successfully inhibited the growth of microorganisms and no differences in microbiological growth or biogenic amine formation were observed. However, the application of films inhibited the formation of TVB-N. Antimicrobiological properties of the film should be further investigated during storage of perishable food products at temperatures above 0 °C.

Preparation of chitosan/curcumin nanoparticles based zein and potato starch composite films for Schizothorax prenati fillet preservation

The aim of this study was to develop a zein/potato starch (PS) film based on chitosan nanoparticles incorporated with curcumin (CCN). The CCN film was characterized for encapsulation efficiency, particle size, zeta potential, polydispersity index (PDI), relative release, and DPPH radical scavenging test. Our results showed that the CCN encapsulated effectively curcumin (CUR) (84.8% ± 1.1%) and presented with high oxidation resistance and relative release efficiency. The CCN/zein/PS composite films were round, smooth, and compact. We measured and compared the mechanical properties, oxygen permeability (OP), water vapor permeability (WVP), relative release efficiency, and DPPH radical scavenging properties of the composite films of different mass ratios. We observed that the composite film had good mechanical and barrier properties. Further, we evaluated the preservative efficacy of the composite film on Schizothorax prenati fillets by measuring pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid-reactive substances (TBARS), hardness, microbial counts, organoleptic characteristics, and other fillet quality parameters. The CCN/zein/PS composite film delayed physicochemical changes in the Schizothorax prenati fillets and prolonged their shelf life by up to 15 days. In conclusion, our work shows that CCN/zein/PS composite film holds promise as a potential bioactive packaging material for Schizothorax prenati fillets.

Bis-azo-linkage Schiff bases—Part(II): Synthesis, characterization, photoluminescence and DPPH radical scavenging properties of their novel luminescent mononuclear Zn(II) complexes

In this paper, two luminescent Zn(II) complexes with the formula [ZnH2L1,2] were newly synthesized by a one-step reaction of the bis-azo-Schiff base ligands and metal salt. Their mononuclear structure was characterized by different analytical and spectroscopic measurements (elemental analysis, IR, NMR, UV–vis, mass, powder XRD, conductance and magnetic susceptibility). TGA and DTA techniques showed that the complexes were stable above 400 °C. The host-guest interaction between the ligands and Zn(II) ion was examined by UV–vis titration. It found a low LOD value for Zn(II) ion in the concentration range of 1.30 × 10−6 M and 4.40 × 10-7 M. The stoichiometric ratio and formation constant of ligand-Zn(II) complexation were determined using Benesi–Hildebrand and Job’s plots. Upon photoexcitation with Xenon lamp, Zn(II) complexes emitted green luminescence in DMSO solution. The antioxidant activity of the ligands and new Zn(II) complexes was studied by using DPPH radical scavenging assay by fixed reaction time and steady state measurements. The results indicated that the ligands exhibited higher scavenging activity than that of ascorbic acid, but Zn(II) complexes did not have any activity.

Syntheses, structural characterization, DNA-cleavage and antioxidant features of the new tetra-substituted organo-soluble non-peripherally CoII, CuII, ZnII and MgII phthalocyanines

This paper encompasses the synthesis, structural characterization, and evaluation of supercoiled pBR322 plasmid DNA-cleavage and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging properties of newly synthesized tetra-substituted CoII (5), CuII (6), ZnII (7) and MgII (8) phthalocyanines bearing 4-methyl-N-(4-morpholinophenyl)benzenesulfonamide units at non-peripheral sites of phthalocyanine skeleton. The structural characterization of these new metallated phthalocyanines were performed via UV-vis, elemental analysis, FT-IR (ATR sampling accessory), 1H-NMR and 13C-NMR spectroscopic techniques (for 7 and 8) and MALDI-TOF mass spectral data. The new compounds (5–8) exhibited good solubility in common organic solvents, and as well as no sort of aggregation was perceived at studied concentrations and solvents. Compound 7 indicated oxidative photocleavage activities in the presence of H2O2, indicating the conversion of supercoiled pBR322 plasmid DNA to nicked circular form (19.90%) and linear form (4.40%). Compound 5 displayed the highest radical scavenging activities among the tested compounds. The DPPH-radical scavenging percentages of 5 ranged from 85.35 ± 2.45% (12.5 µM) to 95.38 ± 1.44% (100 µM). These compounds are favorable for further research, owing to a broad range of biological and pharmaceutical activities of morpholine scaffold.

IN VITRO ANTIOXIDANT AND FREE RADICAL SCAVENGING POTENTIAL OF METHANOLIC EXTRACTS OF UVARIA CHAMAE LEAVES AND ROOTS

Objective: This study investigated the in vitro antioxidant and free radical potentials of methanol extracts of Uvaria chamae leaves and roots.Methods: Fresh Uvaria chamae leaves and roots were air dried, pulverized and extracted using methanol. Phytochemical, total phenolic, flavonoids, antioxidant and tannin contents, DPPH, hydroxyl, and superoxide radical scavenging properties of the extracts were determined using standard methods.Results: In vitro antioxidant potentials revealed that methanol extract of Uvaria chamae leaves contains vitamin A (4871±79.21 I. U) and vitamin C (1.72±0.02%) while the root extract contains vitamin A (673.28±0.00I. U) and vitamin C (1.66±0.01%). Both extracts had equal contents of vitamin E (8.83±0.04 mg/100g). The leaf extract scavenged 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) in a concentration dependent manner with the correlation coefficient (R2) of 0.839 and effective concentration (EC50) of 31.19 µg/ml, while the root extract scavenged DPPH with R2 of0.778 and EC50 of 14.00 µg/ml. The leaf and root extracts scavenged superoxide radical and hydroxyl radical with EC50 of 5.93 µg/ml and 719.45 µg/ml; 107.89 µg/ml and 912.01 µg/ml respectively compared to the EC50 of ascorbic standard (30.27 µg/ml) and EC50 of vitamin E standard (106.66µg/ml) respectively. The leaf extract showed significantly higher (p&lt;0.05) anti radical power (ARP) of superoxide (0.17) compared to the root extract (0.0014) and the root extract showed significantly higher (p&lt;0.05) ARP of DPPH (0.071) compared to the leaf extract (0.032).Conclusion: The leaves and roots of Uvaria chamae are rich in natural antioxidants that can be exploited in the treatment of diseases related to oxidative stress.

Comparison of the antioxidant properties and flavonols in various parts of Korean red onions by multivariate data analysis

To compare the antioxidant properties and flavonols in various parts; dry skin (DS) and edible portion (EP), of 8 red onions (Allium cepa L, ROs), total content of phenolics (TPC), flavonoids (TFC), and anthocyanins (TAC) and DPPH radical scavenging properties were estimated and the content of six flavonols were quantified by HPLC–PDA analysis. The major component of DS and EP of RO was quercetin and quercetin-4′-glucoside, respectively. Score plots of the PCA and PLS-DA were segregated by flavonols content and antioxidant properties according to the EP and DS of ROs. Loading plot of the PCA showed that the quercetin and sum of flavonol content were highly correlated with antioxidant activity of ROs. Therefore, flavonol content and antioxidant activity can be used as markers for distinct parts of ROs.

Cardenolides and dihydro-β-agarofuran sesquiterpenes from the seeds of Salacia staudtiana

Phytochemical studies of the seeds of the Cameroonian medicinal plant, Salacia staudtiana, resulted in the isolation and identification of five new cardenolides (1–5) as well as a new dihydro-β-agarofuran (9), along with eight known compounds. The structures of all compounds were elucidated by 1D/2D NMR, ESI-HRMS data and comparison with literature data. The relative configurations of the new compounds were defined by X-ray crystallography analysis, NOESY correlations and coupling constants. We evaluated their antibacterial efficacy against two commonly dispersed environmental strains of Escherichia coli and Bacillus subtilis, and two pathogenic strains of Staphylococcus aureus and Pseudomonas aeruginosa, compared to the standard antibiotics, streptomycin and gentamicin. Moreover, we assessed the antibacterial activity of the crude extract of the seeds in parallel to evaluate the plausible synergistic effects of the compounds in chemical defense of the seeds during germination and plant reproduction. The isolated compounds showed moderate antibacterial activities against the tested organisms. Compounds 1 and 3 and the crude extract exhibited distinct antibacterial activities against B. subtilis and S. aureus. The isolated compounds showed weak DPPH radical scavenging properties compared to the reference standard (Trolox). Our study lends evidence to the antibacterial chemical defense of S. staudtiana seeds by seed-borne compounds.

Changes in the amino acid profiles and free radical scavenging activities of Tenebrio molitor larvae following enzymatic hydrolysis.

Tenebrio molitor (T. molitor) larvae provide food at low environmental cost and contribute positively to livelihoods. In this research, we compared the amino acids compositions and antioxidant activities of various extracts of T. molitor to enhance their quality as food. For the comparison, distilled water extracts, enzymatic hydrolysates, and condensed enzymatic hydrolysates of T. molitor larvae were prepared. Their amino acids (AAs) profiles and antioxidant activities, including ferric-reducing antioxidant power, oxygen radical absorption capacity, and DPPH, hydroxyl radical, and hydrogen peroxide radical scavenging properties assay were analyzed. DW extracts had the lowest AAs contents and antioxidant activity compared with enzymatic extracts. Condensed hydrolysates with a combination of alcalase and flavourzyme (C-A+F) exhibited the highest levels of total free AAs (11.1759 g/100 g). C-A+F produced higher total hydrolyzed AAs (32.5292 g/100 g) compared with the other groups. The C-A+F possessed the strongest antioxidant activity. Notably, the antioxidant activities of the hydrolysates and the total hydrolyzed AAs amount were correlated. Taken together, our findings showed that C-A+F was a promising technique for obtaining extracts of T. molitor larvae with antioxidant activity as potential nutritious functional food.

Synthesis of Coumarin Appended 1,3-Oxazines as Potent Antimicrobial and Antioxidant Agents

A convenient protocol for the synthesis of coumarin appended 1,3-benzoxazine derivatives (4a – 4g) is described. Cyclisation of hydrazones (3a – 3g) using triphosgene in dichloromethane gave the corresponding 1,3-oxazines in a relatively good yield. The proposed structures of newly synthesized compounds were confirmed by spectral methods and elemental analysis. Oxazine derivatives 4a – 4g were evaluated for their in vitro antimicrobial activity against various bacteria and fungi. Compounds 4b and 4d inhibited growth of test microbes thus proving significant antimicrobial activity. In addition, in vitro antioxidant activity of the synthesized compounds was evaluated and compared to that of standards, showing DPPH, NO, and OH radical scavenging properties. Compounds 4b and 4f exhibited higher antioxidant activity than a standard drug.