Antioxidant potential and α-glucosidase inhibitory activity of onion (Allium cepa L.) peel and bulb extracts

Allium cepa L. is a commonly consumed vegetable that belongs to the Amaryllidaceae family and contains nutrients and antioxidants in ample amounts. In spite of the valuable food applications of onion bulb, its peel and outer fleshy layers are generally regarded as waste and exploration of their nutritional and therapeutic potential is still in progress with a very slow progression rate. The present study was designed with the purpose of doing a comparative analysis of the antioxidant potential of two parts of Allium cepa, i.g., bulb (edible part) and outer fleshy layers and dry peels (inedible part). Moreover, the inhibitory effect of the onion bulb and peel extracts on rat intestinal α-glucosidase and pancreatic α-amylase of porcine was also evaluated. The antioxidant potential of onion peel and bulb extracts were evaluated using 2,2-diphenyl- 1-picryl hydrazyl (DPPH), ferric-reducing antioxidant power assay (FRAP), 2,2’-azino-bis- 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay, H2O2 radical scavenging activity and Fe2+ chelating activity. Total flavonoids and phenolic content of ethanolic extract of onion peel were significantly greater as compared to that of onion bulb. Ethanolic extract of onion peel also presented better antioxidant and free-radical scavenging activity as compared to the ethanolic extract of bulb, while the aqueous extract of bulb presented weakest antioxidative potential. Onion peel extract’s α-glucosidase inhibition potential was also correlated with their phenolic and flavonoid contents. The current findings presented onion peel as a possible source of antioxidative agents and phenolic compounds that might be beneficial against development of various common chronic diseases that might have an association with oxidative stress. Besides, outer dry layers and fleshy peels of onion exhibited higher phenolic content and antioxidant activities, compared to the inner bulb. The information obtained by the present study can be useful in promoting the use of vegetable parts other than the edible mesocarp for several future food applications, rather than these being wasted.

Antimicrobial and Antioxidant Potential of Scenedesmus obliquus Microalgae in the Context of Integral Biorefinery Concept

Small-scale photobioreactors (PBRs) in the inoculum stage were designed with internal (red or green) and external white LED light as an initial step of a larger-scale installation aimed at fulfilling the integral biorefinery concept for maximum utilization of microalgal biomass in a multifunctional laboratory. The specific growth rate of Scenedesmus obliquus (Turpin) Kützing biomass for given cultural conditions was analyzed by using MAPLE software. For the determination of total polyphenols, flavonoids, chlorophyll “a” and “b”, carotenoids and lipids, UHPLC-HRMS, ISO-20776/1, ISO-10993-5 and CUPRAC tests were carried out. Under red light growing, a higher content of polyphenols was found, while the green light favoured the flavonoid accumulation in the biomass. Chlorophylls, carotenoids and lipids were in the same order of magnitude in both samples. The dichloromethane extracts obtained from the biomass of each PBR synergistically potentiated at low concentrations (0.01–0.05 mg/mL) the antibacterial activity of penicillin, fluoroquinolones or oregano essential oil against the selected food-borne pathogens (Staphylococcus aureus, Escherichia coli and Salmonella typhimurium) without showing any in vitro cytotoxicity. Both extracts exhibited good cupric ion-reducing antioxidant capacity at concentrations above 0.042–0.08 mg/mL. The UHPLC-HRMS analysis revealed that both extracts contained long chain fatty acids and carotenoids thus explaining their antibacterial and antioxidant potential. The applied engineering approach showed a great potential to modify microalgae metabolism for the synthesis of target compounds by S. obliquus with capacity for the development of health-promoting nutraceuticals for poultry farming.

EXPLORING THE ANTIOBESITY AND ANTIOXIDANT POTENTIAL OF THE METHANOLIC EXTRACT OF CAMELLIA SINENSIS

The escalating problem of obesity has become a cause of great concern in the world today as it leads to adverse effects on human health, including cardiovascular diseases, cancer etc. The major causes of obesity may be attributed to sedentary lifestyle and bad food habits. Conventional modalities to tackle obesity are not free from side-effects. Urgency of a novel, nontoxic means needs to be developed to control obesity. In this study we aim to screen the phytochemical compounds of Camellia Sinensis and evaluate its antiobesity and antioxidant effects. The methanolic extract of Camellia Sinensis was analyzed for its phytochemical screening and assayed for its in-vitro activity against pancreatic lipase, its antioxidant potential and quantitative estimation of flavonoids and phenolics were done. The methanolic extract of Camellia Sinensis strongly inhibited pancreatic lipase by 63% and it also possesses a strong antioxidant effect and there was a significant positive correlation between phenolics, flavonoids and with alkaloid contents. From these results, it could be concluded that methanolic extracts of Camellia Sinensis possesses antipancreatic lipase compounds. It also possesses antioxidant effect. It is suggested that the phytochemical compounds from there plants may be applied for the prevention and treatment of obesity or hyperlipidemia. Keywords: Obesity, Camellia Sinensis, Pancreatic lipase, Antioxidant, Phenolic

Determination of Polyphenols Content and Antioxidant Activity of Citrus sinensis Fruit Peel

Citrus fruits have long been qualified as veritable foods in view of the many therapeutic benefits they bring to the body. Several researchers have stud-ied the relationship between the bioactive compounds of Citrus and the health benefits and reduction of the risk of disease. Citrus sinensis, used in the food industry and its extracts have also been used in traditional medicine to activate vital energy, circulation, and weight loss, and appetite control. However, limited efforts have been made on collecting data on antioxidant potential of peels orange from the northern region of Algeria. Our study, therefore, focuses on the evaluation of total polyphenols compounds and in vitro assessment of their antioxidant potential of peels orange from the northern region of Algeria. The ethyl acetate and n-butanolic fractions from peels orange have been tested for their antioxidant activities and their lipid peroxidation inhibiting effects. The total phenolic and flavonoids content showed high levels. The preliminary phytochemical screening of tannins, phenolic compounds, flavonoids, coumarin, and alkaloids was also used. DPPH assay possesses strong potency to scavenge free radicals. The NO. radi-cal scavenging test exerts a good inhibitory effect. Furthermore, orange peels have been shown to suppress the lipid peroxidation of linoleic acid. Results further revealed a strong correlation between antioxidant effects and polyphenolic compounds. The high antioxidant activity of peel orange suggests that it could serve as a good natural antioxidant additive or food dietary supplement.

Synthesis, Molecular Modeling, DNA Damage Interaction, and Antioxidant Potential of Hesperidin Loaded on Gold Nanoparticles

The flavonoglycone hesperidin is recognized as a potent anti-inflammatory, anticancer, and antioxidant agent. However, its poor bioavailability is a crucial bottleneck regarding its therapeutic activity. Gold nanoparticles are widely used in drug delivery because of its unique properties that differ from bulk metal. Hesperidin loaded gold nanoparticles were successfully prepared to enhance its stability and bioactive potential, as well as to minimize the problems associated with its absorption. The free radical scavenging activities of hesperidin, gold nanoparticles, and hesperidin loaded gold nanoparticles were compared with that of Vitamin C and subsequently evaluated in vitro using 2,2-diphenyl-1-picrylhydrazyl assay. The antioxidant pharmacophore-based structure-activity relationship analysis was assessed by the density functional theory as well as quantum chemical calculations. Moreover, the structural properties were utilized using Becke’s three-parameter hybrid exchange and Lee-Yang-Parr’s correction of functional approaches. Hesperidin-loaded gold nanoparticles were found to decrease hydrogen peroxide (H2O2) and thus induce Deoxyribonucleic acid (DNA) instability. In addition, hesperidin-gold nanoparticles were observed to display important antioxidant potential as well as ameliorate the functional activity of macrophages against Escherichia coli, possibly protecting DNA. These particles might be appropriate for clinical trials and could prove useful for the treatment of various life-threatening disorders.

Effect of Hydroxyl Groups Esterification with Fatty Acids on the Cytotoxicity and Antioxidant Activity of Flavones

Flavonoids and polyunsaturated fatty acids due to low cytotoxicity in vitro studies are suggested as potential substances in the prevention of diseases associated with oxidative stress. We examined novel 6-hydroxy-flavanone and 7-hydroxy-flavone conjugates with selected fatty acids (FA) of different length and saturation and examined their cytotoxic and antioxidant potential. Our findings indicate that the conjugation with FA affects the biological activity of both the original flavonoids. The conjugation of 6-hydroxy-flavanone increased its cytotoxicity towards prostate cancer PC3 cells. The most noticeable effect was found for oleate conjugate. A similar trend was observed for 7-hydroxy-flavone conjugates with the most evident effect for oleate and stearate. The cytotoxic potential of all tested conjugates was not specific towards PC3 because the viability of human keratinocytes HaCaT cells decreased after exposure to all conjugates. Additionally, we showed that esterification of the two flavonoids decreased their antioxidant activity compared to that of the original compounds. Of all the tested compounds, only 6-sorbic flavanone showed a slight increase in antioxidant potential compared to that of the original compound. Our data show that conjugated flavonoids are better absorbed and enhance cytotoxic effects, but the presence of FA lowered the antioxidant potential.

Response Surface Optimization for Antioxidant Extraction and Attributes Liking from Roasted Rice Germ Flavored Herbal Tea

The optimal process conditions when examining the antioxidant potential, total polyphenol content, and attribute liking in roasted rice germ flavored herbal tea were investigated using response surface methodology (RSM). The influence upon the extraction process of time and temperature was assessed using a full factorial design on three levels with two variables (32), involving five central point replicates. Extraction temperature (70 °C, 80 °C, and 90 °C) and extraction time (3 min, 4.5 min, and 6 min) served as independent variables, while the dependent variables were allocated to the regression equation to determine antioxidant activity (R2 = 0.941) along with total polyphenol content (R2 = 0.849), flavor liking score (R2 = 0.758), and overall liking score (R2 = 0.816). Following experimentation, it was determined that the optimal time and temperature conditions to maximize total polyphenol content, antioxidant activity, flavor, and overall liking score were in a range of 86 °C to 90 °C for 3.4 min to 5.9 min. When these conditions were imposed, the antioxidant potential, total polyphenol content, flavor, and overall liking score were >70% for DPPH scavenging activity, >75 mgGAE/g, >6.7 (like moderately), and >6.5 (like moderately), respectively.

Chitosan oligosaccharide alleviates the growth inhibition caused by physcion and synergistically enhances resilience in maize seedlings

The use of biopesticides has gradually become essential to ensure food security and sustainable agricultural production. Nevertheless, the use of single biopesticides is frequently suboptimal in agricultural production given the diversity of biotic and abiotic stresses. The present study investigated the effects of two biopesticides, physcion and chitosan-oligosaccharide (COS), alone and in combination, on growth regulation and antioxidant potential of maize seedlings by seed coating. As suggested from the results, physcion significantly inhibited the growth of the shoots of maize seedlings due to the elevated respiration rate. However, COS significantly reduced the growth inhibition induced by physcion in maize seedlings by lowering the respiration rate and increasing the content of photosynthetic pigments and root vigor, which accounted for lower consumption of photosynthesis products, a higher photosynthetic rate and a greater nutrient absorption rate. Thus, an improved growth was identified. As indicated from the in-depth research, the application of physcion and COS combination is more effective in down-regulated the malondialdehyde (MDA) content by facilitating the activities of the antioxidative enzymes (i.e., superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (G-POD)). Such results indicated that the combined use of physcion and COS neither affected the normal growth of maize seedlings, but also synergistically improved the antioxidant potential of the maize plants, resulting in plants with high stress resistance. Thus, the combined use of physcion and COS by seed coating in maize production has great potential to ensure yield and sustainable production of maize.