New Source Of Natural Antioxidants Research Articles

Extraction, analysis of antioxidant activities and structural characteristics of flavonoids in fruits of Diospyros lotus L.

Flavonoid compounds are considered important components of new sources of natural antioxidants. This study was performed to optimize the ultrasound-assisted extraction processes of flavonoids from date plum persimmon (DPP) fruits, along with the in vitro antioxidant capacities and identities of those components. First, the effects of liquid/solid ratio, ethanol concentration, extraction time, and extraction temperature on flavonoid yields were investigated by independent variables analysis. Then the response surface methodology was used to optimize the extraction process, and the maximum flavonoid content was 3.05 ± 0.03 mg/g DW under the conditions of liquid/solid ratio 27:1 (mL/g), 74 mL ethanol/100 mL, extraction time 27 min, and extraction temperature 80 °C. Moreover, by DPPH and ABTS assays, the crude extracts of flavonoids in DPP fruits exhibited robust scavenging capacities with IC50 values of 1.76 and 0.82 μg/mL, respectively. In addition, 17 bioactive compounds of DPP were isolated and identified by HPLC-ESI-QTOF-MS/MS, among which two were phenolic acid derivatives, two were flavanones, eight were flavones, four were pentacyclic triterpenoids and one was xanthone. This study provided information regarding the phytochemical composition and functional properties of DPP fruits, supporting future research to facilitate the development and utilization of DPP as a functional food.

Exploring the Chemical Profile, In Vitro Antioxidant and Anti-Inflammatory Activities of Santolina rosmarinifolia Extracts.

In this study, the phytochemical composition, in vitro antioxidant, and anti-inflammatory effects of the aqueous and 60% ethanolic (EtOH) extracts of Santolina rosmarinifolia leaf, flower, and root were examined. The antioxidant activity of S. rosmarinifolia extracts was determined by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. The total phenolic content (TPC) of the extracts was measured by the Folin-Ciocalteu assay. The anti-inflammatory effect of the extracts was monitored by the Griess assay. The chemical composition of S. rosmarinifolia extracts was analysed using the LC-MS technique. According to our findings, 60% EtOH leaf extracts showed the highest Trolox equivalent antioxidant capacity (TEAC) values in both ABTS (8.39 ± 0.43 µM) and DPPH (6.71 ± 0.03 µM) antioxidant activity assays. The TPC values of the samples were in good correspondence with the antioxidant activity measurements and showed the highest gallic acid equivalent value (130.17 ± 0.01 µg/mL) in 60% EtOH leaf extracts. In addition, the 60% EtOH extracts of the leaves were revealed to possess the highest anti-inflammatory effect. The LC-MS analysis of S. rosmarinifolia extracts proved the presence of ascorbic acid, catalpol, chrysin, epigallocatechin, geraniol, isoquercitrin, and theanine, among others, for the first time. However, additional studies are needed to investigate the direct relationship between the chemical composition and physiological effects of the herb. The 60% EtOH extracts of S. rosmarinifolia leaves are potential new sources of natural antioxidants and anti-inflammatory molecules in the production of novel nutraceutical products.

Phytochemical Profile and In Vitro Bioactivities of Wild Asparagus stipularis.

In this study, Asparagus stipularis was characterized concerning its phytochemical composition, antioxidant potential, cytotoxicity, and pancreatic lipase inhibitory activities. Twenty-seven compounds were identified and quantified by HPLC-DAD-MS in the leaf, stem, pericarp, and rhizome of ethanolic extracts. Seven steroidal saponins were detected, and the highest content was quantified in rhizome and pericap. A. stipularis also contained significant amounts of flavonoids in the aerial part. Isorhamnetin tetra-glycoside, quercetin-3-glucosyl-rutinoside, and rutin were the main flavonoid derivatives in leaf, stem, and pericarp extracts, respectively. In addition, eleven phenolic acids were also detected; among them, caffeic acid, protocatechuic acid, p-hydroxybenzoic acid, and ferulic acid were the predominant phenolics, with these having the highest amounts quantified in the rhizome extracts. All the tested extracts possessed antioxidant capacities, with pericarp and rhizome extracts exhibiting the highest activity in DPPH, ABTS, and FRAP assays. The extracts from pericarp and rhizome were revealed to also be the strongest inhibitors of pancreatic lipase. The rhizome extracts exhibited potent cytotoxic activity against HCT-116 and HepG2 with IC50 values of 30 and 54 µg/mL after 48 h of treatment. The present study demonstrated that A. stipularis can be used as a new source of natural antioxidants and potential anticancer and antiobesity compounds.

Genista tridentata Phytochemical Characterization and Biological Activities: A Systematic Review.

Genista tridentata (L.) Willk., known as "prickled broom", is a Leguminosae (Fabaceae) species native to the Iberian Peninsula, Morocco, Algeria, and Tunisia. It is used in folk medicine as an anti-inflammatory, for gastrointestinal and respiratory disorders, rheumatism, and headaches, to lower blood pressure, against hypercholesterolemia and hyperglycemia. This study aimed to systematically review the literature on the bioactivities and phytochemical profile of Genista tridentata to understand its pharmacological potential. For this, four electronic databases (PubMed, GoogleScholar, Repositórios Cientificos de Acesso Aberto de Portugal (RCCAP), and ScienceDirect) were searched from inception up to 31 December 2022. From a total of 264 potentially eligible studies considered for screening, 34 papers were considered eligible for this systematic review. The sampling included 71 extracts, collected mainly in Portugal. Genista tridentata extracts present a high level of flavonoids and phenolic compounds. The flowers and aerial parts of the plant were the most studied, and aqueous extracts were the most used. The results predict a high potential for the application of Genista tridentata as a new source of natural antioxidants and preservatives for the food industry with subsequent health benefits, such as the production of nutraceuticals. Moreover, the results indicate that the plant can be collected at all seasons of the year, which represents a benefit for the industry.

Phenolic Content and Antioxidant Activity of Leaves and Rhizomes of Etlingera coccinea (Blume) S.Sakai and Nagam. (Zingiberaceae)

Most of the Zingiberaceae species in the Philippines have been used as ethnomedicinal plants due to the benefits they possess. One of these species is Etlingera coccinea (Blume) S.Sakai and Nagam. (Zingiberaceae), a species with a variety of uses in Malaysia, Borneo, and Philippines. In this study, ethanolic extracts of the dry weight leaves and rhizomes of E. coccinea were used to determine its phenolic content and antioxidant activity. The total phenolic content and total antioxidant activity were determined using Folin-Ciocalteu and phosphomolybdenum methods, respectively. Data revealed that the total phenolic content of dry weight, expressed as milligram gallic acid equivalent per gram sample (mg GAE/g sample) recorded that the leaves (11.69 ± 0.47 mg GAE/g sample) have greater amount of phenolics than the rhizomes (0.58 ± 0.06 mg GAE/g sample). The total antioxidant activity (TAA), expressed as milligram ascorbic acid equivalent per gram sample (mg AAE/g sample), obtained higher activity in the leaves (12.76 ± 0.31 mg AAE/g sample) than the rhizomes (0.85 ± 0.12 mg AAE/g sample), and the reducing power, expressed as milligram gallic acid reducing power equivalent per gram sample (mg GRPE/g sample) also revealed higher activity for the leaves (9.37 ± 1.88 mg GRPE/g sample) compared to rhizomes (0.28 ± 0.07 mg GRPE/g sample). Based on the correlation analysis, a perfect positive linear relationship was observed among the TPC, TAA, and RP (r=1, p<0.001), which means that phenolic compounds significantly contribute to the antioxidant activities of the extracts of E. coccinea. These data imply that E. coccinea could be potentially used as a new source of natural antioxidant. Furthermore, this paper adds information on the habitat and ecology, phenology, and coloured photographs of this species for future related studies and conservation initiatives.

ANTIOXIDANT AND ANTIDIABETIC ACTIVITY OF DECALEPIS HAMILTONII LEAVES EXTRACT

In most nations, diabetes mellitus is a serious and rising health issue. The goal of the study was to compare the antidiabetic effects of leaves extracts of Decalepis hamiltonii in normal and diabetic rats induced with alloxan. Using 120 mg/kg of alloxan monohydrate, diabetes was induced. In order to considerably lower blood glucose levels in both normal and alloxan-induced diabetic rats, D. hamiltonii methanolic extract was given at doses of 200 mg and 400 mg, along with glibenclamide at a dose of 7 mg/kg bwt. Additionally, the injection of the extract dramatically reduced the levels of AST, ALT, triglycerides, and total blood cholesterol while simultaneously raising the amount of liver glycogen. In order to perform the oral glucose tolerance test (OGTT), separate groups were given doses of D. hamiltonii methanolic extract (200 mg, 400 mg), and glibenclamide (7.5 mg), which effectively reduced blood sugar levels following an oral glucose load at all time points. These findings indicate that diabetic rats' blood glucose levels were successfully lowered by the methanolic extract of D. hamiltonii leaves. The antioxidant potential of the leaves was measured using various in vitro assays. The methanolic extracts showed high antioxidant activity measured as scavenging of DPPH, superoxide and hydroxyl radicals. The antioxidant activity did not correlate with the phenolic content of the extracts. These results demonstrate the antioxidant potency of the leaves extracts which could be the basis for its alleged health promoting potential of D. hamiltonii. The leaves of D. hamiltonii could serve as a new source of natural antioxidants or nutraceuticals with potential applications to reducing the level of oxidative stress and related health benefits. KEYWORDS: Decalepis hamiltonii, Antidiabetic, Antioxidant, Alloxan, AST, OGTT

Looking beyond Arthrospira: Comparison of antioxidant and anti-inflammatory properties of ten cyanobacteria strains

Cyanobacteria are a widely distributed group of photosynthetic prokaryotes with potential to produce biologically active compounds. Arthrospira is the most widespread grown cyanobacteria for commercial purposes; however, many other species could be used as sources of a wide variety of bio-products. The pigment phycocyanin explains part of the therapeutic properties attributed to Arthrospira (e.g. antioxidant and anti-inflammatory). Many chronic diseases include, on its etiology, oxidative stress and abnormalities in the inflammatory response; thus, there is great interest in finding new sources of natural antioxidants and anti-inflammatory compounds. The aim of this work was to evaluate growth attributes, chemical composition and antioxidant and anti-inflammatory properties of ten cyanobacteria isolates. After 15 days of culture, biomass production ranged between 0.06 g/L (Anabaena) and 0.27 g/L (Phormidium) in 20 L volume cultures. Protein content of dry biomass ranged between 28.86 % (Nodularia) and 56.39 % (Arthrospira) while phycocyanin content ranged between 0.86 % (Nodularia) and 6.66 % (Spirulina). Aqueous extracts were evaluated regarding total phenolic content (TPC), total flavonoids content (TFC) and antioxidant activities (DPPH, ABTS and FRAP). Spirulina and Desertifilum exhibited the highest phenols and flavonoids contents; as well as the highest ABTS and FRAP antioxidant activities. Five strains were selected for measuring anti-inflammatory activity by the human erythrocyte membrane stabilization assay. All the strains evaluated exhibited a remarkable anti-inflammatory capacity, being the highest value for Desertifilum. Strains of Spirulina and Desertifilum were also tested for their ability to scavenge reactive oxygen species (ROS) on Hek293 cells; both strains showed significant intracellular antioxidant capacity and were not cytotoxic. This research demonstrated that other cyanobacterial strains, besides the popular Arthrospira, might be new sources of antioxidant and anti-inflammatory compounds for biotechnological applications in functional food, nutraceutical or pharmaceutical industries.

Up-Regulation of the Nrf2/HO-1 Antioxidant Pathway in Macrophages by an Extract from a New Halophilic Archaea Isolated in Odiel Saltworks.

The production of reactive oxygen species (ROS) plays an important role in the progression of many inflammatory diseases. The search for antioxidants with the ability for scavenging free radicals from the body cells that reduce oxidative damage is essential to prevent and treat these pathologies. Haloarchaea are extremely halophilic microorganisms that inhabit hypersaline environments, such as saltworks or salt lakes, where they have to tolerate high salinity, and elevated ultraviolet (UV) and infrared radiations. To cope with these extreme conditions, haloarchaea have developed singular mechanisms to maintain an osmotic balance with the medium, and are endowed with unique compounds, not found in other species, with bioactive properties that have not been fully explored. This study aims to assess the potential of haloarchaea as a new source of natural antioxidant and anti-inflammatory agents. A carotenoid-producing haloarchaea was isolated from Odiel Saltworks (OS) and identified on the basis of its 16S rRNA coding gene sequence as a new strain belonging to the genus Haloarcula. The Haloarcula sp. OS acetone extract (HAE) obtained from the biomass contained bacterioruberin and mainly C18 fatty acids, and showed potent antioxidant capacity using ABTS assay. This study further demonstrates, for the first time, that pretreatment with HAE of lipopolysaccharide (LPS)-stimulated macrophages results in a reduction in ROS production, a decrease in the pro-inflammatory cytokines TNF-α and IL-6 levels, and up-regulation of the factor Nrf2 and its target gene heme oxygenase-1 (HO-1), supporting the potential of the HAE as a therapeutic agent in the treatment of oxidative stress-related inflammatory diseases.

A Study of the Chemical Composition and Biological Activity of Michelia macclurei Dandy Heartwood: New Sources of Natural Antioxidants, Enzyme Inhibitors and Bacterial Inhibitors.

The wood of Michelia macclurei Dandy (MD) is an excellent material that is widely used in the furniture, handicraft, and construction industries. However, less research has been conducted on the chemical composition and biological activity of heartwood, which is the main valuable part of the wood. This study aimed to investigate the chemical composition and biological activities of the heartwood of Michelia macclurei Dandy (MDHW) and to confirm the active ingredients. Triple quadrupole gas chromatography-mass spectrometry (GC-MS) was used to characterize the volatile components of MDHW, while ultra-performance liquid chromatography-mass spectrometry was used to analyze the non-volatile components (UPLC-MS). The total reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assays, acetylcholinesterase and α-glucosidase inhibition assays, and an antimicrobial test of 4 gram bacteria were used to describe the in vitro bioactivities. The GC-MS analysis showed that the volatile components of MDHW were mainly fatty compounds and terpenoids, with sesquiterpenes and their derivatives dominating the terpene composition. β-elemene was the main terpene component in the steam distillation (11.88%) and ultrasonic extraction (8.2%) methods. A total of 67 compounds, comprising 45 alkaloids, 9 flavonoids, 6 lignans, and others, were found by UPLC-MS analysis. The primary structural kinds of the non-volatile components were 35 isoquinoline alkaloids. Alkaloids were the predominant active constituent in all MDHW extracts, including crude extracts, alkaloid fractions, and non-alkaloid fractions. These extracts all demonstrate some biological effects in terms of antioxidant, enzyme inhibition, and bacterial inhibition. The findings of this study show that MDHW is abundant in chemical structure types, has great bioactivity assessment, and has the potential to be used to create natural antioxidants, products that postpone Alzheimer's disease and lower blood sugar levels and antibacterial agents.

Morphology, Phenolic Content, and Antioxidant Activity of Etlingera fimbriobracteata (K.Schum.) R.M.Sm. and E. philippinensis (Ridl.) R.M.Sm. (Zingiberaceae)

Two of the most studied Etlingera species of the ginger family (Zingiberaceae) in the Philippines were Etlingera fimbriobracteata (K.Schum.) R.M.Sm. and E. philippinensis (Ridl.) R.M.Sm. However, little is known about the biochemical analyses of these species to support their potential as ethnomedicinal plants in the country. Thus, this study was carried out to describe the morphology and determine the phenolic content and antioxidant activity of the ethanolic extracts of the two Etlingera species. Data revealed that the two species are correctly identified and their full description, updated distribution, phenology, and habitat and ecology are provided in this paper. The two species are recognizable in both vegetative and reproductive parts. E. fimbriobracteata has reddish color towards the base of the pseudo stem, bright yellow flowers incurved upon maturity, and green sterile bracts that form reddish upon maturity, whereas E. philippinensis has mandarin to deep red inflorescence and has a long outward labellum. The total phenolic content (TPC) expressed as milligram gallic acid equivalent per gram dried sample (mg GAE/g dried sample) revealed the highest phenolics in the leaves (13.20 ± 0.35 in E. fimbriobracteata and 7.21 ± 0.33 in E. philippinensis) than rhizomes (1.44 ± 0.04 in E. fimbriobracteata and 0.46 ± 0.30 in E. philippinensis). Further, total antioxidant activity (TAA) expressed as milligram ascorbic acid equivalent per gram dried sample (mg AAE/g dried sample) was also observed highest in leaves (12.69 ± 0.36 in E. fimbriobracteata and 7.22 ± 0.26 in E. philippinensis) compared to the rhizomes (1.82 ± 0.01 in E. fimbriobracteata and 1.38 ± 0.07 in E. philippinensis). The reducing power (RP) expressed as milligram gallic RP equivalent per gram dried sample (mg GPRE/g dried sample) also revealed higher for the leaves (10.16 ± 2.18 in E. fimbriobracteata and 7.53 ± 0.80 in E. philippinensis) than rhizomes (0.97 ± 0.18 in E. fimbriobracteata and 0.09 ± 0.09 in E. philippinensis). The high contents of phenolic compounds contribute to the antioxidant activity of extracts from the two species. Based on the correlationanalysis, a perfect positive linear relationship was observed among the TPC, TAA, and RP (r= 1, p < 0.001). These imply that E. fimbriobracteata and E. philippinensis could potentially beused as new sources of natural antioxidants.

Exploring the Potential of Grape Pomace Extract to Inhibit Thermo-Oxidative Degradation of Sunflower Oil: From Routine Tests to ATR-FTIR Spectroscopy.

Exploring new sources of natural antioxidants is of great interest to edible oil producers, in line with the toxicological problems generated by the use of synthetic antioxidants. This study assesses the potential of lyophilized Pinot Noir grape pomace extract (GPE) to enhance the sunflower oil stability against thermo-oxidative damage compared to BHT during a prolonged exposure to convective heat at 185 °C. Oil thermo-oxidation was monitored based on specific indices such as peroxide value (PV), para-anisidine value (p-AV), inhibition of oil oxidation (IO), total oxidation (TOTOX) value, conjugated dienes and trienes (CDs, CTs), but also by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), where absorbance ratios A 3009 cm-1/A 2922 cm-1 (RI), A 3009 cm-1/A 2853 cm-1 (RII), A 3009 cm-1/A 1744 cm-1 (RIII) and RIV = A 1744 cm-1/A 2922 cm-1 (RIV) were investigated. GPE showed a significant inhibitory effect on oil thermo-oxidation and this response was concentration-dependent. Substantial decreases in the investigated indices, compared to the control without added antioxidants, were obtained after 4 h and 8 h of heat exposure of the 800 ppm GPE sample: PV (47%; 42%), p-AV (38%; 33%), IO (54%; 46%), TOTOX (41%; 37%), CDs (46%; 39%), CTs (44%; 29%). Oil exposure to heat resulted in changes in RI-RIV attributed to the reduction in the degree of unsaturation, in response to primary and secondary lipid oxidation. FTIR spectroscopy can be used to differentiate untreated and heat-treated oils based on the absorbance ratios. An inhibitory effect close to that of BHT was achieved by 500 ppm GPE, while a dose of 800 ppm provided greater protection against thermo-oxidation. Our results promote GPE as a natural additive to limit the thermo-oxidative damage of plant oils.

Phenolic contents and antioxidant activities of solvent extracts from four edible flowers

In order to identify new sources of natural antioxidants, the antioxidant activities of various solvent extracts from four edible flower samples [Wisteria sinensis (Sims) DC., Benincasa hispida (Thunb.) Cogn, Luffa cylindrica (L.) Roem, and Cucurbita pepo L.) were systemically investigated. The total phenolic content (TPC) and total flavonoid content (TFC), and individual phenolic profile of each extract were investigated, and antioxidant activities were measured by the DPPH radical scavenging activity, superoxide radical scavenging activity, total reduction capability, and ferrous ions chelating activity. Results revealed that all flower extracts exhibited antioxidant activities, and contained certain amounts of phenolic compounds. Specifically, different solvents exhibited different efficiencies in the extraction of phenolics, flavonoids, and compounds with antioxidant activities. The 70% ethanolic extract from B. hispida yielded the highest TPC (49.92 mg GAE/g DW), superoxide radical scavenging activity (IC50, 0.073 mg/mL), and FRAP value (18.05 mg of GAE/g DW). The highest TFC was obtained with the ethanolic extract of W. sinensis (30.39 mg QE/g DW), and the contents of apigenin, luteolin, and myricetin in the ethanolic extract of W. sinensis were significantly higher than those in the other extracts. The 40% ethanolic extract of L. cylindrica yielded the highest DPPH scavenging capacity (IC50, 0.340 mg/mL), and water extract of B. hispida yielded the highest chelating activity (0.027 mg/mL). Correlation analysis indicated that total phenolics and flavonoids in the extracts were the major contributors to the DPPH scavenging activities and FRAP activities. Overall, results demonstrated that these edible flowers could serve as useful source of natural antioxidants, and be used as functional food ingredients.

Phenolic Content and Antioxidant Activity of ethanol extracts of Etlingera pubimarginata (Zingiberaceae), including notes on its Morphology

Ethanolic extracts of the dry weight leaves and rhizomes of Etlingera pubimarginata (Elmer) A.D.Poulsen were used in this study to determine its phenolic content and antioxidant activity. Total phenolic content was determined using the Folin-Ciocalteu method, while phosphomolybdenum method was used for the total antioxidant activity. Data revealed that the total phenolic content in E. pubimarginata leaves (27.25 ± 0.72 mg GAE/g dried sample) have greater amount of phenolics than its rhizomes (0.76 ± 0.11 mg GAE/g dried sample). Further, total antioxidant activity of E. pubimarginata was observed higher in leaves (34.83 ± 0.49 mg AAE/g dried sample) than rhizomes (1.82 ± 0.09 mg AAE/g dried sample), as well as the reducing power revealed to have higher amounts in the leaves (24.83 ± 2.99 mg GRPE/g dried sample) than the rhizomes (0.33 ± 0.10 mg GRPE/g dried sample). The high contents of phenolic compounds contribute to the antioxidant activity of extracts of E. pubimarginata. A perfect positive linear relationship was observed among the total phenolic content, total antioxidant activity, and reducing power (r=1, p<0.001) based on the correlation analysis. These imply that E. pubimarginata could be potentially used as a new source of natural antioxidant. Furthermore, a description of the species, including its updated distribution, phenology, and habitat and ecology are provided in this paper.

Antioxidant and Antibacterial Activity of The Stem Bark Extract of Sterculia Foetida L.

Free radicals are compounds that contain one or more unpaired electrons which are very reactive, causing damage to cells or tissues and implication in the emergence of various degenerative diseases. Several methods of exploring medicinal plants have been carried out to find new sources of natural antioxidants and antibacterials that can reduce the use of synthetic drugs. This study aimed to examine the antioxidant and antibacterial activity of the stem bark extract of the plant Sterculia foetida L. The antioxidant activity of S. foetida was tested using the ABTS radical method (2,2-Azinobis 3-ethyl benzothiazoline 6-sulfonic acid). The principle of this method is that the color intensity or absorbance of the ABTS solution is inversely proportional to the concentration of antioxidant compounds. ABTS absorbance measurements were carried out at a wavelength of 734 nm. The results showed that the bark extract of the plant S. foetida could inhibit ABTS radicals with an IC50 value of 5.54 g/mL. The antibacterial activity of S. foetida was tested by measuring the optical density (OD) at a wavelength of 630 nm and expressed by the Inhibition Concentration 50 (IC50) value of 10442.29 g/mL.

Proximate Composition and Determination of Epigallocatechin Gallate Content in Melon Manis Terengganu

Melon Manis Terengganu (MMT), Cucumis melo L., is a newly developed variety of melon introduced specifically for Terengganu. MMT has been claimed to have a high antioxidant value. Epigallocatechin gallate (EGCG) has become one of the leading naturally derived polyphenols studied for its potential health benefits. In the present study, the proximate composition and EGCG content of MMT were determined and compared among the fruit parts (flesh, seeds, and peels). The powdered samples have undergone proximate analyses followed by the determination of EGCG concentration using high performance liquid chromatography (HPLC). The result revealed that MMT seed has highest protein (27.99 ± 0.36%), fat (28.79 ± 0.32%) and crude fibre (31.64 ± 1.25%) contents as compared to peel and flesh. MMT peel contained the highest carbohydrate (67.48 ± 0.37%) as compared to flesh and seed. The EGCG concentrations of MMT seed, flesh and peel were significantly different (p < 0.05) among one another with MMT peel as the highest EGCG concentration (0.042 ± 0.003 mg/mL). Therefore, MMT peel has the potential to consider as new sources of natural antioxidants for food and nutraceutical products as it contained the highest EGCG concentration as compared to seed and flesh

Phytochemical and Antioxidant Activities of Eucheuma spinosum as Natural Functional Food from North Sulawesi Waters, Indonesia.

Research to find functional food from new natural sources has caught the attention of many researchers through the characterization of phytochemicals and biological activities. One potential source of natural ingredients is the red alga Eucheuma spinosum, which has been used as a daily source of natural food. The purpose of this study was to obtain a prospective new source of natural antioxidants from various extracts of tropical red alga (E. spinosum) through several tests, which were used as determinants of whether the alga can be used as a functional food source. Algal sample was extracted with organic solvents (methanol, n-hexane, ethyl-acetate and water) and purified by a combination of normal and reverse phase chromatography methods. The algal extracts had antioxidant compounds based on free radical scavenging activities using 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and superoxide dismutase (SOD). The ethyl acetate extract of E. spinosum scavenged DPPH and SOD free radicals, so that this extract was indicated contained powerful antioxidants. The result of the isolation of the antioxidant compound showed the presence of pure compound 3-(3-methoxyphenyl) propanal. This study concluded that red algae E. spinosum contained natural antioxidants which have the potential to be developed as a functional food and disease prevention and treatment. In addition, the components of these antioxidant compounds from the algae have the potential to be used as natural sources of new functional ingredients.

Biomarkers and Utility of the Antioxidant Potential of Probiotic Lactobacilli and Bifidobacteria as Representatives of the Human Gut Microbiota.

Lactobacilli and bifidobacteria are an important part of human gut microbiota. Among numerous benefits, their antioxidant properties are attracting more and more attention. Multiple in vivo and in vitro studies have demonstrated that lactobacilli and bifidobacteria, along with their cellular components, possess excellent antioxidant capacity, which provides a certain degree of protection to the human body against diseases associated with oxidative stress. Recently, lactobacilli and bifidobacteria have begun to be considered as a new source of natural antioxidants. This review summarizes the current state of research on various antioxidant properties of lactobacilli and bifidobacteria. Special emphasis is given to the mechanisms of antioxidant activity of these bacteria in the human gut microbiota, which involve bacterial cell components and metabolites. This review is also dedicated to the genes involved in the antioxidant properties of lactobacilli and bifidobacteria strains as indicators of their antioxidant potential in human gut microbiota. Identification of the antioxidant biomarkers of the gut microbiota is of great importance both for creating diagnostic systems for assessing oxidative stress and for choosing strategies aimed at restoring the normal functioning of the microbiota and, through it, restoring human health. In this review, the practical application of probiotic strains with proven antioxidant properties to prevent oxidative stress is also considered.

Application of natural antioxidants in the oxidative stabilization of fish oils: A mini‐review

Fish oils are a source of omega-3 unsaturated fatty acids which are known for their beneficial effects on human health. These acids are highly unstable and are easily oxidized on storage, whereby their nutrition value deteriorate, undesirable flavor develops, and toxic compounds are generated. Antioxidants extend the fish oil shelf-life. However, synthetic antioxidants may annihilate the health-promoting properties of omega-3 fatty acids, which is not the case when natural antioxidants are used. Application of the latter may bring about many benefits. However, the number of approved natural antioxidants is still very low. Therefore, new sources of natural antioxidants are explored among polyphenol compounds in plants, for example, in herbs, spices, or by-products of fruit and vegetable processing. A review of studies addressing the application of natural antioxidants in the extension of fish oil shelf-life is presented and the effectiveness of natural antioxidants in protecting long-chain omega-3 fatty acids is discussed. Practical applications The use of natural antioxidants in foods and food supplements raises no reservations as to the toxicological safety and is accepted by consumers. Many natural antioxidants are highly effective in inhibiting oxidation and may be successfully used to extend the shelf-life of health-promoting omega-3 polyunsaturated fatty acids.

Onion husk (Állium cépa) as a promising source of natural antioxidants

The search for new sources of natural antioxidants is an important area of research. The total antioxidant capacities (TAC) of ethanol and aqueous extracts of yellow, red and white onion husks, rosemary and basil were determined by the Oxygen Radical Absorbance Capacity method using fluorometer Fluoroskan Ascent FL and the Ferric Reducing/Antioxidant Power spectrophotometer SF-2000 and expressed in µmol-equiv. Trolox/g of a sample and µmol-equiv. dihydroquercetin / g of a sample, respectively. Ethanol and aqueous extracts of red onion husk demonstrated the greatest TACs and amounted to 709.17±21.68 µmol-equiv. Trolox/g and 2048.83±64.97 µmol-equiv. Trolox/g, and these significantly exceeded the TACs of such popular spices in the food industry as basil and rosemary. TACs of both extracts of yellow onion husk were approximately equivalent to rosemary. Ethanol extracts of red and yellow onion husk demonstrated the greatest TACs and amounted to 2005.64±33.59 µmol-equiv. dihydroquercetin /g and 941.39±65.43 µmol-equiv. dihydroquercetin /g, respectively, and these significantly exceeded the corresponding TACs of basil and rosemary. TACs of aqueous extracts were approximately equivalent to rosemary, but below the TAC of basil. The absence of bright taste and aroma of red and yellow onion husk extracts, high total antioxidant capacity for neutralization of free radicals by both mechanisms of interaction, as well as the availability of raw materials in large scale confirms that this waste of the fruit and vegetable industry is a promising source of natural antioxidants.

An overview of antioxidant capacity, total phenolics, and amino acids of Aureobasidium pullulans GM6

Aureobasidium pullulans grown in submerged flask culture for 5 days was investigated for antioxidant activity. The ethanolic extract of mycelium was used for determination of the antioxidant properties using different methods: total antioxidant activity, linoleic acid bleaching, DPPH free radical scavenging, hydrogen peroxide and hydroxyl radical scavenging activities, reduction of metal ions, and chelating abilities against ferrous ions. Total phenolics and amino acids content was establish in amount of 5.78 mg GAE and 5.16 µg Gly/g dry extract, respectively. The result of total antioxidant activity showed 7.83 µg AA/g dry extract. The results for free radical-scavenging activities in terms of DPPH, H2O2, and OH expressed as EC50 were 61.81, 26.61, and 69.79 µg/ml, respectively. The extract showed very potent reducing and chelating power (EC50 = 0.51 and 35.02 μg/ml, respectively). Total phenolics and amino acids contents of the extract were attributed to overall antioxidant capacity (r = 0.707–1.000) and (r = 0.140–0.978), respectively. Practical applications Aureobasidium pullulans is most famous fungus belonging to the family Dothioraceae. The fungus produces a broad range of natural products which have been regarded as safe and very important for nutraceutical, pharmaceutical, and environmental application. Among the best known products are: pullulan (exopolysaccharide), numerous commercially enzymes (protease, lipase, xylanase, amylase, pectinase, etc.), secondary metabolites, and antibiotics. Investigating isolates of the fungus that live in different extreme conditions and optimizing the experimental conditions for the production of natural products are of great importance for their practical application. The current study was focused on the details evaluation of antioxidant profile, content of total phenolics and amino acids in EtOH extract of mycelium A. pullulans GM6, after 5 days of incubation in submerged conditions. These data will provide some useful information relevant to understanding the antioxidant role of the fungus and further screening of isolate as potential source of new natural antioxidants.