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The purpose of this paper is to determine the antioxidant properties and phenol content of methanolic extracts of six white varieties and six purple/brown varieties of Indian rice and to find some relationship between the antioxidant properties, phenolic content in the varieties analyzed.

Methanolic extracts of different rice varieties were analyzed for their superoxide radical scavenging activity, 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity, total antioxidant capacity, reducing power and ferrous ion chelating properties. The extracts were analyzed for determination of total phenol content, anthocyanin content, oryzanol content. Phenolic acids were determined by HPLC.

All the rice varieties (white and purple/brown) showed activity in a dose‐dependent manner. Free phenolic acids, e.g. protocatechuic acid, caffeic acid, vanillic acid, p‐coumaric acid (PCA), ferulic acid and sinapic acid and the phenolic aldehyde vanillin could be detected in all the rice samples analyzed. No relationship could be established between activity and metabolite content. Principal component analysis and classification shows that superoxide radical scavenging activity, total phenolic acid, protocatechuic acid and ferulic acid are the components to differentiate the varieties from each other.

Little work has been done on the antioxidant activity of white rice. The authors report superoxide radical scavenging activity, DPPH radical scavenging activity, total antioxidant activity, reducing power and ferrous ion chelating properties and phenolic contents of six white varieties and six purple/brown varieties of Indian rice. Free phenolic acids like protocatechuic acid, caffeic acid, vanillic acid, PCA, ferulic acid and sinapic acid are reported from all the 12 varieties of rice.

The purpose of this paper is to carry out phytochemical investigations of different extracts of Eucalyptus globulus bark such as aqueous, methanolic and supercritical carbon dioxide fluid extract (SCFE) with ethyl acetate as entrainer. Three fractions (Eu 8, 9 and 10) containing steroidal δ‐lactone were isolated from SCF extract and the structure of Eu‐10 was earlier determined on the basis of NMR, HPLC‐MS, X‐Ray crystallography.

Column chromatography led to the isolation of flavonoids, tannins, steroids, etc. in different solvent systems. Isolated steroidal lactone (Eu‐8,9&10) of Withanolide series were tested for the presence of total phenolic content, total flavonoid content and the results were expressed as gGAE/100 g (TPC), and gQE/100 g (TFC), respectively. The antioxidant capacity was evaluated based on their ability to scavenge free radicals generated from ABTS, DPPH, FRAP and H₂O₂ by spectrophotometric method.

The result of the present study showed that different extracts of E. globulus bark and the isolated fractions, exhibited different antioxidant activity. This was due to the fact that they contained different amounts of flavonoid and phenolic compounds as per their ability to solubilize these compounds; the high scavenging property of E. globulus may be attributed to hydroxyl groups existing in the phenolic compounds. All the samples exhibited different extent of antioxidant activity (AOA) and showed higher potency when compared with BHT in scavenging action of DPPH free radical. Comparative data analysis showed SCF extract to be better than methanolic and aqueous extracts, both in terms of yield and AOA, while Eu‐10 was the best amongst purified fractions.

The present research has serious implications on identification of natural antioxidants from E. globulus. Natural antioxidants with better structure‐activity relationship are under investigation. Isolation of withanolide from Eucalyptus bark has opened newer horizon for its use.

Collection of Eucalyptus bark from the forest (a forest waste) by women folk can be a source of revenue generation and thus has social implication as well. It is an important agro product.

The steroidal lactone (Eu‐10) showed highest radical scavenging effect even at IC50, thus the isolated lactone proved to be the best potential scavenger of free radicals amongst all crude extracts and the isolated fractions.

This paper aims to study carotenoids as a natural food colorant from Canna flowers. There is a growing demand for eco-friendly and non-toxic colorants, specifically for health-sensitive applications such as colours of food and textiles. Red Canna variety can be grown in normal garden situations and gives ample of flowers yielding good amount of natural colorant for both the purposes.

In the present work, ultrasound extraction of natural colorant from Canna indica flowers has been studied. The use of ultrasound is found to have a significant improvement in the extraction efficiency of colorants obtained from dry and fresh Canna flowers in different mediums. Ultrasonic cavitational processing has twofold advantages, it is an eco-friendly and cost-effective process.

The total carotenoid content in dry and fresh flower extract was found to be between 136.56 and 978.89 mg/kg. The assessment of antioxidant activity (AOA) in dry and fresh flower extract was found to be 5.78-78.33 per cent assayed by scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and identified by electron paramagnetic resonance (EPR) studies.

The use of ultrasonication for the extraction of colorant has been the main feature and a step towards technological advancement in the area of finding newer method of efficient extraction of the colorant.

The ease of extraction due to ultrasound waves has been the highlight.

It is for the first time that the phytochemical data of red Canna flower and has been studied, the total carotenoid content and antioxidant activities of different extracts of Canna were measured. The extraction of natural dye from C. indica flowers using ultrasound has been found to have significant improvement in the extraction efficiency of the colorant obtained from flowers.

The purpose of this paper is to investigate various extracts of Annona squamosa L (Annonanceae) and Carica papaya L (Caricaceae) seeds for their antioxidant activity, free radical scavenging ability, total phenolic and flavonoid contents.

Samples from both the seeds were prepared by subjecting them to microwave‐assisted extraction. After determining their antioxidant properties and polyphenolic contents, correlation between them was also investigated.

Highest antioxidant activity (3,179.66 g gallic acid equivalent/g of dry extract) and phenol content were registered by chloroform:methanol extract of C. papaya seeds. Maximum radical scavenging activity (3,201.63 ascorbic acid equivalent antioxidant capacity g/100 g of dry extract) was exerted by water extract of A. squamosa seeds, whereas acetone extract of C. papaya registered highest flavonoid content among all extracts. Polar extracts were found to be better free radical scavengers compared with those less polar. Hexane extracts showed least DPPH radical scavenging activity. Acetone proved efficient in extracting flavonoids, whereas phenols were best extracted in a mixture of chloroform and methanol. Phenolic metabolites seem to be contributing significantly towards antioxidant activity of the C. papaya extracts, but less so in the case of A. squamosa.

There have been few reports on antioxidant activity of non‐edible parts of commonly consumed fruits. The research indicates that seeds may be a promising source of antioxidants, which may have therapeutic implications.

This study aims to investigate the effect of spray drying temperature and maltodextrin addition on the contents of phenolics, flavonoids, anthocyanins and antioxidant activities (2,2-diphenyl-1-picrylhydrazyl [DPPH] radical scavenging activity, ferric reducing antioxidant power and reducing power) of karonda powder.

Over the past few decades, the demands for application of natural colorants in food production have been attracting the attention of academic research and food industry. Anthocyanins, a red pigment commonly found on plants, show high potentials in the preparation of spray-dried pigment powder. This study, therefore, was conducted using full factorial design with two factors, namely, inlet temperature (150°C and 160°C) and soluble solid concentration (10, 15 and 20°Brix) with maltodextrin as carrier to produce pigment powder from karonda, an anthocyanin-rich fruit which is native to southeast Asia.

Increasing soluble solid content from 10 to 15°Brix resulted in a 42%–57% reduction in phenolic, flavonoid and anthocyanin contents. However, when increasing the amount of maltodextrin from 15 to 20°Brix, a lower reduction (approximately 11%–19%) was observed. In samples with the same °Brix, there was no significant variation in antioxidant contents and activities, especially at high maltodextrin ratios. In addition, the reducing power of samples dried at higher temperature (160°C) was higher than that of samples dried at lower temperature. Karonda spray-dried powder showed a good positive correlation (p < 0.01) between antioxidant contents and DPPH• activity.

To the best of the authors’ knowledge, in this study, for the first time, the effect of spray drying conditions on the quality of karonda powder was investigated.

The purpose of this paper is to evaluate the antioxidant and type II diabetes related enzyme inhibition properties of phenolic extract from raw and traditionally processed Indian under‐utilized food legume grains, Bauhinia purpurea L. (purple camel's foot seeds).

The methanolic extract was prepared from the raw and traditionally processed seed samples and analyzed for total phenolic content. The antioxidant activity and type II diabetes related enzyme inhibition properties of methanolic extract and their relationship with phenolic content was demonstrated.

The methanolic extract of raw seed materials contained total free phenolic content of 14.45±1.62 g catechin equivalent/100 g extract DM. Encouraging levels of ferric reducing/antioxidant power (FRAP, 1203 mmol Fe[II]/mg extract), inhibition of ß‐carotene degradation (45.37 percent) and scavenging activity against DPPH (63.60 percent) and superoxide (42.14 percent) radicals were exhibited by the raw samples. Further, it also recorded 80.69 percent of α‐amylase and 63.74 percent of α‐glucosidase enzyme inhibition characteristics under in vitro starch digestion bioassay. Sprouting+oil‐frying caused an apparent increase on the total free phenolic content, antioxidant and free radical scavenging capacity, while soaking+cooking as well as open‐pan roasting treatments show diminishing effects.

Identification of suitable processing technique offered a good strategy to improve the phenolic content and health relevant functionality of B. purpurea seeds, which could be envisaged as a dietary ingredient in the formulation of supplementary foods with therapeutic value to manage type II diabetic patients.

The purpose of this paper is to evaluate the antioxidant activity and toxicity of Clinacanthus nutans leaves from three conventional extraction methods, i.e. maceration, Soxhlet and magnetic stirring.

Total flavonoid content (TFC) and phenolic content (TPC) were determined using colorimetric method of aluminum chloride and Folin-Ciocalteu (FC) assay, respectively. Antioxidant property of C. nutans was evaluated using 2,2'-diphenyl-1-pierylhydrazyl (DPPH) free radical scavenging assay. Cytotoxic activity of C. nutans against brine shrimp was evaluated based on LC50 (lethality concentration) after 24 h exposure to the plant extract.

The highest TPC of C. nutans was observed with Soxhlet extraction method (98.87 ± 10.43 mg of gallic acid equivalents (GAE/g) followed by maceration (68.77 ± 2.45 mg of GAE/g) and magnetic stirring (46.75 ± 2.45 mg of GAE/g). Interestingly, remarkable highest TFC was observed with magnetic stirring (568.90 ± 4.85 mg of rutin equivalent (RE)/g) followed by maceration (249.60 ± 2.79 mg of RE/g) and Soxhlet (174.8 ± 1.74 mg of RE/g). On the other hands, the extract obtained using maceration method showed the highest antioxidant activity (IC50: 14.18 mg/mL compared to ascorbic acid 144.36 µg/mL). Cytotoxicity of C. nutans from all extraction methods showed similar LC50 values with maceration (3.81 mg/mL), Soxhlet (2.61 mg/mL) and magnetic stirring (4.56 mg/mL), respectively.

Both phenolic and flavonoids are responsible for the antioxidant activity, of C. nutans extracts. Based on Meyer's toxicity index, all extracts were nontoxic (LC50>1 mg/mL).

The cowpea plant, being affordable and protein‐rich, is considered poor man's meat. The aim of this paper is to undertake a detailed investigation regarding in vitro total antioxidant capacity (TAC) and chemical constituents of the vegetable oils from seeds of this plant, taking its nutritional value into consideration.

Vegetable oils of different indigenous cowpea varieties were obtained using soxhelt extraction assembly and subjected to GC‐MS analyses and various antioxidant assays including 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulpohonic acid) (ABTS) radical cation scavenging, ferr, 2.2′‐diphenyl‐1‐picrylhydrazil (DPPH) radical scavenging, total phenolic contents (TPC), lipid peroxidation inhibition, and iron chelation activity.

Various chemical constituents including different hydrocarbons, tocopherols, ketones, fatty esters, estragole and cedrene were identified. TPCs were found to be 5.439, 5.7279, 7.6126, 6.7573 and 10.0591 mg/L gallic acid equivalent for S.A. Dandy, Elite, White Star, CP‐386 and FBD Rawan varieties, respectively. Employing ABTS radical decoloration assay a significant linear correlation (R²=0.997, 0.996, 0.997, 0.996 and 0.997 for S.A. Dandy, Elite, White Star, CP‐386 and FBD Rawan varieties, respectively) was found between the percent inhibition of ABTS radical cation and the amount of vegetable oils. The percent inhibition of the Fe(II)‐Ferrozine complex formation was found to be 29.45, 53.76, 82.91, 86.59 and 57.87 for the same varieties, respectively.

GC‐MS and standard in vitro antioxidative capacity analyses data clearly demonstrated the potency of the cowpea as antioxidant and radical scavenger plant which may be used as a good source of natural antioxidants. The plant seeds may prove a better and cost‐effective substitute of expensive food items.

This paper aims to study the effect of cooking and food additives, such as lemon juice and vinegar, on phenols and flavonoids contents and antioxidant activity of purslane.

The Folin–Ciocalteu method was used to determine total phenols content (TP), while total flavonoid content (TF) was determined by the aluminum chloride method. Two methods were used for determination of antioxidant activity: DPPH (1, 1-diphenyl-2-picrylhydrazyl) assay to determine radical scavenging activity, and ferric-reducing antioxidant power (FRAP) to measure the reducing power.

According to the results, leafs had higher values of TP, TF and antioxidant activity than aerial parts. Both lemon juice and vinegar retracted antioxidant properties of leafs. TP and TF of leaves showed deterioration after treatment with lemon by 58% and 21.8%, respectively, and FRAP and radical scavenging activity decreased by 75.8% and 74.5%, respectively (p < 0.001). Also, TP, TF, FRAP and DPPH radical scavenging activity decreased in leaves by 82.2%, 30.5%, 87.8% and 90.9%, respectively, after treatment of leaves with vinegar. TF increased after cooking in studied parts, where no significant statistical difference was observed in TP and antioxidant activity (DPPH assay and FRAP) of cooked aerial parts. Adding lemon juice after cooking increased antioxidant properties of purslane (p < 0.001).

Purslane has antioxidant activity because it is rich in polyphenols and flavonoids. Effects of food additives and cooking were studied using different measurements. According to the authors’ knowledge, this is the first work that studied the effect of food additives on antioxidant properties of purslane.

The purpose of this paper was to determine and compare nutritional composition of different parts of citrus fruits, namely, Citrus aurantium (peel: albedo, flavedo and pulp: juice, pomace) . This study was conducted through three stages of fruit maturity (green, yellow and orange). Total polyphenols, flavonoids, β-carotene, total chlorophyll, ascorbic acid, acidity, total soluble solid and the minerals (Ca, Mg, Zn, Na, K, Fe, Mn Cu) were evaluated. Moreover, the relationship between the total polyphenol, flavonoids and the antioxidant activity was determined.

Total polyphenols were determined by the Folin-Ciocalteu method. Flavonoids were assessed by the aluminum chloride colorimetric method. Ca, Mg, Zn, Fe, Mn and Cu were measured using an atomic absorption spectrophotometer. K and Na contents were determined by using a flame photometer. Other nutritional composition was determined by volumetric method.

The result showed that the concentrations of antioxidants, total polyphenols, flavonoids, vitamin C, total chlorophyll, total acidity and antioxidant activity (DPPH%) decreased during the maturity of fruit while the value of pH and β-carotene increases. In addition, the concentrations of the most minerals decreased through the maturation of fruit except Na. Anova statistical analysis of all the studied chemical variables was shown significant differences between all the samples. The pH, total soluble solids, β-caroteniod: orange juice had the highest average while green juice had the lowest. Ascorbic acid, total acidity, total chlorophyll: green juice had the highest average while orange juice has the lowest. Total phenol, K, Mg, Fe, Cu, Mn: green flavedo had the highest average while orange juice had the lowest. Flavonoid, antioxidant activity (DPPH%), Ca, Zn: green albedo had the highest average while orange juice had the lowest. Na: orange flavedo had the highest average while green juice had the lowest. The correlations between total polyphenol, flavonoid and antioxidant capacity were significantly higher (R = 0.935 and 0.960, respectively).

The stage of maturity affects nutritional composition in Citrus aurantium fruits (C. aurantium) peel and pulp, where some minerals of composition increased and others decreased, according to the results. This is the first study on comparing the nutritional composition of pulp: juice, pomace and peel: albedo, flavedo of Citrus aurantium L. during maturity in Syria, and it was also not found in previous works.