Red Onion Extract Research Articles

EFFECT OF IMMERSION TIME OF SHALLOT EXTRACT AND ATONICON SEED GERMINATION OF SHALLOT

The need for raw materials of fried onions derived from 'lembah palu Shallot tubers variety is high enough and can not be fulfilled, because the productivity is still low. This study aimed to find the type of plant growth regulator substances (PGR) with a long period of proper immersion to improve the germination of Shallot tuber. The research was conducted on Mei until June 2017 in Bulupontou Village, Sigi Regency. The study used two factorial Randomized Block Design (RBD). First factor of type RGS: (Z1) onion extract 100 g/l water, and (Z2) atonic 5 ml/l water. The second factor was long seed immersion in PGR: (T1)=30 min; (T2)=60 minutes; (T3)=90 minutes, and (T4)=120 minutes. Each treatment was represented 20 plants and repeated 3 times, so it was used 480 plants. The results showed that (i) red onion tubers soaked with Shallot extract 100 g/liter of water for 30-90 minutes yielded 100% Germinations, and tubers soaked in red onion extract for 30 minutes resulted in germination rate 31.3%/etmal, (ii) the type of growth regulator of shallot extract and atonic (PGR) effect was not significant on the germination of shallot; and (iii) the 30 minute long growth regulator immersion produced the highest hypothetical vigor index.

PENURUNAN KADAR GLUKOSA MENCIT AKIBAT PEMBERIAN KOMBINASI METRFORMIN DAN EKSTRAK BAWANG MERAH

Diabetes mellitus (DM) is a metabolic disorder characterized by the high blood glucose level (hyperglycemia). This research aims to know the effect of adding combination of red onion (Allium cepa L.) extract and metformin against male house mice (Mus musculus) on reducing the blood glucose level. This study uses oral glucose tolerance test (OGTT) to determine the body's ability to tolerate the glucose administration by using 18 male house mice (Mus musculus) that divided into 6 groups and each group consisting of 3 mice. Group I as the negative control given 1% of NaCMC suspension; Group II as the Positive Control given metformin suspension of 1.95 mg; Group III as the Positive Control given red onion extract suspension of 7.5 mg; group IV as the Positive Control given red onion extract suspension of 15 mg; group V as the Treatment Control I given a combination of onion extract suspension 7.5 mg + metformin 1,95 mg; and group VI as the Treatment Control II given red onion extract suspension of 15 mg + metformin 1,95 mg. This research result is then analysed using One-Way Anova statistical method. The obtained results show that the dose of the Treatment Control II has significant effect on reducing the blood glucose level. This research needs to be followed up by looking at the effectiveness of the drugs combination.

Therapeutic effect of topical administration of red onion extract in a murine model of allergic rhinitis

The aim of this study was to evaluate the effect of topical administration of onion (Allium cepa) extract on nasal cavity for treatment of allergic rhinitis (AR). BALB/c mice were sensitized by intraperitoneal injection of ovalbumin (OVA) and challenged with intranasal instillation of OVA with or without onion extracts for five times a week on 3 consecutive weeks. Allergic symptom score according to frequencies of sneezing, serum total and OVA specific immunoglobulin E (IgE) level, cytokine levels of nasal mucosa and eosinophilic infiltration were analyzed. Allergic symptom score, serum total and OVA specific IgE, cytokine levels of nasal mucosa (interleukin (IL)-4, IL-5, IL-10, IL-13, IFN-γ, TNF-α and COX-2) and eosinophilic infiltration were higher in allergic mouse group than negative control group. Topical application of onion extracts significantly reduced allergic symptoms and OVA specific IgE levels. Cytokine levels of IL-4, IL-5, IL-10, IL-13 and IFN-γ were significantly decreased in groups treated with onion extract. In addition, eosinophil infiltration of nasal turbinate mucosa was also significantly decreased after treatment with onion extract. Topical administration of onion extract significantly reduces allergic rhinitis symptom and allergic inflammatory reaction in a murine allergic model. It can be assumed that the topical application of onion extract regulates allergic symptoms by suppressing the type-1 helper (Th1) and type-2 helper (Th2) responses and reducing the allergic inflammatory reaction.

Kajian Penggunaan Biourine Sapi dan Ekstrak Bawang Merah Terhadap Sifat Agronomi Tanaman Kubis (Brasicca oleracea L.) Dataran Rendah

Cabbage (Brasicca oleracea L.) is one type of vegetable plant from the Brassicaceae family. This plant is a source of nutrients that contain nutrients, vitamins, minerals and fiber for the human body. And has economic value. Cabbage cultivation is influenced by the types of cultivated varieties that are in accordance with growing conditions. In general, cabbage plants grow on highlands. Along with advances in plant breeding technology, cabbage plants are available that can adapt to the lowlands and technically attempt to increase production by fertilizing. The study aimed to determine the effect of beef biourine, red onion extract and beef biourine and red onion extract on the agronomic properties of cabbage plants. The study was conducted for 4 months, from February to June 2018. The location of the study was carried out in the Sempaja Timur Village, Samarinda City, East Kalimantan Province. cabbage seeds, top soil, manure, husks, NPK fertilizer, cow urine, empon-empon, soybeans, brown sugar, shallots. The design used in this study is Factorial Randomized Block Design (RBD) with 2 treatments. The first treatment was beef biourine (S) with 4 levels, namely with 3 replications: s0: control (water), s1: 25% concentration of cow biourine, s2: 75% concentration of bovine biourine, s3: 100% concentration of bovine biourine and second treatment red onion extract (B) with 4 levels, namely: b0: control (water), b1: 25% concentration of red onion extract, b2: 75% concentration of red onion extract, b3: 100% concentration of shallot extract. The results of research on bovine biourine influenced plant height, number of leaves at ages 7, 14, 21, 28.35 and 42 days after planting. The weight of the crop with the best results at the level of b2 (75% biourine cow) weighing 596.58 grams, onion extract affects plant height, number of leaves at 7, 14, 21, 28.35 and 42 hst, crop weight with the best results at the m2 level (75% red onion extract) with a weight of 567.14 grams and the interaction of the treatment of beef biourine and shallots affects plant height, number of leaves at the ages of 7, 14, 21, 28.35 and 42 days and days formed at the level b2m2 (75% beef biourine and 75 red onion extracts).

Enrichment and Assessment of the Contributions of the Major Polyphenols to the Total Antioxidant Activity of Onion Extracts: A Fractionation by Flash Chromatography Approach.

The present study extensively fractionated crude red onion extract in order to identify the polyphenols which contributed most in the total antioxidant capacity of the onion extract using a flash chromatography system. The flash separations produced 70 fractions which were tested for their total phenol content, total flavonoid content, and antioxidant capacities as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Out of these 70 fractions, four fractions which were representatives of the four major peaks of the flash chromatograms, were further analysed for their constituent polyphenols using liquid chromatography tandem mass spectrometry (LC-MS/MS). The main contributor of onion antioxidant capacity is quercetin glycoside followed by quercetin aglycone although quercetin aglycone had higher antioxidant capacity than its glycosidic counterparts. High abundance of quercetin glycosides such as quercetin-3,4′-diglucoside and quercetin-4′-glucoside had compensated for their relatively low antioxidant capacities. A Higher degree of glycosylation resulted in lower antioxidant capacity. The fractionation approach also contributed in enrichment of the onion antioxidant polyphenols. A >9 folds enrichment was possible by discarding the early fractions (fractions 1–15) which contained the main bulk of the extracts, predominantly sugars.

AKTIVITAS PENGHAMBATAN EKSTRAK BERBAGAI JENIS BAWANG TERHADAP PEMBENTUKAN BLACKSPOT PADA UDANG VANNAMEI

Blackening is a problem occurring in crustaceans, such as whiteleg shrimps (Litopenaeus vannamei), during post-mortem storage. Although blackspot seems to be harmless to consumers, it decreases the product’s market value, consumer’s acceptance and causes a considerable financial loss. The objective of the study was to determine the best Allium extracts from five Allium types with the ability to inhibit blackspot and apply the extracts on whiteleg shrimp. The five types of Allium were red onion (Allium cepa L. var Aggregatum), garlic (Allium sativum), yellow onion (Allium cepa Linneaus), leek (Allium fistulosum) and chives (Allium schoenoprasum L). Extraction of Allium was conducted using 80% methanol as the solvent. The dry extracts were tested in vitro using a commercial polyphenol oxidase (PPO) enzyme and a melanosis test was conducted on whiteleg shrimp treated with the extracts and stored at 0°C for 10 days. The results showed that the highest inhibition of blackspot formation was obtained by red onion extract at 69.79±1.91% and the lowest was by garlic extract at 14.06±1.41%. The shrimps dipped in red onion extract had the lowest melanosis values and browning index values at 5.1±0.8 and 16.76±0.94, respectively. Red onion extract had the best ability to inhibit blackspot and has the potential to be used in shrimp.

Anew Medium for Isolation and Diagnosis of Cryptococcus neoformans

Melanin produce by Cryptococcus neoformans yeastwas used to characterize this yeast.In present study,we used red onion extract in prepared a new medium.The isolates of yeast were cultivation. After 48 hours results show,the isolates of C.neoformans were appear in dark brown colonies while the colonies on SDA not produce any pigment.Also analysis resultsof red onion extract by usedUV-Spectometerand FT-IR appear this extract content phenolic compounds which causes to produce brown pigment.thus, this medium Red Onion Agar (RO A) useful for rapid identification of yeast C.neoformans

Dietary Quercetin Attenuates Adipose Tissue Expansion and Inflammation and Alters Adipocyte Morphology in a Tissue-Specific Manner

Chronic inflammation in adipose tissue may contribute to depot-specific adipose tissue expansion, leading to obesity and insulin resistance. Dietary supplementation with quercetin or botanical extracts containing quercetin attenuates high fat diet (HFD)-induced obesity and insulin resistance and decreases inflammation. Here, we determined the effects of quercetin and red onion extract (ROE) containing quercetin on subcutaneous (inguinal, IWAT) vs. visceral (epididymal, EWAT) white adipose tissue morphology and inflammation in mice fed low fat, high fat, high fat plus 50 μg/day quercetin or high fat plus ROE containing 50 μg/day quercetin equivalents for 9 weeks. Quercetin and ROE similarly ameliorated HFD-induced increases in adipocyte size and decreases in adipocyte number in IWAT and EWAT. Furthermore, quercetin and ROE induced alterations in adipocyte morphology in IWAT. Quercetin and ROE similarly decreased HFD-induced IWAT inflammation. However, quercetin and red onion differentially affected HFD-induced EWAT inflammation, with quercetin decreasing and REO increasing inflammatory marker gene expression. Quercetin and REO also differentially regulated circulating adipokine levels. These results show that quercetin or botanical extracts containing quercetin induce white adipose tissue remodeling which may occur through inflammatory-related mechanisms.

Evaluation of the antiviral effects of aqueous extracts of red and yellow onions (Allium Cepa) against avian influenza virus subtype H9N2

Avian influenza virus subtype H9N2 causes important economic losses in industrial poultry worldwide. Biosecurity and vaccination have not completely prevented the outbreak of avian influenza virus subtype H9N2 in poultry, and there are no appropriate medicines available. Onion is one of the plants used from the ancient times both as food and medicine. The purpose of this study was to evaluate the antiviral effects of aqueous extract of red and yellow onion against avian influenza virus subtype H9N2. First, a study was performed to evaluate the toxic effects of the extracts on the embryonated chicken eggs. For antiviral evaluation, three mixtures were prepared: mixture of the virus and the red onion extract, mixture of the virus and the yellow onion extract, and mixture of the virus and PBS, as a control group. The mixtures were separately inoculated to the chorioallantoic sac of the embryonated eggs after 2, 8 and 24 hours incubation at room temperature. Mortality rate and hemagglutination assay titers were recorded. The results indicated that the red onion extract decreases mortality of the embryos and the yellow onion extract increases the life of the embryos, and both of the extracts decrease HA titers. In conclusion, it seems that both extracts especially aqueous extract of the red onion not only destroys the avian influenza virus subtype H9N2, but also they probably decrease the propagation of the virus in the embryonated chicken eggs.

Quercetin and Quercetin-Rich Red Onion Extract Alter Pgc-1α Promoter Methylation and Splice Variant Expression.

Pgc-1α and its various isoforms may play a role in determining skeletal muscle mitochondrial adaptations in response to diet. 8 wks of dietary supplementation with the flavonoid quercetin (Q) or red onion extract (ROE) in a high fat diet (HFD) ameliorates HFD-induced obesity and insulin resistance in C57BL/J mice while upregulating Pgc-1α and increasing skeletal muscle mitochondrial number and function. Here, mice were fed a low fat (LF), high fat (HF), high fat plus quercetin (HF + Q), or high fat plus red onion extract (HF + RO) diet for 9 wks and skeletal muscle Pgc-1α isoform expression and DNA methylation were determined. Quantification of various Pgc-1α isoforms, including isoforms Pgc-1α-a, Pgc-1α-b, Pgc-1α-c, Pgc-1α4, total NT-Pgc-1α, and FL-Pgc-1α, showed that only total NT-Pgc-1α expression was increased in LF, HF + Q, and HF + RO compared to HF. Furthermore, Q supplementation decreased Pgc-1α-a expression compared to LF and HF, and ROE decreased Pgc-1α-a expression compared to LF. FL-Pgc-1α was decreased in HF + Q and HF + RO compared to LF and HF. HF exhibited hypermethylation at the −260 nucleotide (nt) in the Pgc-1α promoter. Q and ROE prevented HFD-induced hypermethylation. −260 nt methylation levels were associated with NT-Pgc-1α expression only. Pgc-1α isoform expression may be epigenetically regulated by Q and ROE through DNA methylation.

Effects of Onion (Allium cepa) and Lemongrass (Cymbopogon citratus) Extracts on Lipid Oxidation and Acceptability of Frozen Deboned Milkfish (Chanos chanos)

This study was conducted to determine the effectiveness of red onion (Allium cepa) and lemongrass (Cymbopogon citratus) extracts on lipid oxidation and on its effect on acceptability of frozen deboned milkfish (Chanos chanos). The deboned milkfish fillets were immersed in 5% (v/v) aqueous solutios of onion and lemongrass extracts including the Vitamin C and stored up to 30 days in frozen storage (18°C). Chemical indices of lipid oxidation were analyzed by Peroxide Value Determination, pH and Free Fatty Acid Determination. Changes in the organoleptic properties particularly flavor, color and odor were also determined using a Sensory Descriptive Score sheet and General Acceptability was likewise assessed using a 5-point hedonic scale. Results of the study showed that among the treatments, onion extract-treated samples exhibited a significant decrease in Peroxide Value at R=0.941 with a final Peroxide Value of 0.75 meq/kg sample which did not exceed the USFDA standard at 7-8 meq/kg, not exceeding to 20 meq/kg and not more than ≤ 5.0 meq/kg sample. No significant difference, however, were observed in Free Fatty Acid Value between treatments throughout the 30-day study period which denotes that the extracts have no effect on lipid hydrolysis brought about by lipolytic activity enzyme. Sensory evaluation revealed that among the treatments the lemongrass extract treated samples yielded the highest general acceptability scores within the 30-day storage period. Statistical analysis however reveals that there is no significant difference between treatments at 5% level of significance.

Development of Biocomposites with Antioxidant Activity Based on Red Onion Extract and Acetate Cellulose.

Antioxidant biocomposites have been successfully developed from cellulose acetate, eco-friendly triethyl citrate plasticizer and onion extract as a source of natural antioxidants. First, an onion extraction process was optimized to obtain the extract with highest antioxidant power. Extracts under absolute ethanol and ethanol 85% were the extracts with the highest antioxidant activity, which were the characterized through different methods, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2ʹ-azinobis(3-ethylbenzothiazoline-6-sulphonate)), that measure radical scavenger activity, and polyphenolic and flavonoid content. Afterwards, the extract was incorporated in cellulose acetate as polymer matrix owing to develop an active material intended to oxidative sensitive food products packaging. Different concentrations of onion extract and plasticizer were statistically studied by using response surface methodology in order to analyze the influence of both factors on the release of active compounds and therefore the antioxidant activity of these materials.

In vivo effects of dietary quercetin and quercetin-rich red onion extract on skeletal muscle mitochondria, metabolism, and insulin sensitivity.

Red onions and low doses of the flavonoid, quercetin, increase insulin sensitivity and improve glucose tolerance. We hypothesized that dietary supplementation with red onion extract (RO) would attenuate high fat diet (HFD)-induced obesity and insulin resistance similar to quercetin supplementation by increasing energy expenditure through a mechanism involving skeletal muscle mitochondrial adaptations. To test this hypothesis, C57BL/6J mice were randomized into four groups and fed either a low fat diet (LF), HFD (HF), HFD+quercetin (HF+Q), or HFD+RO (HF+RO) for 9weeks. Food consumption and body weight and composition were measured weekly. Insulin sensitivity was assessed by insulin and glucose tolerance tests. Energy expenditure and physical activity were measured by indirect calorimetry. Skeletal muscle incomplete beta oxidation, mitochondrial number, and mtDNA-encoded gene expression were measured. Quercetin and RO supplementation decreased HFD-induced fat mass accumulation and insulin resistance (measured by insulin tolerance test) and increased energy expenditure; however, only HF+Q showed an increase in physical activity levels. Although quercetin and RO similarly increased skeletal muscle mitochondrial number and decreased incomplete beta oxidation, establishing mitochondrial function similar to that seen in LF, only HF+Q exhibited consistently lower mRNA levels of mtDNA-encoded genes necessary for complexes IV and V compared to LF. Quercetin- and RO-induced improvements in adiposity, insulin resistance, and energy expenditure occur through differential mechanisms, with quercetin-but not RO-induced energy expenditure being related to increases in physical activity. While both treatments improved skeletal muscle mitochondrial number and function, mtDNA-encoded transcript levels suggest that the antiobesogenic, insulin-sensitizing effects of purified quercetin aglycone, and RO may occur through differential mechanisms.

Strategies for differentiation of isobaric flavonoids using liquid chromatography coupled to electrospray ionization mass spectrometry.

Flavonoids are a class of secondary plant metabolites existing in great variety in nature. Due to this variety, identification can be difficult, especially as overlapping compounds in both chromatographic separations and mass spectrometric detection are common. Methods for distinguishing isobaric flavonoids using MS(2) and MS(3) have been developed. Chromatographic separation of various plant extracts was done with RP-HPLC and detected with positive ESI-MS operated in information-dependent acquisition (IDA) mode. Two methods for the determination of flavonoid identity and substitution pattern, both featuring IDA criteria, were used together with the HPLC equipment. A third method where the collision energy was ramped utilized direct infusion. With the developed strategies, it is possible to differentiate between many isobaric flavonoids. Various classes of flavonoids were found in all of the plant extracts, in the red onion extract 45 components were detected and for 29 of them the aglycone was characterized, while the substituents were tentatively identified for 31 of them. For the strawberry extract, those numbers were 66, 30 and 60, and for the cherry extract 99, 56 and 71. The great variety of flavonoids, several of them isobaric, found in each of the extracts highlights the need for reliable methods for flavonoid characterization. Methods capable of differentiating between most of the isobars analyzed have been developed.

Quercetin and Red Onion Extract Reduce Visceral and Subcutaneous Fat but not Systemic Adipokines

Quercetin and Red Onion Extract Reduce Visceral and Subcutaneous Fat but not Systemic Adipokines

Quercetin and red onion extract attenuate high fat diet‐induced insulin resistance while increasing energy expenditure and skeletal muscle mitochondrial number despite a decrease in Pgc1a (829.1)

Quercetin (Q), a bioflavonoid abundant in onions, attenuates the development of insulin resistance (IR) and increases expression of the transcriptional coactivator, peroxisome proliferator‐activated receptor gamma coactivator‐1 alpha (PGC1α). We investigated the effects of Q and Q‐rich red onion extract (RO) on ameliorating high fat diet (HFD)‐induced IR and altering skeletal muscle Pgc1a expression and mitochondrial biogenesis. 9wks of Q and RO supplementation on a 45% HFD decreased adiposity (P<0.05) in C57BL6/J mice and increased energy expenditure (P<0.05) compared to HFD‐fed mice. Q and RO mice exhibited increased insulin sensitivity (P<0.05) and muscle mitochondrial number (P<0.05). Pgc1a gene expression was decreased in Q (P<0.01) and RO (P<0.05) groups. In direct contradiction to the 9wk Q‐ and RO‐induced decreases in the present study, we previously found that Q significantly increased Pgc1a after 8wks of supplementation, suggesting that (1) Q and RO may mediate their effects on mitochondrial adaptation independent of changes in Pgc1a or (2) Q‐ and RO‐induced increases in Pgc1a are necessary for establishing but not sustaining mitochondrial adaptation. We conclude that dietary Q and RO supplementation ameliorate HFD‐induced obesity and prevent IR by increasing energy expenditure and skeletal muscle mitochondrial number.Grant Funding Source: Supported by NIH 5T32‐DK064584‐09, 5P50‐AT002776‐09, 8P20‐GM103528‐07 and 5P30‐DK072476‐07 grants.

Phytochemical Properties and Staining Ability of Red Onion (Allium cepa)Extract on Histological Sections

The staining ability of Allium cepa (red onion) skin extract on tissue sections was determined. The dried red onion skin was ground into small pieces and 300 g (150 g for aqueous and 150 g for ethanolic extraction) of the milled dried red onion skin was used for extraction. Dark red-pigmented granules were obtained. The aqueous and ethanolic extract of mordanted (Potassium aluminum alum and ferric chloride), non-mordanted and acidified solution prepared from the extract were used to stain tissue sections. Cytoplasm of cells and connective tissues were remarkably stained in shades of redish to yellowish brown colours. Preliminary phytochemical screening of these extracts reveals that it contained alkaloid steroid ring, saponin, Tannin, Flavonoid, Cardiac glycoside and anthraquinone. The presence of pigments, saponin, tannin, contributed to the staining ability of the extract.

Total phenolics, antioxidant and xanthine oxidase inhibitory activity of three colored onions (Allium cepa L.)

Methanolic extracts from bulbs of three onion (Allium cepa L.) varieties: red (Pusa Red), white (Pusa White Round), and yellow (Arka Pitamber) and the CHCl 3, Et 2O, EtOAc, and n-BuOH fractions obtained from those extracts were investigated for their total phenolics and antioxidant activity. The antioxidant activity measurements, expressed as total antioxidant status (TAS), were 5.2–50.18, 2.2–35.6 and 3.5–42.2 mg ml−1 for red, white and yellow onion bulb extracts, respectively, as compared to trolox (IC 50, 40.2 mg ml−1). The total phenolic content of the samples was 62–186, 56–156 and 68–165 mg GAE ml−1 for red, white and yellow onion bulb extracts, respectively, with all solvents. There was a positive correlation between the total phenolic content and antioxidant activity for MeOH extracts and EtOAc fractions (R2=0.96, 0.8 respectively). Of the selected colored onion bulbs the red onion (IC 50=14.2 μg ml−1) revealed more potent xanthine oxidase inhibitory activity to those of yellow (IC 50=15.5 μg ml−1) and white onion (IC 50=17.0 μg ml−1) in vitro and as compared to control allopurinol (IC 50=10.5 μg ml−1). The kinetic study by xanthine oxidase revealed that the white and yellow onion extracts were non-competitive inhibitors, as Km values were constant, while Vmax consequently decreased with increased inhibitor concentration. In the red onion extract there was an increase in Km values while Vmax remained constant at all extract concentrations, thus confirming a competitive type of inhibition by the Lineweaver–Burk equation. These findings suggest that these onion varieties can be considered as potential sources of antioxidants and XO inhibitory agents.

Anticancer and Antimutagenic Activities after Simulated Digestion of Ethanol Extracts from White, Red and Yellow Onions

The beneficial effects of digested onion extracts have been assessed by antimutagenic and anticancer activities by Ames test and SRB test. The total phenolic acids and flavonoids in onion extracts were determined. Red and yellow onions contain more phenolic acids and flavonoids than those in the white onion. Digested, extracts showed antimutagenic activity and anticancer activity, and it appears that the antimutagenic activity of digested extracts of onion against mutagens and anticancer activities were related to their phenols and flavonoids contents. Moreover, the extracts inhibited the proliferation of four human tumorigenic cell lines such as HT-29 (colon), MCF-7 (breast), DU-145 (prostate) and HepG2 (liver), in a dose-dependent manner. Phenolic acids and flavonoids caused oxidative damage to the cancer cell lines and induced apoptosis. Generally, red onion extracts showed effective antimutagenic and anticancer activity, and the digested red onion extracts elicited stronger antimutagenic activity than those of the onion extracts without digestion.

Free-radical scavenging capacity and antioxidant properties of some selected onions (Allium cepa L.) and garlic (Allium sativum L.) extracts

The radical scavenging activity (RAS), chain-breaking activity, H2O2-scavenging, reducing capacity and total phenolics of four types of onions (Green onion, Yellow, Red and Purple) and garlic were investigated. Total phenolics varied from 30 mg (green onion) to 49 mg.100 g-1 fresh weight (garlic). Garlic extract showed the highest RAS, while green onion showed the lowest one. The chain-breaking activity of green onion extract was higher (0.48) than garlic extract (0.029). Chain-breaking activity of yellow, red and purple onion extracts was 0.19, 0.048 and 0.032 respectively. However, heating treatment (90 ºC, 3h) caused an increase in this activity. Low ability of green onion extract to scavenge hydrogen peroxide was noted (35%), whereas high ability was noted in other onion and garlic extracts and ranged from 60 to 90%. The lowest reducing capacity was noted in green onion extract (18%), whereas the highest in garlic extract (196%). Statistically, high significant correlations were observed between total phenolics content and reducing power, scavenging of hydrogen peroxide and chain-breaking activity of extract