Radical Scavenging Activity and LC-MS Metabolic Profiling of Petals, Stamens, and Flowers of Crocus sativus L

Radical scavenging activities of Crocus sativus petals, stamens and entire flowers, which are waste products in the production of the spice saffron, by employing ABTS radical scavenging method, were determined. At the same time, the metabolic profiles of different extract (obtained by petals, stamens and flowers) were obtained by LC-ESI-IT MS (liquid chromatography coupled with electrospray mass spectrometry equipped with Ion Trap analyser). LC-ESI-MS is a techniques largely used nowadays for qualitative fingerprint of herbal extracts and particularly for phenolic compounds. To compare the different extracts under an analytical point of view a specific method for qualitative LC-MS analysis was developed. The high variety of glycosylated flavonoids found in the metabolic profiles could give value to C. sativus petals, stamens and entire flowers. Practical Application: Waste products obtained during saffron production, could represent an interesting source of phenolic compounds, with respect to the high variety of compounds and their free radical scavenging activity.     

天然抗氧化物体外活性评价方法的优选与优化

选用抗坏血酸(VC)和茶多酚标准品为实验对象,对目前常用的抗氧化体外活性检测方法进行了评价,通过稳定性、可靠性、精密度及重现性实验,最终确定了可行性大、稳定性好、精密度高、重现性好的天然抗氧化物体外活性评价方法体系,并对有些检测体系进行了优化.同时,用本实验筛选优化的方法对石榴多酚的抗氧化活性进行了实际样品测定.     

Natural volatile treatments increase free‐radical scavenging capacity of strawberries and blackberries

Free‐radical scavenging capacities of strawberries and blackberries treated with methyl jasmonate (MJ), allyl isothiocyanate (AITC), essential oil of Melaleuca alternifolia (tea‐tree oil or TTO), and ethanol (EtOH) were investigated. All of these natural volatiles tested reduced the severity of decay in both strawberries and blackberries during storage at 10 °C as compared to the control. Most of these compounds enhanced antioxidant capacity and free‐radical scavenging capacity, except the AITC treatment. The MJ treatment for strawberries and blackberries had the highest antioxidant capacity, expressed as oxygen radical absorbance capacity (ORAC) values, after 7 days of storage. Moreover, the MJ treatment promoted the antioxidant capacity in strawberries and blackberries as measured by the radical 2,2‐di (4‐tert‐octylphenyl) ‐1‐picrylhydrazyl (DPPH) and the radical cation 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt (ABTS^?+) scavenging activity in both 7 and 14 days after storage. The MJ treatment also increased scavenging capacities on the superoxide radical (O₂^??), hydrogen peroxide (H₂O₂), hydroxyl radical (^?OH), and singlet oxygen (¹O₂) in strawberries and blackberries. Treatment with TTO or EtOH enhanced most of these free‐radical scavenging capacities, except for H₂O₂ in strawberries, and for O₂^?? and ¹O₂ in blackberries. These results indicated that all of the natural volatile compounds tested in this study, except AITC, promoted the antioxidant capacity and scavenging capacity of most major free radicals and, thus, helped to improve the physiology of berry fruits and enhanced their resistance to decay. While AITC was also very effective in reducing decay, its effect on free‐radical scavenging capacity was inconsistent, suggesting that additional mechanisms may be involved in its inhibition of fungal growth. Copyright © 2007 Society of Chemical Industry     

天然桑椹红色素体外清除自由基活性的研究

采用超氧阴离了自由基体系、羟基自由基体系、过氧化氢自由基体系、烷基自由基引发的亚油酸氧化体系及DPPH（二苯代苦味酰肼自由基）自由基体系对桑椹红色素的清除自由基活性进行了研究，并同VC进行了比较。结果表明，桑椹红色素对这几种自由基均有不同程度的清除作用，其对超氧阴离子自由基、羟基自由基和过氧化氢自由基的清除能力较好，且高于VC。清除DPPH自由基的能力低于VC。在所选浓度范围内，清除烷苯自由基的能力小明显，和VC相当，清除率均低于50％。桑椹红色素是一种很好的天然白由基清除剂。     

Valorisation of Crocus sativus flower parts for herbal infusions: impact of brewing conditions on phenolic profiling,antioxidant capacity and sensory traits

Saffron production from Crocus sativus flowers produces large amounts of by-products that may represent an excellent source of polyphenols. The aim of this work was to evaluate infusions originating from different brewing processes and from different saffron flower portions, in terms of both functional and sensory traits. For this aim, total polyphenols and total flavonoids, in vitro antioxidant assays and an untargeted phenolic profiling were applied. In general, tepals showed higher polyphenol and flavonoid content than stamen infusions, and their bioactive content depended more on brewing temperature than brewing time. These findings were consistent with both antioxidant capacity and phenolic profiling. Multivariate statistics highlighted polyphenols discriminating ‘boiled’ vs. ‘cold’ infusions, being mainly flavonoids, phenolic acids and the alkylphenol 5-pentadecylresorcinol (showing a strong down-accumulation at the higher brewing temperatures). Positive correlations could be highlighted between anthocyanins, flavones, flavonols and lignans, and the in vitro antioxidant assays. In general, cold brewing was successful in extracting phenolic compounds and provided better sensory properties, thus indicating that this may represent a valuable strategy to develop saffron-based functional beverages with better consumers' acceptability.     

Evaluation of the Ability of Eleutherine americana Crude Extract as Natural Food Additive in Cooked Pork

ABSTRACT:  The scavenging activities of crude ethanolic extract from  Eleutherine americana , on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radicals were investigated. The results revealed that the extract produced IC₅₀ values of 8.4 μg/mL and 0.78 mg/mL on DPPH and hydroxyl free radicals, respectively. The total phenolic content of the extract was determined using the Folin–Ciocalteu reagent and the crude extract yielded high phenolic content of 4.56 μmol gallic acid equivalent per milligram dried extract. The extract, at different concentrations, was incorporated into pork, cooked in the microwave, and stored at 4 °C for 9 d. The crude extract demonstrated antioxidant activity, which increases with increased extract concentrations and retarded lipid oxidation in the cooked pork. Antibacterial activity of the extract against  Staphylococcus aureus  in the cooked pork revealed that at a concentration of 10.8 mg/100 g, the extract reduced the bacterial population by 0.57 log compared to control at 9 d of storage. The sensory results revealed that the pork samples treated with the extract and the control sample were not significantly different from day 0 to 6; however, on day 9 the treatments were significantly scored higher than the control. Furthermore, addition of the extract led to an increase in the redness values of the pork and this was acceptable from the sensory point of view.  E. americana  crude extract could be a promising novel antioxidant to prevent lipid oxidation and a potential natural color enhancer of red meat and meat products.     

青梅花、枝、叶中多酚的抗氧化活性及稳定性的研究

以我国特有的青梅品种"大叶青"为原料,测定了青梅花、枝、叶3种提取物(PF,PB,PL)中总酚含量,采用化学发光法、DPPH.,ABTS+.等评价自由基清除能力,采用铁离子还原法(FRAP)来评价还原力,分析了提取物中多酚含量与其活性的相关性,研究了青梅不同提取物的热稳定性。结果表明:青梅花、枝、叶等3种提取物富含多酚物质,在不同的评价体系中青梅提取物的抗氧化能力也不同,在清除O2-.、DPPH.、ABTS+.等自由基能力时青梅枝(PB)提取物的清除能力最强,而青梅花(PF)提取物的还原能力最强,相关性分析表明,自由基清除能力与总酚含量呈正相关(P<0.05)。3种提取物中以青梅叶提取物(PL)的热稳定性最强。     

Qualities and antioxidant properties of bread as affected by the incorporation of yam flour in the formulation

Yams (the tubers of Dioscorea spp.) are widely consumed but are also regarded as a medicinal food in China. Traditional Chinese herbal medicines using yams are only available on a seasonal basis, as yams quickly deteriorate during winter storage. Yam (Dioscorea purpurea, a major variety of yams in Taiwan) was freeze‐dried and ground to obtain yam flour. Bread was made by replacing up to 25% of wheat flour with yam flour. Although the loaf volume decreased with the addition of yam flour, the results showed that up to 20% of yam flour could be included in bread formulation without altering the sensory acceptance of the blended bread. The incorporation of yam flour in bread markedly increased the antioxidant capacity of the bread as tested by both DPPH free radical scavenging and total antioxidation tests. Breads containing yam flour can broaden the utilization of yams and may be regarded as possible health‐promoting foods.     

Effect of mother corm dimension and sowing time on stigma yield,daughter corms and qualitative aspects of saffron (Crocus sativus L.) in a Mediterranean environment

BACKGROUND: Saffron is one of the most appreciated and expensive spices known and has been used from the oldest times as a dye for fabrics, a condiment to enrich food and for medicinal purposes. The aim of this study was to evaluate the effect of crop management methods on the quantitative and qualitative characteristics of the spice in southern Italy. Two sowing times (end of July and end of August) and two corm dimensions (4 and 3 cm horizontal diameter) were evaluated. RESULTS: Flowering period and duration were not influenced by the studied factors, while early sowing time and greater corm dimension resulted in a greater number of flowers per m², increased stigma yield and a greater total yield of replacement corms. Early sowing time also showed a significant positive influence on stigma quality measured as apocarotenoid content according to ISO guidelines. CONCLUSION: The results show that, in a Mediterranean environment, appropriate crop techniques and selection of corms can result in economic levels of production and improve the quantitative and qualitative characteristics of saffron. In fact, according to their apocarotenoid contents, samples from the early (July) and late (August) sowing times belonged to the first and second ISO categories respectively. Copyright © 2008 Society of Chemical Industry     

桉叶提取物中抗氧化活性物分离纯化、结构鉴定及其活性的研究

为进一步探索桉叶提取物抗氧化活性的物质基础,本文采用反相硅胶和制备液相等方法对桉叶提取物中高醇组分进行分离纯化得到4个化合物。接着应用~1H-NMR和~(13)C-NMR光谱分析鉴定化合物的结构,最终鉴定出3个化合物,分别为金丝桃苷、番石榴苷和槲皮素-3-O-α-吡喃阿拉伯糖-2"-棓酸盐。最后采用DPPH·、ABTS+·和ORAC三种体外检测体系进行抗氧化活性的研究。在DPPH·和ORAC方法中,番石榴苷的抗氧化能力最强,槲皮素-3-O-α-吡喃阿拉伯糖-2"-棓酸盐的抗氧化能力最低。在ABTS·+方法中金丝桃苷的抗氧化能力最强,番石榴苷的抗氧化能力最低。但与抗氧化剂Trolox相比,三者都表现出更强的抗氧化能力,是有较好发展前景的天然抗氧化剂。本文为桉叶资源的综合开发提供理论指导作用。     

Phenolic Compounds and Antioxidant Capacities of 10 Common Edible Flowers from China

The free and bound phenolic compounds in 10 common Chinese edible flowers were investigated using reversed phase high‐performance liquid chromatography. Their antioxidant capacities were evaluated using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging activity, 2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) radical‐scavenging activity, oxygen radical absorption capacity (ORAC), ferric reducing antioxidant power (FRAP), and cellular antioxidant activity (CAA). Free factions were more prominent in phenolic content and antioxidant capacity than bound fractions. Paeonia suffruticosa and Flos lonicerae showed the highest total phenolic content (TPC) 235.5 mg chlorogenic acid equivalents/g of dry weight and total flavonoid content 89.38 mg rutin equivalents/g of dry weight. The major phenolic compounds identified were gallic acid, chlorogenic acid, and rutin. P. suffruticosa had the highest antioxidant capacity in the DPPH, ABTS, and ORAC assays, which were 1028, 2065, 990 μmol Trolox equivalents/g of dry weight, respectively, whereas Rosa chinensis had the highest FRAP value (2645 μmol Fe²⁺ equivalents /g of dry weight). The P. suffruticosa soluble phenolics had the highest CAA, with the median effective dose (EC₅₀) 26.7 and 153 μmol quercetin equivalents/100 g of dry weight in the phosphate buffered saline (PBS) and no PBS wash protocol, respectively. TPC was strongly correlated with antioxidant capacity (R = 0.8443 to 0.9978, P < 0.01), which indicated that phenolics were the major contributors to the antioxidant activity of the selected edible flowers.     

Comparison of the antioxidant and pro‐oxidant activities of broccoli amino acids with those of common food additives

The antioxidant and pro‐oxidant activities of broccoli amino acids were compared with those of common food additives. In decreasing order, the data showed that Asp, SMC, GABA, Glu, Gln, Pro, Phe, Leu, Lys, Arg, Asn, Val, Ile, His, Ser, Gly, Orn and Ala, when dissolved in water at concentrations of 0.5 and 0.05 mM , partially inhibited damage to deoxyribose in the presence of ferric‐EDTA and H₂O₂. In contrast, Tyr and Thr acted as pro‐oxidants in this system. The amino acids present in broccoli had no hydrogen peroxide‐scavenging effect. When dissolved in water, methanol or ethanol, SMC, Glu, Thr, Gln, Ser, GABA, Pro, Ala, Ile, Phe, Asp, Orn and Tyr inhibited lipid peroxidation. However, Asn, Val, Arg, Leu, Lys, His and Gly were not effective in decreasing peroxidation at concentrations of 0.5 and 0.05 mM . Asp > SMC > Ala > Phe > Hys > Orn > Gln = Ser > Lys > Leu = GABA = Gly > Tyr > Arg = Thr > Val > Asn > Pro > Ile > Glu (p < 0.025) showed scavenging activity towards hypochlorous acid, protecting α₁‐antiproteinase against inactivation. In this paper it has been established that some amino acids premixed with propyl gallate increase its hypochlorous acid‐scavenging capacity, while other amino acids have an additive effect with propyl gallate, permitting smaller quantities of propyl gallate to be used as food additives in some products which contain these amino acids. © 2001 Society of Chemical Industry     

紫苏提取物体外清除自由基能力的研究

以紫苏茎、叶为研究对象,采用不同溶剂获取各种提取物,用茶多酚、维生素E、TBHQ作为对照,采用DPPH自由基体系、烷基自由基引发的亚油酸氧化体系、超氧阴离子自由基体系、羟基自由基体系,研究各种提取物对不同自由基的清除作用。结果表明,提取物对四种自由基均有清除作用,其清除效果依次为羟基自由基>DPPH自由基>烷基自由基>超氧阴离子自由基。紫苏茎、叶的95％乙醇(v/v)与碱水混合物提取物(8:2v/v)的总黄酮得率最高,紫苏叶提取物的抗氧化性强于紫苏茎提取物。      

Radical Scavenging Capacity and Antioxidant Activity of the E Vitamer Fraction in Rice Bran

ABSTRACT: Radical scavenging capacity and antioxidant activity of an E vitamer fraction from rice bran were investigated. The E vitamer fraction was prepared by a liquid-liquid extraction method. The free radical scavenging capacity of the E vitamer fraction was measured by the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) method at the concentration range of 2.5 to 640 ppm, whereas the antioxidant activities were measured by both the reducing power and ferric thiocyanate (FTC) methods at different concentrations (0, 2.5, 10, 40, and 160 ppm). Radical scavenging capacity of the fraction was effective up to 160 ppm, then remained stable. Also, at a concentration of 160 ppm, it was highly effective in inhibiting linoleic acid peroxidation. Similarly, superoxide scavenging and antioxidant activities of the E vitamer fraction were compared with those of the synthetic phenol compounds. Results showed that with a concentration of the E vitamer fraction at 160 ppm, the antioxidant activity was comparable to both butylated hydroxytoluene (BHT, 160 ppm) and butylated hydroxyanisole (BHA, 160 ppm). No significant differences (P > 0.05) were found among them. The E vitamer fraction may be a good substitute for the synthetic phenol antioxidants currently used in industry because the former is more natural and comparatively effective in its radical scavenging capacity and antioxidant activity.     

Phenolic acid composition and antioxidant properties of Malaysian honeys

Abstract: The phenolic acid and flavonoid contents of Malaysian Tualang, Gelam, and Borneo tropical honeys were compared to those of Manuka honey. Ferric reducing/antioxidant power assay (FRAP) and the 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) radical‐scavenging activities were also quantified. All honey extracts exhibited high phenolic contents (15.21 ± 0.51– 42.23 ± 0.64 mg/kg), flavonoid contents (11.52 ± 0.27– 25.31 ± 0.37 mg/kg), FRAP values (892.15 ± 4.97– 363.38 ± 10.57 μM Fe[II]/kg), and high IC₅₀ of DPPH radical‐scavenging activities (5.24 ± 0.40– 17.51 ± 0.51 mg/mL). Total of 6 phenolic acids (gallic, syringic, benzoic, trans‐cinnamic, p‐coumaric, and caffeic acids) and 5 flavonoids (catechin, kaempferol, naringenin, luteolin, and apigenin) were identified. Among the Malaysian honey samples, Tualang honey had the highest contents of phenolics, and flavonoids, and DPPH radical‐scavenging activities. We conclude that among Malaysian honey samples, Tualang honey is the richest in phenolic acids, and flavonoid compounds, which have strong free radical‐scavenging activities.     

Free radical scavenging, cytotoxic, and hemolytic activities of an active antioxidant compound ethyl gallate from leaves of Acacia nilotica (L.) Wild. Ex. Delile subsp. indica (Benth.) Brenan

Abstract: In the present study, free radical scavenging, cytotoxic, and hemolytic activities of the polyphenolic compound ethyl gallate isolated from ethanol extract of Acacia nilotica Wild. Ex. Del. leaves were determined. The free radical‐scavenging activities of the ethyl gallate were demonstrated in several in vitro assays in order to evaluate the possible antioxidant mechanism. The results revealed ethyl gallate as hydrogen donor, metal chelator, and free radical scavenger. Ethyl gallate was effective in scavenging 1,1‐Diphenyl‐2‐picrylhydrazyl (DPPH) radicals and the IC₅₀ value was lower than all the positive controls used in this study. Deoxyribose degradation assay revealed that ethyl gallate had more iron‐chelating ability than the direct hydroxyl radical‐scavenging ability. The results of the cytotoxic study revealed that the compound was moderately active and IC₅₀ value was found to be >100 μg/mL for Vero cell lines and 72 μg/mL for Hela cell lines. The compound possessed no hemolytic activity against rat and human erythrocytes revealing its cytotoxic mechanism and nontoxicity. The results from this work will provide an important information for the food and pharmacological industries with respect to the use of the compound as an antioxidant and a health‐related drug. Practical Application: Antioxidant from plant sources is safe to use, as compared to synthetic products. It also can be used as a supplement to alleviate most of the diseases because of its free radical‐scavenging activity.     

Evaluation of free radical‐scavenging activities of sweet potato protein and its hydrolysates as affected by single and combination of enzyme systems

To evaluate the free radical‐scavenging activities of sweet potato protein (SPP) and its hydrolysates, single enzymes alone (alcalase, neutrase, protamex) or in combination with flavourzyme were employed. Compared with SPP, free radical‐scavenging activities of the resulting hydrolysates were all significantly increased (P < 0.05). Alcalase (ALC) hydrolysates exhibited the highest superoxide, hydroxyl and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical‐scavenging activities (P < 0.05), which was 18.71 ± 0.22, 27.13 ± 0.24 and 90.10 ± 0.15% respectively. Compared with SPP hydrolysates by single enzymes, the hydrolysates obtained by combination of enzyme systems exhibited higher degree of hydrolysis, but lower free radicals scavenging activities. In addition, the content of several antioxidant amino acid residues, such as His, Met, Tyr and Phe, in ALC hydrolysates was much higher compared with SPP and other hydrolysates using amino acids composition assay. The results suggested that peptides with free radical‐scavenging activity could be released from entire SPP chain via moderate enzymatic hydrolysis.     

Increasing the oxidative stability of soybean oil through fortification with antioxidants

Vegetable oils high in polyunsaturated fatty acids (PUFA), like soybean oil (SO), are known for lowering the risk of consumers for contracting cardiovascular disease as well as improving cognitive health. However, they are more susceptible to lipid oxidation than recently introduced high‐oleic cultivars like high‐oleic sunflower oil (HOSFO). Thus, the objective of this study was to increase the stability of PUFA oils to maintain the aforementioned health benefits by supplementing them with industrially relevant antioxidant compounds that prevent or delay oxidation during food production and storage. Herein, a variety of synthetic and natural antioxidants tested alone or in mixtures was screened to bring the stability of SO closer to that of HOSFO. Oils were stored under accelerated conditions (35 °C) in the dark for 28 weeks, and the evolution of primary (hydroperoxides) and secondary (hexanal) lipid oxidation products was monitored. Oxidative stability index data showed that addition of 300 ppm of ascorbyl palmitate (AP) stabilised SO to the greatest magnitude. Further, a combination of AP (300 ppm) and M‐TOC (1000 ppm) was able to limit hydroperoxide and hexanal formation in SO at 35 °C for 12 weeks. It was demonstrated that assessing multiple quality parameters for lipid stability are a necessary undertaking.