Distribution pattern of a flavonoid extract in the gastrointestinal lumen and wall of rats

Purified flavonoid extract from illuminated parsley (Petroselinum crispum (Mill.) Nym.) cell culture was administered by gavage to Wistar rats. The dose corresponded to 6.9 mg flavonoids on aglycone base/kg body mass. Segments of the gastrointestinal wall from stomach to colon, their luminal contents, and liver and kidneys were collected at time intervals between 1 and 12 h and investigated by HPLC of the respective extracts for flavonoids. The spreading of the flavonoids was accompanied by partial deglycosylation that began already in the stomach where at first quercetin and later apigenin, chrysoeriol and isorhamnetin aglycones were detected. We got evidence of flavonoid absorption by the stomach that does not require the liberation of aglycones. Due to obvious differences in metabolization and absorption rates the composition and the content of flavonoids changes in the gastrointestinal segments and their contents with time. Flavonoids could be detected neither within the gastrointestinal lumen after 12 h nor in the kidneys at any time. But traces of flavonoids were found in the livers at 1.5 and 12 h.     

天山茶茎黄酮苷元提取工艺优化及其生物活性

为了优化天山茶藨茎5种黄酮苷元（木犀草素、槲皮素、山奈酚、异鼠李素、芹菜素）的酸水解提取工艺,评价其体外抗氧化和α-葡萄糖苷酶抑制活性,本文利用UPLC-MS/MS法测定天山茶藨茎5种黄酮苷元的提取率,通过单因素实验和正交试验优化天山茶藨茎黄酮苷元酸水解提取工艺。利用DPPH、ABTS自由基清除实验测定天山茶藨茎提取物及5种黄酮苷元的抗氧化活性,并测定了其α-葡萄糖苷酶抑制活性。结果表明,5种黄酮苷元的检出限、定量限分别在0.8~1.6、2.9~5.4 μg/L,在3.2~207.0 μg/L范围内具有良好的线性关系（R2≥ 0.9962）,方法的稳定性、精密度和重复性良好（RSD≤4.4%）。确定最佳酸水解提取工艺为:90%甲醇溶液（含5%盐酸）、提取温度:70℃、提取时间:100 min,该条件下,总黄酮苷元提取率为4.06 mg/g,RSD<5%,表明正交试验优化的提取条件稳定可行。天山茶藨茎提取物及5种黄酮苷元均具有一定的α-葡萄糖苷酶抑制活性和抗氧化活性,其中甲醇盐酸提取物与5种黄酮苷元的α-葡萄糖苷酶抑制活性均高于阳性对照阿卡波糖（IC₅₀:53.84±2.41 mg/L）,槲皮素对DPPH自由基的清除活性最好（IC₅₀:（2.94±0.18） mg/L）,木犀草素、山奈酚对ABTS自由基清除活性较好（IC₅₀分别为（5.34±0.10）、（5.55±0.17） mg/L）,它们的抗氧化活性高于阳性对照V_C。本研究建立的UPLC-MS/MS方法灵敏、精确、高效,可以对天山茶藨茎5种黄酮苷元化合物同时进行定量分析。优化的酸水解提取工艺能有效提高天山茶藨茎黄酮苷元的提取率。     

Major chemical constituents and antioxidant activities of different extracts from the peduncles of Hovenia acerba Lindl

Hovenia acerba Lindl. is a perennial tree of Rhamnaceae family. In the present study, four solvents (80% methanol, ethyl acetate, n-hexane, and water) were used to extract the compounds of Hovenia acerba Lindl. peduncles (HAP). The total contents of phenolics and tannins (TPC and TTC), as well as their antioxidant activities (DPPH, ABTS, and FRAP) of these four different extracts including 80% methanol extract (ME), ethyl acetate extract (EE), n-hexane extract (HE) and water extract (WE) were compared. The antioxidant activities of HAP showed positive correlations with TPC and TTC, indicating that phenolics maybe a major contributor to the antioxidant activities of HAP. The significant difference between antioxidant activities and TPC/TTC implied the respective contribution extent of phenolics for the antioxidant activities of four solvent extracts. Besides, a total of 117 compounds, including 7 oligosaccharides, 11 organic acids, 41 phenolics, 1 steroids, 25 terpenes, 11 fatty acids, 9 amino acids, and 12 other compounds were identified or tentatively characterized in HAP for the first time. Among them, 23 bioactive constituents, including 4 organic acids, 5 phenolic acids, and 14 flavonoids, were quantified. The comparison of characterization and quantitation of 4 extracts demonstrated that 80% methanol showed the widest range of selectivity for both HAP flavonoid aglycones and glycosides, while ethyl acetate preferred to extract the flavonoids aglycone from HAP. Secondly, water and 80% methanol were excellent solvents for the extraction of phenolic acids. And both ethyl acetate and 80% methanol perform well at the extraction of terpenes and steroids.     

Flavonoid recovery and stability from Ginkgo biloba subjected to a simulated digestion process

Absorption from the diet is normally a prerequisite for the potential in vivo beneficial role of flavonoids. Antioxidant activity of flavonoids in vitro has been the subject of several studies, and important structure–activity relationships of the antioxidant activity have been established. However, there is still debate about the stability and absorption of polyphenols under gastrointestinal conditions. Ginkgo biloba, a product well known for its flavonoid content, was chosen for this study. Ginkgo biloba leaves, standardised leaf extract EGb 761 and commercial tablets (containing EGb761) were incubated in simulated gastrointestinal fluids to determine the stability of their flavonoid profiles. The experiment was designed to mimic the human gut condition. HPLC analysis was then conducted to determine the resulting breakdown compounds and intact flavonoids after the incubation, thus indicating those compounds likely to be available for absorption. The different samples seem to react differently to the simulated digestion process. The results indicate a trend of conversion from the glycosides to the aglycones for some samples and subsequent degradation of the aglycones. This may indicate a need to further investigate the reported benefits of Ginkgo flavonoids as in vivo antioxidants and/or to consider the antioxidant activity of the resulting digestion-derived compounds.     

UPLC-UV-QDa联用系统快速分析野生樱桃李叶化学成分

采用UPLC-UV-QDa联用系统测定了4种不同野生樱桃李叶中黄酮苷元的含量,并对醇提物成分进行快速分析。结果表明,槲皮素和山奈酚为野生樱桃李叶主要黄酮苷元。UPLC测定2种苷元可在7.0min内达到基线分离,线性关系良好,平均回收率分别为98.65%(RSD=1.08%,n=3),102.02%(RSD=1.17%,n=3),表明该方法快速、准确、重复性好。不同品种和生长环境的野生樱桃李叶中黄酮苷元含量有差异,但均以山奈酚为主。阳坡紫果叶山奈酚含量最高为(7.68±0.45)mg/g,沟谷红果叶最低为(4.59±0.32)mg/g,总黄酮含量变化幅度为16.21～33.25 mg/g。通过UPLC-UV-QDa联用系统快速鉴别,阳坡紫果叶醇提物主成分为1种单咖啡酰奎宁酸、4种槲皮素苷、7种山奈酚苷。     

植物乳杆菌对淫羊藿黄酮苷类成分的转化作用

以淫羊藿为研究对象,植物乳杆菌（Lactobacillus plantarum）为发酵菌株,考察淫羊藿发酵过程中1,1-二苯基-2-三硝基苯肼（DPPH）和羟基自由基清除能力和多酚、黄酮、多糖含量的变化,采用超高效液相色谱-飞行时间质谱（UPLC-Q-TOF-MS）法分析了淫羊藿灭菌前后及发酵过程中主要活性成分的变化。淫羊藿经植物乳杆菌发酵后,DPPH自由基清除率、羟自由基清除率、总黄酮、多酚、多糖含量均有了显著提高,当发酵时间为37 h时,分别为29.59%、46.33%、11.90 mg/L、1.51 mg/L、0.18 g/L;UPLC-Q-TOF-MS共鉴定出57种活性化学成分,其中黄酮类51种,酚酸类4种、其他类2种;经植物乳杆菌发酵后,淫羊藿中黄酮苷元、单糖苷和酚酸类成分总体上相对含量升高,黄酮多级糖苷和二级糖苷的相对含量降低。     

青钱柳叶活性成分的抗氧化活性及UPLC-QTOF-MS/MS分析

利用96孔板法测定青钱柳叶不同溶剂(水、70%乙醇、乙酸乙酯和正己烷)提取物中总酚、总黄酮含量及抗氧化活性(DPPH自由基清除能力、还原能力、总抗氧化能力),考察酚类物质含量与抗氧化活性的相关性,并采用超高效液相色谱-四极杆飞行时间串联质谱(ultra performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spetrometry,UPLC-QTOF-MS/MS)分析提取物中主要活性成分。结果表明:不同提取物中总酚、总黄酮含量及抗氧化活性存在显著性差异且70%乙醇溶液提取物表现出最高的总酚(219.01 mg GAE/g)、总黄酮含量(7.23 mg CE/g)及最强的DPPH自由基清除能力(35.46 mg TE/g)和还原能力(1.89 mmol Fe SO_4/g);总酚、总黄酮含量与DPPH自由基清除能力、还原能力之间呈正相关,与总抗氧化能力呈显著负相关,表明多酚类物质是青钱柳中主要的抗氧化剂。UPLC-QTOF-MS/MS分析70%乙醇溶液提取物并初步鉴定出22种化合物,包括2种有机酸、4种酚酸、5种黄酮、8种三萜皂苷类和3种酯类,其中酚酸和黄酮类化合物是主要的抗氧化活性成分,有机酸、三萜皂苷及酯类化合物可能是潜在的抗氧化活性成分。     

Comparison of methods for the hydrolysis of flavonoids and phenolic acids from onion and spinach for HPLC analysis

For the quantitative determination of individual flavonoid glycosides in plant materials, the glycosides are normally hydrolysed and the resulting aglycones are identified and quantified. However, the hydrolysis conditions which result in optimal breakdown of glycosides are too harsh for some of the other phenolic compounds present in the same plant material. Therefore, the effects of different hydrolysis conditions and different antioxidants on pure flavonoid glycones and aglycones were studied. On the basis of the results obtained with standards, suitable hydrolysis methods for red spring onion and spinach were developed. The best results from these vegetables were obtained by refluxing at 80 °C for 2 h with 1.2 M HCl in 50% aqueous methanol with addition of 2 mg ascorbic acid as an antioxidant. The method developed in this study is suited to the screening of flavonoids in vegetables and leafy vegetables.     

Dietary flavonoid aglycones and their glycosides: Which show better biological significance?

The dietary flavonoids, especially their glycosides, are the most vital phytochemicals in diets and are of great general interest due to their diverse bioactivity. The natural flavonoids almost all exist as their O-glycoside or C-glycoside forms in plants. In this review, we summarized the existing knowledge on the different biological benefits and pharmacokinetic behaviors between flavonoid aglycones and their glycosides. Due to various conclusions from different flavonoid types and health/disease conditions, it is very difficult to draw general or universally applicable comments regarding the impact of glycosylation on the biological benefits of flavonoids. It seems as though O-glycosylation generally reduces the bioactivity of these compounds - this has been observed for diverse properties including antioxidant activity, antidiabetes activity, anti-inflammation activity, antibacterial, antifungal activity, antitumor activity, anticoagulant activity, antiplatelet activity, antidegranulating activity, antitrypanosomal activity, influenza virus neuraminidase inhibition, aldehyde oxidase inhibition, immunomodulatory, and antitubercular activity. However, O-glycosylation can enhance certain types of biological benefits including anti-HIV activity, tyrosinase inhibition, antirotavirus activity, antistress activity, antiobesity activity, anticholinesterase potential, antiadipogenic activity, and antiallergic activity. However, there is a lack of data for most flavonoids, and their structures vary widely. There is also a profound lack of data on the impact of C-glycosylation on flavonoid biological benefits, although it has been demonstrated that in at least some cases C-glycosylation has positive effects on properties that may be useful in human healthcare such as antioxidant and antidiabetes activity. Furthermore, there is a lack of in vivo data that would make it possible to make broad generalizations concerning the influence of glycosylation on the benefits of flavonoids for human health. It is possible that the effects of glycosylation on flavonoid bioactivity in vitro may differ from that seen in vivo. With in vivo (oral) treatment, flavonoid glycosides showed similar or even higher antidiabetes, anti-inflammatory, antidegranulating, antistress, and antiallergic activity than their flavonoid aglycones. Flavonoid glycosides keep higher plasma levels and have a longer mean residence time than those of aglycones. We should pay more attention to in vivo benefits of flavonoid glycosides, especially C-glycosides.     

油菜蜂花粉中黄酮类化合物的提取与鉴定

以湖北大宗油菜蜂花粉为材料,对其中微量特征成分黄酮类化合物进行鉴定。采用超声波辅助技术提取,运用二次回归正交旋转组合实验优化提取工艺,通过响应面分析和岭嵴寻优分析,确定黄酮类化合物的最佳提取条件;采用HPLC-DAD 以及HPLC-MS 对酸解后的提取液进行分析。结果表明：超声波辅助技术提取油菜蜂花粉中黄酮类化合物的最佳条件为体积分数76% 乙醇、料液比1:30、超声波时间33min,超声波温度为51℃。蜂花粉中总黄酮含量的理论得率为2.12%,实际得率为1.89%,实测得率达到理论预测值的89.15%。HPLC-DAD 以及HPLCMS分析结果证实油菜蜂花粉中可能含有9 种黄酮苷元。其中可以推定的黄酮类物质是槲皮素、山奈酚、异鼠李素和柚皮素。可为识别蜂花粉的植物来源,鉴别真伪提供研究方法和实验依据。     

Major flavonoids of Argentinean honeys. Optimisation of the extraction method and analysis of their content in relationship to the geographical source of honeys

In the present research we optimised an extraction procedure for the flavonoid aglycones: myricetin, quercetin and luteolin from honeys (as natural biological matrices), based on Amberlite XAD-4 resin followed by HPLC quantification. In addition, honeys from three geographical regions of Argentina were analysed with regard to the contents of these flavonoids. The extraction procedure was optimised for XAD-4 resin considering: resin/honey ratio, elution volume to desorb flavonoids and colour intensity of honeys. Differences in flavonoid recoveries were observed depending on the colour intensity. The flavonoid aglycones contents, in accordance with differences in geochemical characteristics and typical vegetation, varied with the geographical origin of honeys. The results obtained allowed us to consider these three flavonoids as chemical markers for the phytogeographical origin of honeys. In the case of monofloral honeys, the contribution of each one of the flavonoids was associated with the presence of a dominant pollen kind in these samples.     

Biological activities of flavonoids from Nitraria retusa (Forssk.) Asch. and their acylated derivatives

The antioxidant activity and antiproliferative property towards Caco2 cells of water and methanol extracts/fractions of Nitraria retusa were investigated. The total phenolic and flavonoid contents of the extracts/fractions were determined, and the four major flavonoids were identified as isorhamnetin, isorhamnetin-3-O-glucoside, isorhamnetin-3-O-rutinoside and isorhamnetin-3-O-robinobioside. The results showed a relationship between the extracts/fractions activities and their flavonoid contents. Moreover, the chloroform extract which was enriched with the aglycone flavonoid isorhamnetin exhibited the highest activities. The activities of N. retusa flavonoids were compared to those of model flavonoids, quercetin, isoquercitrin and rutin. In all cases, the aglycone compounds were more active than their glycosylated derivatives. Isorhamnetin-based flavonoids presented higher antiproliferative activities than quercetin-based ones, while similar antioxidant properties were observed. The enzymatic acylation of isorhamnetin-3-O-glucoside with ethyl laurate and ethyl butyrate enhanced its capacity to inhibit xanthine oxidase and its antiproliferative activity but decreased its radical scavenging activity.     

辣木叶黄酮结构分析及其对胰脂肪酶的抑制作用

对辣木叶中黄酮类化合物的结构进行分析,并测定其对胰脂肪酶的抑制作用及抑制作用类型。以70%乙醇溶液为提取溶剂,用微波辅助提取法提取辣木叶黄酮,提取率达到（5.53±0.11）%;用聚酰胺层析柱对获得的粗提物进行纯化,冷冻干燥得到样品粉末,测定其总黄酮含量为（661.10±9.20）mg/g。借助超高效液相色谱-四极杆/静电场轨道阱质谱联用技术对纯化后的辣木叶黄酮结构进行分析,共鉴定出11?个黄酮类化合物。以对硝基苯丁酸酯为底物,测定了辣木叶黄酮对胰脂肪酶的抑制活性,结果表明纯化后的辣木叶黄酮对胰脂肪酶有较好的抑制作用,半数抑制浓度（IC50）为0.94?mg/mL,通过Lineweaver-Burk法测定出其抑制作用类型为非竞争性抑制。     

改性凹土对银杏叶总黄酮的静态吸附性能研究

采用改性凹土吸附银杏叶总黄酮,通过对4 种不同改性凹土的筛选,发现壳聚糖改性凹土对银杏叶总黄酮有较大的吸附量,为112.70mg/g;对壳聚糖改性凹土对银杏叶总黄酮的吸附性能进行研究,得到溶液总黄酮质量浓度、pH 值对吸附量的影响趋势曲线、吸附等温线、吸附动力学曲线及吸附速率曲线;以解吸率、总黄酮纯度为指标对洗脱剂进行选择,发现1% 乙酸-70% 乙醇溶液洗脱较好,解吸率为91%,纯度为56%。     

金线莲总黄酮提取工艺优化及不同月龄、品系金线莲黄酮含量比较

目的:应用均匀设计法优化金线莲总黄酮提取工艺,并比较不同月龄和不同品系金线莲总黄酮的含量。方法:采用均匀设计法,考察乙醇浓度、液料比、提取时间和提取次数对金线莲总黄酮得率的影响,进行验证并测定不同月龄、不同品系金线莲总黄酮含量。结果:金线莲总黄酮最佳提取工艺为40倍量88%乙醇超声提取3次,每次80 min;验证试验总黄酮得率为1.68%(RSD=0.27%,n=3)。金线莲总黄酮含量与品系和月龄有关,组培金线莲总黄酮平均含量为11.091 mg/g,栽培4月龄和5月龄各品系金线莲总黄酮平均含量分别为14.359和18.730 mg/g,栽培4月龄的金线莲总黄酮含量由高到低为:大圆叶 > 尖叶 > 红霞 > 本地尖叶 > 本地圆叶 > 本地野生,组培金线莲经土壤种植其次级代谢产物总黄酮含量呈逐渐累积状态,在5月龄达到最高值。结论:优化的超声提取工艺合理、稳定、可行,为金线莲总黄酮测定和质量评价提供参考。组培金线莲和栽培金线莲总黄酮含量存在差异,土壤栽培有利于金线莲有效成分的积累,因此组培金线莲经土壤栽培是必要的。     

Phenolic acids and flavonoids in leaf and floral stem of cultivated and wild Cynara cardunculus L. genotypes

Ten genotypes, cultivated and wild of Cynara cardunculus L. were evaluated for their content of phenolic acids, flavonoids and their antioxidant activity. The major compounds present in the leaf were luteolin derivatives in globe artichoke and apigenin derivatives in wild and cultivated cardoon. Apart from ‘Cimiciusa di Mazzarino’ (var. scolymus), caffeoylquinic acids represent the main phenolic compounds in the floral stem. In particular, ‘Sylvestris Creta’ (var. sylvestris) and ‘Violetto di Sicilia’ (var. scolymus) show the highest content of caffeoylquinic acid ∼95% of the total measured polyphenols. The antioxidant capacity, in both leaf and floral stem, was qualitatively and quantitatively dependent on the phenolic acid and flavonoid profile. The phenolic acids and flavonoids in normally uneaten parts of wild and cultivated artichoke could be exploited as sources of natural antioxidants.     

HPLC测定红凤菜提取物的总黄酮含量及对提取方法的评价

为了解从红凤菜新鲜茎叶中所得提取物的有效成分含量以及提取方法的分离效果,在提取过程的不同阶段取样得到6 个不同提取物,测定其总黄酮含量。首先对提取物进行酸解,再用高效液相色谱法测定槲皮素和山柰酚的含量,根据所测样品中黄酮类成分的组分折算为总黄酮含量。结果显示,经过大孔树脂和聚酰胺2 次柱层析后,所得提取物的总黄酮质量分数达到84.8%,重结晶得到的2 个结晶物总黄酮质量分数分别为97.1%和99.7%。可见,采用乙醇提取-大孔树脂柱层析-聚酰胺柱层析-重结晶的方法可有效地从红凤菜新鲜茎叶中提取纯化总黄酮。     

LC–DAD–ESIMS/MS characterization of antioxidant and anticholinesterase constituents present in the active fraction from Persicaria hydropiper

Persicaria hydropiper or ‘kesum’ is a herb used extensively as flavoring agent in food. The antioxidant activity was evaluated by measuring the hydroperoxide production resulting from linoleic acid oxidation using ferric thiocyanate (FTC) as well as the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging ability. Moreover, inhibition activity against cholinesterase, an enzyme that responsible in several physio-pathological processes, was also determined. Identification of phytochemical constituents in the bioactive fraction of P. hydropiper was carried out by LC–DAD–ESIMS/MS technique. Fifteen compounds were identified including flavonoids, flavonoid glycosides and phenylpropanoid glycosides. Six of the compounds were isolated and their structures were elucidated in order to confirm their identities. The antioxidant and antiacetylcholinesterase activities of the isolated compounds were also evaluated.     

Chemical variability in propolis from Santiago del Estero,Argentina, related to the arboreal environment as the sources of resins

BACKGROUND: Propolis composition is extremely variable and depends on the plant resin sources that grow around the apiary. Polyphenols have been reported to be responsible of its pharmacological and biological properties. The contents of polyphenols and flavonoid aglycones were studied in propolis from different provenances to correlate these contents with the nature of the flora surrounding the hive. RESULTS: Nineteen of these bioactive substances were identified in 30 samples classified into three arboreal categories according to their main species. A noticeable variability was observed in the concentration of each component depending on the plant origin of the samples. Higher amounts were found for pinocembrin (0.2–102.3 g kg^?1), quercetin (0.08–86.6 g kg^?1) and chrysin (0.8–18.8 g kg^?1). Salicylic, 4‐hydroxybenzoic, benzoic, ferulic and gallic acids were other remarkable constituents. CONCLUSION: Statistical significant differences in polyphenol and flavonoid contents were observed among arboreal groups, while very strong linear correlations were found between polyphenol and flavonoid contents for all the samples as well as for all the groups (R²% > 87). Copyright © 2009 Society of Chemical Industry     

Distribution of quercetin-3,4′-O-diglucoside,quercetin-4′-O-monoglucoside,and quercetin in different parts of the onion bulb (Allium cepa L.) influenced by genotype

Flavonoids have gained much attention because of their proposed positive effects for human health. Onions are a rich source of flavonoids, consisting mainly of the major flavonols quercetin-3,4′-O-diglucoside (QDG) and quercetin-4′-O-monoglucoside (QMG) in the bulb and the aglycone quercetin in the outer scales. In this study, distribution of these three flavonoids was determined in 16 onion cultivars (Allium cepa) using HPLC–DAD. Three different parts of the onion bulb, the inner layers, the middle layers and the outer scales were analysed. The analysis showed varietal differences in the selected onion cultivars. The cultivars with the highest total flavonoid content were the red skinned ‘Red Baron’ and the yellow skinned cultivars ‘Ailsa Craig’ and ‘Prilep’. The distribution of the total flavonoid content in the different parts of the onion bulb showed the following order: middle layers > outer scales > inner layers. In the inner layers QDG was the major flavonoid, while in the middle layers QDG and QMG were in equal amounts. In the outer scales quercetin was the major flavonoid prior to QMG.