Human plasma protein binding of water soluble flavonoids extracted from citrus peels

The human plasma protein binding of water soluble flavonoids in the peels of five spices of citrus fruits was studied by ultrafiltration combined with HPLC.The flavonoids were extracted separately by hot and cold water,and higher total flavonoid contents were detected in the former extracts than the latter ones.All the extracts show significant scavenging abilities to both ABTS and DPPH free radicals,which indicates the health benefits of the water extracts of citrus fruits peels.For DPPH radical,the IC50values of hot extract follow as Navel orange(NO)≈Mandarin orange(MO)< Lemon(LE)< Lo tangerine(LO)< Pomelo(PO),while the rank is NO< PO<LE≈MO<LO for ABTS radical.The HPLC results reveal that the kinds and contents of the flavonoids detected in the extracts are different among the species.MO extract has the most neohesperidin dihydrochalcone of 118.76 μmol/L and quercetrin of 211.81 μmol/L of which are much more than the rest extracts.Pomelo extract has the most plentiful flavonoids of naringin with a concentration of 303.28 μmol/L.The high contents of myricetrin and dihydromyricetin which both are potent free radical scavengers may explain the highest free radical scavenging activity of the NO extract.The plasma binding rates decrease with the increasing concentrations of flavonoids,and the flavonoids having plenty hydroxyl groups on both A ring and B ring of the molecular skeleton have relative higher plasma binding rates.In addition,the plasma binding rates of flavonoids with saturated C3-C4 bond decrease significantly with the increasing concentrations.

An experimental study exploring the influencing factors for ultrasonic-assisted extraction of flavonoid compounds from leaves of Amorpha fruticosa L.

In this paper,the ultrasonic-assisted extraction process of flavonoid compounds from leaves of Amorpha fruticosa is optimized.In single factor experiments,solid/liquid ratios,ultrasonic power,ethanol concentrations and extraction cycles were experimental factors.Box–Behnken central composite design and RSM analyzed the effects of the four factors on the yield of total flavonoids.The optimal extraction parameters were solid/liquid ratio 1:50 g/mL,ultrasonic power 316 W,ethanol concentration 50%,4 extraction cycles.In the optimized condition,the estimated value of the regression model was 66.6456 mg/g while the measured value was 66.4329 mg/g.

The Optimization of Ultrasonic Extraction Technology of Total Flavonoids in Leaves of Mallotus apelta by Response Surface Analysis Methodology

[Objectives] Response surface analysis methodology was used to optimize the extraction technology of total flavonoids from Mallotus apelta leaves. [Methods] The total flavonoids were extracted using ultrasonic assisted ethanol extraction,and extraction rate of total flavonoids was taken as evaluation index. On the basis of single-factor experiment,Box-Behnken response surface methodology was employed for selecting the optimum extraction process. [Results]The optimum extraction conditions of total flavonoids were as follows: 75% of ethanol concentration,1∶ 25 of ratio of material to liquid,31 min of ultrasonic time. Under these conditions,the extraction rate of total flavonoids was 1. 115%.[Conclusions] The extraction process obtained by response surface methodology was stable,reasonable,accurate and reliable. It was a feasible method to extract the total flavonoids from M. apelta leaves.

Extraction Process and Content Determination of Total Flavonoids in Ginkgo( Ginkgo biloba L. ) Leaves

[Objectives]This study was conducted to study the extraction process and the content determination of flavonoids in ginkgo( Ginkgo biloba L.) leaves.[Methods]Ethanol extraction and methanol extraction of total flavonoids in ginkgo leaves were studied,and the optimal extraction conditions for flavonoids were determined by orthogonal test; and with quercetin as reference substance,total flavonoid content in ginkgo leaves was determined by UV spectrophotometry.[Results]The optimal extraction process was 4 h of Soxhlet extraction with methanol; and the total flavonoid contents had a good linear relation in the range of 0. 006 5-0. 039 mg/ml( R^2= 0. 999 9),the average content was stabilized at 1. 135%,and the average recovery of the method was 102. 0%. [Conclusions]This study selected the optimal extraction process for total flavonoids in ginkgo leaves. The test method is simple with high accuracy and precision,and is suitable for the extraction and determination of total flavonoids in ginkgo leaves.

Optimization of Extraction Process of Clerodendrum philippinum Schauer var. simplex Mlodenke Total Flavonoids(CPTF) by Central Composite Design-Response Surface Methodology

[Objectives] The research aimed to optimize extraction process of Clerodendrum philippinum Schauer var. simplex Mlodenke total flavonoids( CPTF),and provide reference for its development and utilization. [Methods] Based on single-factor test,ethanol concentration,extraction temperature and extraction time were taken as independent variables,and total flavonoids yield was taken as dependent variable. The test was conducted according to central composite design principle. Multivariate linear regression and binomial equation fitting of the result were conducted,and extraction process of CPTF was optimized by using response surface methodology. [Results]The optimal extraction process of CPTF was as below: ethanol concentration 54. 76%,extraction temperature 83. 92℃,extraction time 102. 64 min,solid-liquid ratio 1:20,extraction for twice. [Conclusions] The extraction process of CPTF by central composite design-response surface methodology was simple and feasible,with reliable prediction result,which was suitable for industrial production.

Research on Extraction Process of Flavonoids from Hawthorn Fruit

[ Objective] This study aimed to optimize the extraction process of flavonoids from hawthorn fruit. [ Method] By single-factor and orthogonal experi- ments, effects of different technological conditions on extraction efficiency of flavonoids from hawthorn fruit were analyzed to investigate the optimal extraction process and relevant parameters. [ Result] Percolation extraction was the most appropriate method for extracting flavonoids from hawthorn fruit. The optimal techno- logical conditions were ： 50% ethanol as the solvent, solid-liquid ratio 1 ： 8 （ g/ml）, soaking time 72 h, moderate flow rate （3 ml/min）. [ Conclusion ] The extrac- tion process is simple, low-cost, high-efficiency without the need for heating or harmful residues, which is suitable for mass extraction and production of hawthorn flavonoids.

Extraction and separation of total flavonoids from Flos Puerariae and its antioxidant activity

Objective To study the optimum extraction and separation process of total flavonoids in the flowers of Flos Puerariae and its antioxidative activity.Methods The total flavonoids were extracted with assistance of ultrasonic wave and the content was determined at 265 nm wavelength by Spectrophotometric method.Orthogonal experiment L9(34)was carried out to investigate the effects of concentration of solvent,the ratio of material to liquid,time length of extraction,and frequency of extraction on extraction results of total flavonoids from Flos Puerariae.The extracted solution was purified by petroleum ether and ethanol sequently.Under these conditions,the total flavonoids was eluted gradiently with mixed mobile phase of methanol-chloroform solution in the silica gel column system,and then determined by UV scanning and HPLC.Fenton reaction was used to produce and detect hydroxyl radicals(·OH),and pyrogallol system was used to produce and detect the superoxide radical anion(O2-·).Results The optimum conditions were as follows;using 40%(V/V)methanol as extractor with the ratio of material to liquid at 1∶30,and extracting for 2.5 h a time for 3 times.The extraction yield of total flavonoids was 13.6%.Six isoflavone compounds were isolated from the flowers of Flos Puerariae by the method of silica gel column chromatography.Antioxidative test results showed good performance of flavonoid scavenging capacity in both hydroxyl radical system and superoxide radical system and its IC50 was 7.65 μg·mL-1 and 0.18 mg·mL-1,respectively.Conclusions This study provided scientific basis for further development and utilization of Flos Puerariae and make preparation for later pharmacological research.

Isolation and Extraction of Total Flavonoids from Epimedium Koreanum Nakai by Supercritical Fluid Extraction

In the present paper is reported the method for the isolation and extraction of total flavonoids of Epimedium Koreanum Nakai by means of supercritical fluid extraction(SFE). By examining pressure, temperature, amounts of modifier and extraction time, the optimized condition of SFE is confirmed as 30 MPa and 60 ℃, with 70% ethanol as the modifier. The samples were statically extracted for 30 min, followed by dynamic extraction for 120 min at a flow rate of 6 mL/min. The quantitative analysis of total flavonoids was performed by UV-Vis spectrophotometry. Compared with the conventional method, the SFE method is more efficient, more rapid and more friendly environmentally.

Comparative Study on Extraction Technology and Activity of Total Flavonoids from Ginseng Flowers

[Objectives] To compare the effects of different extraction technologies on the extraction of total flavonoids from ginseng flowers.[Methods]Taking the ginseng flower as raw material,and the total flavonoids of ginseng flower were extracted by water extraction,ethanol extraction,freeze-thaw,ultrasonic extraction,and microwave extraction.The scavenging ability of total flavonoids and Vc to DPPH free radicals and hydroxyl radicals were compared between ultrasonic extraction and water extraction.[Results]The yield of ultrasonic and microwave technology was relatively high.In this study,the ultrasonic extraction was taken as the main method,ethanol aqueous solution was used as the solvent,and single factor experiment was carried out with ultrasonic power,ethanol volume,solid to liquid ratio and time as the variables.The best extraction process of flavonoids was ultrasonic power of 120 Hz,ethanol concentration of 60%,solid to liquid ratio of 1∶ 30,and ultrasonic time of 80 s.Under these conditions,the yield of flavonoid extraction was 6.72 mg/g.[Conclusions] The flavonoids obtained by ultrasonic extraction and microwave extraction have the highest antioxidant capacity,65.4% and 53.5%,respectively,indicating that the ultrasonic extraction and microwave extraction technologies are more suitable for the extraction of flavonoids from the ginseng flower.

In vitro total phenolics,flavonoids contents and antioxidant activity of essential oil,various organic extracts from the leaves of tropical medicinal plant Tetrastigma from Sabah

Objective:To detect the in vitro total phenolics,flavonoids contents and antioxidant activity of essential oil,various organic extracts from the leaves of tropical medicinal plant Tetrastigma from Sabah.Methods:The dry powder leaves of Tetrastigma were extracted with different organic solvent such as hexane.ethyl acetate,chloroform,butanol and aqueous methanol.The total phenolic and total flavonoids contents of the essential oil and various organic extracts such as hexane,ethyl acetate,chloroform,butanol and aqueous ethanol were determined by Folin-Ciocalteu method and the assayed antioxidant activity was determined in vitro models such as antioxidant capacity by radical scavenging activity usingα,α-diphenyl-β-picrylhydrazyl (DPPH) method.Results:The total phenolic contents of the essential oil and different extracts as gallic acid equivalents were found to be highest in methanol extract(386.22 mg/g) followed by ethyl acetate(190.89 mg/g).chloroform(175.89 mg/g).hexane(173.44 mg/g).and Imtanol extract (131.72 mg/g) and the phenolic contents not detected in essential oil.The antioxidant capacity of the essential oil and different extracts as ascorbic acid standard was in the order of methanol extract】ethyl acetate extract】chloroform】butanol】hexane extract also the antioxidant activity was not detected in essential oil.Conclusions:The findings show that the extent of antioxidant activity of the essential oil and all extracts are in accordance with the amount of phenolics present in that extract.Leaves of Tetrastigma being rich in phenolics may provide a good source of antioxidant.

The Optimization of Ultrasonic Extraction Process of Total Flavonoids from Rhodiola Crenulata by Response Surface Method

[Objectives]To study the optimal extraction process of total flavonoids in Rhodiola rosea L.,and further facilitate the development and utilization of Rhodiola rosea L. [Methods]With Rhodiola crenulata as raw material,ethanol as extractant,ultrasonic extraction as the extraction method,the single factor method was first used for preliminary investigation of effect of ethanol volume fraction,solid-liquid ratio,extraction temperature and extraction time on the flavonoids extraction rate,and then the Box-Behnken response surface method was used to optimize the extraction process of total flavonoids in R. crenulata. [Results] The optimal extraction conditions: ethanol concentration of 72%;solid-liquid ratio of 1∶ 43; extraction temperature of 66℃; extraction time of 50 min. Under these conditions,the extraction rate of total flavonoids from R. crenulata was 2. 591%. [Conclusions] The results showed that the method of response surface was reasonable and feasible for the optimization of ultrasonic extraction of total flavonoids from R. crenulata.

Study on Ultrasonic Extraction of Total Flavonoids from Angelica keiskei Koidzumi

[Objective] This study aimed to optimize the ultrasonic extraction process of total flavonoids from Angelica keiskei Koidzumi. [Method] Using the yield of total flavonoids as an indicator, the ultrasonic extraction process of total flavonoids from A. keiskei was optimized by orthogonal experimental design. [ Result ] Among four factors in orthogonal experimental design, extraction time exhibited the most significant effect on the extraction result; ethanol concentration exhib- ited a significant effect on the extraction result; ultrasonic power and solid-to-liquid ratio had no significant effect. The optimal conditions for ultrasonic extraction of total flavonoids from A. keiskei were extraction time of 25 min, ethanol concentration of 80%, ultrasonic power of 60 W, solid-to-liquid ratio of 1：20 （g/ml）, under which the yield of total flavonoids reached 1.56%. [ Conclusion] This study provides the basis for further development and utilization of total flavonoids from A. keiskei.

Optimization of Extraction Process of Total Flavonoids from Akebia trifoliata (Thunb.) Koidz. by Central Composite Design-Response Surface Methodology

[Objectives]To optimize extraction process of total flavonoids from Akebia trifoliata( Thunb.) Koidz.,so as to provide references for development and use of Akebia trifoliata( Thunb.) Koidz. [Methods]The extraction rate of total flavonoids of Akebia trifoliata( Thunb.)Koidz. was taken as observation indicator. On the basis of single factor experiment,central composite design( CCD) was used to evaluate the effects of the extraction temperature,extraction time,and ethanol concentration on the extraction process. Multiple linear regression and binomial fitting were used,and response surface methodology( RSM) was used to select the optimum extraction process. [Results] The optimum extraction process conditions for total flavonoids of Akebia trifoliata( Thunb.) Koidz. was extraction temperature: 83. 92 ℃; extraction time:96. 47 min; ethanol concentration: 63. 92%; extraction times: two times; solid to liquid ratio: 1 ∶ 20; extraction rate of total flavonoids:4. 55%. [Conclusions] The central composite design-response surface methodology( CCD-RSM) is simple,convenient,and feasible for extraction of total flavonoids from Akebia trifoliata( Thunb.) Koidz.,and the prediction results are reliable.

Optimization on Ultrasonic Extraction Method of Total Flavonoids for Liriodendron chinense Sarg.×L.tulipifera L. by Response Surface Methodology (RSM)

With the leaves,bark and roots of Liriodendron chinense Sarg.× L.tulipifera L.as experiment materials,the ultrasonic-assisted extraction conditions of total flavonoids were optimized by response surface Box-Behnken test design.Ultrasonic time and liquid-to-solid ratio had significant effects on the extraction amount of flavonoids from the leaves of L.chinense Sarg.× L.tulipifera L.;ultrasonic temperature and liquid-to-solid ratio had an interaction on the extraction amount of flavonoids;and the optimum ultrasonic time,temperature and liquid-to-solid ratio for the extraction of flavonoids from leaves of L.chinense Sarg.× L.tulipifera L.were 19.82 min,28.60 ℃ and 9.48 ml/g,respectively.Ultrasonic time,temperature and liquid-to-solid ratio had significant effects on the extraction amount of flavonoids from L.chinense Sarg.× L.tulipifera L.;there was a significant interaction between any two of the factors,which had a significant effect on the extraction of flavonoids;and the optimum extraction parameters for flavonoids in the bark were the ultrasonic time of 33.66 min,the ultrasonic temperature at 32.85 ℃ and the liquid-to-solid ratio of 11.39 ml/g.Ultrasonic time and liquid-to-solid ratio had significant effects on the extraction of flavonoids from roots;there was a significant interaction between ultrasonic time and liquid-to-solid ratio and between ultrasonic temperature and liquid-to-solid ratio;and the optimum extraction parameters for flavonoids from the roots of L.chinense Sarg.× L.tulipifera L.were the ultrasonic time of 32.38 min,the ultrasonic temperature at 25.0 ℃ and the liquid-to-solid ratio of 8.00 ml/g.The results of the three models were stable.The models are feasible and have good application value.

Study on Extraction Technology of Total Flavonoids from Vitex rotundifolia

[ Objective ] This study aimed to establish the optimal extraction technology of total flavonoids from Vitex rotundifolia and provide a theoretical basis for the utilization and development of V. rotundifolia. [ Method ] With the extraction temperature, extraction time, solid-liquid ratio and ethanol concentration as various factors, the content of total flavonoids as an indicator, the extraction technology of total flavonoids from V. rotundifolia was optimized by orthogonal experiment. [ Result] The optimal combination of extraction conditions was extraction temperature 70℃, extraction time 1 h, solid-liquid ratio 1： 12, ethanol concentration 70%. [Condusion] The optimized extraction technology was simple and efficient for extracting total flavonoids from V. rotundifolia.

Extraction of Flavonoids from Bitter Melon

Bitter melon, Momordica charantia L, is a popular traditional medicinal fruit in tropical and subtropical countries. It has been linked with therapeutic effects, some of which are likely due to its flavonoids. To determine its total flavonoid content (TFC) and to prepare extracts for use as nutritional supplements or ingredients for nutraceutical functional foods, various solvents have been used, including water, which is the preferred solvent because it is inexpensive, safe and environmentally friendly. The study aimed to extract bitter melon, using five solvents (ethanol, methanol, n-butanol, acetone and water) before and after the optimal conditions for water were determined in terms of extraction temperature, time, ratio of water to bitter melon (mL/g) and number of times the same material was extracted. The TFC of six varieties of bitter melon was also determined. Acetone was the best of the five solvents for extracting flavonoids from the Moonlight variety (23.2 mg Rutin Equivalents (RE)/g). Even after increasing the extraction by 88% (1.24 vs 0.66 mg RE/g) using optimised conditions for the aqueous extraction (two extractions at 40℃ for 15 min at a ratio of 100:1 mL/g of bitter melon powder), the flavonoids extracted from the Moonlight variety using water was very little (5.4%) compared to acetone. Furthermore, using acetone, it was shown that the Moonlight variety (23.2 mg RE/g) bought at a local market had higher levels of flavonoids than the greenhouse-grown Jade (15.3 mg RE/g), Niddhi (16.9 mg RE/g), Indra (15.0 mg RE/ g), Hanuman (3.9 mg RE/g) and White (6.9 mg RE/g) varieties. Therefore, acetone was the best solvent for extracting flavonoids from bitter melon and the aqueous extraction could only be improved to extract 5.4% of the flavonoids extracted with acetone from the Moonlight variety, which had the highest TFC of the six varieties of bitter melon.

Extraction Technology of Total Flavonoids from Pueraria lobata (Willd.) Ohwi and Content Determination of Pueraria lobata (Willd.) Ohwi at Different Altitudes

[Objectives]To optimize the extraction technology of total flavonoids from Pueraria lobata( Willd.) Ohwi. [Methods]The ultraviolet-visible spectrophotometry was used to determine the content of total flavonoids in Pueraria lobata( Willd.) Ohwi. With the puerarin as index,the reflux extraction and single factor test were employed to investigate the effects of temperature,time,ethanol concentration and solid-liquid ratio on the content of total flavonoids in Pueraria lobata( Willd.) Ohwi,respectively. Under the optimal extraction technology,the content of total flavonoids in Pueraria lobata( Willd.) Ohwi at different altitudes was determined.[Results] The optimum extraction process was as follows: 70%ethanol; solid-liquid ratio of 1∶ 30; 1 h reflux extraction. Under these conditions,the extraction rate of flavonoids in Pueraria lobata( Willd.) Ohwi was 11. 48%,the total flavonoids content of different kudzu parts was in the order of roots > stems > leaves,and the total flavonoids content of the sample at about an altitude of 1000 m was significantly higher than at the altitudes of 1400 m and 1700 m.[Conclusions]It was suggested that the Pueraria lobata( Willd.) Ohwi should not be cultivated as medicinal plant in too high mountains,and the stems and leaves of Pueraria lobata( Willd.) Ohwi could be used as raw materials for extracting total flavonoids.

Studies on Optimal Extraction Conditions of Flavonoid in Leaves of Black Currnt

Employing the orthogonal design,the optimal extraction conditions for flavonoid in leaves of black currant were determined by colorimetric estimation,which were extraction agent of 75% EtOH-H 2O,the material ratio(ratio of weight of fresh leaves to volume of the solvent)of 1:16,the temperature of 35℃,the time of 1 h and times of three.A total extraction rate of over 97% and the flavonoid contents of 179 33 mg/100 g were obtained under the optimal extraction conditions.

Supercritical Fluid Extraction of Total Flavonoids from Leaves of Acanthopanax Senticosus Harms

The herbal plant Acanthopanax Senticosus Harms is natural herb of Changbaishan in Jilin Province of China, which belongs to the Araliaceae family. As the ingredients of folk medicine, it has long been used to treat a variety of human diseases, such as cerebrovascular disease, diabetes, tumor, isochemic heart diseases, hypertension, rheumatic arthritis, etc. E2,33. Flavonoids, a class of constituent compounds, which have a broad distribution in the nature and are found in Acanthopanax Senticosus Harms, have gained particular attention. A number of studies have shown that flavonoid compounds have wide biological activities, such as anti-aging, anticancer, anti-HIV,