Yield Of Flavonoids Research Articles

Response surface method was used to optimize the ultrasonic assisted extraction of flavonoids from Crinum asiaticum.

In this study, ultrasound-assisted extraction of flavonoid from Crinum asiaticum was studied through response surface methodology (RSM) to gain the best extraction process of flavonoid and enhance the extraction rate of flavonoid. In the following RSM experiment, we selected the corresponding data of every factor as the center point through the single-factor experiments, then the experimental data was subjected to multiple regression analysis. According to the statistical analysis results, the results were consistent with the polynomial regression model, the determination coefficient (R2) was 0.9769. The best conditions for maximum flavonoid yield were 60% ethanol concentration, 64 °C for extraction temperature, 1:28 (v/w) solid-to-liquid ratio with extraction time for 47 min. The best response of flavonoid yield was 1.63972%. The predicted results for best reaction conditions were in good agreement with experiment values. Ultrasound-assisted extraction method can enhance the extraction rate of flavonoid significantly. It is a powerful tool to extract of important phytochemicals from nature plant.

Study of the variability of rutin, vitexin, hyperoside, quercetin in “Crataegi folium cum flore” of hawthorn (Crataegus L.) species from Russian flora

The genus Crataegus L. involving several hundred species is distributed throughout the temperate zne of the nothern hemisphere. Nevertheless, only a few species are included in Pharmacopoeias and used for medical purpose. As hawthorn plants usually grow in small groups, the harvesting of raw material is complicated. The search of species suitable for further inclusion in Pharmacopoeia may facilitate this task. Thus, a comparative analysis of the flavonoid content in herbal raw material ("folium cum flore") from Crataegus species growing in Russia was performed. We compared section Crataegus (7 species) widely distributed in Europe, South-Western and Central Asia and often used for medical purpose with section Sanguineae(8 species) growing in the Asian region of the Russian Federation. Total flavonoid (expressed as hyperoside) yields of the 15 Crataegus spp. investigated by UV–vis spectrophotometry ranged from 12.1 ± 1.1 (C. maximowiczii) to 22.1 ± 0.9 mg/g (C. ambigua), average – 16.5 mg/g. Assays for rutin, vitexin, hyperoside and quercetin were performed using the HPLC-UV method. Hyperoside was the predominant compound in all species except C. nigra and ranged from 1.55 (C. nigra) to 12.59 mg/g (C. monogyna), median – 4.47 mg/g. Rutin ranged from 0.35 to 5.37 mg/g, median 1.17 mg/g. Vitexin – from 0.52 to 3.90 mg/g, median 1.67 mg/g. Quercetin ranged from 0.072 to 0.945 mg/g, while the average value was tenfold lower than that in other flavonoids – 0.144 mg/g. Hyperoside, rutin and quercetin content in plant material demonstrated no significant difference between sections Sanguineae and Crataegus, while the content of vitexin was higher in sect. Sanguineae. Thus, the resource base of Crataegus species might be expanded for "folium cum flore" raw material harvesting.

Hypolipidemic Effect of Apigenin Extracted From Parsley (Petroselinum sativum L.) Leaves In Cadmium Chloride Treated Rats (Part II)

Cadmium has been reported to have cumulative effects on mortality ,cardiovascular , renal and neurologic .flavonoids (apigenin) are naturally occurring phytochemicals possessed divers pharmacological effects hypolipidemic and antioxidant activity .this study was carried out to investigate the protective effect of the flavonoids extracted from (Petroselinum sativum) parsley leaves on some parameters related to cardiac risk in adult male rats exposed to 50 ppb cadmium chloride in drinking water . Crude flavonoids were extracted from parsley leaves . Further purification of flavonoids was performed by gel permeation column chromatography (TLC) . Thirty adult Albino male rats randomly and equally divided into three group (10 rats for each) and were treated daily for 60 days as follows : The rats were kept on ordinary tab water as control (group c) , received drinking water containing 50 ppb of cadmium chloride (group T1) and simultaneously given orally 150mg/kg B.W. of flavonoids (apigenin) extracted from parsley in addition to 50ppb of cadmium chloride in drinking water (group T2). Fasting blood sample were collected by cardiac puncture technique at 0,30 and 60 days of experiment for measuring the flowing parameters : serum lipid profile including: a. triacylglycerol (TAG) .b. serum total cholesterol (TC) .c. serum high density lipoprotein (HDL-C). d. serum low density lipoprotein (LDL-C).e. serum very low density lipoprotein (VLDL-C) concentration .Besides section from heart, aorta were taken at the end of experiment for histopathological study .The results showed that the yield of crude flavonoids from parsley leaves were approximately 2.68% of dray leaves .Purification of crude flavonoids on Sephadex LH-20 clarified three peaks activity and the proportions of the purified fraction P1, P2 and P3 were 14.06, 82.43 and 3.5% respectively. Thin layer chromatography confirmed that p2 was pure apigenin . the result revealed that animal exposed to 50 ppb of cdcl2 water for 60 days caused cardiac damage manifested by a significant elevation in serum TC,TAG,HDL-C,VLDL-C and LDL-C concentrations, with a significant depression in serum HDL-C concentration . Gavage of flavonoids and Cd concurrently caused a significant correction of the previous studies parameters . Histological section of the heart and aorta of cd treated (T1) group revealed an occurrence of early signs of atherosclerotic lesions . Such histological change could not be observed in heart and aorta of animal in group T2 after oral intubation of flavonoids (apigenin). It could be concluded that apigenin is effective in prevention the deleterious effect of cadmium chloride on major rick factors of cardiovascular system.

Supercritical CO2 fluid extraction of flavonoid compounds from Xinjiang jujube (Ziziphus jujuba Mill.) leaves and associated biological activities and flavonoid compositions

In this study, the supercritical CO2 fluid extraction (SFE−CO2) conditions for obtaining the maximum flavonoid yield from Xinjiang jujube leaves (XJL) were optimized using response surface methodology (RSM). Box-Behnken design (BBD) was applied to evaluate the effects of four variables on flavonoid yield. The optimal conditions were a temperature of 52.52 °C, a pressure of 27.12 MPa, a time of 113.42 min, and a cosolvent flow rate of 0.44 mL/min. The flavonoid yield under the optimal conditions was 29.052 ± 0.38 mg/g. The major flavonoid profiles in the extracts were further analyzed using ultra-performance liquid chromatography-electrospray ionization mass spectrometry (UPLC-ESI-MS). Eight flavonoid compounds were identified and quantified in each extract, and all of these compounds were kaempferol and quercetin glycosides. Compared with conventional Soxhlet extraction (CSE) and ultrasound-assisted extraction (UAE) extracts, the SFE−CO2 extracts had higher concentrations of total flavonoids and stronger antioxidant and antiproliferative activities. Therefore, SFE−CO2 is an alternative to CSE and UAE for obtaining flavonoid compounds from XJL at high concentrations and with strong bioactivity.

Flavonoids from Morus alba L. Leaves: Optimization of Extraction by Response Surface Methodology and Comprehensive Evaluation of Their Antioxidant, Antimicrobial, and Inhibition of α-Amylase Activities through Analytical Hierarchy Process.

To explore the flavonoids from Morus alba L. leaves (MLF), the process of extracting was optimized by a response surface methodology and the antimicrobial and antioxidant activities were evaluated in vitro. The yield of flavonoids reached 50.52 mg g−1 under the optimized extraction conditions (i.e., extraction temperature, 70.85 °C; solvent concentration, 39.30%; extraction time, 120.18 min; and liquid/solid ratio, 34.60:1). The total flavonoids were extracted in organic solvents with various polarities, including petroleum ether (MLFp), ethyl acetate (MLFe), and n-butanol (MLFb). In vitro, the four MLF samples exhibited good antioxidant activities for scavenging of 2, 2′-azinobis-(3-ethylbenz-thiazoline-6-sulphonate) radical, 1, 1-diphenyl-2-picrylhydrazyl radical, and total reducing power. Regarding antimicrobial efficacy, the MLF samples suppressed the development of Staphylococcus aureus, Bacillus subtilis, and Bacillus pumilus. The MLF samples inhibited α-amylase activity to a certain extent. The analytical hierarchy process (AHP) was used to evaluate comprehensively the bioactivities of the MLF samples. The AHP results revealed that the bioactivity comprehensive score (78.83 μg mL−1) of MLFe was optimal among the four MLF samples. Morus alba L. leaves also exhibited non-hemolytic properties. All bioactivities suggested the potential of MLFe as a candidate resource in the food and drug industries.

Ultrasound-assisted aqueous extraction of total flavonoids and hydroxytyrosol from olive leaves optimized by response surface methodology

Olive leaves were often extracted with methanol or ethanol at different proportions. In this study, ultrasound-assisted aqueous extraction was adopted for olive leaf extraction. The yields of total flavonoids (TF) and hydroxytyrosol (HT) were optimized by central composite experimental design. Two second-order polynomial equations were established to quantify the relationship between the responses and the processing parameters. Under the optimal condition of extracting at 60 °C for 60 min with the solvent-to-material ratio of 40, TF and HT amounted to 57.31 ± 0.35 and 1.80 ± 0.02 mg/g dry leaves (DL), respectively. The scavenging rate of all extracts against α, α-diphenyl-β-picrylhydrazyl (DPPH) and hydroxyl free radicals was screened. The integrated scores, representing both active ingredients and antioxidant capacity of the extracts, were calculated by principle component analysis (PCA). The optimal extract gained the highest score in PCA. In addition, compared to the extracts from 80% methanol to 44% ethanol, the ultrasound-assisted aqueous extract was richer in TF, HT, and polyphenols, while it also presented stronger ferric reducing antioxidant power (FRAP), but poorer strength to quench hydroxyl radicals. The study indicated that the aqueous extract of olive leaves may present broad potential opportunities in health-care sector.

Phytochemical Analysis and Evaluation of Antimicrobial Activity of Peumus boldus, Psidium guajava, Vernonia polysphaera, Persea Americana, Eucalyptus citriodora Leaf Extracts and Jatropha multifida Raw Sap.

Currently, the treatment of infectious diseases has not always been successful due to the emergence of microbial resistance worldwide. This study aimed to evaluate the antioxidant activity, content of total phenolic compounds and flavonoids, antifungal potential and antibacterial action of six medicinal plants found in the Cerrado, leaf extracts of Boldo (Peumus boldus), Goiaba (Psidium guajava), Assa-Peixe (Vernonia polysphaera), Abacate (Persea americana), Eucalipto (Eucalyptus citriodora) and raw sap of Bálsamo (Jatropha multifida). The antioxidant activity was also determined through the DPPH, ABTS and phosphomolybdenum assays. In addition, the total phenolic content and flavonoid dosage were analyzed using the Folin- Ciocalteu method and the aluminum chloride test, respectively. All extracts, except from Assa-Peixe, showed promising values against Staphylococcus aureus, with halos varying from 13-20 mm. Analysis of the minimum inhibitory concentration (MIC) values of the six medicinal plants revealed inhibitory activity of S. aureus, with concentrations varying from 3.12-12.5 mg/mL, which is a significant result considering that S. aureus is one of the main causes of hospital infections. In the analysis of the phytochemical profile, Goiaba contained the best yield of phenolic compounds and total flavonoids, as well as higher antioxidant activity by DPPH and phosphomolybdenum, demonstrating that this species contains antioxidant components that can sequester free radicals under in vitro conditions. Therefore, the crude extracts investigated are promising and their antibacterial and antioxidant actions should be thoroughly studied.

Subcritical Water for Recovery of Polyphenols from Comfrey Root and Biological Activities of Extracts

In the present study, subcritical water was used for extraction of bioactive compounds of Symphytum officinale root. Temperature (120-200 °C), extraction time (10-30 min) and HCl concentration in extraction solvent (0-1.5%) were investigated as independent variables in order to obtain the optimal conditions for extraction and to maximize the yield of total phenols, flavonoids and antioxidant activity of obtained extracts. The application of optimal conditions (200 °C, 25.6 min and 0.0075%) provided extracts rich in total phenols and flavonoids and high antioxidant activity. Results also demonstrated that subcritical water extraction showed significant advantages for recovery of comfrey root bioactive compounds comparing to maceration and ultrasound-assisted extraction techniques. In addition, subcritical water extracts of S. officinale root are the promising sources of compounds with antioxidant, ACE inhibition, and antiproliferative properties and could potentially be used for production of new pharmacologically-active formulations.

Polarity-dependent extraction of flavonoids from citrus peel waste using a tailor-made deep eutectic solvent

Choline chloride-based deep eutectic solvents (DESs) were used as green alternatives to conventional organic solvents for extracting valuable flavonoids from citrus peel waste. The effects of viscosity, pH, and polarity of DESs on the extraction efficiency were investigated. Results revealed linear dependence of extraction yield of citrus flavonoids on the polarity of the hydrogen bond donor (HBD). To simultaneously and effectively extract polymethoxylated flavonoids (PMFs) and glycosides of flavonoids (GoFs) with different polarities, five ternary DESs were designed and prepared by combining the effective HBD components. Among the tailor-made DESs studied, choline chloride–levulinic acid–N-methyl urea showed the highest extraction yield of total flavonoids. Under optimized extraction conditions, 18.75 mg/g PMFs and 47.07 mg/g GoFs were extracted from citrus peel with recoveries of 95.87% and 86.32%, respectively. This study presents a useful strategy based on tailor-made DESs to selectively extracted value-added flavonoids from waste peels in the citrus-processing industry.

Research in the Development and Validation of the Method of Quantitative Determination of Flavonoids in the Common Sorrel Herba, Gathered in the Altai Territory

Introduction. Common sorrel (Rumex acetosa L.) is a biennial herb from the Buckwheat family (Polygonaceae L.). In our previously studies of phenolic compounds composition of alcohol extraction and ethereal, ethyl acetate, butanol fractions of common sorrel herba and flavonoids of the flavonol group was found. From the literature sources it is known that flavonoids are one of the groups of biologically active compounds with anti-inflammatory action. In this regard, the actual task is to assess the quantitative content of flavonoids in common sorrel herba.Aim. Is the development and validation of a method for the quantitative determination of flavonoids in common sorrel herba.Materials and methods. It has been established that the flavonoid complex of common sorrel herba includes rutin, therefore, the reference sample (RS) rutin was used as a standard for calculating the amount of flavonoids. Alcohol extract of common sorrel herba and a solution of rutin RS were prepared. The complexation reaction with aluminum chloride was carried out. The resulting solutions were investigated by the method of differential spectrophotometry. The spectral characteristics of the test and standard samples were compared. Then we studied the effect of extraction conditions on the yield of flavonoids from the raw material: the extractant, the particle size of the raw material, the ratio of «raw material – extractant», temperature, frequency and duration of extraction. Purified water and ethyl alcohol of various concentrations (20%, 40%, 70%, 90%) were used as the extractant. Next, carried out the selection of the optimal conditions for the complexation reaction (the complexation reaction time, the ratio of «aliquot – aluminum chloride alcohol solution»). The method was validated according to GPM.1.1.0012.15 of the State Pharmacopoeia (SF) XIII edition and generally accepted methods for the following indicators: specificity, analytical field, linearity, accuracy, precision.Results and discussion. The optimal parameters for extracting flavonoids from raw materials were determined (threefold extraction with ethyl alcohol 70% in a water bath, the ratio of «raw material – extractant» – 1:30 for 30 minutes, the particle size of the raw material – 2.0 mm). The conditions for the complexation reaction were selected (the ratio «aliquot: aluminum chloride alcohol solution» – 1: 2.5, the complexing agent – aluminum chloride solution 5% alcohol, the appearance of a stable solution color after 40 minutes). When carrying out the validation of the developed method, it was established that the validation characteristics under study are within the acceptance criteria. When analyzing the raw materials harvested in the Altai Territory in different years, it was found that the content of flavonoids in common sorrel herba ranges from 0,596 to 0,632%.Conclusion. The optimal parameters of extraction of flavonoids from raw materials were determined, the conditions for the complexation reaction were selected, and the developed method was validated. The quantitative content of flavonoids in terms of rutin in sorrel sour grass harvested in the Altai Territory in different years has been established.

A rapid and efficient extraction method based on industrial MCM-41-miniaturized matrix solid-phase dispersion extraction with response surface methodology for simultaneous quantification of six flavonoids in Pollen typhae by ultra-high-performance liquid chromatography.

An industrial MCM-41-miniaturized matrix solid-phase dispersion extraction coupled with response surface methodology was explored to determine L-epicatechin, typhaneoside, isorhamnetin-3-O-neohespeidoside, naringenin, kaempferol, and isorhamnetin in Pollen typhae by ultra-high performance liquid chromatography connected to a photodiode array detection. Several variables were optimized in detail, including mesh number of sieve, type of adsorbent, mass ratio of sample to adsorbent, grinding time, methanol concentration, and elution volume. Central composite design was applied to optimize the best conditions for the maximum yields of the total flavonoids. The results displayed a good linear relationship (R>0.9992) and the recoveries ranged from 92.9 to 103% (RSD<4.53%) of the six flavonoids. The optimal method with high efficiency and low consumption was obviously better than heating reflux and ultrasonic extraction. It was proven that the developed industrial MCM-41-miniaturized matrix solid-phase dispersion extraction coupled with simple ultra-high performance liquid chromatography method could be a rapid and efficient tool for extraction and determination of flavonoids in natural products.

Effective extraction of flavonoids from Lycium barbarum L. fruits by deep eutectic solvents-based ultrasound-assisted extraction

The efficient extraction of natural products from biomass is deemed an essential area of interest using green technology in the pharmaceutical and biochemical industries. In recent years, deep eutectic solvents (DESs) have been paying broad interest as compatible, safe, and inexpensive solvents. In this study, we addressed, for the first time, to give a fruitful illustration to extract bioactive compounds from favourite Lycium barbarum L. fruits using DESs as green designer solvents, and displaying the tuneability of DESs to extract bioactive compounds from biomass efficiently. Among the studied DESs, the 1 : 2 M mixture of choline chloride and p-toluene sulfonic acid (DESs-6) with an ultra-sound assisted extraction (UAE) method was more efficient to get high extraction yields of flavonoids including myricetin (57.2 mg/g), morin (12.7 mg/g), and rutin (9.1 mg/g) in net DESs. The resulting extraction method in which 50 mg of sample powder was extracted by UAE for 1.5 h using DESs-6 was found to be a more efficient process than conventional extraction methods such as heating plus stirring. Operational conditions including the extractant to sample solid ratio, the effect of water content, the effect of temperature, recycling of DESs, and the effect of ultra-sound irradiation time were investigated. The proposed DESs based extraction procedure attained recovery for flavonoids were in the range 75.6%–96.9%. Therefore, p-toluenesulfonic acid-based DESs may have strong potential as promising materials for the green and efficient extraction of pharmaceutical compounds from other plants or fruits.

Ultrasonicated sour Jujube seed flavonoids extract exerts ameliorative antioxidant capacity and reduces Aβ-induced toxicity in Caenorhabditis elegans

Ethnopharmacological relevanceSour Jujube seed from Ziziphus jujuba Mill. var. Spinosa (Bunge) Hu ex H. F. Chow is a traditional Chinese herb. It was demonstrated with significant activities in anti-depression and antioxidant by numerous pharmacological studies. Flavonoids is one of the main constituents in sour Jujube seed. Aim of the studyThe aim of this study was to propose a green ultrasound-assisted extraction (UAE) process of flavonoids from sour Jujube seed. Materials and methodsThe extraction parameters were investigated and optimized using single factor experiments, Plackett-Burman design (PBD) and response surface methodology (RSM). Moreover, a comparative analysis between ultrasound-assisted extraction and heat reflux extraction was performed to verify the ameliorating effects of ultrasound-assisted extraction on the flavonoids yield, the composition, antioxidant capacities in vitro and ROS scavenging capacity in PC12 cells. Meanwhile, the effects of flavonoids extract (FE) on Aβ transgenic Caenorhabditis elegans (GMC101) behavior were investigated. ResultsThe optimal extracting conditions of total flavonoids were as follows: ethanol concentration 70.60 (v/v%), liquid-solid ratio 15.02:1 mL/g, ultrasonic power 404 W, extraction time 60.03 min. The highest extraction yield was 1.59%. When compared to Heat reflux extraction (HRE) that only has gained a yield of 1.356%. Approximately, the UAE method was able to increase the yield by 17.11%. Moreover, FE extracted by UAE displayed larger capacity of scavenging ABTS, DPPH, superoxide, and hydroxyl radicals and reducing the level of ROS accumulation in PC12 cells, suggesting the biological functions of these compounds could be also better protected under UAE conditions. Furthermore, FE could also increase the chemotaxis and heat stress resistance ability, delay the paralysis and extend the lifespan of Caenorhabditis elegans. ConclusionUAE is a green and efficient technique for the preparation of flavonoids from sour Jujube seed. The flavonoids extract can reduce Aβ-induced toxicity in Caenorhabditis elegans.

Optimization and Kinetics of the Solid-liquid Extraction Process of Polyphenols from Black Mulberry Fruit

This paper investigates the influence of operating conditions and extraction techniques (maceration and ultrasonic) on the yield and extraction of dry extract, total phenolic, flavonoids and anthocyanins from black mulberry fruit (Morus nigra L.). The optimal extraction conditions and kinetic parameters of the extraction process are determined.

Extraction of Flavonoids from the Saccharification of Rice Straw Is an Integrated Process for Straw Utilization.

To date, bioethanol is not economically competitive. One strategy to overcome this limitation is co-producing ethanol and high value-added products as an integrated process. The results of this study demonstrated that flavonoids could be extracted from rice straw, and the flavonoids apigenin and kaempferol were detected by HPLC. Compared with untreated straw, ball-milling slightly increased the total amount of flavonoids and antioxidant activity measured by ABTS, DPPH, and FRAP assays. The saccharification step in the bioconversion of straw strongly affected the extraction of flavonoids from straw. The residue obtained after saccharification of ball-milled straw for glucose production was more suitable for flavonoid extraction than untreated and ball-milled straw. The yield of flavonoids from the residue was 1.51-fold higher than that from untreated straw. The antioxidant activity of flavonoids derived from the residue was similar to that of flavonoid-rich biomasses such as rice bran and wheat bran. More importantly, saccharification may significantly affect the conditions of flavonoid extraction. In this respect, treatment with cellulase may reduce the extraction time from 2.0 to 0.5h and the extraction temperature from 80 to 30°C. Therefore, saccharification in the bioconversion of straw may be considered as an enzyme pretreatment step for the efficient extraction of flavonoids from straw, serving as a sustainable process for straw utilization.

Optimization of the Solid-Liquid Extraction Process of Phenolic Compounds from Mulberry Fruit

The study was designed to examine the influence of solvent concentration (ethanol/water 20-80% by volume), extraction time (15-240 min) and extraction technique on the extraction yield of phenolic compounds, flavonoids and antioxidant activity from Morus nigra L., Morus rubra L. and Morus alba L. fruits. The optimum conditions for the extraction of total phenols, flavonoids and monomeric anthocyanins by the maceration and ultrasonic extraction processes were: 213.6 min with 80% ethanol, and 182.1 min and 71.2% ethanol, respectively (black mulberry), and 216.5 min with 78.3% ethanol and 198.7 min and 70.6% ethanol, respectively (red mulberry). In case of white mulberry for the extraction of total phenols and flavonoids optimum extraction conditions (maceration and ultrasonic) were 232.7 min and 80% ethanol, and 187.2 min and 68.7% ethanol, respectively (white mulberry). Obviously, ultrasonic extraction was less time consuming, and it requires for all performed extractions solvent with less percentage of ethanol.&#x0D; &#x0D; *********&#x0D; In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue.&#x0D; *********

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.

Optimization of Supercritical CO2 Fluid Extraction of Flavonoids from Spina Gleditsiae by Response Surface Method

In order to optimize the supercritical CO2 fluid extraction of flavonoids from spina gleditsiae, single-factor experiments were utilized to investigate the influences of the extraction temperature, extraction pressure, and entrainment dosage firstly. Then the optimal extraction process for flavonoids extraction was determined by response surface methodology and the quadratic mathematical model was established which reliability was finally verified. The optimal supercritical CO2 fluid extraction conditions were as follows: entrainment dosage of 36mL, extraction temperature of 48°Cand extraction pressure of 40Mpa. Under this condition, the yield of flavonoids from spina gleditsiae was 0.793%.

Coupling Ultrasound with Heat-Reflux to Improve the Extraction of Quercetin, Kaempferol, Ginkgetin and Sciadopitysin from Mairei Yew Leaves

The coupling of ultrasound and heat–reflux extraction (UHRE) was developed for separation for quercetin (QU), kaempferol (KA), ginkgetin (GI) and sciadopitysin (SC) from Mairei Yew leaves. The Box–Behnken design was used to optimize the UHRE conditions for obtaining the maximum yield of flavonoids. The optimal extraction conditions were as follows: boiling 80% methanol (V/V) for extraction solvent, 20 min for the extraction time, 200 W for the ultrasonic power and 26 mL/g for the liquid–solid ratio. By UHRE, the yields of QU, KA, GI and SC were, respectively, 0.109, 0.406, 0.031 and 0.355 mg/g, and total yield of four flavonoids was 0.901 mg/g, which were, respectively, 1.25-fold and 1.23-fold higher than those by using ultrasonic-assisted extraction (UAE) and heating reflux extraction (HRE). Moreover, the extraction time for the equilibrium yields of flavonoids using UHRE was 83.3% and 27.8%, respectively, less than the corresponding time using UAE and HRE. Compared with HRE and UAE, UHRE showed the increase of cell disruption degree as observed by scanning electron microscopy, which may be the reason for high yield and rapid extraction of target compounds.

Enzymolysis-ultrasonic assisted extraction of flavanoid from Cyclocarya paliurus (Batal) Iljinskaja:HPLC profile, antimicrobial and antioxidant activity

This study aimed to describe Enzymolysis-ultrasonic assisted extraction of flavanoid from Cyclocarya paliurus (Batal) Iljinskaja: HPLC profile, antimicrobial and antioxidant activity. An enzymolysis-ultrasonic assisted extraction (EUAE) method was developed and optimized for the extraction of Cyclocarya paliurus flavonoids in liquid form (CPF). The key factor influencing the extraction yield of Cyclocarya paliurus flavonoids was identified by two-level Plackett-Burman Design (PBD) with eight factors. Plackett-Burman Design determined the following four key factors as significant for the extraction yield of Cyclocarya paliurus flavonoids viz. Enzymatic temperature, enzymatic pH, complex enzyme concentration and ultrasonic power. The Box-Behnken Design (BBD) was subsequently applied to optimize the four key factors identified from Box-Behnken Design. Chemical composition of Cyclocarya paliurus flavonoids was investigated by high performance liquid chromatography (HPLC). Antimicrobial activity was carried out with the disc diffusion method. Antioxidant activities were investigated by DPPH assays, O2·− assays, ABTS+ assays and the reducing power. The optimal extraction conditions were as follow: enzymatic temperature of 50.71 °C, enzymatic pH of 5.08, complex enzyme concentration of 3.23% and ultrasonic power of 108.03 W. Under the optimal extraction conditions, the extraction yield of Cyclocarya paliurus flavonoids was 34.24 ± 0.32 mg/g, which was well-matched with the predicted value (34.47 mg/g). Isoquercetin, quercetin-3-O-α-l-rhamnoside, kaempferol-3-O-α-l-rhamnoside, quercetin and kaempferol were identified from Cyclocarya paliurus flavonoids with the content of 2.37%, 1.94%, 15.77%, 4.86% and 2.64%, respectively. The inhibition zones diameters of Cyclocarya paliurus flavonoids at the concentration of 80 μg/mL against Staphylococcus aureus, Salmonella and Escherichia coli were 21.5 ± 0.45, 17.5 ± 0.35 and 13.5 ± 0.25 mm, respectively. Results also showed a dose dependent scavenging activity as evidenced by IC50 values for superoxide (0.152 mg/mL) and ABTS+ (0.185 mg/mL) radicals. These results indicated that Cyclocarya paliurus flavonoids could be used as antimicrobial and antioxidant agents applying in pharmaceutical, functional foods and natural cosmetics.