Optimised ultrasonic-assisted extraction of flavonoids from Folium eucommiae and evaluation of antioxidant activity in multi-test systems in vitro

Geographic Variation in the Chemical Composition and Antioxidant Properties of Phenolic Compounds from Cyclocarya paliurus (Batal) Iljinskaja Leaves

Cyclocarya paliurus has been widely used as an ingredient in functional foods in China. However, the antioxidant properties of phenolic compounds and the effect of the plant origin remain unclear. The present study evaluated the geographical variation of this plant in term of its phenolic composition and antioxidant activities based on leaf materials collected from five regions. high-performance liquid chromatography (HPLC) analysis showed that there are three major components, quercetin-3-O-glucuronide, kaempferol-3-O-glucuronide, and kaempferol-3-O-rhamnoside, and their contents varied significantly among sampling locations. The investigated phenolic compounds showed substantial antioxidant activities, both in vitro and in vivo, with the highest capacity observed from Wufeng and Jinzhongshan. Correlation analysis revealed that quercetin and kaempferol glycosides might be responsible for the antioxidant activities. Our results indicate the importance of geographic origin, with sunny hours and temperature as the main drivers affecting the accumulation of C. paliurus phenolics and their antioxidant properties.

Optimized microwave extraction, characterization and antioxidant capacity of biological polysaccharides from Eucommia ulmoides Oliver leaf

Microwave-induced technique was combined with response surface methodology for optimizing the isolation of polysaccharides from Eucommia ulmoides Oliver leaf. The maximum polysaccharides yield of 12.31% was achieved by microwave extraction at 74 °C for 15 min with a solid to liquid ratio of 1:29 g/mL, which agreed with the predicted value and was 2.9-fold higher than that of the conventional heat-reflux extraction method. The dominant bioactive constituent in extracts was chlorogenic acid (1.3-1.9%), followed by geniposidic acid (1.0-1.7%). The polysaccharides from the optimized extraction had a high molecular weight and polydispersity (Mw 38,830 g/mol, Mw/Mn 2.19), as compared to the fraction prepared in the absence of microwave (Mw 12,055 g/mol, Mw/Mn 1.26). Glucose was the dominant sugar component (38.2-39.1%) of heterogeneous polysaccharides which belonged to a structure of β-type acidic heteropolysaccharides with a glucan group and highly branched degree. The polysaccharides showed a higher DPPH radical scavenging index (0.87-1.22) than BHT (0.41) but lower than BHA (3.56), which can act as a favorable antioxidant in functional food.

Multi-Response Extraction Optimization Based on Anti-Oxidative Activity and Quality Evaluation by Main Indicator Ingredients Coupled with Chemometric Analysis on Thymus quinquecostatus Celak

Thymus quinquecostatus Celak is a species of thyme in China and it used as condiment and herbal medicine for a long time. To set up the quality evaluation of T. quinquecostatus, the response surface methodology (RSM) based on its 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was introduced to optimize the extraction condition, and the main indicator components were found through an UPLC-LTQ-Orbitrap MSn method. The ethanol concentration, solid-liquid ratio, and extraction time on optimum conditions were 42.32%, 1:17.51, and 1.8 h, respectively. 35 components having 12 phenolic acids and 23 flavonoids were unambiguously or tentatively identified both positive and negative modes to employ for the comprehensive analysis in the optimum anti-oxidative part. A simple, reliable, and sensitive HPLC method was performed for the multi-component quantitative analysis of T. quinquecostatus using six characteristic and principal phenolic acids and flavonoids as reference compounds. Furthermore, the chemometrics methods (principal components analysis (PCA) and hierarchical clustering analysis (HCA)) appraised the growing areas and harvest time of this herb closely relative to the quality-controlled. This study provided full-scale qualitative and quantitative information for the quality evaluation of T. quinquecostatus, which would be a valuable reference for further study and development of this herb and related laid the foundation of further study on its pharmacological efficacy.

Effect of carotenoids, extracted from dry tomato waste, on the stability and characteristics of various vegetable oils

In this study, various vegetable oils were enriched with carotenoids originating from dry tomato waste using ultrasound-assisted extraction, microwave-assisted extraction and maceration. Analyses of total carotenoids, color and oxidative stability (determined by free radical scavenger activity, peroxide value, Rancimat method and DSC analysis) were carried out. Commercial oils without enrichment were used for comparison. The results showed that the carotenoid contents of the oils increased significantly by increasing incorporation of dry tomato waste. Also, maceration proved to extract significantly higher amounts of these compounds. In some oils the extraction of dry tomato waste improved their oxidative and thermal stability while in others it caused an increase in the peroxide value and a decrease in induction time. Finally, the color parameters of the oils were significantly influenced. Enriched oils could be a potential source of bioactive compounds and might have significant antioxidant activity when ingested as part of a dietary regime.

Continuous high voltage electrical discharge extraction of flavonoids from peanut shells based on "annular gap type" treatment chamber

A continuous high voltage electric discharge (HVED) extraction system with "annular gap type" treatment chamber was for the first time designed and optimized for flavonoids extraction from peanut shells, and a comparison with the HVED system with the "converged electric field type" treatment chamber and warm maceration was carried out. The optimal conditions for the "annular gap type" design were: 25% ethanol concentration as solvent, 30:1 mL/g liquid to solid ratio, 13 kV peak pulse voltage and 60 mL/min flow rate of material. Under these conditions, the maximum yield of flavonoids was 0.948 ± 0.014%. Compared with the "converged electric field type" design and warm maceration, the "annular gap type" design possessed shorter duration and higher efficiency for the flavonoids extraction, and had no effects on the composition of extracted flavonoids. The results showed that the "annular gap type" design was a promising alternative method in extracting flavonoids from peanut shells.

Light quality affects flavonoid production and related gene expression in Cyclocarya paliurus

Understanding the responses of plant growth and secondary metabolites to differential light conditions is very important to optimize cultivation conditions of medicinal woody plants. As a highly valued and multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medical use. In this study, LED-based light including white light (WL), blue light (BL), red light (RL), and green light (GL) were used to affect leaf biomass production, flavonoid accumulation and related gene expression of one-year C. paliurus seedlings in controlled environments. After the treatments of 60 days, the highest leaf biomass appeared in the treatment of WL, while the lowest leaf biomass was found under GL. Compared to WL, the total flavonoid contents of C. paliurus leaves were significantly higher in BL, RL, and GL, but the highest values of selected flavonoids (kaempferol, isoquercitrin and quercetin) were observed under BL. Furthermore, the greatest yields of total and selected flavonoids in C. paliurus leaves per seedling were also achieved under BL, indicating that blue light was effective for inducing the production of flavonoids in C. paliurus leaves. Pearson's correlation analysis showed that there were significantly positive correlations between leaf flavonoid content and relative gene expression of key enzymes (phenylalanine ammonia lyase, PAL; 4-coumaroyl CoA-ligase, 4CL; and chalcone synthase, CHS) in the upstream, which converting phenylalanine into the flavonoid skeleton of tetrahydroxy chalcone. It is concluded that manipulating light quality may be potential mean to achieve the highest yields of flavonoids in C. paliurus cultivation, however this needs to be further verified by more field trials.

Identification of Major Flavone C-Glycosides and Their Optimized Extraction from Cymbidium kanran Using Deep Eutectic Solvents

Cymbidium kanran, an orchid exclusively distributed in Northeast Asia, has been highly valued as a decorative plant and traditional herbal medicine. Here, C. kanran extracts were prepared in 70% aqueous methanol using ultrasound-assisted extraction (UAE) and subjected to liquid chromatography-photodiode array detection and ultra-high performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry analysis, which were used for quantitative and qualitative analysis, respectively. It was found that the extracts were rich in flavone C-glycosides including vicenin-2, vicenin-3, schaftoside, vitexin, and isovitexin. Ten deep eutectic solvents (DESs) were synthesized by combining choline chloride (hydrogen bond acceptor) with various polyols and diols (hydrogen bond donors) and were tested as a medium for the efficient production of extracts enriched with potentially bioactive flavone C-glycosides from C. kanran. A DES named ChCl:DPG, composed of choline chloride and dipropylene glycol at a 1:4 molar ratio, exhibited the best extraction yields. Then, the effects of extraction conditions on the extraction efficiency were investigated by response surface methodology. Lower water content in the extraction solvent and longer extraction time during UAE were desirable for higher extraction yields. Under the statistically optimized conditions, in which 100 mg of C. kanran powder were extracted in 0.53 mL of a mixture of ChCl:DPG and water (74:26, w/w) for 86 min, a total of 3.441 mg g^-1 flavone C-glycosides including 1.933 mg g^-1 vicenin-2 was obtained. This total yield was 196%, 131%, and 71% more than those obtained using 100% methanol, water, and 70% methanol, respectively.

Protective Effect of Flavonoids from Ziziphus jujuba cv. Jinsixiaozao against Acetaminophen-Induced Liver Injury by Inhibiting Oxidative Stress and Inflammation in Mice

This study was aimed to investigate the chemical composition, antioxidant activities and hepatoprotective effect of flavonoids from Ziziphus jujuba cv. Jinsixiaozao (ZJF). The composition of ZJF was analyzed by high performance liquid chromatography (HPLC) and Liquid chromatography-mass spectrometry (LC-MS), and antioxidant properties were investigated by biological assays in vitro. The hepatoprotective activity of ZJF was evaluated in acetaminophen (APAP)-treated BALB/c mice. Results indicate that ZJF displayed significant antioxidant capacity. Pretreatment with ZJF significantly decreased APAP-elevated serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and total bilirubin (TB). Activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were enhanced with ZJF administration, while malondialdehyde (MDA) level and glutathione (GSH) depletion were reduced. Meanwhile, ZJF reversed the suppression of nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation, and up-regulated the protein expression of NAD(P)H: quinone oxidoreductase 1(NQO1) in liver damage mice. Furthermore, ZJF attenuated APAP-induced inflammatory mediator production, such as nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β). Expression of p65 showed that ZJF dampened nuclear factor-κB (NF-κB) activation. The results strongly indicate that the hepatoprotective role of ZJF in APAP-induced hepatotoxicity might result from its induction of antioxidant defense via activation of Nrf2 and reduction of inflammation via inhibition of NF-κB.

Inhibitory Effects of Culinary Herbs and Spices on the Growth of HCA-7 Colorectal Cancer Cells and Their COX-2 Expression

It is unclear if the anti-inflammatory properties of culinary herbs and spices (CHS) are linked to their ability to inhibit Colorectal cancer cell (CRC) growth. Furthermore, their therapeutic potential with regards to CRC is unknown. The aim of this study was to establish if the inhibition of HCA-7 CRC cell growth by a selection of culinary herbs and spices (CHS) is linked to the inhibition of the cells’ cyclooxygenase-2 (COX-2 )expression, and to investigate their therapeutic potential. CHS inhibited the growth of Human colon adenocarcinoma-7 (HCA-7) cells; the order of potency was turmeric, bay leaf, ginger, sage, and rosemary; their combinations had a synergistic or additive effect on cell growth inhibition. CHS also inhibited COX-2 expression and activity; this action was comparable to that of the specific COX-2 inhibitor Celecoxib. Coincident with COX-2 inhibition was the accumulation of cells in the sub G1 phase of the HCA-7’s cell cycle and, using bay leaf and turmeric, the cleavage of caspase 3 and poly (ADP-ribose) polymerase (PARP). This latter effect showed that the effect of these CHS on growth arrest was irreversible, and was comparable to that of the caspase activator Etoposide. This study provides evidence of a link between the inhibition of HCA-7 growth, and its COX-2 expression, by CHS, and their therapeutic potential.

Quantitative studies of rhubarb using quantitative analysis of multicomponents by single marker and response surface methodology

In this work, we developed a novel approach to evaluate the contents of bioactive components in rhubarb. The present method was based on the quantitative analysis of multicomponents by a single-marker and response surface methodology approaches. The quantitative analysis of multicomponents by a single-marker method based on high-performance liquid chromatography coupled with photodiode array detection was developed and applied to determine the contents of 12 bioactive components in rhubarb. No significant differences were found in the results from the quantitative analysis of multicomponents by a single-marker and the external standard method. In order to maximize the extraction of 12 bioactive compounds in rhubarb, the ultrasonic-assisted extraction conditions were obtained by the response surface methodology coupled with Box-Behnken design. According to the obtained results, we showed that the optimal conditions would be as follows: proportion of ethanol/water 74.39%, solvent-to-solid ratio 24.07:1 v/w, extraction time 51.13 min, and extraction temperature 63.61°C. The analytical scheme established in this research should be a reliable, convenient, and appropriate method for quantitative determination of bioactive compounds in rhubarb.

Novel Approaches to Extraction Methods in Recovery of Capsaicin from Habanero Pepper (CNPH 15.192)

Introduction:

The objective of this study was to compare three capsaicin extraction methods: Shoxlet, Ultrasound-assisted Extraction (UAE), and Shaker-assisted Extraction (SAE) from Habanero pepper, CNPH 15.192.

Materials and Methods:

The different parameters evaluated were alcohol degree, time extraction, and solid–solvent ratio using response surface methodology (RSM).

Results:

The three parameters found significant (p < 0.05) were for UAE and solvent concentration and extraction time for SAE. The optimum conditions for the capsaicin UAE and SAE were similar 95% alcohol degree, 30 minutes and solid–liquid ratio 2 mg/mL. The Soxhlet increased the extraction in 10–25%; however, long extraction times (45 minutes) degraded 2% capsaicin.

Conclusion:

The extraction of capsaicin was influenced by extraction method and by the operating conditions chosen. The optimized conditions provided savings of time, solvent, and herbal material. Prudent choice of the extraction method is essential to ensure optimal yield of extract, thereby making the study relevant and the knowledge gained useful for further exploitation and application of this resource.

SUMMARY

Habanero pepper, line CNPH 15.192, possess capsaicin in higher levels when compared with others species

Higher levels of ethanolic strength are more suitable to obtain a higher levels of capsaicin

Box-Behnken design indicates to be useful to explore the best conditions of ultrasound assisted extraction of capsaicin.

Abbreviations used: Nomenclature UAE: Ultrasound-assisted Extraction; SAE: Shaker-assisted Extraction.

Optimized ultra-high-pressure-assisted extraction of procyanidins from lychee pericarp improves the antioxidant activity of extracts

To establish optimal ultra-high-pressure (UHP)-assisted extraction conditions for procyanidins from lychee pericarp, a response surface analysis method with four factors and three levels was adopted. The optimum conditions were as follows: 295 MPa pressure, 13 min pressure holding time, 16.0 mL/g liquid-to-solid ratio, and 70% ethanol concentration. Compared with conventional ethanol extraction and ultrasonic-assisted extraction methods, the yields of the total procyanidins, flavonoids, and phenolics extracted using the UHP process were significantly increased; consequently, the oxygen radical absorbance capacity and cellular antioxidant activity of UHP-assisted lychee pericarp extracts were substantially enhanced. LC-MS/MS and high-performance liquid chromatography quantification results for individual phenolic compounds revealed that the yield of procyanidin compounds, including epicatechin, procyanidin A2, and procyanidin B2, from lychee pericarp could be significantly improved by the UHP-assisted extraction process. This UHP-assisted extraction process is thus a practical method for the extraction of procyanidins from lychee pericarp.

Quality Evaluation of Prunellae Spica Based on Simultaneous Determination of Multiple Bioactive Constituents Combined with Grey Relational Analysis

Prunellae Spica (PS) is an important traditional Chinese herbal medicine (TCM) with massive consumption because of its therapeutical and seasoning effects. However, little attention has been paid to simultaneous analyze its bioactive components for quality control of PS based on its different growing habitats and different growth periods. In this study, the quality of PS was evaluated based on simultaneous determination of multiple bioactive components combined with grey relational analysis (GRA). A reliable method based on high-performance liquid chromatography tandem triple quadrupole mass spectrometry (HPLC-QTRAP-MS/MS) was established to simultaneously determine the contents of 21 components in PS, including 9 phenolic acids, 3 coumarins, 8 flavonoids and 1 pentacyclic triterpene. Furthermore, GRA was performed to evaluate the quality of PS samples according to the contents of these 21 components. The results showed that the quality of PS harvested on withering period, cultivated in Anhui was better than that of other PS samples. The proposed method is useful for the overall assessment on the quality of PS, and this study provides valuable information for revealing the dynamic change laws of metabolite accumulation in PS and choosing the most suitable harvesting time and genuine producing area of PS to obtain the best quality.

Comparative evaluation of maceration and ultrasonic-assisted extraction of phenolic compounds from fresh olives

Ultrasonic-assisted extraction (UAE) and maceration extraction (ME) were optimized using response surface methodology (RSM) for total phenolic compounds (TPC) from fresh olives. The main phenolic compounds and antioxidant activity of TPC were also investigated. The optimized result for UAE was 22mL/g of liquid-solid ratio, 47°C of extraction temperature and 30min of extraction time, 7.01mg/g of yielding, and for ME was 24mL/g of liquid-solid ratio, 50°C of extraction temperature and 4.7h of extraction time, 5.18mg/g of yielding. The HPLC analysis revealed that the extracts by UAE and ME possessed 14 main phenolic compounds, and UAE exhibited more amounts of all phenols than ME. The most abundant phenolic compounds in olive extracts were hydroxytyrosol, oleuropein and rutin. Both extracts showed excellent antioxidant activity in a dose-dependent manner. Taken together, UAE could effectively increase the yield of phenolic compounds from olives. In addition these phenolic compounds could be used as a potential source of natural antioxidants.

Optimization of microwave-assisted extraction of zerumbone from Zingiber zerumbet L. rhizome and evaluation of antiproliferative activity of optimized extracts

Background

The extraction of bioactive compounds from herbal materials requires optimization in order to recover the highest active dose. Response surface methodology was used to optimize variables affecting the microwave extraction of zerumbone from Zingiber zerumbet using the Box–Behnken design. The influence of variables, such as ethanol concentration (X₁), microwave power (X₂), irradiation time (X₃), and liquid-to-solid ratio (X₄), on the extraction of zerumbone was modeled using a second-order regression equation. The antiproliferative activity of optimized and non-optimized extracts was evaluated against the HeLa cancer cell line using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay.

Results

Two linear parameters, X₁ and X₄, and their quadratic parameters were highly significant at the P < 0.01 level. Two interaction parameters, X₁X₄ and X₂X₃ were significant, whereas interactions of X₁X₂, X₁X₃, X₂X₄ and X₃X₄ were insignificant (P > 0.05). The optimum microwave extraction conditions were as follows: ethanol concentration, 44%; microwave power, 518 W; irradiation time, 38.5 s; and liquid-to-solid ratio, 38 mL/g. Under these conditions, the maximum zerumbone yield was 5.88 mg/g DM, which was similar to the predicted value (5.946 mg/g DM). Optimized and non-optimized Z. zerumbet rhizome extracts exhibited significant antiproliferative activity against HeLa cancer cells, with half-maximal inhibitory concentration (IC₅₀) values of 4.3 and 7.8 μg/mL, respectively, compared with 1.68 μg/mL for the anticancer drug cisplatin. When the extract concentration increased from 4.3 to 16.0 μg/mL, the inhibition of cancer cell growth increased from 50.0 to 79.5%.

Conclusions

In this study, the optimized microwave protocol developed for extracting zerumbone from Z. zerumbet was faster and consumed less solvent than previous methods, while improving and enhancing the antiproliferative activity.

Effect of light regime and provenance on leaf characteristics, growth and flavonoid accumulation in Cyclocarya paliurus (Batal) Iljinskaja coppices

BACKGROUND

As a highly valued and multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medical use. However, limited information is available on its genotype selection and cultivation for growth and phytochemicals. Responses of growth and secondary metabolites to light regimes and genotypes are useful information to determine suitable habitat conditions for the cultivation of medicinal plants.

RESULTS

Both light regime and provenance significantly affected the leaf characteristics, leaf flavonoid contents, biomass production and flavonoid accumulation per plant. Leaf thickness, length of palisade cells and chlorophyll a/b decreased significantly under shading conditions, while leaf areas and total chlorophyll content increased obviously. In the full light condition, leaf flavonoid contents showed a bimodal temporal variation pattern with the maximum observed in August and the second peak in October, while shading treatment not only reduced the leaf content of flavonoids but also delayed the peak appearing of the flavonoid contents in the leaves of C. paliurus. Strong correlations were found between leaf thickness, palisade length, monthly light intensity and measured flavonoid contents in the leaves of C. paliurus. Muchuan provenance with full light achieved the highest leaf biomass and flavonoid accumulation per plant.

CONCLUSIONS

Cyclocarya paliurus genotypes show diverse responses to different light regimes in leaf characteristics, biomass production and flavonoid accumulation, highlighting the opportunity for extensive selection in the leaf flavonoid production.

Optimization of ultrasound-assisted hydroalcoholic extraction of phenolic compounds from walnut leaves using response surface methodology

Context Walnut leaves are highly appreciated for their pharmacological effects and therapeutic properties which are mainly attributed to their high content of phenolic compounds. Objective This study optimizes ultrasound assisted hydroalcoholic extraction (UAE) of phenolic compounds from dried walnut leaves by the maximization of total phenolics content (TPC) and total flavanoids content (TFC) of the extracts. Materials and methods Optimal conditions with regard to ethanol concentration (X1: 12.17-95.83% v/v), extraction time (X2: 8.17-91.83 min) and liquid-to-solid ratio (X3: 4.96-25.04 v/w) were identified using central composite design combined with response surface methodology. A high-performance liquid chromatography method with diode-array detection was used to quantify phenolic acids (gallic, vanillic, chlorogenic, caffeic, syringic, p-coumaric, ferulic, sinapic, salicylic, ellagic and trans-cinnamic), flavonoids (catechin, epicatechin, rutin, myricetin and quercetin) and juglone in the extracts. Results Liquid-to-solid ratio and ethanol concentration proved to be the primary factors affecting the extraction efficiency. The maximum predicted TPC, under the optimized conditions (61% ethanol concentration, 51.28 min extraction time and 4.96 v/w liquid-to-solid ratio) was 10125.4 mg gallic acid equivalents per liter while maximum TFC (2925 mg quercetin equivalents per liter) occurred at 67.83% ethanol concentration, 4.96 v/w liquid-to-solid ratio and 49.37 min extraction time. High significant correlations were found between antioxidant activity and both TPC (R(2 )=( )0.81) and TFC (R(2 )=( )0.78). Discussion and conclusion Extracts very rich in polyphenols could be obtained from walnut leaves by using UAE, aimed at preparing dietary supplements, nutraceuticals or functional food ingredients.

Optimization of Ultrasound-Assisted Extraction of Natural Antioxidants from Sugar Apple (Annona squamosa L.) Peel Using Response Surface Methodology

Sugar apple (Annona squamosa L.) is a popular tropical fruit and its peel is a municipal waste. An ultrasound-assisted extraction method was developed for the recovery of natural antioxidants from sugar apple peel. Central composite design was used to optimize solvent concentration (13.2%–46.8%), ultrasonic time (33.2–66.8 min), and temperature (43.2–76.8 °C) for the recovery of natural antioxidants from sugar apple peel. The second-order polynomial models demonstrated a good fit of the quadratic models with the experimental results in respect to total phenolic content (TPC, R² = 0.9524, p < 0.0001), FRAP (R² = 0.9743, p < 0.0001), and TEAC (R² = 0.9610, p < 0.0001) values. The optimal extraction conditions were 20:1 (mL/g) of solvent-to-solid ratio, 32.68% acetone, and 67.23 °C for 42.54 min under ultrasonic irradiation. Under these conditions, the maximal yield of total phenolic content was 26.81 (mg GA/g FW). The experimental results obtained under optimal conditions agreed well with the predicted results. The application of ultrasound markedly decreased extraction time and improved the extraction efficiency, compared with the conventional methods.

Optimization of Ultrasonic-Assisted Extraction of Flavonoid Compounds and Antioxidants from Alfalfa Using Response Surface Method

Ultrasonic-assisted extraction (UAE) was used to extract flavonoid-enriched antioxidants from alfalfa aerial part. Response surface methodology (RSM), based on a four-factor, five-level central composite design (CCD), was employed to obtain the optimal extraction parameters, in which the flavonoid content was maximum and the antioxidant activity of the extracts was strongest. Radical scavenging capacity of the extracts, which represents the amounts of antioxidants in alfalfa, was determined by using 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonicacid) (ABTS) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) methods. The results showed good fit with the proposed models for the total flavonoid extraction (R² = 0.9849), for the antioxidant extraction assayed by ABTS method (R² = 0.9764), and by DPPH method (R² = 0.9806). Optimized extraction conditions for total flavonoids was a ratio of liquid to solid of 57.16 mL/g, 62.33 °C, 57.08 min, and 52.14% ethanol. The optimal extraction parameters of extracts for the highest antioxidant activity by DPPH method was a ratio of liquid to solid 60.3 mL/g, 54.56 °C, 45.59 min, and 46.67% ethanol, and by ABTS assay was a ratio of liquid to solid 47.29 mL/g, 63.73 °C, 51.62 min, and 60% ethanol concentration. Our work offers optimal extraction conditions for total flavonoids and antioxidants from alfalfa.

Extraction optimization and nanoencapsulation of jujube pulp and seed for enhancing antioxidant activity

The aim of this study was to optimize extraction conditions for jujube pulp and seed in order to obtain maximum active ingredient yield and antioxidant activity, as well as to prepare chitosan nanoparticles loaded with jujube pulp and seed extracts for enhancing stability. The extraction conditions, i.e. temperature, time, and ethanol concentration, were optimized at the following respective values: 61.2 °C, 38 h, and 60.4% for pulp, and 58 °C, 34 h, and 59.2% for seed. The jujube nanoparticle size significantly increased with a higher chitosan/sodium tripolyphosphate ratio and extract concentration. Entrapment efficiency was greater than 80% regardless of preparation conditions. The stabilities of jujube pulp and seed extract in terms of total phenolic content and antioxidant activity were effectively enhanced by nanoencapsulation. In conclusion, jujube pulp and seed extracts prepared using optimal conditions could be useful as a natural functional food ingredient with antioxidant activity, and nanoencapsulation can be used to improve the stability of jujube extract. Therefore, these results could be used to promote the utilization of not only jujube pulp but also seed, by product.

Inhibitory properties of aqueous ethanol extracts of propolis on alpha-glucosidase

The objective of the present study was to evaluate the inhibitory properties of various extracts of propolis on alpha-glucosidase from baker's yeast and mammalian intestine. Inhibitory activities of aqueous ethanol extracts of propolis were determined by using 4-nitrophenyl-D-glucopyranoside, sucrose and maltose as substrates, and acarbose as a positive reference. All extracts were significantly effective in inhibiting α-glucosidase from baker's yeast and rat intestinal sucrase in comparison with acarbose (P < 0.05). The 75% ethanol extracts of propolis (75% EEP) showed the highest inhibitory effect on α-glucosidase and sucrase and were a noncompetitive inhibition mode. 50% EEP, 95%, EEP and 100% EEP exhibited a mixed inhibition mode, while water extracts of propolis (WEP) and 25% EEP demonstrated a competitive inhibition mode. Furthermore, WEP presented the highest inhibitory activity against maltase. These results suggest that aqueous ethanol extracts of propolis may be used as nutraceuticals for the regulation of postprandial hyperglycemia.

Beneficial mycorrhizal symbionts affecting the production of health-promoting phytochemicals

Fresh fruits and vegetables are largely investigated for their content in vitamins, mineral nutrients, dietary fibers, and plant secondary metabolites, collectively called phytochemicals, which play a beneficial role in human health. Quantity and quality of phytochemicals may be detected by using different analytical techniques, providing accurate quantification and identification of single molecules, along with their molecular structures, and allowing metabolome analyses of plant-based foods. Phytochemicals concentration and profiles are affected by biotic and abiotic factors linked to plant genotype, crop management, harvest season, soil quality, available nutrients, light, and water. Soil health and biological fertility play a key role in the production of safe plant foods, as a result of the action of beneficial soil microorganisms, in particular of the root symbionts arbuscular mycorrhizal fungi. They improve plant nutrition and health and induce changes in secondary metabolism leading to enhanced biosynthesis of health-promoting phytochemicals, such as polyphenols, carotenoids, flavonoids, phytoestrogens, and to a higher activity of antioxidant enzymes. In this review we discuss reports on health-promoting phytochemicals and analytical methods used for their identification and quantification in plants, and on arbuscular mycorrhizal fungi impact on fruits and vegetables nutritional and nutraceutical value.

Optimization of ultrasound-assisted extraction (UAE) of phenolic compounds from Crataegus pinnatifida leaves and evaluation of antioxidant activities of extracts

In this study, a highly efficient BBD–RSM optimized ultrasound-assisted extraction combined with HPLC method has been established for the simultaneous extraction and determination of CA, VG, VR, ORT, RT, VIT and HYP from Crataegus pinnatifida leaves.

Ultrasonic-assisted extraction of antioxidative compounds from Bene (Pistacia atlantica subsp. mutica) hull using various solvents of different physicochemical properties

Extraction yield, phenolics content, and antioxidant activities of the materials extracted conventionally and/or ultrasonically from Bene hull by a number of aqueous and organic solvents were investigated. Higher extraction yields in general were obtained by the less polar solvents (12.1-47.5%). Polar protic solvents exhibited the highest content of total phenolics extracted (110-150 mg/g), followed by polar aprotic (30.0-43.5 mg/g) and non-polar solvents (3.3-5.2 mg/g). Good correlation (R(2)=0.9721) was obtained between the DPPH radical-scavenging activities and total phenolics contents. Many similarities were observed between the results of the DPPH (EC50=0.6-1105.3 μg/ml) and FRAP (0.1-8.5 mmol/g) assays. The highest oxidative stability index (OSI) value belonged to the methanol and water extracts, respectively. All the extraction factors significantly improved by 30 min sonication, especially in polar protic solvents. A 10-min sonication in water extraction could provide the same achievements as those of the 24-h conventional method.

The optimum conditions for the extraction of antioxidant compounds from the Persian gulf green algae (Chaetomorpha sp.) using response surface methodology

The potential of antioxidant activity of the green algae (Chaetomorpha sp.) was studied in this work. The optimum processing conditions for the extraction of antioxidant compounds from dried green algae were determined using response surface methodology (RSM). A central composite design (CCD) was applied to determine the effects of three process variables as follows: solvent concentration (percent), extraction time (min) and microwave power (w) on total phenolic contents, ferric reducing power, 2'2-dipheny-l-picrylhydrazyl (DPPH) radical scavenging activity and total antioxidant capacity assays. The independent variables were coded at five levels and CCD included 20 experimental runs with six replications at the center point. The statistical analysis of data was performed using design expert software and second-order polynomial models generated after analysis of variance (ANOVA) applied for predicting the responses. The results revealed that the highest total phenol content and reducing power were 1.09 and 0.12 mg of tannic acid equivalent/g dry weight, respectively. The maximum antioxidant activity was 0.19 mg ascorbic acid equivalent/g dry weight and DPPH was 99.8 % under MAE. The optimum conditions using RSM for the predicted responses were: microwave power 300 W, extraction time 8 min and solvent concentration 25 %, respectively. Furthermore the actual experimental values were adjacent to the corresponding predicted values which demonstrated fitness of the employed models and suitability of RSM in extraction parameters optimization.

Tissue-smashing based ultra-rapid extraction of chemical constituents in herbal medicines

Sample extraction is the first challenge in analysis of herbal medicines (HMs). Numerous methods have been developed to improve extraction efficiency, use less solvent and short time. In this work, a tissue-smashing based ultra-rapid extraction (TSURE) method has been proposed through the designed particle crushing, drastic stir, and dynamic molecular permeation at normal temperature. Factors in TSURE like extraction time, volts, and solvents were optimized for extraction efficiency of salvianolic acid B, cryptotanshinone, and tanshinone IIA from Salvia miltiorrhiza. The TSURE method was validated in terms of repeatability (RSD<2.2%) and extraction recoveries (93-106% with RSD<5.0%). TSURE showed a comparable extraction efficiency to conventional heat reflux extraction (HRE) and better than ultrasonic assisted extraction (UAE). The extraction time was about 2.0-3.0 min for TSURE, 60 times faster than the performance of HRE and 20 times faster than UAE. Microscopic analysis showed that the Krummbein diameter of plant particles after extraction were about 600-1200 μm for HRE and UAE, and decreased to 50-80 μm for TSURE. Subsequently, the developed TSURE was applied to high-throughput extraction of 19 S. miltiorrhiza samples collected in different regions of China. Besides, application of TSURE to other herbal medicines was also investigated, including Panax quinquefolius and Lonicera japonica. TSURE method provided an ultra-rapid and promising alternation for extraction of ingredients in herbal medicines, and can be extended to pharmaceutics, foods and cosmetics.

Chemical compositions and antioxidative and antidiabetic properties of underutilized vegetable palm hearts from Plectocomiopsis geminiflora and Eugeissona insignis

Underutilized vegetables are currently studied not only for their nutrient values but also for their health-promoting components for protection against chronic diseases. The present study was performed to evaluate chemical compositions and antioxidant properties of underutilized vegetable palm hearts, namely, lalis (Plectocomiopsis geminiflora) and pantu (Eugeissona insignis). Additionally, the vegetable extracts were evaluated for their activities in the inhibition of digestive enzymes and effects on insulin secretion using BRIN BD11 pancreatic cell lines. Both vegetables contain valuable sources of dietary fiber, potassium, and zinc. For the first time, the phenolic compounds of the vegetables were identified and quantified using HPLC-DAD and LC-ESI-MS. Appreciable amounts of chlorogenic acid were found in the studied vegetables. The sample extracts exhibited potential antioxidant capacities through chemical and biological in vitro assays. High inhibition of α-amylase activity (>50%) was found from the extracts. Thus, it was suggested the vegetable consumption could fulfill the nutrient requirements among local communities.

Effect of ultrasonic treatment on the polyphenol content and antioxidant capacity of extract from defatted hemp, flax and canola seed cakes

The effectiveness of ultrasonic extraction of phenolics and flavonoids from defatted hemp, flax and canola seed cakes was compared to the conventional extraction method. Ultrasonic treatment at room temperature showed increased polyphenol extraction yield and antioxidant capacity by two-fold over the conventional extraction method. Different combinations of ultrasonic treatment parameters consisting of solvent volume (25, 50, 75 and 100 mL), extraction time (20, 30 and 40 min) and temperature (40, 50, 60 and 70 °C) were selected for polyphenol extractions from the seed cakes. The chosen parameters had a significant effect (p<0.05) on the polyphenol extraction yield and subsequent antioxidant capacity from the seed cakes. Application of heat during ultrasonic extraction yielded higher polyphenol content in extracts compared to the non-heated extraction. From an orthogonal design test, the best combination of parameters was 50 mL of solvent volume, 20 min of extraction time and 70 °C of ultrasonic temperature.

Separation and purification of flavonoid from Taxus remainder extracts free of taxoids using polystyrene and polyamide resin

An efficient separation process of flavonoid from Taxus wallichiana var. mairei remainder extracts free of taxoids was developed in this study. AB-8 macroporous resin and polyamide resin offered the fine adsorption capacity, and its adsorption rate at 30°C fitted well to the Langmuir and Freundich isotherms. Resin dynamic adsorption and desorption experiments were conducted to optimize the separation process of total flavonoids from T. wallichiana var. mairei remainder extracts free of taxoids. The optimum parameters for adsorption by AB-8 resin were as follows: (1) the concentration of flavonoids in a sample solution of 5.61 mg/mL with a processing volume of 2 bed volume (BV) (60 mL); (2) for desorption, ethanol-water (80:20, v/v), with 6 BV as an eluent at a flow rate of 2 BV/h. After a one-run treatment with AB-8 resin, the content of flavonoids was increased 5.10-fold from 4.05 to 20.65%. The optimum parameters for adsorption by polyamide resin were as follows: processing volume of 2 BV (30 mL); for desorption, ethanol-water (70:30, v/v), with 8 BV as an eluent at a flow rate of 2 BV/h. After one-run treatment with polyamide resin, the content of total flavonoids increased from 20.65 to 65.21%. The method will provide a potential approach for large-scale separation and purification of flavonoid for its wide pharmaceutical use.