Optimization of the ultrasound‐assisted extraction of antioxidant phloridzin from Lithocarpus polystachyus Rehd. using response surface methodology

The purpose of this study was to optimize the extraction process of phloridzin from Lithocarpus polystachyus Rehd. leaves using response surface methodology and to determine the antioxidant capacity of the extract. A Box–Behnken design was used to analyze the effects of ethanol concentration, liquid–solid ratio, soak time and extraction time on the extraction yield of phloridzin. The content of phloridzin was determined by high‐performance liquid chromatography. To assess the antioxidant capacity of the extract, three in vitro test systems were used (1,1‐,diphenyl‐2‐picrylhydrazyl, hydroxyl radical scavenging test and reduction force). The optimal parameters obtained by response surface methodology were a volume fraction of ethanol of 64%, a liquid–solid ratio of 37:1, a soaking time of 35 h and a sonication time of 38 min. The proportion of the extraction of phloridzin from L. polystachyus under these industrial process conditions was 3.83%. According to the obtained results, response surface methodology could be suggested as an adequate model for optimizing the extraction process of phloridzin from L. polystachyus . Ultrasound extraction significantly increased the extraction rate of phloridzin, which could be used as an antioxidant in pharmaceutical and food products.     

Supercritical Carbon Dioxide Extraction of Salidroside from Rhodiola rosea L var. rosea Root

Salidroside from the root of Rhodiola rosea L var. rosea was extracted by supercritical carbon dioxide with and without methanol as modifier. Three parameters, i.e. temperature, pressure and different concentrations of methanol were optimized. Salidroside determinations were carried out using high‐performance liquid chromatography (HPLC) with UV‐Vis detector. An experimental design of response surface methodology (RSM) was used to map the effect of pressure (at 200, 300 and 400 bar), temperature (at 50, 60 and 70 °C) and percentage of methanol modifier (at 80, 90 and 100%) on the extraction yield of the active compound and to determine the optimal conditions for the extraction of salidroside from the root of plant. The results showed that supercritical carbon dioxide failed to extract salidroside from the plant material without a methanol as modifier. The yield obtained after 1.5 h extraction with the rate of modifier 0.4 mL/min and 300 bar, 70 °C, and 80 percent of methanol modifier condition was the highest (17.15 mg/g). The optimum conditions were 70 °C, 295.49 bar and 80 percent of methanol as modifier with the yield of 16.17 mg/g. In addition, the yield obtained with supercritical fluid extraction (SFE) was compared with the Soxhlet extraction, whose yield was 8.64 mg/g.     

Optimized microwave‐assistant extraction combined ultrasonic pretreatment of flavonoids from Periploca forrestii Schltr. and evaluation of its anti‐allergic activity

Microwave extraction combined ultrasonic pretreatment of flavonoids from Periploca forrestii Schltr. was investigated in this study, extraction process was first performed in an ultrasonic cleaner, then treated by microwave irradiation. The optimum ultrasonic time of 25 min was selected by single‐factor experiments. A response surface methodology has been used to obtain a mathematical model that describes the process and analyzes the significant parameters ethanol concentration 59.92%, liquid to raw materials ratio 21.24 mL/g, microwave radiation time 209.53 s, and microwave power 274.14 w. In these optimum conditions, the yield of flavonoids from P. forrestii (TFPF) could be up to 9.11 ± 0.08%, which was increased by 14.30 and 19.86% compared microwave extraction and ultrasonic extraction, respectively. In vitro suppress hyaluronidase experimentation showed that TFPF purified using polyamide exhibited good anti‐hyaluronidase ability with IC₅₀ value of 1.033 mg/mL, possessing certain anti‐antiallergic and potential application prospect in pharmaceutical production of treating inflammation and other related fields.     

Analysis of volatile oil composition of Citrus aurantium L. by microwave‐assisted extraction coupled to headspace solid‐phase microextraction with nanoporous based fibers

Nanoporous silica was prepared and functionalized with amino propyl‐triethoxysilane to be used as a highly porous fiber‐coating material for solid‐phase microextraction (SPME). The prepared nanomaterials were immobilized onto a stainless steel wire for fabrication of the SPME fiber. The proposed fiber was evaluated for the extraction of volatile component of Citrus aurantium L. leaves. A homemade microwave‐assisted extraction followed by headspace (HS) solid‐phase apparatus was used for the extraction of volatile components. For optimization of factors affecting the extraction efficiency of the volatile compounds, a simplex optimization method was used. The repeatability for one fiber (n = 4), expressed as RSD, was between 3.1 and 8.6% and the reproducibility for five prepared fibers was between 10.1 and 14.9% for the test compounds. Using microwave‐assisted distillation HS‐SPME followed by GC‐MS, 53 compounds were separated and identified in C. aurantium L., which mainly included limonene (62.0%), linalool (7.47%), trans‐β‐Ocimene (3.47%), and caryophyllene (2.05%). In comparison to a hydrodistillation method, the proposed technique could equally monitor almost all the components of the sample, in an easier way, which was rapid and required a much lower amount of sample.     

Optimization of microwave‐assisted extraction of protopine and allocryptopine from stems of Macleaya cordata (Willd) R. Br. using response surface methodology

The purpose of the research was to investigate the multiple response optimizations for the extraction of protopine and allocryptopine from the stems of Macleaya cordata (Willd) R. Br. by using microwave‐assisted extraction (MAE). A three‐level, three‐factor Box–Behnken design of response surface methodology was used to develop response model, and desirability function was employed to optimize the effects of main extraction parameters. Three variables, ethanol concentration (20–80%, v/v), extraction temperature (30–70°C) and solvent/solid ratio (10:1 to 30:1, mL/g), were investigated in this study. The results showed that the optimum parameters of MAE were ethanol concentration of 45.2 % (v/v), extraction temperature of 54.7°C and solvent/solid ratio of 20.4:1 (mL/g). Under these conditions, the extraction yields of protopine and allocryptopine were 89.4 and 102.0%, respectively, and the extracta sicca yield was 12.5%. The combination use of response surface methodology, Box‐Behnken design and the appropriate desirability function could provide an insight into a lab‐scale MAE process, and help to develop procedures for commercial production of active ingredients from medical plants.     

Gas Chromatographic Method for Analysis of p-Synephrine in Citrus aurantium L. Products

A method has been developed and validated for the identification and quantification of p-synephrine in Citrus aurantium L. products. The approach comprises GC-FID analysis followed by GC-MS confirmation after clean-up by solid phase extraction with a strong cation-exchange phase and derivatization with cyclohexanone. Oxazolidine derivative of p-synephrine was subjected to analysis by nuclear magnetic resonance (¹H and ¹³C NMR), GC-FID and GC-MS. The GC method was validated and was found to be linear in the range of 125–500 mg%. Intra-day and inter-day precisions were 3.60 and 3.59%, respectively. Mean recovery from extract of C. aurantium was 78.1 ± 3.64%. The selectivity of the method was further improved by confirmation of oxazolidine derivative of p-synephrine by GC-MS.     

Activity antifungal of the essential oils; aqueous and ethanol extracts from Citrus aurantium L.

Our study is about the essential oil of Citrus aurantium L. in Tunisia and its plant extract. The yield of this essential oil is 0, 56% but the yield of the extract of plant was 17.1% for the aqueous extract ant 18.3% for the ethanolic extract. The analysis of chemical composition by using GC and GC/MS showed the essential oil of C. aurantium L. species to be rich in monoterpenes such as α-terpineol, lianolyl acetate, linalool and limonene. The antifungal activity of this oil showed us an inhibition of the germination of mushrooms, in the same way we could note that the biologic activities are generally assigned to the chemotypes high content in oxygenated monoterpene.     

A Green Extraction Method to Achieve the Highest Yield of Limonin and Hesperidin from Lime Peel Powder (Citrus aurantifolia)

Green extraction is aimed at reducing energy consumption by using renewable plant sources and environmentally friendly bio-solvents. Lime (Citrus aurantifolia) is a rich source of flavonoids (e.g., hesperidin) and limonoids (e.g., limonin). Manufacturing of lime products (e.g., lime juice) yields a considerable amount of lime peel as food waste that should be comprehensively exploited. The aim of this study was to develop a green and simple extraction method to acquire the highest yield of both limonin and hesperidin from the lime peel. The study method included ethanolic-aqueous extraction and variable factors, i.e., ethanol concentrations, pH values of solvent, and extraction temperature. The response surface methodology was used to optimize extraction conditions. The concentrations of limonin and hesperidin were determined by using UHPLC-MS/MS. Results showed that the yields of limonin and hesperidin significantly depended on ethanol concentrations and extraction temperature, while pH value had the least effect. The optimal extraction condition with the highest amounts of limonin and hesperidin was 80% ethanol at pH 7, 50 °C, which yields 2.072 and 3.353 mg/g of limonin and hesperidin, respectively. This study illustrates a green extraction process using food waste, e.g., lime peel, as an energy-saving source and ethanol as a bio-solvent to achieve the highest amount of double bioactive compounds.     

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.     

Optimum extraction Process of polyphenols from the bark of Phyllanthus emblica L. based on the response surface methodology

Phyllanthus emblica L. is an economic plant used in Chinese medicine for the treatment of various diseases. The bark of P. emblica is rich in polyphenols and its extractions have shown strong antioxidative and radical scavenging activity. Response surface methodology (RSM) was used to assess the optimal extraction of polyphenols from P. emblica bark. Various extraction parameters including ethanol concentration, extraction time, temperature, solid–liquid ratio, and extraction times were chosen to identify their effects on polyphenols extraction. Among these parameters, extraction times and solvent concentration were found to have significant effect on polyphenols extraction. RSM was applied to obtain the optimal combination of solvent concentration, extraction time, temperature, and extraction time for maximum rate of extraction. The most suitable condition for the extraction of polyphenols was at ethanol concentration 75%, extraction time 25 min, extraction temperature 45°C, and extraction times 3. At these optimal extraction parameters, the maximum extraction of polyphenols obtained experimentally was found to be very close to its predicted value. The extraction rate of polyphenols was 19.78% at the optimum conditions. The mathematical model developed was found to fit with the experimental data of polyphenols extraction.     

Enrichment of flavonoid-rich extract from Bidens bipinnata L. by macroporous resin using response surface methodology,UHPLC–Q-TOF MS/MS-assisted characterization and comprehensive evaluation of its bioactivities by analytical hierarchy process

The extract of Bidens bipinnata L. exhibited wide spectrum of bioactivities owing to the presence of flavonoids. In this study, a purification process was developed to enrich the flavonoid-rich extract from B. bipinnata L. (BBTF). AB-8 resin was selected for the purification of total flavonoids. Response surface methodology coupled with Box–Behnken design was employed to optimize the purification condition; it was optimized as pH 5.1, volume of ethanol 80 ml, flow rate of ethanol 1.8 bed volume per hour (BV/h) and concentration of ethanol 76.0%. The total flavonoid content of BBTF was 56.48% under the optimal conditions. The identification of flavonoids in BBTF was conducted using UHPLC–ESI-Q-TOF MS. A total of 14 compounds, including 12 flavonoids, were identified in BBTF. Finally, the in vitro antioxidant activities, α-glucosidase and α-amylase inhibitory activities of BBTF were comprehensively analyzed by an analytical hierarchy process. The results indicated that it exhibited higher bioactivities than the crude extract. These findings suggested that the optimized process could significantly enhance the purity of flavonoids and their bioactivities. This study showed a comprehensive analysis of a total flavonoid extract of B. bipinnata L. for the first time, which could provide a useful approach for its purification process and quality control as well as bioactivities.     

Optimization of Flavonoid Extraction from Xanthoceras sorbifolia Bunge Flowers,and the Antioxidant and Antibacterial Capacity of the Extract

In the present work, the extraction process of total flavonoids (TFs) from X. sorbifolia flowers by ultrasound-assisted extraction was optimized under the response surface methodology (RSM) on the basis of single-factor experiments. The optimal extraction conditions were as follows: ethanol concentration of 80%, solid–liquid ratio of 1:37 (g/mL), temperature of 84 °C, and extraction time of 1 h. Under the optimized conditions, the extraction yield of the TFs was 3.956 ± 0.04%. The radical scavenging capacities of TFs against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) were much greater than that of rutin. The results of antibacterial experiments indicated that the TFs displayed strong inhibitory activities on E. coli, S. aureus and Bacillus subtilis. Therefore, X. sorbifolia flowers can be used as a novel source of natural flavonoids, and the TFs have potential applications as natural antioxidants or antibacterial agents in the food and pharmaceutical industries.     

Citrus aurantium L. Active Constituents,Biological Effects and Extraction Methods. An Updated Review

Citrus genus is a prominent staple crop globally. Long-term breeding and much hybridization engendered a myriad of species, each characterized by a specific metabolism generating different secondary metabolites. Citrus aurantium L., commonly recognized as sour or bitter orange, can exceptionally be distinguished from other Citrus species by unique characteristics. It is a fruit with distinctive flavor, rich in nutrients and phytochemicals which possess different health benefits. This paper presents an overview of the most recent studies done on the matter. It intends to provide an in-depth understanding of the biological activities and medicinal uses of active constituents existing in C. aurantium. Every plant part is first discussed separately with regards to its content in active constituents. All extraction methods, their concepts and yields, used to recover these valuable molecules from their original plant matrix are thoroughly reported.     

Response surface optimized ultrasonic-assisted extraction of flavonoids from Sparganii rhizoma and evaluation of their in vitro antioxidant activities

An efficient ultrasound-assisted extraction technique was employed to extract total flavonoids from Sparganii rhizoma. The optimum extraction conditions for the highest yield of total flavonoids were ethanol concentration 53.62%, ultrasonication time 29.41 min and ultrasound power 300 W, which were determined using response surface methodology. The extraction yields of the optimal ultrasound-assisted extraction were higher than using conventional extraction. The crude extract was then purified on a polyamide resin, whereby the flavonoids content in the purified extract increased to 94.62%. The antioxidant activities of the purified flavonoids including DPPH radical scavenging activity, ABTS+ radical scavenging activity, reducing power, hydroxyl radical scavenging activity and superoxide anion scavenging activity, were evaluated in vitro, which suggested that the flavonoids showed significant antioxidant activities. Rutin, kaempferol and formononetin were identified in the extract by comparing relative retention times and UV-Vis spectra with those of reference standards.     

Efficient approach for the extraction of proanthocyanidins from Cinnamomum longepaniculatum leaves using ultrasonic irradiation and an evaluation of their inhibition activity on digestive enzymes and antioxidant activity in vitro

Proanthocyanidins were separated for the first time from Cinnamomum longepaniculatum leaves. An experiment‐based extraction strategy was used to research the efficiency of an ultrasound‐assisted method for proanthocyanidins extraction. The Plackett–Burman design results revealed that the ultrasonication time, ultrasonic power and liquid/solid ratio were the most significant parameters among the six variables in the extraction process. Upon further optimization of the Box–Behnken design, the optimal conditions were obtained as follows: extraction temperature, 100°C; ethanol concentration, 70%; pH 5; ultrasonication power, 660 W; ultrasonication time, 44 min; liquid/solid ratio, 20 mL/g. Under the obtained conditions, the extraction yield of the proanthocyanidins using the ultrasonic‐assisted method was 7.88 ± 0.21 mg/g, which is higher than that obtained using traditional methods. The phloroglucinolysis products of the proanthocyanidins, including the terminal units and derivatives from the extension units, were tentatively identified using a liquid chromatography with tandem mass spectrometry analysis. Cinnamomum longepaniculatum proanthocyanidins have promising antioxidant and anti‐nutritional properties. In summary, an ultrasound‐assisted method in combination with a response surface experimental design is an efficient methodology for the sufficient isolation of proanthocyanidins from Cinnamomum longepaniculatum leaves, and this method could be used for the separation of other bioactive compounds.     

Fast and non–derivative method based on high–performance liquid chromatography–charged aerosol detection for the determination of fatty acids from Agastache rugosa (Fisch. et Mey.) O. Ktze. seeds

This study utilised response surface methodology to optimise the conditions for the extraction of A. rugosa seeds oil (ARO). Single–factor experiment and response surface methodology (RSM) were performed to identify the extraction time, liquid–solid ratio and extraction temperature that provided the highest yield of ARO. The optimal extraction time, liquid–solid ratio and extraction temperature were 8 h, 4:1 mL/g and 55 °C. The fatty acids (FAs) content and oil yield obtained through the optimised impregnation–extraction process were 19.67 mg/g and 32.1%. These values matched well with the predicted values. Linolenic acid was identified to be the main active ingredient of ARO. The high–performance liquid chromatography–charged aerosol detection method presented here is fast and does not require derivatisation. Therefore, it could be used to quantitatively analyse the FAs present in ARO and applied to detect compounds with low or no ultraviolet response.     

Solid‐phase extraction based on a molecularly imprinted polymer nanoshell at the surface of silica nanospheres for the specific enrichment and identification of alkaloids from Crinum asiaticum L. var. sinicum

A molecularly imprinted nanoshell on the surface of silica nanospheres was prepared for specific enrichment and identification of alkaloids from Crinum asiaticum L. var. sinicum . The nanoshell was synthesized by surface polymerization using lycorine as the template, acrylamide as the functional monomer, ethylene glycol dimethacrylate as the cross‐linker, 2′,2‐azobisisobutyronitrile as the initiator and acetonitrile as the pore‐forming agent. The core–shell nanospheres were characterized by transmission electron microscopy and infrared spectroscopy, and the results show that the nanoshell layer was homogeneously attached to the surface of vinyl‐modified SiO₂ nanospheres. The adsorption capacity of the nanospheres was estimated by binding equilibrium and adsorption kinetics experiments. The maximum adsorption amount of lycorine on the nanospheres was 6.68 μmol/g and the imprinting factor was nearly 2.5, indicating a good imprinting effect. The nanospheres were successfully applied in solid‐phase extraction for lycorine from Crinum asaticum L. var. sinicum and detection of target molecule in rat metabolites. The average recoveries of lycorine in Crinum asaticum L. var. sinicum extraction and rat metabolites were 93.5 ± 0.6% (n = 3) and 91.6 ± 1.9% (n = 3), respectively. This work provides a simple approach for the fabrication of a molecularly imprinted nanoshell at the surface of silica nanospheres‐based solid‐phase extraction for drug analysis.     

Red Orange and Bitter Orange IntegroPectin: Structure and Main Functional Compounds

DRIFT, HPLC-MS, and SPME-GC/MS analyses were used to unveil the structure and the main functional compounds of red (blood) orange (Citrus sinensis) and bitter orange (Citrus aurantium). The IntegroPectin samples show evidence that these new citrus pectins are comprised of pectin rich in RG-I hairy regions functionalized with citrus biophenols, chiefly flavonoids and volatile molecules, mostly terpenes. Remarkably, IntegroPectin from the peel of fresh bitter oranges is the first high methoxyl citrus pectin extracted via hydrodynamic cavitation, whereas the red orange IntegroPectin is a low methoxyl pectin. C. aurantium IntegroPectin has a uniquely high concentration of adsorbed flavonoids, especially the flavanone glycosides hesperidin, naringin, and eriocitrin.     

Enantiomeric Separation of Adrenergic Amines in Citrus Species, Related Genera and Dietary Supplements by Capillary Electrophoresis

Citrus aurantium L. (Rutaceae) fruit extracts have recently been used for weight loss. Among the adrenergic amines the most important active constituent is the sympathomimetic compound synephrine and commercially available extracts are standardized for their content of this active principle. A capillary electrophoresis method was developed for the quantitative and qualitative determination of d-synephrine, l-synephrine, d-octopamine, l-octopamine, tyramine, n-methyl tyramine and hordenine. The electrophoretic separation was performed using a 75 cm × 50 µm ID (66.5 cm effective length) fused silica capillary. The samples were injected by pressure for 5s at 50 mbar and the running voltage was 30 kV at the injector end of the capillary. The method developed was successively applied to the determination of the adrenergic amines in dietary supplements, in various Citrus species including Citrus aurantium, jams and juices. Synephrine was the main component and present in the levels from 0.02–0.17% in various Citrus species and 0.42–69.28 mg in dietary supplements claiming to contain Citrus aurantium. Parameters affecting the resolution between (+) and (−)-enantiomers, such as pH, cyclodextrin concentration, temperature, organic modifier, buffer concentration and capillary dimensions were reported.     

Gas Chromatographic Method for Analysis of p-Synephrine in Citrus aurantium L. Products

A method has been developed and validated for the identification and quantification of p-synephrine in Citrus aurantium L. products. The approach comprises GC-FID analysis followed by GC-MS confirmation after clean-up by solid phase extraction with a strong cation-exchange phase and derivatization with cyclohexanone. Oxazolidine derivative of p-synephrine was subjected to analysis by nuclear magnetic resonance (¹H and ¹³C NMR), GC-FID and GC-MS. The GC method was validated and was found to be linear in the range of 125–500 mg%. Intra-day and inter-day precisions were 3.60 and 3.59%, respectively. Mean recovery from extract of C. aurantium was 78.1 ± 3.64%. The selectivity of the method was further improved by confirmation of oxazolidine derivative of p-synephrine by GC-MS.