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A novel extraction method, homogenate-assisted negative pressure cavitation extraction (HNPCE), was designed for the extraction and determination of the main phenolic compounds of Pyrola incarnata Fisch. by LC-MS/MS. The particle sizes and extraction yields in the process of homogenization were compared with conventional pulverization. The results showed that homogenization for less than 120 s could produce more suitable particle size powders for analyte extraction. The following NPCE parameters were optimized by a BBD test and under the optimal conditions, the maximum extraction yields of arbutin, epicatechin, hyperin, 2'-O-galloylhyperin and chimaphilin increased by 68.7%, 72.0%, 43.3%, 62.5% and 34.5% with respect to normal NPCE. The LC-MS/MS method was successfully applied for the quantification of five target compounds in pyrola, and the results of the precision test indicated a high accuracy of the present method for the quantification of the target compounds in pyrola. Furthermore, the antioxidant activities of the pyrola extracts were also determined. The results showed that pyrola had good antioxidant activities and it was a valuable antioxidant natural source.

A novel negative pressure and microwave assisted extraction technique (NMAE) was first proposed and applied for extraction of phenolic compounds from pyrola. [C₄MIM]BF₄ aqueous solution was selected as extraction solvent. Optimal extraction conditions were microwave power 700 W, negative pressure -0.07 MPa, temperature 40 °C, liquid-solid ratio 20 : 1, ionic liquid (IL) concentration 0.5 M, extraction time 15 min. The predominance of NMAE was investigated by comparing with microwave-assisted extraction (MAE) and negative pressure cavitation extraction (NPCE) using a first-order kinetics equation. The C∞ values of the target compounds by NMAE were from 0.406 to 5.977 mg g⁻¹ higher than these by MAE and NPCE, which indicated that NMAE had higher extraction yields. The K values of NMAE were also the highest; it was testified that the target compounds could be transferred from matrix into solvent much more effectively by NMAE than by MAE and NPCE. In addition, the NMAE method was validated in terms of repeatability and reproducibility, the relative standard deviation for relative recovery was lower than 5.43 and 8.78%, respectively. Therefore, NMAE was a developed extraction technique for analytical sample preparation. The RP-HPLC-UV method was also successfully applied for the quantification of six target compounds in pyrola.

Guangdong, Guangxi and Chongqing are emerging sericulture areas in China where the production of mulberry leaves is huge. In order to identity high quality mulberry leaves that are suitable for healthy products to expand planting, 24 samples from three regions (Guangdong, Guangxi, Chongqing) in the south of China were quantified for two alkaloids (1-deoxynojirimycin and fagomine) and five phenols (chlorogenic acid, rutin, isoquercitrin, etc.) using high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). Additionally, the total phenolic and total flavonoid contents, antioxidant and glycosidase inhibitory activities (hypoglycemic activity) were tested using different assays (DPPH, ABTS, FRAP) to comprehensively evaluate the quality of the mulberry leaves. The contents of DNJ and fagomine ranged from 0.401±0.003 to 5.309±0.036 mg/g and from 0.279±0.031 to 2.300±0.060 mg/g, respectively. The main phenolic constituents were chlorogenic acid, rutin and isoquercitrin, with chlorogenic acid present in the highest concentrations, ranging from 3.104±0.191 to 10.050±0.143 mg/g. The antioxidant activity exhibited a tendency as follows: Guangxi > Guangdong > Chongqing, except for two samples from Chongqing, which showed the highest antioxidant activity. Based on our study, mulberry leaves from Guangdong and Guangxi could be future sources of natural hypoglycemic and antioxidant products. [ABSTRACT FROM AUTHOR]

A group of green solvent named polyols-based deep eutectic solvents (PDES) combined with microwave assisted extraction (MAE) was first successfully applied in extracting phenolic compounds from pyrola. A series of PDES with mixing different ratios choline chloride (ChCl) to different polyols were investigated for extraction, and ChCl/1,4-Butanediol (1/4) was found to be the suitable extraction solvent. MAE was more effective than heat-stirring extraction and ultrasonic assisted extraction with PDES. The extraction parameters were optimized by BBD test combined with response surface methodology. The optimal extraction conditions were 30% of water in ChCl/1,4-Butanediol (1/4) at 70 °C for 20 min and liquid/solid ratio 10 mL/g. Moreover, RP-HPLC-UV was developed for the determination of five main active components in pyrola. This method exhibited satisfactory linearity ( R 2 > 0.999), precision (RSD < 4.03%) and recovery (96.17–103.25%). Sample analysis showed that the contents of hyperin, 2′-O-galloylhyperin, quercitrin, quercetin-O-rhamnoside and chimaphilin in pyrola were 1.627, 4.958, 0.041, 0.089 and 0.349 mg/g, respectively. These results revealed that PDES would be promising green solvents for analytical sample preparation from plant herbs. [ABSTRACT FROM AUTHOR]

In this study, a deep eutectic solvent based microwave assisted extraction (DES-MAE) method was developed. This method was used for the extraction of five target phenolic acids, namely chlorogenic acid, caffeic acid, 3,5-dicaffeoylquinic acid, 3,4-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid from Lonicerae japonicae Flos. Twelve kinds of aqueous deep eutectic solvents were investigated. The results indicated that deep eutectic solvents (DESs) showed remarkable effects on the extraction efficiency of phenolic acids. In addition, the parameters of DES-MAE, including concentration of water in DES, liquid/solid ratio, extraction temperature, and extraction time were optimized. The proposed approach was evaluated by comparison with the conventional heat-reflux extraction (HRE) and ultrasound assisted extraction (UAE). Finally, the recovery of active compounds from DES was also investigated. Recovery rates of chlorogenic acid, caffeic acid, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid reached 79.25%, 80.03%, 85.96%, 86.01% and 85.52%, respectively. [ABSTRACT FROM AUTHOR]

Disinfecting microbially contaminated water in a safe and sustainable way is a great challenge. The phenolics and flavonoids in plants are ideal antibacterial agents for biosafety. Herein, an all-plant-derived antibacterial sponge with a hierarchical cellular structure was prepared from natural phenolic and flavonoid crude extracts and cellulose for water purification. After being modified by quercetin, the quercetin-cellulose sponge (Q-CS) exhibits great toughness, elasticity and a large specific surface area, which benefited from a unique hierarchical cellular structure. Q-CS shows ultrahigh water flux (4.5 × 105 L·m−2·h−1·bar−1) and excellent antibacterial abilities against Escherichia coli and Staphylococcus aureus (<1.87 % viability). Sponges modified with crude pyrola (P-CS) and mulberry leaf extracts (M-CS) have similar properties compared with Q-CS. The good performances of P-CS and M-CS show the strong antibacterial applications of natural crude extract. This work provides a strategy for fabricating sustainable and safe antibacterial sponges for water disinfection. [Display omitted] • An all-plant-derived hierarchical cellular cellulose sponge is fabricated. • The sponge is tough, elastic and stable because of hierarchical cellular structure. • Phenolics and flavonoids are grafted on cellulose as antibacterial agent. • The sponge shows ultrahigh water flux under 1 bar driving pressure. • The modified sponge has great stable water disinfection ability. [ABSTRACT FROM AUTHOR]