Inhibitory mechanisms of promising antimicrobials from plant byproducts: A review.

Plant byproducts and waste present enormous environmental challenges and an opportunity for valorization and industrial application. Due to consumer demands for natural compounds, the evident paucity of novel antimicrobial agents against foodborne pathogens, and the urgent need to improve the arsenal against infectious diseases and antimicrobial resistance (AMR), plant byproduct compounds have attracted significant research interest. Emerging research highlighted their promising antimicrobial activity, yet the inhibitory mechanisms remain largely unexplored. Therefore, this review summarizes the overall research on the antimicrobial activity and inhibitory mechanisms of plant byproduct compounds. A total of 315 natural antimicrobials from plant byproducts, totaling 1338 minimum inhibitory concentrations (MIC) (in µg/mL) against a broad spectrum of bacteria, were identified, and a particular emphasis was given to compounds with high or good antimicrobial activity (typically <100 µg/mL MIC). Moreover, the antimicrobial mechanisms, particularly against bacterial pathogens, were discussed in-depth, summarizing the latest research on using natural compounds to combat pathogenic microorganisms and AMR. Furthermore, safety concerns, relevant legislation, consumer perspective, and current gaps in the valorization of plant byproducts-derived compounds were comprehensively discussed. This comprehensive review covering up-to-date information on antimicrobial activity and mechanisms represents a powerful tool for screening and selecting the most promising plant byproduct compounds and sources for developing novel antimicrobial agents.

Screening and identification of tyrosinase inhibitors in edible plant materials by on-line UPLC-enzyme reactor coupled with UHPLC-FTMS.

Tyrosinase plays a primary role in melanin biosynthesis and enzymatic browning of freshly cut fruits and vegetables. Herein, an on-line ultraperformance liquid chromatography diode array detector biochemical detection (UPLC-DAD-BCD) method was established to identify trace amount potent tyrosinase inhibitors and antibrowning agents in complex mixtures. The tyrosinase inhibition activities of some representative compounds were evaluated by using the established method and their chromatography-activity relationships were obtained. Then the proposed UPLC-DAD-BCD method was applied to screen tyrosinase inhibitors in edible herbal extracts and identified two tyrosinase inhibitors in green tea and three in cinnamon. The above active ingredients were determined by ultra-high-performance liquid chromatography linear ion trap/orbitrap high resolution mass spectrometry (UHPLC-FTMS). The on-line UPLC-DAD-BCD in combination with UHPLC-FTMS was confirmed to be a powerful technique to screen and elucidate the active ingredients in complex matrixes and could be applied to evaluate the integrated effects of multiple ingredients against corresponding targets.

Challenges of pectic polysaccharides as a prebiotic from the perspective of fermentation characteristics and anti-colitis activity.

Several studies are described that contribute to the systematic exploration of new aspects of digestion, fermentation, and biological activities of pectic polysaccharides (PPS) leading to a better understanding of prebiotics. Inflammatory bowel disease (IBD) is thought to be associated with the dysbacteriosis induced by different environmental agents in genetically susceptible persons. PPS are considered as an indispensable gut-microbiota-accessible carbohydrate that play a dominant role in maintaining gut microbiota balance and show a better effect in ameliorating IBD than some traditional prebiotics. The aim of this review is to summarize the fermentation characteristics of PPS, highlight its role in improving IBD, and propose a view that PPS may be a new and effective prebiotic.

Dietary pectic substances enhance gut health by its polycomponent: A review.

Pectic substances, one of the cell wall polysaccharides, exist widespread in vegetables and fruits. A surge of recent research has revealed that pectic substances can inhibit gut inflammation and relieve inflammatory bowel disease symptoms. However, physiological functions of pectins are strongly structure dependent. Pectic substances are essentially heteropolysaccharides composed of homogalacturonan and rhamnogalacturonan backbones substituted by various neutral sugar sidechains. Subtle changes in the architecture of pectic substances may remarkably influence the nutritional function of gut microbiota and the host homeostasis of immune system. In this context, developing a structure-function understanding of how pectic substances have an impact on an inflammatory bowel is of primary importance for diet therapy and new drugs. Therefore, the present review has summarized the polycomponent nature of pectic substances, the activities of different pectic polymers, the effects of molecular characteristics and the underlying mechanisms of pectic substances. The immunomodulated property of pectic substances depends on not only the chemical composition but also the physical structure characteristics, such as molecular weight (Mw ) and chain conformation. The potential mechanisms by which pectic substances exert their protective effects are mainly reversing the disordered gut microbiota, regulating immune cells, enhancing barrier function, and inhibiting pathogen adhesion. The manipulation of pectic substances on gut health is sophisticated, and the link between structural specificity of pectins and selective regulation needs further exploration.

Manothermosonication (MTS) treatment by a continuous-flow system: Effects on the degradation kinetics and microstructural characteristics of citrus pectin.

Modified pectin (MP) was reported to have increased bioactivities compared with the original one. However, traditional modification methods such as using an acidic solvent with heating are not only costly but causing severe pollution as well. In this study, manothermosonication (MTS) with a continuous-flow system was utilized to modify citrus pectin. The citrus pectin (5 g/L) treated by MTS (3.23 W/mL, 400 kPa, 45 °C) exhibited lower molecular weight (Mw, 248.17 kDa) and PDI (2.76). The pectin treated by MTS (400 KPa, 45 °C, 5 min) exhibited a narrower Mw distribution and lowered more Mw (48.8%) than the ultrasound(US)-treated (23.8%). Pectin degradation data fitted well to kinetic model of 1/Mwt -1/Mw0 = kt (45-65 °C). A lower activation energy of 13.33 kJ/mol was observed in the MTS treatment compared with the US-treated (16.38 kJ/mol). The MTS-treated pectin lowered the degree of methoxylation (DM), mol% of rhamnose and galacturonic acid (GalA) while increased mol% of galactose (Gal), xylose (Xyl), and arabinose (Ara). The 1H and 13C nuclear magnetic resonance showed that MTS could not alter the primary structures of citrus pectin. However, an elevated (Gal + Ara)/Rha and reduced GalA/(Rha + Ara + Gal + Xyl) molar ratios after MTS suggested that MTS resulted in more significant degradation on the main chains and less on the side chains of pectin, in agreement with the result of atomic force microscope. Moreover, the MTS-treated pectin exhibited a higher 1,1-diphenyl-2picryl hydrazyl radical scavenging capacity compared with original pectin.

Novel steroidal saponin isolated from Trillium tschonoskii maxim. exhibits anti-oxidative effect via autophagy induction in cellular and Caenorhabditis elegans models.

BACKGROUND: Emerging evidences indicate the important roles of autophagy in anti-oxidative stress, which is closely associated with cancer, aging and neurodegeneration. OBJECTIVE: In the current study, we aimed to identify autophagy inducers with potent anti-oxidative effect from traditional Chinese medicines (TCMs) in PC-12 cells and C. elegans. METHODS: The autophagy inducers were extensively screened in our herbal extracts library by using the stable RFP-GFP-LC3 U87 cells. The components with autophagic induction effect in Trillium tschonoskii Maxim. (TTM) was isolated and identified by using the autophagic activity-guided column chromatography and Pre-HPLC technologies, and MS and NMR spectroscopic analysis, respectively. The anti-oxidative effect of the isolated autophagy inducers was evaluated in H2O2-induced PC-12 cells and C. elegans models by measuring the viability of PC-12 cells and C. elegans, with quantitation on the ROS level in vitro and in vivo using H2DCFDA probe. RESULTS: The total ethanol extract of TTM was found to significantly increase the formation of GFP-LC3 puncta in stable RFP-GFP-LC3 U87 cells. One novel steroidal saponin 1-O-[2,3,4-tri-O-acetyl-α-L-rhamnopyranosyl-(1→2)-4-O-acetyl-α-L-arabinopyranosyl]-21-Deoxytrillenogenin, (Deoxytrillenoside CA, DTCA) and one known steroidal saponin 1-O-[2,3,4-tri-O-acetyl-α-L-rhamnopyranosyl-(1→2)-4-O-acetyl-α-L-arabinopyranosyl]-21-O-acetyl-epitrillenogenin (Epitrillenoside CA, ETCA) were isolated, identified and found to have novel autophagic effect. Both DTCA and ETCA could activate autophagy in PC-12 cells via the AMPK/mTOR/p70S6K signaling pathway in an Atg7-dependent. In addition, DTCA and ETCA could increase the cell viability and decrease the intracellular ROS level in H2O2-treated PC-12 cells and C. elegans, and the further study demonstrated that the induced autophagy contributes to their anti-oxidative effect. CONCLUSION: Our current findings not only provide information on the discovery of novel autophagy activators from TTM, but also confirmed the anti-oxidative effect of the components from TTM both in vitro and in vivo.

Pectic oligosaccharides hydrolyzed from citrus canning processing water by Fenton reaction and their antiproliferation potentials.

Citrus canning processing water contains a valuable and renewable source of biopolymers and bioactive compounds including pectic polysaccharides. Upgrading these processing wastes can not only alleviate environmental pollution but also add value to the commodity's production. In a previous study we recovered pectic polysaccharides from citrus canning processing water. In the present study, pectic polysaccharides recycled from citrus canning processing water was depolymerized by an optimized Fenton system. The hydrolyzate was fractionated via size-exclusion chromatography into six fractions: 500 Da < LMP1 < 3 kDa; 3 kDa < LMP2 < 5 kDa; 5 kDa < LMP3 < 12 kDa; 12 kDa < LMP4 < 25 kDa; 25 kDa < LMP5 < 100 kDa and LMP6 > 10 wDa. Structure analyses showed that LMP1 were homogalacturonans-enriched non-esterified polysaccharides. While LMP2 contained both HG and rhamnogalacturonan-I (RG-I). Further antitumor assay showed that in comparison with the native pectic polysaccharide with moderate antitumor activity, both LMP1 and LMP2 possessed significant antitumor activity, while the inhibitory effect of LMP1 was higher than that of LMP2, suggesting that the biological properties of LMPs was influenced by structural characteristics, including molecular weight and monosaccharide composition.

Co-Encapsulation of EGCG and Quercetin in Liposomes for Optimum Antioxidant Activity.

Although different delivery systems have been developed to overcome the limits of Epigallocatechin-3-gallate (EGCG) and quercetin in food application, none have referred to their simultaneous encapsulation. In this study, these two polyphenols were successfully co-loaded into liposomes. Under the optimal conditions (lecithin-total polyphenols ratio 25:1, lecithin-cholesterol ratio 6:1, lecithin-Tween 80 ratio 8:1 and ultrasonic time 2 min), the mean size, polydispersity index (PDI) and zeta potential of liposomes were 111.10 ± 0.52 nm, 0.259 ± 0.006 and -19.83 ± 0.45 mV, with an encapsulation efficiency of 64.05 ± 1.56% and 61.73 ± 2.55% for EGCG and quercetin, respectively. After 30-day storage, an increase of 4.05% was observed in the mean size with no significant change (P ≥ 0.05) in the PDI and zeta potential. Moreover, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay revealed a synergistic antioxidant effect of the two compounds in liposomal system. These results demonstrated that co-encapsulation of EGCG and quercetin enhances their effectiveness. PRACTICAL APPLICATION: EGCG and quercetin are natural polyphenols abound in the human diet with diverse biological activities. These two polyphenols were successfully co-encapsulated into a homogeneous and stable liposomal system. Interestingly, a synergistic antioxidant effect of the two polyphenols was observed due to co-encapsulation. This indicated that the simultaneous delivery of EGCG and quercetin was an attractive approach to improve their functionality for expanding their application in food, cosmetic and pharmaceutical industries.

Novel antibacterial modalities against methicillin resistant Staphylococcus aureus derived from plants.

Methicillin-resistant Staphylococcus aureus (MRSA) is a notorious bacterial pathogen that induces high mortality and morbidity. Due to the emergence of multiple resistance, antibiotic treatments are rapidly becoming ineffective for the related infections. Natural products, especially those derived from plants, have been proven to be effective agents with unique antibacterial properties through different mechanisms. This review interprets the resistance mechanisms of MRSA with the aim to conquer public health threat. Further, recent researches about plant antimicrobials that showed remarkable antibacterial activity against MRSA are recorded, including the crude plant extracts and purified plant-derived bioactive compounds. Novel anti-MRSA modalities of plant antimicrobials such as alteration in efflux pump, inhibition of pyruvate kinase, and disturbance of quorum sensing in MRSA are also summarized which may be promising alternatives to antibacterial drug development in future.

Acoustic cavitation assisted extraction of pectin from waste grapefruit peels: A green two-stage approach and its general mechanism.

In the present study, acoustic cavitation assisted extraction (ACAE) which is a green approach was used for two-stage extraction of pectin from waste grapefruit peels regarding the specific two stages and different peel particle sizes. The yields, physicochemical properties and structure prediction of pectin from different peel particle sizes and different stages by two methods were compared. Highest pectin yield of 23.49% was achieved at the peel size of 0.9mm and was slightly higher than the yield of 23.44% at finer particle size. ACAE achieved four times higher yield compared with conventional heating method (CHE) at the second stage. ACAE pectin which had lower molecular weight and degree of methoxylation was richer in rhamnogalacturonan-I (RG-I) region with long side chains compared with CHE pectin from chemical and FT-IR analysis. Based on the results, a potential general mechanism for ACAE of plant cell wall viscous polysaccharides was discussed in terms of the effects of cavitation on the swelling index and morphological study of residue to reveal the "barrier effect" during the process. Furthermore, the energy consumption for ACAE was significantly lower than the conventional method, indicating its promising application in industrial scale.

Degradation kinetics and structural characteristics of pectin under simultaneous sonochemical-enzymatic functions.

This study investigated the degradation kinetics and structural properties of pectin with combining ultrasound and pectinase treatment. Ultrasound at an intensity of 4.5WmL(-1) and a time of 10min significantly enhanced the enzymatic degradation of pectin weight-average molecular weight (Mw). The degradation kinetics model of pectin followed 1/Mwt-1/Mw0=kt, suggesting the randomness of the degradation process. Synergistic effects of ultrasound and pectinase were observed at 20-60°C and were more effective at lower temperatures. Furthermore, the degree of methoxylation (DM) of sonoenzymolysis pectin significantly decreased whereas the degree of acetylation (DAc) remained unchanged compared to the original and enzymolysis pectin. Simultaneous functions of ultrasound and pectinase caused severe decomposition in pectin homogalacturonan (HG) regions without altering the monosaccharides types, configurations and glycoside linkages of the pectin samples. The complex polymeric structures of pectin transformed into smaller units with simpler branches and shorter chains after sonoenzymolysis reactions.

Multiple on-line HPLC coupled with biochemical detection methods to evaluate bioactive compounds in Danshen injection.

On-line high performance liquid chromatography (HPLC) coupled with three biochemical detection (BCD) methods was applied to evaluate bioactive components in Danshen injection. On-line HPLC-photo-diode array-fluorescence detection based on the fluorogenic substrate 7-acetoxy-1-methyl quinolinium iodide, was built to search acetylcholinesterase (AChE) inhibitors in Danshen injection. On-line HPLC coupled with the scavenging assay of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radicals was developed to screen antioxidants. The three active profiles were obviously different. Radical scavenging profiles revealed seven strong peaks in the chromatographic fingerprint possessing obvious free radical inhibition effects, while some minor peaks exhibited stronger AChE inhibition activities. The main radical scavengers and AChE inhibitors were identified by HPLC-MS. Several unknown ingredients showing strong AChE inhibition activities needed further identification except protocatechuic aldehydrate, salvianolic acid H or I and lithospermic acid. The on-line multiple on-line HPLC-BCD methods will provide powerful tools in the field of pharmacognosy for fast-track identification of interesting and/or novel bioactive compounds.

[Introduction trial of medicine mulberry (Morus nigra) in Chongqing].

Medicine mulberry (Morus nigra) mainly distributed in southern areas of Xinjiang Uighur Autonomous Region and introduced by grafting, is a unique Morus species, whose plant number is little. As a traditional herbal medicine, medicine mulberry with high levels of secondary metabolites has important values of scientific research and utilization. In order to solve the introduction problems for medicine mulberry, we have established its rapid propagation system through tissue culture since 2011. The shoots of medicine mulberry through tissue culture were transplanted into the field to carry out an introduction experiment. Here, we firstly reported that the growth status and pest and disease occurrence of medicine mulberry in the field of Chongqing and found that the medicine mulberry through tissue culture had well-developed root system, it showed better growth than medicine mulberry by grafting technique, and Pseudodendrothrips moil was a major pest of medicine mulberry. The introduction technique for medicine mulberry established successfully in this study could lay the foundation for large-scale cultivation and high efficiency utilization of medicine mulberry.

Ultrasound-assisted heating extraction of pectin from grapefruit peel: optimization and comparison with the conventional method.

The extraction of pectin from grapefruit peel by ultrasound-assisted heating extraction (UAHE) was investigated using response surface methodology and compared with the conventional heating extraction (CHE). The optimized conditions were power intensity of 12.56 W/cm(2), extraction temperature of 66.71°C, and sonication time of 27.95 min. The experimental optimized yield was 27.34%, which was well matched with the predicted value (27.46%). Compared with CHE, UAHE provided higher yield increased by 16.34% at the temperature lowered by 13.3°C and the time shortened by 37.78%. Image studies showed that pectin extracted by UAHE showed better color and more loosen microstructure compared to that extracted by CHE, although Fourier Transform Infrared Analysis indicated insignificant difference in their chemical structures. Furthermore, UAHE pectin possessed lower viscosity, molecular weight and degree of esterification, but higher degree of branching and purity than CHE pectin, indicating that the former was preliminarily modified during the extraction process.

Observation and Thinking of Diseased Tongue amongShanghuo(Heatiness) People / 世界科学技术-中医药现代化

This study was aimed to discuss the diagnosis significance of the diseased tongue demonstration in Shanghuo (heatiness) people. Based on 303Shanghuo cases, the relevance of diseased tongue demonstration and inquiry data were analyzed. The results showed that 53.14%Shanghuo cases had at least more than 2Shanghuo inducing causes. The most common inducing cause combinations were pathogenic factors neither endogenous nor exogenous (unbalanced diet, overworked) and internal factors (over stressed, emotional). When there were several Shanghuo causes occurred at the same time, the probability of appearing diseased tongue demonstration increased significantly. There were 29.95%Shanghuo cases occurredShanghuo experience frequently. And in these cases, the probability of appearing diseased tongue demonstration increased significantly. It was concluded that when Shanghuo people had diseased tongue demonstration appeared, it was not merely just“is going to get ill”, but was already suffering from heat syndrome. In traditional Chinese medicine (TCM) physical examination, to effectively differentiate“is going to get ill” and“being ill” was initially important. And the diseased tongue demonstration was a crucial diagnostic basis.

"Study on Congenital Constitution Terms Consist of ""Bing"" Before Qing Dynasty" / 世界科学技术-中医药现代化

This study was aimed to investigate the congenital constitution terms consist of Bing and connotation in medical books before Qing dynasty. By searching the character Bing as a keyword in the Encyclopedia of Tradi-tional Chinese Medicine (TCM), 6480 articles were retrieved. Through reading each of the articles, 9 congenital con-stitution terms were concluded. The results showed that Sui dynasty recorded the earliest congenital constitution term. And till the end of Ming dynasty, altogether 9 terms, which were Bing Qi, Bing Zhi, Bing Shou, Bing Fu, Suo Bing, Fu Bing, Qi Bing, Bing Ti and Su Bing, appeared in sequence. The terms appeared with high frequency were Bing Shou ( 33 . 27%) and Bing Fu ( 32 . 99%) . There were 5 congenital constitution relat-ed factors altogether , which were physique , parental heredity , life span , qi and blood as well as region , ap-peared in sequence . And the term appeared with high frequency was physique ( 32.11%) . It was concluded that before Qing dynasty, all congenital constitution terms occurred with the character of Bing (endowment). The usage of different terms to state congenital constitution was intended to describe different associated factors . It reflected the understanding of congenital constitution process. The first known congenital constitution factor was not parental heredity but physique . Qi and blood was the second most appeared factor . This indicated that con-genital constitution does not only involve the structure of the body ( physique ) , but also the function of the body (qi and blood). The investigation about congenital constitution of ancient TCM brings a positive practical signifi-cance for the modern health cognition and health maintenance .

Study on Congenital Constitution Components in Medical Books before Qing Dynasty / 世界科学技术-中医药现代化

This study was aimed to discuss the connotation of congenital constitution in medical books before Qing dynasty. By searching the character Bing as a keyword in the Encyclopedia of Traditional Chinese Medicine (TCM), 6 480 articles were retrieved. Through reading each of the articles, 9 congenital constitution terms were con-cluded. A total of 1 041 valid entries involved in 165 medical books were retrieved. The results showed that congen-ital constitution was affected by parent heredity and region factors. Parent heredity factor includes the influence of both parents and the influence of mother during pregnancy where the influence of both parents includes both parents' habits and conditions when having sex; the influence from the mother includes habits and medication during her pregnancy. Congenital constitution embodiment includes the body's growth and development, body structure and vis-cera, qi and blood, pulse and forefinger blood vessels (of young children), mental state and life span. In three other factors of congenital constitution (i.e. qi and blood, body structure and life span), both body structure and life span depend on the endowment of qi and blood. It was concluded that TCM practitioners before Qing dynasty judged one's congenital constitution through observing the speed of its growth and development, appearance, mental state, strength of visceral functions, condition of its mind, forefinger blood vessels, pulse, susceptible to types of disease and etc. Therefore, body structure is an important factor of congenital constitution judgment. TCM practitioners before Qing dynasty paid attention to the effect on mother to her offspring's health.

Ultrasound effects on the degradation kinetics, structure and rheological properties of apple pectin.

The effects of ultrasound on the molecular weight of apple pectin were investigated. The structure and rheological properties of the degradation products were also tentatively identified by High Performance Liquid Chromatography-Photodiode Array Detector (HPLC-PAD), Infrared spectroscopy (IR), Nuclear Magnetic Resonance spectroscopy (NMR) and Rheometer. The results indicated that the weight-average molecular weight of apple pectin decreased obviously after ultrasound treatment. The molecular weight of degradation products had a uniform and narrow distribution. Ultrasound intensity and temperature play an important role in the degradation reaction. Degradation kinetics model of apple pectin fitted to 1/M(t) - 1/M(0) = kt from 5 to 45 °C. The degree of methylation of apple pectin reduced according to IR analysis when ultrasound was applied. Ultrasound treatment could not alter the primary structure of apple pectin according to the results determined by HPLC, IR and NMR. Meanwhile, the viscosity of apple pectin was 10(3) times as large as that of ultrasound-treated apple pectin. The ultrasound-treated apple pectin showed predominantly viscous responses (G' < G") over the same frequency range. The results suggested that ultrasound provided a viable alternative method for the modification of pectin.