The direct effect of lipopolysaccharide on an isolated heart is different from the effect on cardiac myocytes in vitro.

Introduction: Lipopolysaccharide (LPS) is widely used to induce experimental animals. However, its effects on cardiac contraction is controversial. Although LPS probably induces its influence in vivo both directly and indirectly, we focused on the direct effects of LPS in this report. Material and methods: Isolated ventricular myocytes mounted on a Langendorff apparatus were perfused with LPS. The changes in cultured H9c2 cells incubated with LPS over a 3-h exposure were compared with the changes after a 24-h incubation. Apoptosis was identified using flow cytometry and Western blotting. The mRNA levels were also determined. Results: LPS directly stimulated cardiac contractility at low doses, although it produced inhibition at higher doses. The TLR4-coupled JAK2/STAT3 pathway was identified in H9c2 cells after LPS treatment, with an increase in intracellular calcium levels. LPS dose-dependently activated hypertrophic signals in H9c2 cells and induced apoptosis at the high dose. However, apoptosis was observed in H9c2 cells after a 24-h exposure to LPS, even at low doses. This observation appears to be associated with the level of paracrine cytokines. Changes in H9c2 cells by LPS were diminished by NPS2390, an inhibitor of the calcium-sensing receptor (CaSR). LPS also promoted CaSR mRNA expression in H9c2 cells, which may be unrelated to the changes in cytokine expression influenced by an inflammasome inhibitor. Conclusions: In contrast to the isolated hearts, LPS activated hypertrophic signals prior to apoptotic signals in cardiac cells. Thus, LPS injury appears to be associated with CaSR, which was not markedly influenced by an inflammasome inhibitor.

The isolation, structural characterization, and anticancer activity from the aerial parts of Cymbopogon flexuosus.

This study investigated bioactive secondary metabolites from the aerial parts of Cymbopogon flexuosus (CF). Total phenolic and total flavonoid contents, the antioxidant activities including 2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS+ ) and 2, 2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging systems, and cytotoxic effects were determined. 1, 3-O-di-E-caffeoylglycerol (SA3) and 1-O-p-coumaroyl-3-O-caffeoylglycerol (SA4) were firstly isolated from an ethanol extract of CF. Their chemical structures were elucidated by extensive spectroscopic analyses, including MS and NMR spectra as well as by comparison to the data reported in the literature. DPPH and ABTS+ radical scavenging tests showed that the highest antioxidant potent was detected for compound SA3 with IC50 of 4.42 ± 0.18 and 21.84 ± 0.22 µg/ml, respectively. The compound SA3 stimulated the apoptotic factors of caspase-3, bax, and bcl-2 in HepG2 and caspase-3, caspase-9, P53 in A549. PRACTICAL APPLICATIONS: CF has been widely used as both a herbal drink and as a spice in diets. In the food processing industry, CF was used to process candy. In addition, it is used for the treatment of sore throat, cough, skin diseases, and other diseases in traditional oriental medicine. Recently, in Vietnam, CF has also been used to treat liver and lung cancer and consumed daily to process many dishes.

Safety and tolerability of prescription omega-3 fatty acids: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Omega-3 fatty acids [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] are widely recommended for health promotion. Over the last decade, prescription omega-3 fatty acid products (RxOME3FAs) have been approved for medical indications. Nonetheless, there is no comprehensive analysis of safety and tolerability of RxOME3FAs so far. METHODS: A systematic review of randomized controlled trials (RCTs) was carried out based on searches in six electronic databases. The studies involving marketed RxOME3FA products were included, and adverse-effect data were extracted for meta-analysis. Subgroup analysis and meta-regression were conducted to explore the sources of potential heterogeneity. RESULTS: Among the 21 included RCTs (total 24,460 participants; 12,750 from RxOME3FA treatment cohort and 11,710 from control cohort), there was no definite evidence of any RxOME3FA-emerging serious adverse event. Compared with the control group, RxOME3FAs were associated with more treatment-related dysgeusia (fishy taste; p = 0.011) and skin abnormalities (eruption, itching, exanthema, or eczema; p < 0.001). Besides, RxOME3FAs had mild adverse effects upon some non-lipid laboratory measurements [elevated fasting blood sugar (p = 0.005); elevated alanine transaminase (p = 0.022); elevated blood urea nitrogen (p = 0.047); decreased hemoglobin (p = 0.002); decreased hematocrit (p = 0.009)]. Subgroup analysis revealed that EPA/DHA combination products were associated with more treatment-related gastrointestinal adverse events [eructation (belching; p = 0.010); nausea (p = 0.044)] and low-density lipoprotein cholesterol elevation (p = 0.009; difference in means = 4.106mg/dL). CONCLUSION: RxOME3FAs are generally safe and well tolerated but not free of adverse effects. Post-marketing surveillance and observational studies are still necessary to identify long-term adverse effects and to confirm the safety and tolerability profiles of RxOME3FAs.

The stimulating effects of polyphenol and protein fractions from jelly fig (Ficus awkeotsang Makino) achenes against proliferation of leukemia cells.

This study aimed to investigate the direct and immune-stimulated antiproliferative activities of jelly fig achenes fractions including pectinesterase inhibitors, crude polyphenols extract, and purified polyphenols extract (PP). Beside the measurement of cell viability of U937, the quantity of cytokines in conditioned medium and morphologic changes in leukemia were observed. After surveying all fractions in jelly fig, the obtained fractions of polyphenol exhibited the highest stimulating effects and directly cytotoxic effects against leukemia with the lowest effect found in protein fractions. The leukemia treated by our PP fraction showed dose-dependent response between the concentration and G2/M cell numbers of the U937 cells. The PP fraction had more pronounced effect on immune-stimulated than direct antiproliferative activities. The finding was also supported by morphological analysis by showing the formation of apoptotic bodies and differentiation from immature U937 cells into mature monocytes/macrophages on cells cultured with PP-conditioned medium. In conclusion, polyphenol fraction of pectinesterase inhibitors from jelly fig showed the immune-stimulated antiproliferative activities against U937 cell.

Evaluation of the prebiotic effects of citrus pectin hydrolysate.

Citrus pectin enzyme hydrolysate (PEH) of different hydrolysis time intervals (6 hours, PEH-6; 12 hours, PEH-12; 24 hours, PEH-24; or 48 hours, PEH-48) or concentrations (1%, 2%, and 4%) was tested for its growth stimulation effect on two probiotics, Bifidobacterium bifidum and Lactobacillus acidophilus. Higher monosaccharide concentrations and smaller molecular weights of PEHs were obtained by prolonging the hydrolysis time. In addition, higher PEH concentrations resulted in significantly higher (p < 0.05) probiotic populations, pH reduction, and increase in total titratable acidity than the glucose-free MRS negative control. Furthermore, significantly higher populations in the low pH environment and longer survival time in nonfat milk (p < 0.05) were observed when the two probiotics were incubated in media supplemented with 2% PEH-24, than in glucose and the negative control. In comparison with other prebiotics, addition of 2% PEH-24 resulted in a more significant increase in the probiotic population (p < 0.05) than in the commercial prebiotics. This study demonstrated that PEH derived from citrus pectin could be an effective prebiotic to enhance the growth, fermentation, acid tolerance, and survival in nonfat milk for the tested probiotics.

Diosmin, a Citrus Nutrient, Activates Imidazoline Receptors to Alleviate Blood Glucose and Lipids in Type 1-Like Diabetic Rats.

Diosmin is a nutrient that is widely contained in citrus and that has been indicated to improve glucose metabolism in diabetic disorders. Recently, we demonstrated that diosmin induces ß-endorphin to lower hyperglycemia in diabetic rats. However, the mechanisms of diosmin in opioid secretion were unclear. Therefore, we focused on the secretion of opioids from isolated adrenal glands induced by diosmin. The changes in the released ß-endorphin-like immunoreactivity (BER) were determined using ELISA. Diosmin increased the BER level in a dose-dependent manner, and this effect was markedly reduced in the absence of calcium ions. Activation of the imidazoline I-2 receptor (I-2R) has been introduced to induce opioid secretion. Interestingly, we observed that diosmin activates CHO cells expressing I-R. Additionally, diosmin-increased BER was inhibited by the blockade of I-2R in isolated adrenal glands. Additionally, an antagonist of I-2R blocked diosmin-induced effects, including the reduction in hyperglycemia and the increase in plasma BER in streptozotocin-induced diabetic rats (STZ-diabetic rats). Repeated treatment of STZ-diabetic rats with diosmin for one week induced changes in hepatic glycogen, lipid levels, and the expression of phosphoenolpyruvate carboxykinase (PEPCK). Furthermore, an antagonist of I-2R blocked the diosmin-induced changes. Additionally, plasma lipids modified by diosmin were also reversed by the blockade of I-2R in STZ-diabetic rats. Taken together, we suggest that diosmin may activate I-2R to enhance the secretion of ß-endorphin from adrenal glands and to influence metabolic homeostasis, resulting in alleviation of blood glucose and lipids in STZ-diabetic rats.

Effects of Davallia formosana Hayata Water and Alcohol Extracts on Osteoblastic MC3T3-E1 Cells.

The Taiwanese native fern Davallia formosana Hayata (DFH) is used to treat bone diseases in classical Chinese medicine. We analyzed MC3T3E1 osteoblasts treated with different concentrations of water and ethanol extracts (10, 25, and 50 [both], and 100 µg/mL [DFE only]) using cell viability, expression of osteoblast differentiation markers [bone morphogenetic protein 2 (BMP-2), collagen 1 (CoL-1), alkaline phosphatase (ALP), and Runt-related transcription factor 2 (Runx 2)], and mineralization. These were significantly increased by DFW or DFE after 24-h incubation compared with the untreated controls. Compared with other treatments, DFW 50 and DFE 100 µg/mL significantly increased MC3T3E1 cell survival. DFW 25 and 50 µg/mL increased bone BMP-2, CoL-1, ALP, and Runx2 protein expression, ALP activity, and mineralization more than DFE did. Repeated chromatographic separation of DFW yielded compound (-)-epicatechin-3-O-d-allipyranoside (ECAP), which was characterized using 1 H and 13 C nuclear magnetic resonance spectroscopy. (-)-Epicatechin-3-O-d-allipyranoside (0.01 µg/mL) significantly increased cell survival (118.9%) and mineralization (218.7%) compared with that of the control treatment. We inferred that ECAP could mediate the main activity of DFW in bone formation, likely through BMP-2-induced Runx2 transcription, which increased bone cell differentiation factors ALP and CoL-1 and promoted mineralization. (-)-Epicatechin-3-O-d-allipyranoside could be an anti-osteoporotic agent. Copyright © 2017 John Wiley & Sons, Ltd.

Antihyperglycaemic action of diosmin, a citrus flavonoid, is induced through endogenous ß-endorphin in type I-like diabetic rats.

Diosmin is one of the flavonoids contained in citrus and has been demonstrated to improve glucose metabolism in diabetic disorders. However, the mechanism(s) of diosmin in glucose regulation remain obscure. Therefore, we investigated the potential mechanism(s) for the antihyperglycaemic action of diosmin in streptozotocin-induced diabetic rats (STZ-diabetic rats). Diosmin lowered hyperglycaemia in a dose-dependent manner in STZ-diabetic rats. This action was inhibited by naloxone at a dose sufficient to block opioid receptors. Additionally, we determined the changes in plasma ß-endorphin-like immunoreactivity (BER) using enzyme-linked immunosorbent assay (ELISA). Diosmin also increased BER dose-dependently in the same manner. Repeated treatment of STZ-diabetic rats with diosmin for 1 week resulted in an increase in the expression of the glucose transporter subtype 4 (GLUT 4) in the soleus muscle and a reduction in the expression of phosphoenolpyruvate carboxykinase (PEPCK) in the liver. These effects were also inhibited by naloxone at a dose sufficient to block opioid receptors. Bilateral adrenalectomy in STZ-diabetic rats eliminated the actions of diosmin, including both the reduction in hyperglycemia and the elevation of plasma BER. In conclusion, our results suggest that diosmin may act on the adrenal glands to enhance the secretion of ß-endorphin, which can stimulate the opioid receptors to attenuate hepatic gluconeogenesis and increase glucose uptake in soleus muscle, resulting in reduced hyperglycemia in STZ-diabetic rats.

Ruscogenin protects against high-fat diet-induced nonalcoholic steatohepatitis in hamsters.

The protective effects of ruscogenin on nonalcoholic steatohepatitis in hamsters fed a high-fat diet were investigated. Ruscogenin (0.3, 1.0, or 3.0 mg/kg/day) was orally administered by gavage once daily for eight weeks. A high-fat diet induced increases in plasma levels of total cholesterol, triglycerides, and free fatty acids, while the degree of insulin resistance was lowered by ruscogenin. High-fat diet-induced hepatic steatosis and necroinflammation were improved by ruscogenin. Gene expression of inflammatory cytokines and activity of nuclear transcription factor-κB were also increased in the high-fat diet group, which were attenuted by ruscogenin. Ruscogenin decreased hepatic mRNA levels of sterol regulatory element-binding protein-1c and its lipogenic target genes. The hepatic mRNA expression of peroxisome proliferator-activated receptor α, together with its target genes responsible for fatty acid ß-oxidation were upregulated by ruscogenin. In conclusion, these findings suggest that ruscogenin may attenuate high-fat diet-induced steatohepatitis through anti-inflammatory mechanisms, reducing hepatic lipogenic gene expression, and upregulating proteins in the fatty acid oxidation process.

Assessment of oligogalacturonide from citrus pectin as a potential antibacterial agent against foodborne pathogens.

Foodborne diseases are an important public health problem in the world. The bacterial resistance against presently used antibiotics is becoming a public health issue; hence, the discovery of new antimicrobial agents from natural sources attracts a lot of attention. Antibacterial activities of oligogalacturonide from commercial microbial pectic enzyme (CPE) treated citrus pectin, which exhibits antioxidant and antitumor activities, against 4 foodborne pathogens including Salmonella Typhimurium, Staphylococcus aureus, Listeria monocytogenes, and Pseudomonas aeruginosa was assessed. Pectin hydrolysates from CPE hydrolysis exhibited antibacterial activities. However, no antibacterial activity of pectin was observed. Citrus oligogalacturonide from 24-h hydrolysis exhibited bactericidal effect against all selected foodborne pathogens and displayed minimal inhibitory concentration at 37.5 µg/mL for P. aeruginosa, L. monocytogenes, and S. Typhimurium, and at 150.0 µg/mL for S. aureus.

Polysaccharides from Liriopes Radix ameliorate streptozotocin-induced type I diabetic nephropathy via regulating NF-κB and p38 MAPK signaling pathways.

BACKGROUND: The polysaccharides from Liriopes Radix (PSLR) has been indicated to ameliorate insulin signaling transduction and glucose metabolism. We aimed to investigate whether PSLR exerts an ameliorative effect on renal damage in diabetes induced by streptozotocin. METHODS: Diabetes was induced with STZ (60 mg/kg) by intraperitoneal injection in rats. Two weeks after STZ injection, rats in the treatment group were orally dosed with PSLR (200 and 300 mg/kg/day for 8 weeks. The normal rats were chosen as nondiabetic control group. Changes in renal function-related parameters in plasma and urine were analyzed at the end of the study. Kidneys were isolated for pathology histology, immunohistochemistry, and Western blot analyses. RESULTS: Diabetic rats exhibited renal dysfunction, as evidenced by reduced creatinine clearance, blood urea nitrogen and proteinuria, along with marked elevation in the ratio of kidney weight to body weight. All of these abnormalities were significantly reversed by PSLR. The histological examinations revealed amelioration of diabetes-induced glomerular pathological changes following treatment with PSLR. The less protein expressions of renal nephrin and podocin in diabetic rats were increased following treatment with PSLR. PSLR reduced the accumulation of ED-1-expressing macrophages in renal tissue of diabetic rats. PSLR almost completely abolished T cells infiltration and attenuated the expression of proinflammatory cytokines. PSLR treatments not only reduced the degradation of inhibitory kappa B kinase, but also downregulated the protein expression of nuclear factor kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) in diabetic kidney. CONCLUSIONS: The results suggest that the renal protective effects of PSLR occur through improved glycemic control and renal structural changes, which are involved in the inhibition of NF-κB and p-38 MAPK mediated inflammation.

Ruscogenin ameliorates diabetic nephropathy by its anti-inflammatory and anti-fibrotic effects in streptozotocin-induced diabetic rat.

BACKGROUND: Ruscogenin is a major steroid sapogenin in the traditional Chinese herb Ophiopogon japonicus that have multiple bioactivities. Recent studies have demonstrated that ruscogenin is involved in down-regulation of intercellular adhesion molecule-1 (ICAM-1) and nuclear factor-κB (NF-κB) activation in anti-inflammatory pathways. We hypothesized that ruscogenin protects against diabetic nephropathy (DN) by inhibiting NF-κB-mediated inflammatory pathway. To test this hypothesis, the present study was to examine the effects of ruscogenin in rats with streptozotocin (STZ)-induced DN. METHODS: Diabetes was induced with STZ (60 mg/kg) by intraperitoneal injection in rats. Two weeks after STZ injection, rats in the treatment group were orally dosed with 0.3, 1.0 or 3.0 mg/kg ruscogenin for 8 weeks. The normal rats were chosen as nondiabetic control group. The rats were sacrificed 10 weeks after induction of diabetes. Changes in renal function-related parameters in plasma and urine were analyzed at the end of the study. Kidneys were isolated for pathology histology, immunohistochemistry, and Western blot analyses. RESULTS: Ruscogenin administration did not lower the levels of plasma glucose and glycosylated hemoglobin in STZ-diabetic rats. Diabetic rats exhibited renal dysfunction, as evidenced by reduced creatinine clearance, blood urea nitrogen and proteinuria, along with marked elevation in the ratio of kidney weight to body weight, that were reversed by ruscogenin. Ruscogenin treatment was found to markedly improve histological architecture in the diabetic kidney. Renal NF-κB activity, as wells as protein expression and infiltration of macrophages were increased in diabetic kidneys, accompanied by an increase in protein content of intercellular adhesion molecule-1 and monocyte chemoattractant protein-1 in kidney tissues. All of the above abnormalities were reversed by ruscogenin treatment, which also decreased the expression of transforming growth factor-ß1 and fibronectin in the diabetic kidneys. CONCLUSIONS: Our data demonstrated that ruscogenin suppressed the inflammation and ameliorated the structural and functional abnormalities of the diabetic kidney in rats might be associated with inhibition of NF-κB mediated inflammatory genes expression.

Antimicrobial activities of various fractions of longan (Dimocarpus longan Lour. Fen Ke) seed extract.

The antimicrobial activities of longan (Dimocarpus longan Lour. Fen ke) seed extracts were investigated using a disc diffusion method and also determining the minimal inhibitory concentration. The DL-P01-SI01 fraction showed that the strongest activity against Staphylococcus aureus and methicillin-resistant S. aureus at MIC 64 µg/mL, which was found to be due to the phenolic compounds. The HPLC analysis showed that the major phenolic compounds are gallic acid, corilagin, ethyl gallate and ellagic acid.

An Aqueous-Ethanol Extract of Liriope spicata var. prolifera Ameliorates Diabetic Nephropathy through Suppression of Renal Inflammation.

The tuberous root of Liriope spicata var. prolifera (TRLS; Liliaceae family) is valued for the ability to promote glucose homeostasis, and it may therefore be utilized as an adjuvant therapy in the control of diabetic complications. The aim of the present study was to examine the effects of an aqueous ethanol extract from TRLS (TRLS-ext) (100 or 200 mg kg(-1) per day for eight weeks) on rats with streptozotocin-induced diabetic nephropathy (DN). Renal dysfunction in diabetic rats was ameliorated by TRLS-ext as evidenced by reduced creatinine clearance, as well as increased blood urea nitrogen and proteinuria. Treatment with TRLS-ext was found to markedly improve histological architecture in the diabetic kidney. Hyperglycemia induced degradation of inhibitory kappa B and reduced nuclear factor kappa B activation, leading to increased infiltration of macrophages and increased levels of proinflammatory cytokines, including interleukin-1 and tumor necrosis factor- α . All of the above abnormalities were reversed by TRLS-ext treatment, which also decreased the expression of intercellular adhesion molecule-1, monocyte chemoattractant protein-1, and fibronectin in the diabetic kidneys. These findings provide a perspective on the renoprotective effects of TRLS-ext in DN.

Effect of arecoline on regeneration of injured peripheral nerves.

The present study provides in vitro and in vivo evaluation of arecoline on peripheral nerve regeneration. In the in vitro study, we found that arecoline at 50 µg/ml could significantly promote the survival and outgrowth of cultured Schwann cells as compared to the controls treated with culture medium only. In the in vivo study, we evaluated peripheral nerve regeneration across a 10-mm gap in the sciatic nerve of the rat, using a silicone rubber nerve chamber filled with the arecoline solution. In the control group, the chambers were filled with normal saline only. At the end of the fourth week, morphometric data revealed that the arecoline-treated group at 5 µg/ml significantly increased the number and the density of myelinated axons as compared to the controls. Immunohistochemical staining in the arecoline-treated animals at 5 µg/ml also showed their neural cells in the L4 and L5 dorsal root ganglia ipsilateral to the injury were strongly retrograde-labeled with fluorogold and lamina I-II regions in the dorsal horn ipsilateral to the injury were significantly calcitonin gene-related peptide-immunolabeled compared with the controls. In addition, we found that the number of macrophages recruited in the distal sciatic nerve was increased as the concentration of arecoline was increased. Electrophysiological measurements showed the arecoline-treated groups at 5 and 50 µg/ml had a relatively larger nerve conductive velocity of the evoked muscle action potentials compared to the controls. These results indicate that arecoline could stimulate local inflammatory conditions, improving the recovery of a severe peripheral nerve injury.

Ferulic Acid Enhances Peripheral Nerve Regeneration across Long Gaps.

This study investigated the effect of ferulic acid (FA) on peripheral nerve injury. In the in vitro test, the effect of FA on viability of Schwann cells was studied. In the in vivo test, right sciatic nerves of the rats were transected, and a 15 mm nerve defect was created. A nerve conduit made of silicone rubber tube filled with FA (5 and 25 µg/mL), or saline (control), was implanted into the nerve defect. Results show that the number of proliferating Schwann cells increased significantly in the FA-treated group at 25 µg/mL compared to that in the control group. After 8 weeks, the FA-treated group at 25 µg/mL had a higher rate of successful regeneration across the wide gap, a significantly calcitonin gene-related peptide (CGRP) staining of the lamina I-II regions in the dorsal horn ipsilateral to the injury, a significantly diminished number of macrophages recruited, and a significantly shortening of the latency and an acceleration of the nerve conductive velocity (NCV) of the evoked muscle action potentials (MAPs) compared with the controls. In summary, the FA may be useful in the development of future strategies for the treatment of peripheral nerve injury.

Inducing occlusion effect in Y-shaped vessels using high-intensity focused ultrasound: finite element analysis and phantom validation.

High-intensity focused ultrasound (HIFU) surgery offers a truly non-invasive treatment method with no skin incision, but precise targeting of tumour tissues for thermotherapy. Clinical experience reveals that the efficacy of tumour destruction not only involves in coagulating necrosis, but also involves in damaging the tumour vessels, which play an important role in tumour progression. These vessels take the elevated temperature away by perfusion, resulting in uncertainty of the occlusion effect during HIFU treatment. In this study, a Y-shaped vessel model comprising common and tumour vessels and an indirect fabrication method are proposed. The physical properties of the fabricated vessel phantom are measured and compared with human tissue. Simulation is performed using finite element modelling according to the tissue parameter, perfusion rate of the tumour vessel and treatment parameters including power intensity and exposure duration. The phantom experiments are carried out with perfusion of egg white to validate the threshold time prediction obtained from the simulation results. Our findings reveal that the threshold time obtained from experiments is consistent with the simulated one.

Antioxidant activity and emulsion-stabilizing effect of pectic enzyme treated pectin in soy protein isolate-stabilized oil/water emulsion.

The antioxidant activity of pectic enzyme treated pectin (PET-pectin) prepared from citrus pectin by enzymatic hydrolysis and its potential use as a stabilizer and an antioxidant for soy protein isolate (SPI)-stabilized oil in water (O/W) emulsion were investigated. Trolox equivalent antioxidant capacity (TEAC) was found to be positively associated with molecular weight (M(w)) of PET-pectin and negatively associated with degree of esterification (DE) of PET-pectin. PET-pectin (1 kDa and 11.6% DE) prepared from citrus pectin after 24 h of hydrolysis by commercial pectic enzyme produced by Aspergillus niger expressed higher α,α-diphenyl-ß-picrylhydrazyl (DPPH) radical scavenging activity, TEAC, and reducing power than untreated citrus pectin (353 kDa and 60% DE). The addition of PET-pectin could increase both emulsifying activity (EA) and emulsion stability (ES) of SPI-stabilized O/W emulsion. When the SPI-stabilized lipid droplet was coated with the mixture of PET-pectin and pectin, the EA and ES of the emulsion were improved more than they were when the lipid droplet was coated with either pectin or PET-pectin alone. The amount of secondary oxidation products (thiobarbituric acid reactive substances) produced in the emulsion prepared with the mixture of SPI and PET-pectin was less than the amount produced in the emulsion prepared with either SPI or SPI/pectin. These results suggest that PET-pectin has an emulsion-stabilizing effect and lipid oxidation inhibition ability on SPI-stabilized emulsion. Therefore, PET-pectin can be used as a stabilizer as well as an antioxidant in plant origin in SPI-stabilized O/W emulsion and thus prolong the shelf life of food emulsion.

Transacylation and de-esterification reactions of pectin as catalyzed by pectinesterases from tomato and citrus.

The optimal conditions for the de-esterification reaction of tomato pectinesterase (PE) and citrus PE was 0.1-0.2 M NaCl and at pH 7.5-8.5, 65 degrees C, almost identical to those for the transacylation reaction as observed by turbidity (absorbance at 400 nm) change. Among the PEs tested, pea pod PE presented the most remarkable catalysis on the transacylation reaction, and 1.5% pectin solution was determined to be suitable for this reaction. Low methoxy pectin with a DE (degree of esterification) of 31% displayed a slow turbidity increase, revealing that the extent of DE was influential on the transacylation. Besides citrus pectin, apple pectin was also proved to progress transacylation reaction by PEs from tomato and citrus sources as apparently observed by turbidity method.

Changes in molecular weight of transacylated pectin catalyzed by tomato and citrus pectinesterases as determined by gel permeation chromatography.

The changes in molecular masses of pectin in 0.5% pectin-pectinesterase (PE) mixtures (2 units/mL) incubated at various temperatures, pH values, and NaCl levels for 30 min were observed by a Toyopearl TSK HW-65 (F) gel permeation chromatography. The molecular mass of pectin was remarkably increased from 103 to 266 kDa when the incubation temperature of pectin-tomato PE was increased from 25 to 45 degrees C. A further increase in molecular mass was observed when a pectin-citrus PE mixture was incubated at 65 degrees C. The values of pH and NaCl levels were also crucial to the transacylation activity of PEs. Reaction at pH 7.5 with tomato PE and citrus PE remarkably expanded the molecular mass of pectin to 410 and 670 kDa, respectively. The NaCl level of 0.3-0.5 and 0.3 M was favorable for the transacylation reaction of tomato PE and citrus PE, respectively. Only high methoxylpectin was the suitable substrate for PE to conduct the transacylation reaction.