Physicochemical, antioxidant and sensory characteristics of sponge cakes fortified with Clitoria ternatea extract.

Bakery products are a food appreciated by consumers all over the world. There is a great opportunity to incorporate more bioactive compounds to enhance its quality. The objective of this study was to utilize the advantage of CTE in the production of sponge cake. The five different levels of CTE (0, 5, 10, 15 and 20%, w/w) was incorporated into sponge cake. The sponge cakes were evaluated for physicochemical (color, volume, water activity, total phenolic content, and antioxidant properties) and texture characteristics as well as consumer acceptance. Addition of CTE into the sponge cakes increased the polyphenol content and antioxidant activity concomitant with reduced lipid peroxidation. Increasing hardness, adhesiveness, gumminess, and chewiness and decreasing cohesiveness, springiness and resilience of cakes were seen when increasing percentage of CTE in the cake. A significant decrease was observed in the lightness, redness and yellowness in the cake containing CTE. No differences were found in overall acceptability between the control and the cake containing CTE. The findings suggest that CTE could be a potential source for development of sponge cakes with more effective antioxidant properties.

Cyanidin-3-rutinoside attenuates methylglyoxal-induced protein glycation and DNA damage via carbonyl trapping ability and scavenging reactive oxygen species.

BACKGROUND: Advanced glycation end-products (AGEs) play a significant role in the development and progression of vascular complication in diabetes. Anthocyanin has been recently reported to possess antiglycating activity. This study aimed to determine whether a naturally occurring anthocyanin, cyanidin-3-rutinoside (C3R) inhibits methylglyoxal (MG) induced protein glycation and oxidative protein and DNA damage. METHODS: C3R (0.125-1 mM) was incubated with bovine serum albumin and MG (1 mM) for 2 weeks. The formation of fluorescent AGEs was measured by using spectrofluorometer and thiol group content were used to detect protein oxidative damage. Gel electrophoresis was used to determine whether C3R (0.125-1 mM) reduced DNA strand breakage in a glycation model comprising lysine, MG and/or Cu(2+). The generation of superoxide anions and hydroxyl radicals were detected by the cytochrome c reduction assay and the thiobarbituric acid reactive substances assay. MG-trapping capacity was assessed by high performance liquid chromatography (HPLC). RESULTS: C3R (0.25-1 mM) reduced the formation of fluorescent AGEs and depleted protein thiol groups in bovine serum albumin mediated by MG. At 1 mM C3R inhibited oxidative DNA damage in the glycation model (p < 0.05) and at 0.5-1 mM prevented Cu(2+) induced DNA strand breakage in the presence of lysine and MG. The findings showed that C3R reduced the formation of superoxide anion and hydroxyl radicals during the glycation reaction of MG with lysine. C3R directly trapped MG in a concentration and time dependent manner (both p < 0.001). CONCLUSIONS: These findings suggest that C3R protects against MG-induced protein glycation and oxidative damage to protein and DNA by scavenging free radicals and trapping MG.

Protein glycation inhibitory activity and antioxidant capacity of clove extract.

Syzygium aromaticum (L.) (clove) is one of the most widely cultivated spices in many tropical countries. The aim of this study was to determine the phytochemical content, the antioxidant properties and the antiglycation properties of aqueous extract of clove against fructose-mediated protein glycation and oxidation. The result showed that the content of total phenolics and flavonoids in clove extract was 239.58 ± 0.70 mg gallic acid equivalents/g dried extract and 65.67 ± 0.01 mg catechin equivalents/g dried extract, respectively. In addition, clove exhibited antioxidant properties including DPPH radical scavenging activity (IC50 = 0.29 ± 0.01 mg/ml), Trolox equivalent antioxidant capacity (4.69 ± 0.03 µmol Trolox equivalents/mg dried extract), ferric reducing antioxidant power (20.55 ± 0.11 µmol ascorbic acid equivalents/mg dried extract), Oxygen radical absorbance capacity (31.12 ± 0.21 µmol Trolox equivalents/mg dried extract), hydroxyl radical scavenging activity (0.15 ± 0.04 mg Trolox equivalents/mg dried extract), and superoxide radical scavenging activity (18.82 ± 0.50 mg Trolox equivalents/mg dried extract). The aqueous extract of clove (0.25-1.00 mg/ml) significantly inhibited the formation of fluorescent advanced glycation end products (AGEs) and non-fluorescent AGEs (N(ɛ)-(carboxymethyl) lysine (CML)) in glycated BSA during 4 weeks of incubation. The extract also markedly prevented oxidation-induced protein damage by decreasing protein carbonyl formation and protecting against the loss of protein thiol group. These results clearly demonstrated that a polyphenol enriched clove extract, owing to its antioxidant, was capable to inhibit the formation of AGEs and protein glycation. The findings might lead to the possibility of using the clove extract for targeting diabetic complications.

Effect of a Multispecies Synbiotic Supplementation on Body Composition, Antioxidant Status, and Gut Microbiomes in Overweight and Obese Subjects: A Randomized, Double-Blind, Placebo-Controlled Study.

Studies investigating the effect of multispecies synbiotic supplementation in obesity management are limited. The current study was performed to evaluate the effects of multispecies probiotics mixed with fructooligosaccharides on body composition, antioxidant status, and gut microbiome composition in overweight and obese individuals. We employed a randomized, double-blind, placebo-controlled trial design, in which 63 individuals aged 18-45 years were assigned to receive either a synbiotic supplement or placebo for 12 weeks. The synbiotic group consumed a daily dose of 37 × 109 colony-forming units (CFU) of a unique blend of seven different probiotics, along with 2 g of fructooligosaccharides, while the placebo group consumed 2 g of maltodextrin daily. Assessments were performed at baseline, week 6, and the end of the study. The results of the study indicated that synbiotic supplementation resulted in a significant reduction in waist circumference and body fat percentage compared to the baseline measurements, as observed at 12 weeks. At the end of the study, there were no significant differences observed in body weight, BMI, waist circumference, or percentage of body fat between the synbiotic group and the placebo group. An analysis of plasma antioxidant capacity revealed that synbiotic supplementation caused a significant increase in Trolox equivalent antioxidant capacity (TEAC) and a concomitant decrease in malondialdehyde (MDA) in the test group when compared to the placebo. For the gut microbiota analysis, synbiotic supplementation significantly decreased Firmicutes abundance and the Firmicutes/Bacteroidetes (F/B) ratio at week 12 as compared to the placebo group. Nevertheless, the synbiotic group did not exhibit any substantial alterations in other biochemical blood parameters compared to the placebo group. These findings suggest that multispecies synbiotic supplementation could be a beneficial strategy to improve body composition, antioxidant status, and gut microbiome composition in overweight and obese subjects.

Cinnamic acid and its derivatives inhibit fructose-mediated protein glycation.

Cinnamic acid and its derivatives have shown a variety of pharmacologic properties. However, little is known about the antiglycation properties of cinnamic acid and its derivatives. The present study sought to characterize the protein glycation inhibitory activity of cinnamic acid and its derivatives in a bovine serum albumin (BSA)/fructose system. The results demonstrated that cinnamic acid and its derivatives significantly inhibited the formation of advanced glycation end products (AGEs) by approximately 11.96-63.36% at a concentration of 1 mM. The strongest inhibitory activity against the formation of AGEs was shown by cinnamic acid. Furthermore, cinnamic acid and its derivatives reduced the level of fructosamine, the formation of N(ɛ)-(carboxymethyl) lysine (CML), and the level of amyloid cross ß-structure. Cinnamic acid and its derivatives also prevented oxidative protein damages, including effects on protein carbonyl formation and thiol oxidation of BSA. Our findings may lead to the possibility of using cinnamic acid and its derivatives for preventing AGE-mediated diabetic complications.

Cholesterol-lowering activity of the major polyphenols in grape seed.

The major polyphenols in grape seed have been shown to have beneficial health effects in the prevention of dyslipidemia and cardiovascular diseases. In this present study, we investigated the cholesterol-lowering activity of three major polyphenolic compounds found in grape seed. The results showed that gallic acid, catechin, and epicatechin significantly inhibited pancreatic cholesterol esterase in a concentration-dependent manner. Moreover, they bound to taurocholic acid, taurodeoxycholic acid, and glycodeoxycholic acid at levels ranging from 38.6% to 28.2%. At the concentration of 0.2 mg/mL, gallic acid, catechin, and epicatechin reduced the formation of cholesterol micelles 27.26 ± 2.17%, 11.88 ± 0.75%, and 19.49 ± 3.71%, respectively. These findings clearly demonstrate that three major polyphenolic compounds present in a particular grape seed have cholesterol-lowering activity by inhibiting pancreatic cholesterol esterase, binding of bile acids, and reducing solubility of cholesterol in micelles which may result in delayed cholesterol absorption.

Unripe Papaya By-Product: From Food Wastes to Functional Ingredients in Pancakes.

Papaya is one of the most economic and valuable fruits in tropical countries. However, the fruit processing industries generate a high volume of unripe papaya waste and by-products. To reduce this waste, unripe papaya powder (UPP) was manufactured and incorporated into pancake formulation. The results showed that a particle size of UPP was 140.8 ± 2.1 µm, which contained polyphenolic compounds, dietary fiber and demonstrated ferric reducing antioxidant power (FRAP). Compared with wheat flour, UPP had higher values of water absorption index, water solubility index and swelling index and lower level of amylose. In the cholesterol-reducing effect, UPP decreased the formation of cholesterol micellization and bound bile acids. Interestingly, incorporation of 5-20% UPP into pancakes could decrease the glucose release with a concomitant increase in the percentage of undigestible starch. The hardness and chewiness of pancake was increased with a higher amount of UPP (10-20%). The results suggest that UPP from fruit processing waste can be regarded as a promising functional ingredient to incorporate with pancakes.

Effects of Different Cooking Methods and Palm Oil Addition on the Bioaccessibility of Beta-Carotene of Sweet Leaf (Sauropus androgynous).

Beta-carotene is one of phytochemicals which play role as natural antioxidant related to the reduction of oxidative stress that is linked to Non-communicable diseases (NCDs). Sweet leaf (Sauropus androgynous), one of the indigineous plants in Asia, contains high contents of beta-carotene. However, the bioaccessibility of beta-carotene in sweet leaf might be altered among the different cooking methods. Therefore, the effects of different cooking methods (raw, boiling, and microwave cooking) and addition of palm oil on the bioaccessibility of beta-carotene of sweet leaf were investigated before and during in vitro simulated gastrointestinal digestion. We found that the boiling and microwave cooking methods caused the lower beta-carotene contents in cooked sweet leaf compared to raw leaf. However, the addition of 10% (v/w) palm oil during cooking helped increasing the bioaccessible beta-carotene contents after digestion in all cooking methods, compared to those without palm oil addition (p<0.05). In addition, the bioaccessibility of beta-carotenes was found to increase about 20% when the palm oil was added into the microwaved sweet leaf. The findings of this study suggested that the addition of 10% (v/w) palm oil during cooking could improve the bioaccessible beta-carotene contents in the sweet leaf, especially when the sweet leaf was cooked by microwave.

Anthocyanin-rich fraction from Thai berries interferes with the key steps of lipid digestion and cholesterol absorption.

Several studies have documented the hypolipidemic effect of anthocyanin-rich plants in vitro and in vivo. The objective of this study was to elucidate the inhibitory activity of anthocyanin-rich fraction from Thai berries against fat digestive enzymes. The ability of Thai berries to bind bile acid, disrupt cholesterol micellization and the cholesterol uptake into Caco-2 cells was also determined. The content of total phenolics, flavonoid and anthocyanin in Prunus domestica L. (TPE), Antidesma bunius (L.) Spreng, Syzygium cumini (L.) Skeels, and Syzygium nervosum A. Cunn. Ex DC was 222.7-283.5 mg gallic acid equivalents, 91.2-184.3 mg catechin equivalents, and 37.9-49.5 mg cyanidin-3-glucoside equivalents/g extract, respectively. The anthocyanin-rich fraction of all extracts inhibited pancreatic lipase and cholesterol esterase with the IC50 values of 90.6-181.7 µg/mL and 288.7-455.0 µg/mL, respectively. Additionally, all extracts could bind primary and secondary bile acids (16.4-36.6%) and reduce the solubility of cholesterol in artificial micelles (53.0-67.6%). Interestingly, TPE was the most potent extract on interfering the key steps of lipid digestion among the tested extracts. In addition, TPE (0.10-0.50 mg/mL) significantly reduced the cholesterol uptake into Caco-2 cells in a concentration-dependent manner. These results demonstrate a new insight into the role of anthocyanin-rich Thai berry extract on interfering the key steps of lipid digestion and absorption.

Inhibitory Effect of Antidesma bunius Fruit Extract on Carbohydrate Digestive Enzymes Activity and Protein Glycation In Vitro.

Antidesma bunius (L.) spreng (Mamao) is widely distributed in Northeastern Thailand. Antidesma bunius has been reported to contain anthocyanins, which possess antioxidant and antihypertensive actions. However, the antidiabetic and antiglycation activity of Antidesma bunius fruit extract has not yet been reported. In this study, we investigated the inhibitory activity of anthocyanin-enriched fraction of Antidesma bunius fruit extract (ABE) against pancreatic α-amylase, intestinal α-glucosidase (maltase and sucrase), protein glycation, as well as antioxidant activity. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) chromatogram revealed that ABE contained phytochemical compounds such as cyanidin-3-glucoside, delphinidin-3-glucoside, ellagic acid, and myricetin-3-galactoside. ABE inhibited intestinal maltase and sucrase activity with the IC50 values of 0.76 ± 0.02 mg/mL and 1.33 ± 0.03 mg/mL, respectively. Furthermore, ABE (0.25 mg/mL) reduced the formation of fluorescent AGEs and the level of Nε-carboxymethyllysine (Nε-CML) in fructose and glucose-induced protein glycation during four weeks of incubation. During the glycation process, the protein carbonyl and ß-amyloid cross structure were decreased by ABE (0.25 mg/mL). In addition, ABE exhibited antioxidant activity through DPPH radical scavenging activity and Trolox equivalent antioxidant capacity (TEAC) with the IC50 values 15.84 ± 0.06 µg/mL and 166.1 ± 2.40 µg/mL, respectively. Meanwhile, ferric reducing antioxidant power (FRAP) showed an EC50 value of 182.22 ± 0.64 µg/mL. The findings suggest that ABE may be a promising agent for inhibiting carbohydrate digestive enzyme activity, reducing monosaccharide-induced protein glycation, and antioxidant activity.

Postmarket Laboratory Surveillance for Forbidden Substances in Halal-Certified Foods in Thailand.

Limited information exists regarding adulteration of Halal-certified food by substances forbidden under Islamic law (Haram substances). This study was conducted using forensic laboratory testing to investigate the prevalence of this type of adulteration. In this large-scale survey of Halal-certified food products randomly collected from markets in Thailand, 4,829 food samples from 10 food groups were tested in the laboratory for four potentially Haram substances: porcine DNA, porcine fatty acids, ethanol, and hydroxyproline (gelatin). No samples were adulterated with porcine DNA or fatty acids. However, 62 samples (approximately 1.3%) were positive for ethanol (>0.5% for non-naturally fermented products and >1% for naturally fermented products). The hydroxyproline concentration in the samples was compared with that of a negative control. Gelatin, as indicated by the presence of hydroxyproline, was the major suspicious substance found in these products. Further investigations are required to determine whether the gelatin is of Halal origin. These results from this first large-scale postmarket surveillance of Halal-certified food products for forbidden substances reveals the important role of forensic laboratory testing for supporting Halal supervision and certification. These findings provide useful information for government agencies seeking to encourage Halal compliance by food enterprises and for Muslim consumers and Halal food importers and exporters.

Impact of Clitoria ternatea (butterfly pea) flower on in vitro starch digestibility, texture and sensory attributes of cooked rice using domestic cooking methods.

The effect of Clitoria ternatea flower (CTE) incorporated into cooked rice using domestic cooking methods on starch digestibility was determined. The incorporation of 1.25% and 2.5% (w/v) CTE caused a reduction in the starch digestibility of cooked rice using an electric rice cooker. In addition, there was significant alteration on the starch digestibility of cooked rice incorporated with 2.5% CTE using a microwave oven. Moreover, CTE significantly reduced the level of rapidly digestible starch and increased the level of undigested starch in cooked rice using an electric rice cooker. In the textural characteristics, the hardness of cooked rice with CTE remained unchanged, whereas a reduction in stickiness of cooked rice with CTE was observed. The sensory evaluation of cooked rice with CTE given by panelists demonstrated a good overall acceptability. Overall, the results show that CTE is a useful ingredient to incorporate with cooked rice for reduction of starch digestibility.

Developmental changes of glycosphingolipids and expression of glycogenes in mouse brains.

Glycosphingolipids (GSLs) and their sialic acid-containing derivatives, gangliosides, are important cellular components and are abundant in the nervous system. They are known to undergo dramatic changes during brain development. However, knowledge on the mechanisms underlying their qualitative and qualitative changes is still fragmentary. In this investigation, we have provided a detailed study on the developmental changes of the expression patterns of GSLs, GM3, GM1, GD3, GD1a, GD2, GD1b, GT1b, GQ1b, A2B5 antigens (c-series gangliosides such as GT3 and GQ1c), Chol-1alpha (GT1aalpha and GQ1balpha), glucosylceramide, galactosylceramide (O1 antigen), sulfatide (O4 antigen), stage-specific embryonic antigen-1 (Lewis x) glycolipids, and human natural killer-1 glycolipid (sulfoglucuronosyl paragloboside) in developing mouse brains [embryonic day 12 (E12) to adult]. In E12-E14 brains, GD3 was a predominant ganglioside. After E16, the concentrations of GD3 and GM3 markedly decreased, and the concentrations of a-series gangliosides, such as GD1a, increased. GT3, glucosylceramide, and stage-specific embryonic antigen-1 were expressed in embryonic brains. Human natural killer-1 glycolipid was expressed transiently in embryonic brains. On the other hand, Chol-1alpha, galactosylceramide, and sulfatide were exclusively found after birth. To provide a better understanding of the metabolic basis for these changes, we analyzed glycogene expression patterns in the developing brains and found that GSL expression is regulated primarily by glycosyltransferases, and not by glycosidases. In parallel studies using primary neural precursor cells in culture as a tool for studying developmental events, dramatic changes in ganglioside and glycosyltransferase gene expression were also detected in neurons induced to differentiate from neural precursor cells, including the expression of GD3, followed by up-regulation of complex a- and b-series gangliosides. These changes in cell culture systems resemble that occurring in brain. We conclude that the dramatic changes in GSL pattern and content can serve as useful markers in neural development and that these changes are regulated primarily at the level of glycosyltransferase gene expression.

The Effect of Isomaltulose Together with Green Tea on Glycemic Response and Antioxidant Capacity: A Single-Blind, Crossover Study in Healthy Subjects.

Isomaltulose, a naturally-occurring isomer of sucrose, is commonly used as an alternative sweetener in foods and beverages. The goal of this study was to determine the effect of isomaltulose together with green tea on postprandial plasma glucose and insulin concentration, as well as antioxidant capacity in healthy subjects. In a randomized, single-blind, crossover study, 15 healthy subjects (eight women and seven men; ages 23.5 ± 0.7 years; with body mass index of 22.6 ± 0.4 kg/m²) consumed five beverages: (1) 50 g sucrose in 400 mL water; (2) 50 g isomaltulose in 400 mL of water; (3) 400 mL of green tea; (4) 50 g sucrose in 400 mL of green tea; and (5) 50 g isomaltulose in 400 mL of green tea. Incremental area under postprandial plasma glucose, insulin, ferric reducing ability of plasma (FRAP) and malondialdehyde (MDA) concentration were determined during 120 min of administration. Following the consumption of isomaltulose, the incremental 2-h area under the curve (AUC0-2 h) indicated a higher reduction of postprandial glucose (43.4%) and insulin concentration (42.0%) than the consumption of sucrose. The addition of green tea to isomaltulose produced a greater suppression of postprandial plasma glucose (20.9%) and insulin concentration (37.7%). In accordance with antioxidant capacity, consumption of sucrose (40.0%) and isomaltulose (28.7%) caused the reduction of green tea-induced postprandial increases in FRAP. A reduction in postprandial MDA after drinking green tea was attenuated when consumed with sucrose (34.7%) and isomaltulose (17.2%). In conclusion, green tea could enhance the reduction of postprandial glucose and insulin concentration when consumed with isomaltulose. In comparison with sucrose, isomaltulose demonstrated less alteration of plasma antioxidant capacity after being consumed with green tea.

Moringa Oleifera leaf extract increases plasma antioxidant status associated with reduced plasma malondialdehyde concentration without hypoglycemia in fasting healthy volunteers.

OBJECTIVE: To investigate the effect of Moringa Oleifera leaf extract (MOLE) on plasma glucose concentration and antioxidant status in healthy volunteers. METHODS: A randomized crossover design was used in this study. Healthy volunteers were randomly assigned to receive either 200 mL of warm water (10 cases) or 200 mL of MOLE (500 mg dried extract, 10 cases). Blood samples were drawn at 0, 30, 60, 90, and 120 min for measuring fasting plasma glucose (FPG), ferric reducing ability of plasma (FRAP), Trolox equivalent antioxidant capacity (TEAC) and malondialdehyde (MDA). RESULTS: FPG concentration was not signifificantly different between warm water and MOLE. The consumption of MOLE acutely improved both FRAP and TEAC, with increases after 30 min of 30 µmol/L FeSO4 equivalents and 0.18 µmol/L Trolox equivalents, respectively. The change in MDA level from baseline was signifificantly lowered after the ingestion of MOLE at 30, 60, and 90 min. In addition, FRAP level was negatively correlated with plasma MDA level after an intake of MOLE. CONCLUSION: MOLE increased plasma antioxidant capacity without hypoglycemia in human. The consumption of MOLE may reduce the risk factors associated with chronic degenerative diseases.

Moringa oleifera aqueous leaf extract inhibits reducing monosaccharide-induced protein glycation and oxidation of bovine serum albumin.

Advanced glycation end products (AGEs) play an important factor for pathophysiology of diabetes and its complications. Moringa oleifera is one of the medicinal plants that have anti-hyperglycemic activity. However, anti-glycation property of Moringa oleifera leaf extract on the different types of reducing monosaccharides-induced protein glycation has not been investigated. Therefore, the aim of this study was to examine the protective effect of Moringa oleifera aqueous leaf extract (MOE) on reducing sugars-induced protein glycation and protein oxidation. Total phenolic content of MOE was measured using the Folin-Ciocalteu method. Bovine serum albumin was incubated with 0.5 M of reducing sugars (glucose or fructose) with or without MOE (0.5-2.0 mg/mL) for 1, 2, 3 and 4 weeks. The results found that total phenolic content was 38.56 ± 1.50 mg gallic acid equivalents/g dry extract. The formation of fluorescent and non-fluorescent AGEs [N (ε)-(carboxymethyl) lysine (CML)] and the level of fructosamine were determined to indicate protein glycation, whereas the level of protein carbonyl content and thiol group were examined for protein oxidation. MOE (0.5-2.0 mg/mL) significantly inhibited the formation of fluorescent, N (ε)-CML and markedly decreased fructosamine level (P < 0.05). Moreover, MOE significantly prevented protein oxidation manifested by reducing protein carbonyl and the depletion of protein thiol in a dose-dependent manner (P < 0.05). Thus, the findings indicated that polyphenols containing in MOE have high potential for decreasing protein glycation and protein oxidation that may delay or prevent AGE-related diabetic complications.

Protective effects of cyanidin-3-rutinoside against monosaccharides-induced protein glycation and oxidation.

Cyanidin-3-rutinoside (C3R), a naturally occurring anthocyanin, is present in various fruits and vegetables as a colorant. C3R has been well characterized and demonstrated a number of biological activities attributed to its antioxidant properties. The present study compared the effectiveness of C3R against monosaccharide-induced protein glycation and oxidation in vitro using bovine serum albumin (BSA).The results demonstrated that C3R (0.125-1.00 mM) inhibited the formation of fluorescent AGEs in ribose-glycated BSA (2-52%), fructose-glycated BSA (81-93%), glucose-glycated BSA (30-74%) and galactose-glycated BSA (6-79%).Correspondingly, C3R (1.00 mM) decreased the level of N(ɛ)-(carboxymethyl) lysine (56-86%) in monosaccharide-induced glycation in BSA. C3R also reduced the level of fructosamine, ß-amyloid cross structure, protein carbonyl content as well as the depletion of thiol in BSA/monosaccharide system. In summary, C3R might offer a new promising antiglycation agent for the prevention of diabetic complications by inhibiting AGE formation and oxidation-dependent protein damage.

The protective effects of pomelo extract (Citrus grandis L. Osbeck) against fructose-mediated protein oxidation and glycation.

Chronic hyperglycemia induces non-enzymatic protein glycation, which plays an important role in the development of diabetic complications. Immense efforts have been made to determine effective antiglycation compounds from natural products. Pomelo has shown beneficial effects for human health. The objective of this study was to determine the antiglycation effect of pomelo extract against fructose-mediated protein oxidation and glycation. Our results showed that the pomelo extract (0.25 - 2.00 mg/mL) significantly inhibited the overall formation of advanced glycation end products (AGEs) in a concentration-dependent manner. The pomelo extract markedly decreased the level of fructosamine, which is directly associated with reduction in formation of AGEs and N (ε)-(carboxymethyl)lysine (CML). In addition, the pomelo extract inhibited protein oxidation through its ability to prevent the loss of thiol groups and reduced protein carbonyl formation. We characterized the active components in the pomelo extract by using high-performance liquid chromatography (HPLC), which showed that the pomelo extract contained naringin (11.90 ± 0.21 mg/g dried extract), hesperidin (12.04 ± 0.12 mg/g dried extract), neohesperidin (25.4 ± 0.12 mg/g dried extract), and naringenin (9.20 ± 0.19 mg/g dried extract). Our findings could provide a new insight into the antiglycation properties of the extract of the naturally occurring fruit pomelo for preventing AGE-mediated diabetic complications.

Cultivar variations in antioxidant and antihyperlipidemic properties of pomelo pulp (Citrus grandis [L.] Osbeck) in Thailand.

Pomelo (Citrus grandis L. Osbeck) is a native fruit of great economic importance in Southeast Asia. To provide experimental evidence for the antioxidant and antihyperlipidemic properties of pomelo, 6 cultivars, including Kao-Yai (KY), Thong-dee (TD), Kao-Tangkwa (KT), Kao-Numpueng (KN), Ta-Koi (TK), and Tubtim Siam (TS) were evaluated. KY had the highest phenolic content, and the strongest 1,1-diphenyl-2-pireyhydrazyl radical scavenging capacity and hydroxyl radical scavenging activity. From the high-performance liquid chromatography analysis, naringin and naringenin were the major flavonoids in the KT and TK cultivars. Six pomelo cultivars had antihyperlipidemic activities including the inhibition of pancreatic lipase and cholesterol esterase, as well as cholesterol micelle formation and bile acid binding. Hierarchical clustering analysis showed that the 6 cultivars were separated into 2 classifications. In addition, the total phenolics of the pomelo cultivars were significantly correlated with ferric reducing antioxidant power and Trolox equivalent antioxidant capacity. The results suggest that pomelo provides significant health benefits and may be used for developing functional foods.

The Alterations of Erythrocyte Phospholipids in Type 2 Diabetes Observed after Oral High-Fat Meal Loading: The FTIR Spectroscopic and Mass Spectrometric Studies.

Little is known about the postprandial remodelling of erythrocytes phospholipids (PLs) in type 2 diabetics (T2DM). Therefore, this study aims to compare the alterations of erythrocyte PLs in T2DM to those of healthy subjects after ingestion of a high-fat meal. Eleven T2DM and ten healthy subjects underwent a high-fat meal loading. Erythrocytes were isolated from blood obtained after fasting and 4 h after the meal. Fourier Transform Infrared (FTIR) spectroscopy was initially used to screen erythrocyte PLs by monitoring C-H stretching vibrations. Phosphatidylcholine (PC) molecular species were further investigated by Liquid Chromatography-Electrospray Ionisation-Mass Spectrometry (LC-ESI-MS). For the control group, FTIR revealed postprandial changes in C-H stretching vibrations, particularly of the olefinic band. These findings were supported by LC-ESI-MS data, showing marked changes in PC molecular species, especially of the PC34:1 (where 34 and 1 mean the summed number of carbons and double bonds, respectively). However, similar changes of those were not apparent in the T2DM group. Our results reveal marked postprandial alterations of erythrocyte PC species in healthy subjects whereas only mild alterations are observed in T2DM. The discrepant effects of high-fat meal loading suggest abnormal PC remodelling in the diabetic erythrocyte that may affect its membrane fluidity and integrity.