Yoko Akazome

Bio: Yoko Akazome is an academic researcher. The author has contributed to research in topics: Food additive & Triglyceride. The author has an hindex of 6, co-authored 19 publications receiving 501 citations.

Oligomeric procyanidins in apple polyphenol are main active components for inhibition of pancreatic lipase and triglyceride absorption.

Abstract: Inhibitory effects of apple polyphenol extract (AP) and procyanidin contained in AP on in vitro pancreatic lipase activity and in vivo triglyceride absorption in mice and humans were examined. AP and procyanidin considerably inhibited in vitro pancreatic lipase activity. However, polyphenols, except for procyanidin, in AP (i.e., catechins, chalcones, and phenol carboxylic acids) showed weak inhibitory activities on pancreatic lipase. Procyanidins separated by normal-phase chromatography according to the degree of polymerization were also examined. Inhibitory effects of procyanidins increased according to the degree of polymerization from dimer to pentamer. On the other hand, pentamer or greater procyanidins showed maximal inhibitory effects on pancreatic lipase. These results suggested that with respect to in vitro pancreatic lipase inhibition, the degree of polymerization was an important factor and oligomeric procyanidin mainly contributed. Next, we performed a triglyceride tolerance test in mice and humans. Simultaneous ingestion of AP and triglyceride significantly inhibited an increase of plasma triglyceride levels in both models. These results suggested that the oligomeric procyanidins contained in AP inhibited triglyceride absorption by inhibiting pancreatic lipase activity in mice and humans.

Oligomeric Procyanidins in Apple Polyphenol Are Main Active Components for Inhibition of Pancreatic Lipase and Triglyceride Absorption [Erratum: 2007 July 11, v. 55, no. 14, p. 5906.]

Abstract: Inhibitory effects of apple polyphenol extract (AP) and procyanidin contained in AP on in vitro pancreatic lipase activity and in vivo triglyceride absorption in mice and humans were examined. AP and procyanidin considerably inhibited in vitro pancreatic lipase activity. However, polyphenols, except for procyanidin, in AP (i.e., catechins, chalcones, and phenol carboxylic acids) showed weak inhibitory activities on pancreatic lipase. Procyanidins separated by normal-phase chromatography according to the degree of polymerization were also examined. Inhibitory effects of procyanidins increased according to the degree of polymerization from dimer to pentamer. On the other hand, pentamer or greater procyanidins showed maximal inhibitory effects on pancreatic lipase. These results suggested that with respect to in vitro pancreatic lipase inhibition, the degree of polymerization was an important factor and oligomeric procyanidin mainly contributed. Next, we performed a triglyceride tolerance test in mice and humans. Simultaneous ingestion of AP and triglyceride significantly inhibited an increase of plasma triglyceride levels in both models. These results suggested that the oligomeric procyanidins contained in AP inhibited triglyceride absorption by inhibiting pancreatic lipase activity in mice and humans.

Evaluation of Safety of Excessive Intake and Efficacy of Long-term Intake of Beverages Containing Apple Polyphenols

Abstract: In the present study, a randomized, double-blind, placebo-controlled study was performed to evaluate the safety of an excessive intake and the efficacy of a long-term intake of polyphenols derived from apples for moderately underweight to moderately obese subjects (long-term intake: 94 subjects; excessive intake: 30 subjects) For each trial, the subjects were divided into the following two groups: a group that drank beverages with apple polyphenols (600 mg) (hereinafter referred to as the apple group) and a group that drank beverages without apple polyphenols (hereinafter referred to as the placebo group) For the long-term intake trial, the subjects were given a regular amount of the beverage (340 g) each day for 12 weeks For the excessive intake trial, the subjects were given three times the regular amount of the beverage each day for 4 weeks It is noteworthy that the visceral fat area (VFA) of subjects in the apple group for the long-term intake trial had decreased significantly by the 8- and 12-week marks (week 8: p or = 100 cm(2)) had decreased significantly by the 8- and 12-week marks compared to the baseline (week 8: p < 005; week 12: p < 001) However, no significant change in the VFA of subjects in the apple group that started with a normal VFA (VFA < 100 cm(2)) was exhibited by the 8- and 12-week marks No clinical problems arose in the blood examinations or physical examinations for the long-term intake trial or the excessive intake trial No adverse reaction was observed in either trial These results demonstrated the efficacy and the safety of the beverage with apple polyphenols

Hop polyphenols suppress production of water-insoluble glucan by Streptococcus mutans and dental plaque growth in vivo.

Abstract: OBJECTIVE This study determined the effect of Hop polyphenols (HPP) on water-insoluble glucan (WIG), which is a major component of dental plaque along with microorganisms, and the effect of HPP-containing tablets on the growth of dental plaque. METHODS The effects of HPP on Streptococcus mutans MT8148 were determined. HPP concentrations employed in this study were 0% (as the HPP control), 0.001%, 0.01%, 0.1%, and 0.5%. The average result of six independent experiments was obtained at each concentration of HPP. Suppression of plaque formation in vivo was examined by a clinical trial that was designed as a randomized, single-blind, three-treatment study using 28 healthy subjects. The subjects used either 20 mg or seven mg HPP-containing tablets representing high and low dosages, respectively. The composition of each tablet was similar, except for the level of HPP; the control tablet had none. For the treatment period, subjects took one tablet seven times a day (before breakfast, after each meal, between meals, and at bedtime) for three days. The tablets were dissolved in the mouth and naturally swallowed. Plaque levels were then assessed for the subjects in the three groups. RESULTS In vitro, after 24-hour incubation, 0.5% HPP significantly reduced the growth of S. mutans compared to the control (p < 0.01). After 18-hour incubation, HPP at 0.1% and 0.5% significantly reduced lactic acid production (p < 0.05 and p < 0.001, respectively), and HPP at 0.01%, 0.1%, and 0.5% also suppressed WIG production (p < 0.01, p < 0.001 and p < 0.001, respectively). In vivo, the effect of HPP-containing tablets (seven times a day) on three-day dental plaque regrowth was assessed by the plaque scoring system (PSS). The high-dosage group using 20 mg HPP tablets exhibited a reduction in PSS (1.37 +/- 0.48 vs. 2.41 +/- 1.15 in the control group, p < 0.05). CONCLUSION It was concluded that HPP tablets might be a significant means of delivering HPP onto tooth surfaces to prevent dental plaque formation.

Biology of Streptococcus mutans-derived glucosyltransferases: role in extracellular matrix formation of cariogenic biofilms.

Abstract: The importance of Streptococcus mutans in the etiology and pathogenesis of dental caries is certainly controversial, in part because excessive attention is paid to the numbers of S. mutans and acid production while the matrix within dental plaque has been neglected. S. mutans does not always dominate within plaque; many organisms are equally acidogenic and aciduric. It is also recognized that glucosyltransferases from S. mutans (Gtfs) play critical roles in the development of virulent dental plaque. Gtfs adsorb to enamel synthesizing glucans in situ, providing sites for avid colonization by microorganisms and an insoluble matrix for plaque. Gtfs also adsorb to surfaces of other oral microorganisms converting them to glucan producers. S. mutans expresses 3 genetically distinct Gtfs; each appears to play a different but overlapping role in the formation of virulent plaque. GtfC is adsorbed to enamel within pellicle whereas GtfB binds avidly to bacteria promoting tight cell clustering, and enhancing cohesion of plaque. GtfD forms a soluble, readily metabolizable polysaccharide and acts as a primer for GtfB. The behavior of soluble Gtfs does not mirror that observed with surface-adsorbed enzymes. Furthermore, the structure of polysaccharide matrix changes over time as a result of the action of mutanases and dextranases within plaque. Gtfs at distinct loci offer chemotherapeutic targets to prevent caries. Nevertheless, agents that inhibit Gtfs in solution frequently have a reduced or no effect on adsorbed enzymes. Clearly, conformational changes and reactions of Gtfs on surfaces are complex and modulate the pathogenesis of dental caries in situ, deserving further investigation.

Flavan-3-ols: nature, occurrence and biological activity.

Abstract: Representing the most common flavonoid consumed in the American diet, the flavan-3-ols and their polymeric condensation products, the proanthocyanidins, are regarded as functional ingredients in various beverages, whole and processed foods, herbal remedies and supplements. Their presence in food affects food quality parameters such as astringency, bitterness, sourness, sweetness, salivary viscosity, aroma, and color formation. The ability of flavan-3-ols to aid food functionality has also been established in terms of microbial stability, foamability, oxidative stability, and heat stability. While some foods only contain monomeric flavan-3-ols [(-)-epicatechin predominates] and dimeric proanthocyanidins, most foods contain oligomers of degree of polymerization values ranging from 1-10 or greater than 10. Flavan-3-ols have been reported to exhibit several health beneficial effects by acting as antioxidant, anticarcinogen, cardiopreventive, antimicrobial, anti-viral, and neuro-protective agents. This review summarizes the distribution and health effects of these compounds.

Dietary polyphenols as potential nutraceuticals in management of diabetes: a review

Abstract: In recent years, there is growing evidence that plant-foods polyphenols, due to their biological properties, may be unique nutraceuticals and supplementary treatments for various aspects of type 2 diabetes mellitus. In this article we have reviewed the potential efficacies of polyphenols, including phenolic acids, flavonoids, stilbenes, lignans and polymeric lignans, on metabolic disorders and complications induced by diabetes. Based on several in vitro, animal models and some human studies, dietary plant polyphenols and polyphenol-rich products modulate carbohydrate and lipid metabolism, attenuate hyperglycemia, dyslipidemia and insulin resistance, improve adipose tissue metabolism, and alleviate oxidative stress and stress-sensitive signaling pathways and inflammatory processes. Polyphenolic compounds can also prevent the development of long-term diabetes complications including cardiovascular disease, neuropathy, nephropathy and retinopathy. Further investigations as human clinical studies are needed to obtain the optimum dose and duration of supplementation with polyphenolic compounds in diabetic patients.

Flavonoids as Anticancer Agents

Abstract: Flavonoids are polyphenolic compounds subdivided into 6 groups: isoflavonoids, flavanones, flavanols, flavonols, flavones and anthocyanidins found in a variety of plants. Fruits, vegetables, plant-derived beverages such as green tea, wine and cocoa-based products are the main dietary sources of flavonoids. Flavonoids have been shown to possess a wide variety of anticancer effects: they modulate reactive oxygen species (ROS)-scavenging enzyme activities, participate in arresting the cell cycle, induce apoptosis, autophagy, and suppress cancer cell proliferation and invasiveness. Flavonoids have dual action regarding ROS homeostasis—they act as antioxidants under normal conditions and are potent pro-oxidants in cancer cells triggering the apoptotic pathways and downregulating pro-inflammatory signaling pathways. This article reviews the biochemical properties and bioavailability of flavonoids, their anticancer activity and its mechanisms of action.