Improvement of the fermentation performance of Lactobacillus plantarum by the flavanol catechin is uncoupled from its degradation

Aims: To determine the influence of the flavanol catechin on key metabolic traits for the fermentation performance of Lactobacillus plantarum strain RM71 in different media and to evaluate the ability of this strain to catabolize catechin. Methods and Results: Growth monitoring and time course of sugar consumption data tracking in chemically defined medium (CDM), revealed that growth of Lact. plantarum strain RM71 upon catechin was characterized by a noticeable shorter lag period, outcome of earlier sugar consumption and lactic acid production courses. Catechin gave rise to higher cell densities compared to controls because of an increased extension of sugar utilization. Fermentation of media relevant for practical fermentation processes with Lact. plantarum strain RM71 showed that catechin sped up malic acid decarboxylation, which besides quicker and extended consumption of several sugars, resulted in faster and higher lactic acid production and growth. Spectrophotometric evaluation of catechin by HPLC‐DAD and the lack of catechin concentration‐dependent effects showed that the observed stimulations were uncoupled from catechin catabolism by Lact. plantarum. Conclusions: The flavanol catechin stimulated the growth of Lact. plantarum strain RM71 by promoting quicker sugar consumption, increasing the extension of sugar utilization and stimulating malic acid decarboxylation. These stimulations are uncoupled from catechin catabolism as Lact. plantarum did not catabolize it during fermentation. Significance and Impact of the Study: This study, for the first time, examined the influence of the flavanol catechin on the fermentation performance of a Lact. plantarum strain in several media under different fermentation conditions. The information could be relevant to control the production and obtain high‐quality food products fermented by this micro‐organism.     

广西不同产地金樱根及炮制品中没食子酸和儿茶素的含量差异分析

为了建立金樱根中没食子酸和儿茶素含量的测定方法,分析广西不同产地金樱根及炮制品中没食子酸和儿茶素含量的变化,该文以没食子酸和儿茶素的含量作为指标成分,采用HPLC法对广西产金樱根生品、炒炙品、酒炙品、盐炙品及醋炙品进行测定,并采用SPSS 23.0软件进行方差分析和聚类分析。结果表明：广西不同产地金樱根及炮制品中没食子酸和儿茶素含量均存在差异,所有样品中儿茶素的含量均比没食子酸高,南部地区(除贵港桂平外)的没食子酸和儿茶素含量整体上比北部地区高,在炮制品中醋炙后没食子酸和儿茶素含量最高。该研究表明HPLC测定方法简单可行,金樱根中没食子酸和儿茶素含量的变化差异主要表现为产地地域及炮制方法的不同,可为今后金樱根资源的合理利用、质量标准制定以及临床用药的研究提供一定科学依据。     

Utilization of catechin byRhizobium sp.

Rhizobium sp. isolated fromLeucaena leucocephala utilized catechin as sole carbon source. Optimum growth occurred at 2 to 5 mM. From replacement cultures containing catechin, phloroglucinolcarboxylic acid, phloroglucinol, resorcinol, protocatechuate, catechol and hydroxyquinol were separated by chromatography. Rothera's test confirmed theortho ring fission of the end products of catechin.     

Synthesis of Catechin‐Rare Earth Complex with Efficient and Broad‐Spectrum Anti‐Biofilm Activity

Biofilm is the crucial reason of clinical infections. Herein, green tea based polyphenol (catechin) and rare earth (RE) metal ions were employed for the preparation of catechin–RE complexes with significant anti‐biofilm properties. The complexes were characterized by FT‐IR, Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS), which suggested that catechin coordinated with RE³⁺ through its ortho phenolic hydroxy groups. The prepared catechin‐RE showed significant effects in anti‐biofilm growth against P. aeruginosa (Gram‐negative bacteria), S. sciuri (Gram‐positive bacteria), and A. niger (fungi), which significantly exceeded the utilization of catechin or RE³⁺. Morphological observations indicated that catechin supplied cell affinity to transfer RE³⁺ and helped to damage cell membrane, which act as a carrier to exert cytotoxicity of RE³⁺ to realize anti‐biofilm. Differential gene expression analysis described gene expression changes induced by catechin‐RE, including 56, 272 and 2160 downregulated genes for P. aeruginosa, S. sciuri and A. niger, respectively, which suggested critical changes in cellular metabolism, growth and other processes. These results illustrate the outstanding superiority of catechin‐RE complexes in anti‐infection aspect, i. e., the green tea based rare earth complexes are promising candidates for anti‐biofilm applications to address serious challenges in the prevention of multiple infections.     

Utilization of catechin and its metabolites by Bradyrhizobium japonicum

Summary Catechin, a condensed tannin was utilized as sole carbon source by Bradyrhizobium japonicum. Protocatechuic acid, phloroglucinolcarboxylic acid, phloroglucinol, resorcinol and hydroxyquinol were identified as intermediates of catechin degradation. The aromatic substrates favoured good growth up to 5 or 10 mm. B. japonicum tolerated up to 50 mm catechin and phloroglucinolcarboxylic acid, 40 mm phloroglucinol and resorcinol, 30mm protocatechuic acid and 10 mm hydroxyquinol. Catechin-induced cells oxidized catechin more rapidly than uninduced cells. The two final ring compounds of the catechin catabolic pathway, protocatechuic acid and hydroxyquinol, were oxidized differentially. The enzymes of the catechin degradative pathway were inducible in B. japonicum. Offprint requests to: W. Hopper     

Determination of catechin diastereomers from the leaves of Byrsonima species using chiral HPLC‐PAD‐CD

When catechins are found in plant extracts, they are almost always identified as catechin and/or epicatechin probably due to stereoselectivity of the enzymes involved in the biosynthesis of these substances. However, the lack of reports regarding to ent‐catechin as well as ent‐epicatechin does not necessarily mean that these compounds have not been produced. In fact, most of the previous reports used chromatographic conditions not suitable for such separation. This article describes a simple and reliable analytical HPLC‐PAD‐CD method for simultaneous determination of catechin diastereomers both in infusions and extracts from the leaves of Byrsonima species. The direct separation of catechin, ent‐catechin, epicatechin, and ent‐epicatechin was obtained in normal phase by HPLC‐PAD‐CD using Chiralcel OD‐H as chiral stationary phase and n‐hexane/ethanol with 0.1% of TFA as mobile phase. Chirality, 2010. © 2010 Wiley‐Liss, Inc.     

A Catechin‐rich Beverage Improves Obesity and Blood Glucose Control in Patients With Type 2 Diabetes

We investigated the effects of continuous ingestion of a catechin‐rich beverage in patients with type 2 diabetes who were not receiving insulin (Ins) therapy in a double‐blind controlled study. The participants ingested green tea containing either 582.8 mg of catechins (catechin group; n = 23) or 96.3 mg of catechins (control group; n = 20) per day for 12 weeks. At week 12, the decrease in waist circumference was significantly greater in the catechin group than in the control group. Adiponectin, which is negatively correlated with visceral adiposity, increased significantly only in the catechin group. Although the increase in Ins at week 12 was significantly greater in the catechin group than in the control group, no apparent difference was noted between the two groups in glucose and hemoglobin A_1c. In patients treated with insulinotropic agents, the increase in Ins at week 12 was significantly greater in the catechin group than in the control group. This significant increase in Ins levels was observed only in the catechin group. In the catechin group receiving other treatments, Ins levels remained unchanged. In addition, in patients treated with insulinotropic agents, the decrease in hemoglobin A_1c at week 12 was significantly greater in the catechin group than in the control group. These results suggest that a catechin‐rich beverage might have several therapeutic uses: in the prevention of obesity; in the recovery of Ins‐secretory ability; and, as a way to maintain low hemoglobin A_1c levels in type 2 diabetic patients who do not yet require Ins therapy.     

Antioxidative Activity of (-)-Epigallocatechin-3-(3″-O-methyl)gallate Isolated from Fresh Tea Leaf and Preliminary Results on Its Biological Activity

Antioxidative activity of (-)-epigallocatechin-3-(3″-O-methyl)gallate (catechin e) was examined. Catechin e showed a strong antioxidative activity. A preliminary test using rat cancer cells suggests that catechin e also has a strong cytotoxic activity. Among tested catechins, only catechin e has strong activity for both.     

Isolation of catechin-converting human intestinal bacteria

Aims: To isolate and characterize bacteria from the human intestine that are involved in the conversion of catechins, a class of bioactive polyphenols abundant in the human diet. Methods and Results: Two bacterial strains, rK3 and aK2, were isolated from an epicatechin‐converting human faecal suspension. The isolates catalysed individual steps in the degradation of (?)‐epicatechin and (+)‐catechin. Based on their phenotypic characteristics and 16S rRNA gene sequences, the isolates were identified as Eggerthella lenta and Flavonifractor plautii (formerly Clostridium orbiscindens). Eggerthella lenta rK3 reductively cleaved the heterocyclic C‐ring of both (?)‐epicatechin and (+)‐catechin giving rise to 1‐(3,4‐dihydroxyphenyl)‐3‐(2,4,6‐trihydroxyphenyl)propan‐2‐ol. The conversion of catechin proceeded five times faster than that of epicatechin. Higher (epi)catechin concentrations led to an accelerated formation of the ring fission product without affecting the growth of Eg. lenta rK3. Flavonifractor plautii aK2 further converted 1‐(3,4‐dihydroxyphenyl)‐3‐(2,4,6‐trihydroxyphenyl)propan‐2‐ol to 5‐(3,4‐dihydroxyphenyl)‐γ‐valerolactone and 4‐hydroxy‐5‐(3,4‐dihydroxyphenyl)valeric acid. Flavonifractor plautii DSM 6740 catalysed the identical reaction indicating it is not strain specific. Conclusions: The conversion of dietary catechins by the isolated Eg. lenta and F. plautii strains in the human intestine may affect their bioavailability. Significance and Impact of the Study: The majority of catechin metabolites are generated by the intestinal microbiota. The identification of catechin‐converting gut bacteria therefore contributes to the elucidation of the bioactivation and the health effects of catechins.     

Catechin safely improved higher levels of fatness, blood pressure, and cholesterol in children

Objective: The purpose of this study was to evaluate the effects of a catechin‐rich beverage on body fat and cardiovascular disease risk factors in obese children and to verify the safety of its use. Methods and Procedures: Obese or near‐obese Japanese children were recruited for this study. A double‐blind, randomized, controlled study was performed with a 4‐week lead‐in, a 24‐week beverage ingestion period and a 12‐week follow‐up. Subjects ingested green tea containing 576 mg catechins (catechin group) or 75 mg catechins (control group) once per day for 24 weeks. Randomization was stratified by gender, age, and BMI. Subjects were instructed to maintain their usual lifestyles during the study period. Results: Data were analyzed using samples from 40 subjects (catechin group; n = 21, control group; n = 19). There were no significant differences in major outcome variables, such as body fat mass, between the catechin and the control groups. When, however, the analysis was stratified using the median of the week‐0 values, the decrease at week 24 in waist circumference, systolic blood pressure, and low‐density lipoprotein cholesterol in the catechin group was significantly greater than that in the control group for the above‐median category. Ingestion of the catechin‐rich beverage was not associated with any adverse effects. Discussion: These findings suggest that ingestion of a catechin‐rich beverage ameliorates serious obesity and cardiovascular disease risk factors without raising any safety concerns in Japanese children.     

The influence of mycorrhizal colonization on growth in the greenhouse and on catechin, epicatechin and procyanidin in roots of Fagus sylvatica L.

 The influence of mycorrhizal colonization on beech (Fagus sylvatica L.) root tannin (procyanidin polymer) and its putative precursors catechin and epicatechin was investigated by high performance liquid chromatography. Seedlings planted in a sterile mixture of litter, compost, soil and sand were inoculated with brown beech ectomycorrhizas collected from a woodland (Lactarius subdulcis Bull ex Fr. ×  F. sylvatica). The seedlings were not fertilized during the first year of growth. Nonmycorrhizal control plants showed severe nutrient-deficiency symptoms on their leaves and grew less well than mycorrhizal plants. Mycorrhizal roots contained significantly less catechin, epicatechin and procyanidin polymer than nonmycorrhizal roots. In the second year of growth, the plants were fertilized and procyanidin formation in roots was investigated. None of the fertilized plants showed mineral-deficiency symptoms. Fertilized mycorrhizal roots consistently contained significantly less catechin and epicatechin than nonmycorrhizal controls, but procyanidin polymer content varied between replicate experiments. The possible function of catechin and epicatechin in ectomycorrhizal formation is discussed. Accepted: 11 July 1997     

Screening of Grassland Plants for Restoration after Spotted Knapweed Invasion

Invasions of North American grasslands by Spotted knapweed (Centaurea maculosa Lam.) are mediated in part by Spotted knapweed root exudation of (±)‐catechin, a potent phytotoxin. Residual soil (±)‐catechin may interfere with reestablishment of native grassland species even after Spotted knapweed populations are controlled. Grassland species that are resistant to (±)‐catechin may be more successful for restoration of areas infested by Spotted knapweed. We evaluated the (±)‐catechin resistance of 23 grassland species by measuring the effects of seven (±)‐catechin concentrations (0–4.0 mg/mL) on seed germination, seedling root and shoot elongation, and seedling mortality. (±)‐Catechin treatments were chosen to reflect the range of observed Spotted knapweed field soil (±)‐catechin concentrations. Inhibition of root elongation was the strongest and most common effect of (±)‐catechin treatment. High (±)‐catechin concentrations reduced mean root lengths of 5 of the species by more than 75% and another 10 species by more than 55%. Experimentally derived concentrations needed to reduce root length by 50% (EC50), an indicator of (±)‐catechin resistance, ranged from 0.43 mg/mL ± 0.30 SE to greater than 4.0 mg/mL among species. Eight species with EC50s greater than 3.0 mg/mL were identified as resistant to (±)‐catechin and are likely suitable for revegetation of Spotted knapweed–infested areas. (±)‐Catechin resistance was positively correlated with mean seed mass, suggesting that seed carbohydrate reserves may allow seedlings to detoxify (±)‐catechin, develop barriers to (±)‐catechin exposure, or sustain a positive growth rate, despite (±)‐catechin‐induced cell death. Future efforts to identify allelochemical‐resistant grassland species should focus on large‐seeded species.     

A green tea extract high in catechins reduces body fat and cardiovascular risks in humans

Objective: The body fat reducing effect and reduction of risks for cardiovascular disease by a green tea extract (GTE) high in catechins was investigated in humans with typical lifestyles. Research Methods and Procedures: Japanese women and men with visceral fat‐type obesity were recruited for the trial. After a 2‐week diet run‐in period, a 12‐week double‐blind parallel multicenter trial was performed, in which the subjects ingested green tea containing 583 mg of catechins (catechin group) or 96 mg of catechins (control group) per day. Randomization was stratified by gender and body mass index at each medical institution. The subjects were instructed to maintain their usual dietary intake and normal physical activity. Results: Data were analyzed using per‐protocol samples of 240 subjects (catechin group; n = 123, control group; n = 117). Decreases in body weight, body mass index, body fat ratio, body fat mass, waist circumference, hip circumference, visceral fat area, and subcutaneous fat area were found to be greater in the catechin group than in the control group. A greater decrease in systolic blood pressure (SBP) was found in the catechin group compared with the control group for subjects whose initial SBP was 130 mm Hg or higher. Low‐density lipoprotein (LDL) cholesterol was also decreased to a greater extent in the catechin group. No adverse effect was found. Discussion: The continuous ingestion of a GTE high in catechins led to a reduction in body fat, SBP, and LDL cholesterol, suggesting that the ingestion of such an extract contributes to a decrease in obesity and cardiovascular disease risks.     

(+)-Catechin is more bioavailable than (−)-catechin: Relevance to the bioavailability of catechin from cocoa

Catechin is a flavonoid present in fruits, wine and cocoa products. Most foods contain the (+)-enantiomer of catechin but chocolate mainly contains ( ? )-catechin, in addition to its major flavanol, ( ? )-epicatechin. Previous studies have shown poor bioavailability of catechin when consumed in chocolate. We compared the absorption of ( ? ) and (+)-catechin after in situ perfusion of 10, 30 or 50 μmol/l of each catechin enantiomer in the jejunum and ileum in the rat. We also assayed 23 samples of chocolate for (+) and ( ? )-catechin. Samples were analyzed using HPLC with a Cyclobond I-2000 RSP chiral column. At all concentrations studied, the intestinal absorption of ( ? )-catechin was lower than the intestinal absorption of (+)-catechin (p < 0.01). Plasma concentrations of ( ? )-catechin were significantly reduced compared to (+)-catechin (p < 0.05). The mean concentration of ( ? )-catechin in chocolate was 218 ± 126 mg/kg compared to 25 ± 15 mg/kg (+)-catechin. Our findings provide an explanation for the poor bioavailability of catechin when consumed in chocolate or other cocoa containing products.     

Investigation on catechin as a beech wood decay biomarker

A high-performance liquid chromatography (HPLC) method based on the evolution of wood extractives was developed to follow the first stages of fungal degradation of beech wood exposed to Coriolus versicolor. The nature and the quantity of the extracts initially present in wood depended on the extraction conditions and also on the wood-drying conditions (time and temperature). The most interesting fraction was soxhlet extracted with acetone at 56 °C for 6 h. The best conditions to avoid extractives degradation consisted of a moderate drying at 55 °C for 48 h allowing identification of catechin as potential tracer. After 2 weeks of wood blocks exposure to C. versicolor, analysis of their acetonic extractives showed that catechin signal initially detected in beech wood, had totally disappeared. Treatment of wood with an appropriate fungicide such as propiconazole before exposure to C. versicolor, prevents the catechin amount from any variation. The comparison of these results with the classical weight loss (WL) measurements obtained after long-time experiments on treated and untreated wood blocks shows that the catechin amount evolution, monitored during 2 weeks, correlates with the wood resistance evaluated during 16 weeks, allowing the use of this flavonoid as a valuable biomarker of wood decay.     

Epicatechin and catechin may prevent coffee berry disease by inhibition of appressorial melanization of Colletotrichum kahawae

Colletotrichum kahawae is the causal agent of coffee berry disease. Appressorial melanization is essential for the fungal penetration of plant cuticle. Epicatechin is abundant in green coffee berry pericarp. Inoculation of C. kahawae conidial suspension containing 1.2 mg epicatechin or catechin/ml did not affect conidial germination or appressorial formation but appressorial melanization was completely inhibited and infection by the treated conidia was less than 30% of the untreated control. Epicatechin and catechin may, therefore, prevent coffee berry disease by inhibition of the appressorial melanization of C. kahawae.     

Multiple pathways of the reaction of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH and the oxidized form of the polyphenol

The pathways of the reaction of 2,2-diphenyl picrylhydrazyl radicals (DPPH) with (+)-catechin were studied in alcoholic solvents. The reaction mixtures were analysed by using reversed-phase liquid chromatography (HPLC) and electrospray ionization mass spectrometry (ESI-MS). The intermediate o-quinone of catechin, yellow dimers, trimers and, interestingly, an adduct of the oxidized form of catechin with DPPH radicals were identified. The mass of this adduct was 681 Da, suggesting that one molecule of the DPPH radical complexes with the oxidized form of catechin. It is concluded that once the intermediate o-quinone is formed, the reaction proceeds in two pathways, either the o-quinone reacts with catechin to form a hydrophilic dimer (type B), which is further oxidized to hydrophobic dimers (type A) and consequently to oligomers of higher molecular weights; or the A-ring of the o-quinone is further oxidized by a DPPH radical and that this oxidized intermediate then reacts with another DPPH radical to form the observed adduct. The identification of the latter mechanism could explain the contradictory results reported in the literature for the reaction of polyphenols with DPPH radicals.     

Catechin and Catechin Fractions as Biochemical Markers to Study the Diversity of Indian Tea (Camellia sinensis (L.) O. Kuntze) Germplasm

The heterogeneous Indian tea germplasm includes ‘China’, ‘Assam’, ‘Cambod’, and their hybrids which were evaluated using biochemical markers viz., total catechin and their fractions, for varietal identification and characterization. Principal component analysis (PCA) of biochemical characters showed that the total catechin and trihydroxylated catechin has higher eigenvalues. The first two principal components (PCs) could differentiate more than 90% of the clones studied. This grouping based on first two principal component matrices differentiated ‘China’, and their hybrids with ‘Assam’ and ‘Cambod’ variety. Morphologically indistinct large‐leaved ‘Cambod’ variety and ‘Assam’ varieties could not be differentiated using biochemical markers, since both varietal types taxonomically belong to a single species. Clones of ‘China’ type showed low total catechin content and catechin ratio which are distinctly grouped. The ‘China–Assam’ and ‘China–Cambod’ hybrids formed intermediate groups between ‘China’ PC group and ‘Cambod’/‘Assam’ PC groups, providing evidence for genetic control of catechin ratio variation. Tea clones which are differentially positioned in the PC group could be explained based on the genetic contribution by other varietal type as parents. This biochemical characterization will be a useful tool in the development of quality‐tea clones with different proportion of total catechin and their fractions.     

Effects of Catechin Enriched Green Tea on Body Composition

Obesity is a major health problem in the developed and developing world. Many “functional” foods and ingredients are advocated for their effects on body composition but few have consistent scientific support for their efficacy. However, an increasing amount of mechanistic and clinical evidence is building for green tea (GT). This experiment was therefore undertaken to study the effects of a high‐catechin GT on body composition in a moderately overweight Chinese population. In a randomized placebo‐controlled trial, 182 moderately overweight Chinese subjects, consumed either two servings of a control drink (C; 30 mg catechins, 10 mg caffeine/day), one serving of the control drink and one serving of an extra high‐catechin GT1 (458 mg catechins, 104 mg caffeine/day), two servings of a high‐catechin GT2 (468 mg catechins, 126 mg caffeine/day) or two servings of the extra high‐catechin GT3 (886 mg catechins, 198 mg caffeine/day) for 90 days. Data were collected at 0, 30, 60, and 90 days. We observed a decrease in estimated intra‐abdominal fat (IAF) area of 5.6 cm² in the GT3 group. In addition, we found decreases of 1.9 cm in waist circumference and 1.2 kg body weight in the GT3 group vs. C (P < 0.05). We also observed reductions in total body fat (GT2, 0.7 kg, P < 0.05) and body fat % (GT1, 0.6%, P < 0.05). We conclude that consumption of two servings of an extra high‐catechin GT leads to improvements in body composition and reduces abdominal fatness in moderately overweight Chinese subjects.