Cinnamtannin B-1 Research Articles

Chemical composition and hypoglycaemic effect of polyphenol extracts from Litchi chinensis seeds

The hypoglycaemic effects of Litchi chinensis Sonn. seeds extract (LSE) on type 2 diabetic (T2D) rats and the active constituents from LSE were investigated. As a result, 21 compounds including 3,5-dihydroxybenzoic acid, 3,4-dihydroxybenzaldehyde, procyanidin D, cianidanol, cinnamtannin B1, procyanidin A1, scopoletin, rutin, phlorizin and epicatechin–epicatechin–catechin were identified by UPLC-Q/TOF-MS. The content of polyphenols reached 43.37 ± 2.34 g of cianidanol/100 g. After one-month treatment, LSE improved quality of life of streptozotocin (STZ)/high fat diet induced T2D rats and protected against pancreas, liver and kidney tissues damage through the improvement of glucose tolerance and insulin resistance. In addition, LSE influenced lipid metabolism and increased mRNA levels of Bax and NF-κB, thereby inhibiting apoptosis-induced hepatic damage and inflammation to protect the body against diabetic exacerbation. For the first time, this study delineated Litchi seeds' anti-diabetic prospect of treatment for type 2 diabetes.

Identification of phenolics in litchi and evaluation of anticancer cell proliferation activity and intracellular antioxidant activity

Litchi leaf is a good resource for phenolics, which are good candidates for medicines. In this work, three phenolics were isolated from litchi leaf by column chromatography. Their structures were identified by electrospray ionization–mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) spectroscopy as secoisolariciresinol 9′-O-β-D-xyloside (1), 4,7,7′,8′,9,9′-hexahydroxy-3,3′-dimethoxy-8,4′-oxyneolignan (2), and cinnamtannin B1 (3). Cinnamtannin B1 showed better extra- and intracellular antioxidant activities than Compounds 1 and 2. The intracellular antioxidant activity of cinnamtannin B1 was related to the upregulation of endogenous antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase), and inhibition of ROS generation. Furthermore, cinnamtannin B1 exhibited strong antiproliferative effects against HepG2 and Siha cell lines with no significant cytotoxicities. In the case of the HepG2 cell line, cell cycle arrest and apoptosis induction were the underlying anticancer mechanisms of cinnamtannin B1. The results indicated that cinnamtannin B1 was a potent cancer cell proliferation inhibitor and a good intracellular antioxidant.

ChemInform Abstract: Annulation Approach to Doubly Linked (A‐Type) Oligocatechins: Syntheses of (+)‐Procyanidin A2 and (+)‐Cinnamtannin B1.

AbstractThe first stereoselective and high‐yielding syntheses of (+)‐procyanidin A2 (I) and (+)‐cinnamtannin B1 (II) are achieved by exploiting dual activation of the electrophilic flavan units at C‐2 and C‐4, thus allowing catechin annulation with nucleophilic flavan units in a regio‐ and stereoselective manner.

Annulation Approach to Doubly Linked (A‐type) Oligocatechins: Syntheses of (+)‐Procyanidin A2 and (+)‐Cinnamtannin B1

AbstractThe first stereoselective syntheses of doubly linked (A‐type) oligocatechins, (+)‐procyanidin A2 and (+)‐cinnamtannin B1, have been achieved. Ethylenedioxy‐bridged flavans served as excellent platforms, thus allowing annulation with nucleophilic catechin units in a stereoselective manner. An additional key was the new synthetic approach to selectively protected nucleophilic catechin, thus enabling regioselective construction of the key dioxabicyclo skeleton of the A‐type oligocatechins.

Annulation approach to doubly linked (A-type) oligocatechins: syntheses of (+)-procyanidin A₂ and (+)-cinnamtannin B₁.

The first stereoselective syntheses of doubly linked (A-type) oligocatechins, (+)-procyanidin A2 and (+)-cinnamtannin B1, have been achieved. Ethylenedioxy-bridged flavans served as excellent platforms, thus allowing annulation with nucleophilic catechin units in a stereoselective manner. An additional key was the new synthetic approach to selectively protected nucleophilic catechin, thus enabling regioselective construction of the key dioxabicyclo skeleton of the A-type oligocatechins.

Crocin prevents sesamol-induced oxidative stress and apoptosis in human platelets

Recent studies have reported the platelet proapoptotic propensity of plant-derived molecules such as, resveratrol, thymoquinone, andrographolide and gossypol. Meanwhile, there were also reports of phytochemicals such as cinnamtannin B1, which shows antiapoptotic effect towards platelets. Platelets are mainly involved in hemostasis, thrombosis and wound healing. However, altered platelet functions can have serious pathological outcomes that include cardiovascular diseases. Platelets are sensitive to external and internal stimuli including therapeutic and dietary components. The anuclear platelets do undergo apoptosis via mitochondrial pathway. However, exaggerated rate of platelet apoptosis could lead to thrombocytopenia and other bleeding disorders. The present study deals with ameliorative efficacy of crocin on sesamol-induced platelet apoptosis. The antiapoptotic property of crocin and the proapoptotic tendency of sesamol in platelets were previously demonstrated. Therefore, it was interesting to see how these two compounds would interact and wield their effects on human platelets. Crocin effectively inhibited sesamol-induced oxidative stress on platelets, which was evidenced by the measurement of endogenously generated reactive oxygen species, particularly hydrogen peroxide, and changes in thiol levels. Further, crocin abrogated sesamol-induced biochemical events of apoptosis in platelets, which include intracellular calcium mobilization, changes in mitochondrial membrane integrity, cytochrome c release, caspase activity and phosphatidylserine externalization. Even though sesamol has proapoptotic effects on platelets, its anti-platelet activity cannot be neglected. Thus, the study proposes that sesamol could be supplemented with crocin, an approach that could not only abolish the toxic effects of sesamol on platelets, but also enhance the quality of treatment due to their synergistic action.

Flavonoids from Lindera glauca Blume as low-density lipoprotein oxidation inhibitors

In order to identify antioxidant flavonoids from Lindera glauca Blume, we performed phytochemical analysis of L. glauca Blume heartwood and isolated eight flavonoids – lindeglaucol (1), lindeglaucone (2), cilicicone B (3), tamarixetin 3-O-α-L-rhamnoside (4), procyanidin A2 (5), cinnamtannin B1 (6), cinnamtannin D1 (7), and procyanidin A1 (8) – through repeated column chromatography over silica gel (SiO2), octadecyl silica gel (ODS) and Sephadex LH-20. The chemical structures of compounds 1–8 were elucidated from spectroscopic data (NMR, IR and MS). The low-density lipoprotein oxidation inhibitory activities of the isolated compounds were evaluated in vitro by using the thiobarbituric acid reactive substances assay. Compounds 5–8 exhibited high inhibition activity, comparable to the positive control butyl hydroxyl toluene. Compounds 2 and 3 were slightly less active, while 1 and 4 expressed low activity.

Oxidative conversion of B- to A-type procyanidin trimer: Evidence for quinone methide mechanism

Two main types of procyanidin oligomers (A-type and B-type) are present in plants. Previous studies revealed that B-type procyanidin dimers can be converted into A-type dimers by oxidation. However, the mechanism lacks experimental proof. In this study, the conditions of a B-type procyanidin trimer, procyanidin C-1 (PC-1), conversion to A-type cinnamtannin B-1 (CTB-1), including temperature, pH value and four catalysts were investigated. The catalysts include DPPH, O2-, polyphenol oxidase and xanthine oxidase. Results show that the conversion is significantly affected by temperature and pH. Both free radicals and oxidases accelerate the conversion rate with the same products but show no increase in conversion ratio. Moreover, the isolation and identification of continuous oxidation products (P 1–P 4) from CTB-1 are discussed here. These results demonstrate that the oxidative conversion of B- to A- procyanidins in plants might involve a free radical-driven process or an enzyme-catalyzed free radical reaction via a quinone methide mechanism.

Immunosuppressive Effects of A‐Type Procyanidin Oligomers from Cinnamomum tamala

Cinnamon barks extracts have been reported to regulate immune function; however, the component(s) in cinnamon barks responsible for this effect is/are not yet clear. The aim of this study is to find out the possible component(s) that can be used as therapeutic agents for immune-related diseases from cinnamon bark. In this study, the immunosuppressive effects of fraction (named CT-F) and five procyanidin oligomers compounds, cinnamtannin B1, cinnamtannin D1 (CTD-1), parameritannin A1, procyanidin B2, and procyanidin C1, from Cinnamomum tamala or Cinnamomum cassia bark were examined on splenocytes proliferation model induced by ConA or LPS. Then, the effects of activated compound CTD-1 on cytokine production and 2,4-dinitrofluorobenzene (DNFB) induced delayed-type hypersensitivity (DTH) response were detected to evaluate the immunosuppressive activity of CTD-1. It was found that CT-F and CTD-1 significantly inhibited the splenocyte proliferation induced by ConA or LPS. CTD-1 dose-dependently reduced the level of IFN-γ and IL-2 and intensively suppressed DNFB-induced DTH responses. These findings suggest that the immunosuppressive activities of cinnamon bark are in part due to procyanidin oligomers. CTD-1 may be a potential therapeutic agent for immune-related diseases.

Procyanidins from the stem wood of Machilus japonica and their inhibitory effect on LDL oxidation

The stem wood of Machilus japonica Siebold & Zucc were extracted with 80 % aqueous MeOH, and the concentrated extract was successively partitioned with ethyl acetate (EtOAc), normal butanol, and water. From the EtOAc fraction, five procyanidins, procyanidin A1 (1), procyanidin A2 (2), procyanidin B7 (3), cinnamtannin B1 (4), and aesculitannin B (5), were isolated. Their chemical structures were identified through spectroscopic data analyses including NMR, MS, and IR. This is the first time any of these compounds have been isolated from this plant. The compounds were evaluated for inhibition activity on LDL oxidation. All of these compounds and the positive control, BHT, showed a very high inhibition effect with IC50 values of 0.94, 2.1, 1.8, 1.1, 1.0, and 1.9 μM, respectively.

The Effect of Copigmentation on the Stability of Butterfly Pea Anthocyanins

The objective of this research was to study the effects of co-pigmentation on the colour display and stability of Butterfly Pea extracts with plant extracts under different pH. The scopes of the work focus on the effect on co-pigmentation of the Cinnamon, Cumin and Turmeric extract on the colour display. The effects on colour enhancement and the stability of Butterfly Pea extract were evaluated. LC/MS/MS analysis shows that the anthocyanin in Butterfly Pea is highly acylated and therefore, is stable due to intramolecular copigmentation. The flavonoids content in Cinnamon extract was identified as Cinnamtannin B1(m/z 864.7, MW 864.7156) while in.Cumin extract, Apigenin 7-galacturonylglucoside (m/z 609.409, MW 608.524) and Luteolin 7-digalacturonide-4-glucoside (m/z 625.376, MW 624.376) were presented. Dimethoxycurcumin (m/z 394.2, MW 394.0134 and m/z 313.0, MW 312.975) was identified in Turmeric extract. Turmeric was suggested as the best copigment for Butterfly Pea since it showed the highest hyperchromic shift (61.41%), followed by Cinnamon extract (17.04%) and Cumin extract (16.08%).

Transepithelial Permeability Studies of Flavan-3-ol-C-glucosides and Procyanidin Dimers and Trimers across the Caco-2 Cell Monolayer

In this study the permeability of two flavanol-C-glucosides (FCglcs) and five dimeric and trimeric flavan-3-ols, namely, procyanidins (PCs), was investigated with the human colon carcinoma cell line (Caco-2) model. These compounds can be found especially in cocoa, and they are of great interest due to their assumed beneficial health effects. Transepithelial electrical resistance (TEER) and capacitance were measured online with a CellZscope device prior to and during the whole experiment to guarantee the maintenance of the barrier properties. The transport experiments with pure, single compounds (50-300 μM) from apical to basolateral side showed slight permeation of PCs A2, B2, and B5 and cinnamtannin B1 (CB1) as well as (-)-catechin-6-C-glucoside (C6Cglc) and (-)-catechin-8-C-glucoside (C8Cglc) of about 0.02-0.2% after 24 h. Transport of PC C1 could not be detected. Inhibition of P-glycoprotein (Pgp) increased the permeation of PC B2 and CB1 to the basolateral side, which indicates that Pgp counteracts the transport of these compounds. Metabolites (epicatechin, 3'- and 4'-O-epicatechin) in very small amounts were detectable only for PC B2. These are the first data concerning the permeability of flavan-3-ol-C-glucosides across the Caco-2 cell monolayer.

Differential Action of Phytochemicals on Platelet Apoptosis: A Biological Overview

Platelets are anuclear blood cells originating from bone megakaryocytes. Despite being anuclear, their number is maintained by apoptosis, a process of programmed cell death. The rate of apoptotic death of platelets is accelerated by oxidative and shear stress, ex vivo storage (blood banking conditions) and certain pathophysiological disorders. These factors initiate apoptotic events through the mitochondria- mediated intrinsic pathway. Besides, apoptotic platelets also release phosphatidylserine-positive membrane fractions called microparticles, which cause fibrin deposition and thrombus formation, and are involved in the promulgation of a host of disease conditions including cardiovascular diseases. In this context, several phytochemicals have been reported to be cardioprotective and work by inhibiting platelet aggregation or by dissolving the fibrin clots. Besides, ample reports focus on the positive effects of phytochemicals on normal physiology of platelets, but do not focus on their adverse effects on platelets. Moreover, platelets are reported to be extremely sensitive to therapeutic components in the blood. For example, resveratrol and thymoquinone are hitherto known compounds to possess proapoptotic effects on platelets. In contrast, cinnamtannin B1 and crocin exhibit antiapoptotic effects. Thus, the current review aims to elucidate the underlying mechanisms through which the phytochemicals mediate their effects on platelet apoptosis. Moreover, the need for scrutiny of therapeutic compounds for their effects on platelet functions before including them in treatment regimen is also being emphasized.

Intestinal Metabolism of Two A-type Procyanidins Using the Pig Cecum Model: Detailed Structure Elucidation of Unknown Catabolites with Fourier Transform Mass Spectrometry (FTMS)

Procyanidins, as important secondary plant metabolites in fruits, berries, and beverages such as cacao and tea, are supposed to have positive health impacts, although their bioavailability is yet not clear. One important aspect for bioavailability is intestinal metabolism. The investigation of the microbial catabolism of A-type procyanidins is of great importance due to their more complex structure in comparison to B-type procyanidins. A-type procyanidins exhibit an additional ether linkage between the flavan-3-ol monomers. In this study two A-type procyanidins, procyanidin A2 and cinnamtannin B1, were incubated in the pig cecum model to mimic the degradation caused by the microbiota. Both A-type procyanidins were degraded by the microbiota. Procyanidin A2 as a dimer was degraded by about 80% and cinnamtannin B1 as a trimer by about 40% within 8 h of incubation. Hydroxylated phenolic compounds were quantified as degradation products. In addition, two yet unknown catabolites were identified, and the structures were elucidated by Fourier transform mass spectrometry.

Analysis of Flavan-3-ols and Procyanidins in Food Samples by Reversed Phase High-Performance Liquid Chromatography Coupled to Electrospray Ionization Tandem Mass Spectrometry (RP-HPLC-ESI-MS/MS)

Concentrations of the main dimeric and trimeric procyanidins (PC) and their monomeric constitutive units catechin (CT) and epicatechin (EC) were determined in food samples by using reversed phase high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (RP-HPLC-ESI-MS/MS). In a first step, 12 PCs (PC B1, B2, B3, B4, B5, B6, B7, B8, C1, C2, and A2 and cinnamtannin B1), of which most are not commercially available, were isolated from plant materials or synthesized and purified by a combination of column chromatographic separation techniques with different stationary phases. These PCs in combination with CT and EC were used as standard substances for identification and quantification during the following screening of food samples by RP-HPLC-ESI-MS/MS analysis. The main focus of the newly developed RP-HPLC-ESI-MS/MS method is the compensation of matrix effects by using the echo-peak technique simulating internal standard injection. The suitability of this new method was demonstrated by the determination of recovery rates being 90% or higher. Use of this method allowed the determination of patterns and concentrations of PCs in 55 food samples.

Simple solution for a complex problem: Proanthocyanidins, galloyl glucoses and ellagitannins fit on a single calibration curve in high performance-gel permeation chromatography

This study was undertaken to explore gel permeation chromatography (GPC) for estimating molecular weights of proanthocyanidin fractions isolated from sainfoin ( Onobrychis viciifolia). The results were compared with data obtained by thiolytic degradation of the same fractions. Polystyrene, polyethylene glycol and polymethyl methacrylate standards were not suitable for estimating the molecular weights of underivatized proanthocyanidins. Therefore, a novel HPLC–GPC method was developed based on two serially connected PolarGel-L columns using DMF that contained 5% water, 1% acetic acid and 0.15 M LiBr at 0.7 ml/min and 50 °C. This yielded a single calibration curve for galloyl glucoses (trigalloyl glucose, pentagalloyl glucose), ellagitannins (pedunculagin, vescalagin, punicalagin, oenothein B, gemin A), proanthocyanidins (procyanidin B2, cinnamtannin B1), and several other polyphenols (catechin, epicatechin gallate, epicallocatechin gallate, amentoflavone). These GPC predicted molecular weights represented a considerable advance over previously reported HPLC–GPC methods for underivatized proanthocyanidins.

Phytochemical Characterization ofRhododendron ferrugineumandIn VitroAssessment of an Aqueous Extract on Cell Toxicity

Within a systematic phytochemical investigation of the leaves of RHODODENDRON FERRUGINEUM L. (Ericaceae), the volatile oil was isolated (0.7 %) and its constituents were characterized. Eleven flavonoids were isolated and characterized, with quercetin 3- O-[6''- O-(2-methyl-1-oxobutyl)]-β- D-glucopyranoside and 2 R,3 R-dihydromyricetin 3- O- β- L-arabinopyranoside as new natural products. Beside monomeric flavan-3-ols (catechin, epicatechin, gallocatechin, epigallocatechin) from the tannin fraction (about 3.5 % calculated as pyrogallol), the dimeric procyanidins B1 to B7 were identified, as well as the trimeric compounds procyanidin C1, epicatechin-(4 β → 8)-epicatechin-(4 β → 8)-catechin and the trimeric A type-linked cinnamtannin B1. Additionally, phloroacetophenon 4- O- β- D-glucopyranoside and chlorogenic acid were isolated. Water-soluble carbohydrates comprised about 13.5 % of the dried leaves, including fructans (3 %), polysaccharides (1 %) (mainly type II arabinogalactans), glucose, fructose, sucrose, stachyose and raffinose. The IN VITRO effects on cellular vitality (MTT test), proliferation (BrdU incorporation) and necrosis (LDH release) of an aqueous extract were investigated. The extract did not exert any toxic effects, while the vitality and the proliferation rates of epithelial HaCaT keratinocytes were significantly increased at 100 µg/mL, indicating that the aqueous extract does not have negative effects against cellular activity.

Proanthocyanidins and a phloroglucinol derivative from Rumex acetosa L.

From the ethyl acetate soluble fraction of an acetone-water extract of the aerial parts of Rumex acetosa L. (Polygonaceae), a variety of monomeric flavan-3-ols (catechin, epicatechin, epicatechin-3-O-gallate), A- and B-type procyanidins and propelargonidins (15 dimers, 7 trimers, 2 tetramers) were isolated with 5 so far unknown natural products. Dimers: procyanidin B1, B2, B3, B4, B5, B7, A2, epiafzelechin-(4beta-->8)-epicatechin, epiafzelechin-(4beta-->8)-epicatechin-3-O-gallate (new natural product), epiafzelechin-(4beta-->6)-epicatechin-3-O-gallate (new natural product), epiafzelechin-3-O-gallate-(4beta-->8)-epicatechin-3-O-gallate, B2-3'-O-gallate, B2-3,3'-di-O-gallate, B5-3'-O-gallate, and B5-3,3'-di-O-gallate. Trimers: procyanidin C1, epiafzelechin-(4beta-->8)-epicatechin-(4beta-->8)-epicatechin (new natural product), epicatechin-(4beta-->8)-epicatechin-(4beta-->8)-catechin, cinnamtannin B1, cinnamtannin B1-3-O-gallate (new natural product), tentatively epicatechin-(2beta-->7, 4beta-->8)-epiafzelechin-(4alpha-->8)-epicatechin (new natural product), and epicatechin-3-O-gallate-(4beta-->8)-epicatechin-3-O-gallate-(4beta-->8)-epicatechin-3-O-gallate. Tetramers: procyanidin D1 and parameritannin A1. All compounds were elucidated by ESI-MS, CD spectra, 1D- and 2D-NMR experiments as free phenols or peracetylated derivatives and, in part, after partial acid-catalysed degradation with phloroglucinol. A more abundant proanthocyanidin polymer was also isolated, purified and its chemical composition studied by (13)C NMR. In addition a so far unknown phloroglucinolglycoside (1-O-beta-D-(2,4-dihydroxy-6-methoxyphenyl)-6-O-(4-hydroxy-3,5-dimethoxybenzoyl)-glucopyranoside) was isolated.

Phytochemical Composition and Antioxidant Activity ofLaurus nobilisL. Leaf Infusion

Laurus nobilis L. (laurel) leaves are frequently used as a spice for cooking purposes. Folk medicine in many countries uses the infusion of the plant in stomachic and carminative remedies, as well as for the treatment of gastric diseases. Little information is available about the phytochemical composition of the infusion of dried leaves, which is a way to consume this aromatic and medicinal plant. Phytochemical investigations on the infusion were performed by high-performance liquid chromatography (HPLC) with a diode array detector (DAD) and direct electrospray ionization-tandem mass spectrometry. Several flavonoid derivatives were detected. Semipreparative HPLC from the infusion of laurel leaves isolated 10 flavonoid O-glycosides, one flavonoid C-glycoside, catechin, and cinnamtannin B1. Structures of the isolated compounds were computed on the basis of spectral measurements including high-resolution mass spectrometry spectroscopy and one- and two-dimensional nuclear magnetic resonance techniques. The amount of the flavonoids was also determined by HPLC-DAD. The antioxidant activity of the tea and the isolated compounds was also measured using two different in vitro methods: the Briggs-Rauscher oscillating reaction test, at a pH similar to that of the gastric juice, and the Trolox equivalent antioxidant capacity assay, at the pH of blood. For the infusion and the methanol extract the total phenolic content was also measured using the Folin-Ciocalteu reagent.

470 POSTER Target identification permits rational development of the prodrug GMX1777 for the treatment of melanoma

This study was undertaken to explore gel permeation chromatography (GPC) for estimating molecular weights of proanthocyanidin fractions isolated from sainfoin (Onobrychis viciifolia). The results were compared with data obtained by thiolytic degradation of the same fractions. Polystyrene, polyethylene glycol and polymethyl methacrylate standards were not suitable for estimating the molecular weights of underivatized proanthocyanidins. Therefore, a novel HPLC–GPC method was developed based on two serially connected PolarGel-L columns using DMF that contained 5% water, 1% acetic acid and 0.15 M LiBr at 0.7 ml/min and 50 °C. This yielded a single calibration curve for galloyl glucoses (trigalloyl glucose, pentagalloyl glucose), ellagitannins (pedunculagin, vescalagin, punicalagin, oenothein B, gemin A), proanthocyanidins (procyanidin B2, cinnamtannin B1), and several other polyphenols (catechin, epicatechin gallate, epicallocatechin gallate, amentoflavone). These GPC predicted molecular weights represented a considerable advance over previously reported HPLC–GPC methods for underivatized proanthocyanidins.