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PubMed1969

The distribution of polyphenols in the tea plant (Camellia sinensis L.).

1. Methods for the separation and determination of the polyphenolic components of the tea plant by thin-layer chromatography and colorimetric reactions have been devised. 2. High concentrations of catechins, flavonols and depsides were found to be restricted to the young vegetative and floral shoots, whereas leucoanthocyanins or flavylogens were characteristic of the more bulky axial tissues of the plant. 3. In the young shoots cell growth was correlated with an increasing degree of flavonoid B-ring hydroxylation. 4. Maximal flavylogen concentrations occurred in the outer protective layers of stem and of seed coat. 5. Mature leaves were shown to contain derivatives of the flavones apigenin and luteolin. 6. Developing seedlings showed a steady increase in polyphenol complexity; flavylogens were concentrated at shoot and root apices and accumulated at the stem base. 7. It is postulated that the flavanols (leucoanthocyanins and catechins), because they can co-polymerize, are of use to the plant for protection of wood and bark against infection and decay.

Benzopyrans↗
PubMed2001

CYP98A3 from Arabidopsis thaliana is a 3'-hydroxylase of phenolic esters, a missing link in the phenylpropanoid pathway.

The 4- and 5-hydroxylations of phenolic compounds in plants are catalyzed by cytochrome P450 enzymes. The 3-hydroxylation step leading to the formation of caffeic acid from p-coumaric acid remained elusive, however, alternatively described as a phenol oxidase, a dioxygenase, or a P450 enzyme, with no decisive evidence for the involvement of any in the reaction in planta. In this study, we show that the gene encoding CYP98A3, which was the best possible P450 candidate for a 3-hydroxylase in the Arabidopsis genome, is highly expressed in inflorescence stems and wounded tissues. Recombinant CYP98A3 expressed in yeast did not metabolize free p-coumaric acid or its glucose or CoA esters, p-coumaraldehyde, or p-coumaryl alcohol, but very actively converted the 5-O-shikimate and 5-O-d-quinate esters of trans-p-coumaric acid into the corresponding caffeic acid conjugates. The shikimate ester was converted four times faster than the quinate derivative. Antibodies directed against recombinant CYP98A3 specifically revealed differentiating vascular tissues in stem and root. Taken together, these data show that CYP98A3 catalyzes the synthesis of chlorogenic acid and very likely also the 3-hydroxylation of lignin monomers. This hydroxylation occurs on depsides, the function of which was so far not understood, revealing an additional and unexpected level of networking in lignin biosynthesis.

Arabidopsis↗
PubMed1975

Solution conformation of virginiamycins (staphylomycins).

The 1H (at 300 MHz) and 13C nuclear magnetic resonance spectra of virginiamycins S and S4 and vernamycin Balpha have been unravelled and analyzed. Together with model building and theoretical considerations, this allows the detailed description of their solution conformations. The depside bond can rotate and gives to the backbone some conformational mobility. The orientation of the depsicarbonyl bond depends on the surrounding. Apparent discrepancies between the different methods that are applicable for the disclosure of the nature of peptide H-bonding, have found a rational explanation.

Hydrogen Bonding↗
PubMed1985

In vitro evaluation of the antimicrobial activity of lichen metabolites as potential preservatives.

Antimicrobial screening of several lichen species and subsequent isolation and structure elucidation of active compounds revealed that the hydrolysis products of certain lichen metabolites, i.e., depsides, were active against gram-negative bacteria and fungi as well as gram-positive bacteria. The active constituents isolated from Stereocaulon alpinum and Peltigera aphthosa were identified, respectively, as methyl beta-orsellinate and a mixture of methyl and ethyl orsellinates. MIC determinations indicated that activity of these compounds was superior to that of the commonly used preservative agents methyl and propyl p-hydroxybenzoates and was of the same order as that of chlorocresol.

Anti-Bacterial Agents↗
PubMed1981

Thielavin A and B, new inhibitors of prostaglandin biosynthesis produced by Thielavia terricola.

Two potent inhibitors of prostaglandin biosynthesis, thielavin A (C31H34O10) and B (C29H30O10), were isolated from cultures of Thielavia terricola. Both of these compounds were shown to be structurally related to depsides, thus consisting of three hydroxybenzoic acid groups. Concentrations required for 50% inhibition of the conversion of 14C-arachidonic acid into prostaglandins F2 alpha plus E2 by microsomes of ram seminal vesicles were 12 microM for thielavin A and 9 microM for thielavin B, respectively. Of the enzymatic steps involved in prostaglandin synthesis, thielavin A specifically inhibited the conversion of arachidonic acid into prostaglandin H2, while prostaglandin E2 synthesis from the endoperoxide was the most sensitive to thielavin B. Thromboxane A2 synthesis from prostaglandin H2 in bovine platelet microsomes were inhibited by 50% at concentrations of 150 and 350 microM of thielavin A and B, respectively. Thielavin B was significantly effective on carrageenan-induced oedema of rats when administered intravenously but on on oral administration. The anti-inflammatory activity was not detectable with thielavin A either on intravenous injection or on oral administration.

Animals↗
PubMed1999

Preliminary physicochemical evaluations and bioactive properties of column fractions from the lichen.

The chloroform-soluble portion of an ethanolic extract of the lichen Ramalina farinacea was separated by column chromatography using n-hexane: ethylacetate (4:1) as the mobile phase and silica gel S as the stationary phase. Four column fractions (B, C, H and I) and the n-hexane-soluble portion of the ethanolic extract (N) were screened for possible biological activity by the Brine Shrimp Lethality Bioassay Technique. Some physicochemical evaluations of the column fractions such as pH determinations, ultraviolet (UV) absorption spectra, solubility profile and some chemical tests were also carried out. Phytochemical and elemental analysis of the crude lichen material was equally carried out. Results showed that all the fractions and the n-hexane extract were biologically active with the bioactivity of N > B > C > I > H. Fractions B and C were both acidic and evaluation of their solubility profile, UV spectra and some chemical reactions suggest that the fractions are possibly depsides and depsidones respectively.

Animals↗
PubMedDate not supplied

Polyphenolic compounds from Platycodon grandiflorum A. DC.

Flavonoids and phenolic acids from the aerial parts of Platycodon grandiflorum A. DC. were analysed by isocratic TLC, MGD-TLC and HPLC methods. Four flavonoid compounds were determined including luteolin 7-O-glucoside as the main component and apigenin 7-O-glucoside, luteolin and apigenin. When performing HPLC analysis, 12 phenolic acids in the free, depside and glycoside forms were identified. Among them, 3,4-dimethoxycinnamic, caffeic, chlorogenic, ferulic, isoferulic, homovanillic, alpha-resorcylic, m-coumaric, p-coumaric, p-hydroxybenzoic, 2-hydroxy-4-methoxybenzoic and 2,3-dihydroxybenzoic acids.

Chromatography, High Pressure Liquid↗
PubMed1998

[Plant anatomical and phytochemical evaluation of Salvia species].

Plant-anatomical and phytochemical investigations were carried out on three Salvia species: S.officinalis L., S.sclarea L., S.pratensis L. It was established that the structure of the glandular hairs of the three species doesn't differ from each other but the characteristics of the covering hairs are different. The covering hairs of sage (Salvia officinalis) consist of 1-4 cells and have protective function. The hairs of the other two Salvia species are bristle hairs. The highest essential oil content was found in sage and the lowest one in S. pratensis. The qualitative and quantitative composition of the essential oils of Salvia species was also various but the qualitative composition of leaf, calix and petal of the same Salvia species was characteristical standard; significant differences were found only in their quantitative composition. Sclareol diterpene alcohol was the main component of the hexane extract obtained from clary sage flowering herb. In polyphenol ingredients Salvia officinalis was the richest. The results demonstrated that the 20% ethanol is the best of the 20, 40, 70% alcoholic solvents, for the extraction of polyphenol compounds. It was established that the rosmarinic acid depside was the main component of polyphenols. Mineral elements were also analysed in the Salvia species leaves as well in the alcoholic and wateric extracts of sage. The magnesium content was considerable in S. pratensis, the zinc content was the highest in S. officinalis.

Flavonoids↗
PubMed2004

Anti-inflammatory and anti-allergic effect of rosmarinic acid (RA); inhibition of seasonal allergic rhinoconjunctivitis (SAR) and its mechanism.

The present study was undertaken to determine whether oral supplementation with rosmarinic acid (RA) is an effective intervention for patients with SAR. In addition, the anti-inflammatory mechanism of RA also estimated in the ear edema models. CLINICAL TRIAL: Patients were treated daily with RA (200 mg or 50 mg) or placebo for 21 days. Patients recorded symptoms daily and profiles of infiltrating cells and concentration of cytokines were measured in nasal lavage fluid. Compared to placebo, supplementation with RA resulted in a significant decrease in responder rates for each symptom. RA also significantly decreased the numbers of neutrophils and eosinophils in nasal lavage fluid. ANIMAL STUDY: Topical application RA showed anti-inflammatory activity 5-hours after 12-tetradecanoylphorbol 13-acetate (TPA) treatment with marked inhibition of neutrophil infiltration. Up regulation of ICAM-1, VCAM-1 cyclooxygenase-2 (COX-2), KC and MIP-2 by TPA were markedly reduced by pre-treatment with extract of perilla (PE) or RA. Reactive oxygen radical production detected as thiobarbituric acid reactive substance (TBARS), lipid peroxide (LPO) and 8-hydroxy-2'deoxyguanosine (8OH-dG), by double treatment of TPA was reduced by pretreatment with PE or RA. RA is an effective intervention for SAR that is mediated by inhibition of PMNL infiltration. This effect of RA is due to two independent mechanisms: inhibition of the inflammatory response and scavenging of ROS.

Animals↗
PubMed2005

HPLC determination and pharmacokinetic studies of salvianolic acid B in rat plasma after oral administration of Radix Salviae Miltiorrhizae extract.

A precise and reproducible HPLC method has been established and validated for determination of salvianolic acid B (SalB) in rat plasma after oral administration of Radix Salviae Miltiorrhizae extract. Liquid-liquid extraction was adopted for the sample preparation. Separation was accomplished on a C(18) column with a linear gradient elution consisting of acetonitrile and aqueous phosphoric acid. Ultraviolet detection was at 280 nm. The method was validated over the concentration range 10.8-259.4 microg/mL using 1 mL of plasma. The assay was linear over this concentration range with a coefficient of variation less than 7%. The extraction recovery of SalB was within the range 71-83% with RSD 11%. The mean recovery of the internal standard was 84% (n = 6) with RSD of 5.6%. This method is suitable to determine SalB in plasma and to investigate the pharmacokinetics of SalB.

Acetonitriles↗
PubMed2007

A solid-phase extraction method for high-performance liquid chromatographic determination of salvianolic acid B in rabbit plasma: application to pharmacokinetic study.

A sensitive solid-phase extraction/high-performance liquid chromatographic method with ultraviolet detection was established for the analysis of salvianolic acid B in rabbit plasma. The analyte was separated on a reversed-phase column with trifluoroacetic acid-methanol-acetonitrile (70:10:20, v/v/v) as mobile phase at a flow rate of 1 mL/min, and ultraviolet detection at 315 nm. The calibration curve for salvianolic acid B was linear over the range 35-1400 microg/L with coefficients of correlation >0.999. The inter-day and intra-day precisions of analysis were <15%, and assay accuracy ranged from 95.3 to 109.1%. This method is suitable for determining salvianolic acid B in plasma and thus investigating the pharmacokinetics of salvianolic acid B.

Animals↗
PubMed2003

Rosmarinic acid inhibits TCR-induced T cell activation and proliferation in an Lck-dependent manner.

Lck is a T cell-restricted Src family protein tyrosine kinase that plays pivotal roles in TCR-mediated signaling. We aimed to identify novel agents that could disrupt the molecular interaction of the Src homology 2-domain of Lck (Lck SH2) with its binding partners, with the expectation that this would impair TCR signaling and generate immunosuppression. Large-scale screening of plant extracts indicated that rosmarinic acid (RosA) in extracts of Prunella vulgaris consistently inhibits the interaction between Lck SH2 and a peptide containing its consensus binding sequence (pYEEI). The inhibitory effect of RosA was specific for SH2 domains of Src family protein tyrosine kinase. RosA inhibited TCR-induced-Ca(2+) mobilization and IL-2 promoter activation but not phorbol 12-myristate 13-acetate/ionomycin-induced IL-2 promoter activation, indicating its point of inhibition at the membrane proximal site of TCR signaling. Furthermore, RosA inhibited TCR-induced splenocyte proliferation as well as one-way MLR at an IC(50) of 25-50 microM and inhibited cytokine expression such as IL-2 and IFN-gamma. Here, we first report RosA as an inhibitor of TCR-signaling and subsequent T cell proliferation.

Calcium↗
PubMedDate not supplied

Effects of rosmarinic acid against aflatoxin B1 and ochratoxin-A-induced cell damage in a human hepatoma cell line (Hep G2).

Recent findings have suggested that oxidative damage might contribute to the cytotoxicity and carcinogenicity of aflatoxin B(1) (AFB(1)). The induction of oxidative stress also plays an important role in the toxicity of another mycotoxin: ochratoxin A (OTA). In this study, the protective effect of rosmarinic acid (Ros A) against AFB(1) and OTA-induced cytotoxicity was investigated in a human hepatoma-derived cell line (Hep G2). Rosmarinic acid, a natural phenolic compound contained in many Lamiaceae herbs such as Perilla frutescens, sage, basil and mint, inhibits complement-dependent inflammatory processes and may have therapeutic potential. The ability of Ros A to reduce radical oxygen species (ROS) production, protein and DNA synthesis inhibition and apoptosis caused by the two mycotoxins was also investigated. Our experiments proved the significant cytoprotective effect of Ros A in vitro from OTA- and AFB(1)-induced cell damage. In particular, 24-h pretreatment with 50 micro M Ros A inhibited the cytotoxicity of 10 micro M AFB(1) (by 45%) and 10 micro M OTA (by 35%) in Hep G2 cells (P < 0.001). Moreover, Ros A dose dependently attenuated ROS production and DNA and protein synthesis inhibition induced by both of the toxins. Similarly, apoptosis cell death was prevented, as demonstrated by reduction of DNA fragmentation and inhibition of caspase-3 activation (P < 0.001).

Aflatoxin B1↗
PubMed2001

Salvianolic acid B attenuates VCAM-1 and ICAM-1 expression in TNF-alpha-treated human aortic endothelial cells.

Attachment to, and migration of leukocytes into the vessel wall is an early event in atherogenesis. Expression of cell adhesion molecules by the arterial endothelium may play a major role in atherosclerosis. It has been suggested that antioxidants inhibit the expression of adhesion molecules and may thus attenuate the processes leading to atherosclerosis. In the present study, the effects of a potent water-soluble antioxidant, salvianolic acid B (Sal B), and an aqueous ethanolic extract (SME), both derived from a Chinese herb, Salvia miltiorrhiza, on the expression of endothelial-leukocyte adhesion molecules by tumor necrosis factor-alpha (TNF-alpha)-treated human aortic endothelial cells (HAECs) were investigated. When pretreated with SME (50 and 100 microg/ml), the TNF-alpha-induced expression of vascular adhesion molecule-1 (VCAM-1) was notably attenuated (77.2 +/- 3.2% and 80.0 +/- 2.2%, respectively); and with Sal B (1, 2.5, 5, 10, and 20 microg/ml), 84.5 +/- 1.9%, 78.8 +/- 1.2%, 58.9 +/- 0.4%, 58.7 +/- 0.9%, and 57.4 +/- 0.3%, respectively. Dose-dependent lowering of expression of intercellular cell adhesion molecule-1 (ICAM-1) was also seen with SME or Sal B. In contrast, the expression of endothelial cell selectin (E-selectin) was not affected. SME (50 microg/ml) or Sal B (5 microg/ml) significantly reduced the binding of the human monocytic cell line, U937, to TNF-alpha-stimulated HAECs (45.7 +/- 2.5% and 55.8 +/- 1.2%, respectively). SME or Sal B significantly inhibited TNF-alpha-induced activation of nuclear factor kappa B (NF-kappaB) in HAECs (0.36- and 0.48-fold, respectively). These results demonstrate that SME and Sal B have anti-inflammatory properties and may explain their anti-atherosclerotic properties. This new mechanism of action of Sal B and SME, in addition to their previously reported inhibition of LDL, may help explain their efficacy in the treatment of atherosclerosis.

Antioxidants↗
PubMed2005

Salvianolic acid B attenuates plasminogen activator inhibitor type 1 production in TNF-alpha treated human umbilical vein endothelial cells.

Plasminogen activator inhibitor type 1 (PAI-1), which plays a role in the development of atherosclerosis, is produced by endothelial cells following stimulation with various inflammatory cytokines such as tumor necrosis factor (TNF-alpha). In the present study, we investigated the effects of a potent water-soluble antioxidant, salvianolic acid B (SalB; derived from the Chinese herb, Salvia miltiorrhiza), on the expression of PAI-1 in TNF-alpha-treated human umbilical vein endothelial cells (HUVECs). We found that SalB inhibited TNF-alpha-induced PAI-1 mRNA production and protein secretion in HUVECs. Treatment with SalB (0.05 and 0.15 microM) notably attenuated TNF-alpha induced expression of PAI-1 to 90.5% and 74.6%, respectively, after 12 h, and to 75.1% and 64.2%, respectively, after 18 h. We also observed a dose-dependent decrease in PAI-1 protein production in the presence of SalB. We then used pathway inhibitors to investigate which step of the TNF-alpha induced signaling pathway was targeted by SalB. We found that the c-Jun N-terminal kinase (JNK) inhibitor, SP600125, increased the inhibitory effects of SalB on TNF-alpha-induced PAI-1 secretion, whereas the nuclear factor-kappaB (NF-kappaB) inhibitor, emodin, and the extracellular signal-regulated kinase (ERK) inhibitor, PD98059, did not. A gel shift assay further showed that SalB inhibited the TNF-alpha-activated NF-kappaB and AP-1 DNA binding activities in a dose-dependent manner. Collectively, these results indicate that the NF-kappaB and ERK-AP-1 pathways are possible targets of SalB in the regulation of TNF-alpha-stimulated PAI-1 production in HUVECs.

Benzofurans↗
PubMed2006

Salvianolic acid B attenuates cyclooxygenase-2 expression in vitro in LPS-treated human aortic smooth muscle cells and in vivo in the apolipoprotein-E-deficient mouse aorta.

Inflammation plays an essential role in atherosclerosis and post-angioplasty restenosis and the synthesis and release of inflammatory cytokines from vascular smooth muscle cells is an important contributor to these pathologies. It is assumed that drugs that prevent the overproduction of inflammatory cytokines may inhibit cardiovascular disorders. In the present study, the effects of a water-soluble antioxidant, salvianolic acid B (Sal B), derived from a Chinese herb, on the expression of cyclooxygenase (COX) in lipopolysaccharide (LPS)-treated human aortic smooth muscle cells (HASMCs) and in the aortas of cholesterol-fed apoE deficient mice were investigated. In unstimulated HASMCs, COX-2 mRNA and protein were almost undetectable, but were strongly upregulated in response to LPS. In contrast, HASMCs with or without LPS treatment showed constitutive expression of COX-1 mRNA and protein. The activation of COX-2 protein synthesis in LPS-stimulated HASMCs was shown to involve the activation of the extracellular-signal-regulated kinase 1/2 (ERK1/2), c-Jun NH(2)-terminal kinase (JNK), and p38 mitogen-activated protein kinase pathway. Incubation of HASMCs with Sal B before LPS stimulation resulted in pronounced downregulation of COX-2 expression. Sal B treatment suppressed ERK1/2 and JNK phosphorylation and attenuated the increase in prostaglandin E(2) production and NADPH oxidase activity in LPS-treated HASMCs. When apoE-deficient mice were fed a 0.15% cholesterol diet with or without supplementation with 0.3% Sal B for 12 weeks, the intima/media area ratio in the thoracic aortas was significantly reduced in the Sal B group (0.010 +/- 0.009%) compared to the apoE-deficient group (0.114 +/- 0.043%) and there was a significant reduction in COX-2 protein expression in the thickened intima. These results demonstrate that Sal B has anti-inflammatory properties and may explain its anti-atherosclerotic properties. This new mechanism of action of Sal B, in addition to its previously reported inhibition of LDL oxidation, may help explain its efficacy in the treatment of atherosclerosis.

Animals↗