Herbal Science Research - flavonoid

[Research on different processings of Scutellaria baicalensis Georgi]

Site Editor — Mon, 22 Oct 2007 18:19:21 -0700

[Research on different processings of Scutellaria baicalensis Georgi]: Zhong Yao Cai. 2006 Sep;29(9):893-5 Authors: Song SH, Wang BL, Feng JK, Wang ZZ

OBJECTIVE: Comparing the different processings of S. baicalensis Georgi with fresh herb. METHODS: Watering, cooking and steaming method were adopted and the contents of flavonoids was determined by HPLC. RESULTS: Cooking and steaming method could not only intenerate the slices, but also destroy the activity of enzyme. So different means could be choosen according to practice. CONCLUSION: Among them, cooking method with 1 time volume of water, heating 10 min, drying at 80 degrees C and steaming method taking 20 min, drying at 80 degrees C is proper.

PMID: 17212039 [PubMed - indexed for MEDLINE]

A journey of twenty-five years through the ecological biochemistry of flavonoids.

Site Editor — Thu, 27 Sep 2007 19:06:14 -0700

A journey of twenty-five years through the ecological biochemistry of flavonoids.: Biosci Biotechnol Biochem. 2007 Jun;71(6):1387-404 Authors: Tahara S

The ecological biochemistry of flavonoids, in which I have been engaged for 25 years, is summarized in this review article. The review covers (1) a survey of rare bio-active flavonoids in higher plants; (2) the fungal metabolism of prenylated flavonoids; (3) flavonoids antidoting against benzimidazole fungicides; (4) dihydroflavonol ampelopsin in Salix sachalinensis as a feeding stimulant towards willow beetles; and (5) flavones as signaling substances in the life-cycle development of the phytopathogenic Peronosporomycete Aphanomyces cochlioides, a cause of spinach root rot and sugar beet damping-off diseases. Finally recent trends in the ecological biochemistry of flavonoids are briefly described.

PMID: 17587669 [PubMed - indexed for MEDLINE]

[Effects of the flavonoids on cytochrome P-450 CYP1, 2E1, 3A4 and 19]

Site Editor — Wed, 30 May 2007 01:01:34 -0700

[Effects of the flavonoids on cytochrome P-450 CYP1, 2E1, 3A4 and 19]: Yao Xue Xue Bao. 2007 Jan;42(1):8-12 Authors: Zheng J, Zhou HH

Flavonoids are present in fruits, vegetables and beverages derived from plants, and in many dietary supplements or herbal remedies. A number of naturally occurring flavonoids have been shown to modulate the CYP450 system, including the induction or inhibition of these enzymes. This review focuses on the flavonoid effects on cytochrome P450 (CYP) enzyme CYP1, 2E1, 3A4 and 19. Flavonoids alter CYPs by various mechanisms, including the stimulation of gene expression via specific receptors and/or CYP protein, or mRNA stabilization and so on. But in vivo and in vitro, the effects of flavonoids are not always coincident as a result of concentrations of flavonoids, genetic and environmental factors. As well, flavonoids may interact with drugs through the induction or inhibition of their metabolism. Much attention should be paid to the metabolism interaction of the flavonoids when coadministered with other drugs.

Apigenin suppresses cancer cell growth through ERbeta.

Site Editor — Wed, 31 Jan 2007 19:21:50 -0800

Apigenin suppresses cancer cell growth through ERbeta.: Neoplasia. 2006 Nov;8(11):896-904 Authors: Mak P, Leung YK, Tang WY, Harwood C, Ho SM

Two flavonoids, genistein and apigenin, have been implicated as chemopreventive agents against prostate and breast cancers. However, the mechanisms behind their respective cancer-protective effects may vary significantly. The goal of this study was to determine whether the antiproliferative action of these flavonoids on prostate (DU-145) and breast (MDA-MB-231) cancer cells expressing only estrogen receptor (ER) beta is mediated by this ER subtype. It was found that both genistein and apigenin, although not 17beta-estradiol, exhibited antiproliferative effects and proapoptotic activities through caspase-3 activation in these two cell lines. In yeast transcription assays, both flavonoids displayed high specificity toward ERbeta transactivation, particularly at lower concentrations. However, in mammalian assay, apigenin was found to be more ERbeta-selective than genistein, which has equal potency in inducing transactivation through ERalpha and ERbeta. Small interfering RNA-mediated downregulation of ERbeta abrogated the antiproliferative effect of apigenin in both cancer cells but did not reverse that of genistein. Our data unveil, for the first time, that the anticancer action of apigenin is mediated, in part, by ERbeta. The differential use of ERalpha and ERbeta signaling for transaction between genistein and apigenin demonstrates the complexity of phytoestrogen action in the context of their anticancer properties.

Neuroprotective effects of green and black teas and their catechin gallate esters against beta-amyloid-induced toxicity.

Site Editor — Sat, 20 Jan 2007 16:40:11 -0800

Neuroprotective effects of green and black teas and their catechin gallate esters against beta-amyloid-induced toxicity.: Eur J Neurosci. 2006 Jan;23(1):55-64 Authors: Bastianetto S, Yao ZX, Papadopoulos V, Quirion R

Teas represent a large family of plants containing high amounts of polyphenols that may confer health benefits in various diseases. Recently, it has been hypothesized that tea consumption may also reduce the risk of age-related neurodegenerative pathologies. Considering the deleterious role of beta-amyloid (Abeta) in the aetiology of Alzheimer's disease (AD), we investigated green and black tea extracts and flavan-3-ols (present as monomers and dimers in green and black forms, respectively) against toxicity induced by Abeta-derived peptides using primary cultures of rat hippocampal cells as model. Both green and black tea extracts (5-25 microg/mL) displayed neuroprotective action against Abeta toxicity. These effects were shared by gallic acid (1-20 microm), epicatechin gallate (ECG; 1-20 microM) and epigallocatechin gallate (EGCG; 1-10 microM), the former being the most potent flavan-3-ol. In contrast, epicatechin and epigallocatechin were ineffective in the same range of concentrations. Moreover, only tea flavan-3-ol gallate esters (i.e. ECG, EGCG) and gallic acid inhibited apoptotic events induced by Abeta(25-35). Interestingly, EGCG and gallic acid inhibited Abeta aggregation and/or the formation of Abeta-derived diffusible neurotoxin ligands. Taken together, these results indicate that the catechin gallates (through the galloyl moiety) contribute to the neuroprotective effects of both green and black teas. Moreover, the protective effect of EGCG is likely to be associated, at least in part, with its inhibitory action on Abeta fibrils/oligomers formation. These data also support the hypothesis that not only green but also black teas may reduce age-related neurodegenerative diseases, such as AD.

[Pharmacological effects of flavonoids from Scutellaria baicalensis]

Site Editor — Tue, 09 Jan 2007 06:08:15 -0800

[Pharmacological effects of flavonoids from Scutellaria baicalensis]: Przegl Lek. 2006;63(2):95-6 Authors: Kowalczyk E, Krzesiński P, Kura M, Niedworok J, Kowalski J, Błaszczyk J

Scutellaria baicalensis is a plant widely used in Chinese and Japanese herbal medicine. Dry roots of Scutellaria baicalensis are used, especially as alcohol extracts. Flavonoids isolated from Radix Scutellariae have beneficial effects in hepatitis. Flavonoids derived from Scutellaria baicalensis produce antioxidative, antineoplastic, cardiomiocyte-protective activity. They inhibit agregation of platelets, permeability of capillary vessels, have antibacterial and anty-angiogenic effects.

The interaction of new plant flavonoids with rat liver mitochondria: relation between the anti- and pro-oxydant effect...

Site Editor — Wed, 03 Jan 2007 18:52:52 -0800

The interaction of new plant flavonoids with rat liver mitochondria: relation between the anti- and pro-oxydant effect and flavonoids concentration.: Therapie. 2006 Jul-Aug;61(4):347-55 Authors: Lahouel M, Amedah S, Zellagui A, Touil A, Rhouati S, Benyache F, Leghouchi E, Bousseboua H

Flavonoids are polyphenols derivatives of plant origin that possesses a broad range of pharmacological properties, including protection of cells and tissues against the deleterious effects of reactive oxygen species. Their antioxidant activity results from scavenging of free radicals and other oxidizing intermediates, from the chelation of iron or copper ions and from inhibition of oxidases. But a number of studies have found both anti and prooxidant effects for many of these compounds. These reasons prompted us to investigate whether flavonoids compounds alone or combined flavonoids had antioxidant, free radical scavenger and antiapoptotic properties. The investigation was carried in vitro using rat hepatic mitochondria. Respiratory control ratio (RCR), oxygen consumption, adenosine tri phosphate (ATP) synthesis, scavenging action, enzymatic activities of involved complexes, superoxide anion and the release of cytochrome C were measured to assess the mechanisms of action of these drugs. Our data showed that the decrease of RCR induced by high concentrations (0.1 mM and 0.01 mM) of all flavonoids tested was due to a common inhibition of oxidative phosphorylation (State 4) and activation of state 3. At the opposite mitochondrial swelling was slightly induced only by low concentrations (10(-8) and 10(-9) M) of the flavonoids. They had no effects on the mitochondrial complexes (I to V) activity. Furthermore the mitochondrial membrane potential was not affected by any flavonoids. The effect of flavonoids on superoxide anion generation was variable. All the flavonoids studied acted between 10(-4) M and 10(-6) M with no effects at lower concentrations. These effects were similar on lipid peroxidation (malondialdehyde [MDA] levels). We remarked a concentration-dependent in the effect of flavonoids since they acted as antioxidant and also as uncoupler at high concentrations, which is a risk for the cells. We conclude that flavonoids extracted from algerian plants have some protecting effects against oxidative stress by protecting the mitochondria.

Prenylflavonoids as Nonsteroidal Phytoestrogens and Related Structure-Activity Relationships.

Site Editor — Wed, 04 Oct 2006 18:24:37 -0700

Prenylflavonoids as Nonsteroidal Phytoestrogens and Related Structure-Activity Relationships.: ChemMedChem. 2006 Apr 10; 1(4): 482-488 Wang ZQ, Weber N, Lou YJ, Proksch P

In the search for estrogen receptor (ER) modulators, a series of prenylflavonoids were found to be widely distributed amongst tonic herbal medicines and to possess estrogen-like activity in MCF-7/BOS cells, as evaluated by an estrogen-screening assay. Cell-cycle analysis revealed that the stimulatory effects of these compounds toward cell proliferation were elicited at the G1-S checkpoint and could significantly increase the S-phase population of MCF-7 cells under hormone-free conditions. ER-responsive gene (PS2, PgR) and protein (PgR) expression was also detected; mRNA and protein-expression levels for PS2 and PgR were up-regulated by the compounds in a dose-dependent manner. These effects could be inhibited by the pure ER antagonist ICI 182,780 ((7alpha-[9-{4,4,5,5,5-pentafluoropentyl}sulfinyl]nonyl)estra-1,3,5(10)-triene-3,17beta-diol). It was therefore concluded that the estrogen-like effects of these prenylflavonoids were mediated primarily through ERs. Furthermore, to explore the structure-activity relationship based on the estrogen receptor and detailed molecular mechanisms among the prenylflavonoids, protein-ligand docking simulations were carried out by using the DS-MODELING software package. The binding affinity of each prenylflavonoid toward ERalpha was scored, and the receptor-ligand interaction was also analyzed to provide the simulation characteristics of virtual molecular recognition mechanisms.

Beneficial effects of the bioflavonoids curcumin and quercetin on early function in cadaveric renal transplantation...

Site Editor — Fri, 09 Jun 2006 07:12:22 -0700

Beneficial effects of the bioflavonoids curcumin and quercetin on early function in cadaveric renal transplantation: a randomized placebo controlled trial.: Transplantation. 2005 Dec 15;80(11):1556-9 Authors: Shoskes D, Lapierre C, Cruz-Corerra M, Muruve N, Rosario R, Fromkin B, Braun M, Copley J

BACKGROUND: The bioflavonoids quercetin and curcumin are renoprotective natural antioxidants. We wished to examine their effects on early graft function (EF). METHODS: Between September 2002 and August 2004, 43 dialysis dependent cadaveric kidney recipients were enrolled into a study using Oxy-Q which contains 480 mg of curcumin and 20 mg of quercetin, started after surgery and taken for 1 month. They were randomized into three groups: control (placebo), low dose (one capsule, one placebo) and high dose (two capsules). Delayed graft function (DGF) was defined as first week dialysis need and slow function (SGF) as Cr >2.5 mg/dl by day 10. Category variables were compared by chi squared and continuous variables by Kruskal-Wallis. RESULTS: There were four withdrawals: one by patient choice and three for urine leak. The control group had 2/14 patients with DGF vs. none in either treatment group. Incidence of EF was control 43%, low dose 71% and high dose 93% (P=0.013). Serum creatinine was significantly lower at 2 days (control 7.6+/-2.1, low 5.4+/-0.6, high 3.96+/-.35 P=0.0001) and 30 days (control 1.82+/-.16, low 1.65+/-.09, high 1.33 +/-.1, P=0.03). Acute rejection incidence within 6 months was control 14.3%, low dose 14.3% and high dose 0%. Tremor was detected in 13% of high dose patients vs. 46% of others. Urinary HO-1 was higher in bioflavonoid groups. CONCLUSION: Bioflavonoid therapy improved early graft function. Acute rejection and neurotoxicity were lowest in the high dose group. These bioflavonoids improve early outcomes in cadaveric renal transplantation, possibly through HO-1 induction.

Structure-activity relationship for antiinflammatory effect of luteolin and its derived glycosides.

Site Editor — Fri, 09 Jun 2006 04:27:40 -0700

Structure-activity relationship for antiinflammatory effect of luteolin and its derived glycosides.: Phytother Res. 2005 Sep;19(9):782-6 Authors: Odontuya G, Hoult JR, Houghton PJ

Luteolin and its derived glycosides such as a cynaroside, cesioside, isoorientin and stereolensin have been isolated and identified from different kinds of plant species. A (13)C NMR spectroscopic analysis of stereolensin has been done for the first time.These structurally related flavonoids were examined in vitro for their abilities to inhibit enzymes for the synthesis of thromboxane B(2) and leukotriene B(4) as well as hydrogen peroxide scavenging activity. Luteolin exhibited a high inhibitory activity against both thromboxane and leukotriene synthesis. In particular, a remarkable inhibitory effect was observed against leukotriene enzyme activity. The glycosides, cynaroside and cesioside, possessed a moderate inhibition activity against both enzyme synthesis pathways, while isoorientin and stereolensin exhibited selectively good activity against thromboxane synthesis.All the flavonoids showed excellent scavenging activity for the hydrogen peroxide at all the concentrations tested.The results demonstrated that the reactivities of luteolin and its related glycosides against arachidonic acid synthesis and hydrogen peroxide scavenging are dependent on their molecular structures. The presence of ortho-dihydroxy groups at the B ring and OH substitution pattern at C-5 position of the A ring could significantly contribute to the antiinflammatory and antioxidant activities of flavonoids.

Crohn's disease leading to bowel cancer may be avoided by consumption of soya isoflavones: Adjunct-chemotherapy with oxaliplatin

Site Editor — Fri, 09 Jun 2006 04:26:43 -0700

Crohn's disease leading to bowel cancer may be avoided by consumption of soya isoflavones: Adjunct-chemotherapy with oxaliplatin.: Med Hypotheses. 2006 Jan 20; Authors: Wiseman A

Crohn's disease (inflammatory bowel syndrome) is caused by gut exposure to harmful reactive oxygen species (ROS) derived from oxygen, such as the superoxide anion (()O(2)(')), the hydroxyl radical (()OH) or the peroxide anion (O(2)('')): the superoxide anion is generated by breakdown of oxygen-peroxidised phospholipids membranes. Crohn's disease predisposes to bowel cancer in susceptible human sub-populations. It may be preventable in these as yet unpredictable sub-populations by dietary-based intervention strategies, such as the daily consumption of appropriate quantities of soya isoflavones. These isoflavonoids are ROS-directed antioxidants, and they include the phytoestrogens, daidzin and genistin present in soya foods (consumed also in dietary supplements). Oxaliplatin is a platinum-containing Pt(II) organometallic therapeutic agent that binds to tumour DNA. Oxaliplatin may provide, therefore, a form of chemotherapy for some bowel cancers especially when administered in adjunct-chemotherapies that employ inhibitors of proliferation of the tumour cell. Such inhibitors include 5-fluorouracil, which prevents the correct replication of tumour cell DNA that is an essential prerequisite for bowel tumour growth. Furthermore, the therapeutic index for adjunct-chemotherapy with toxic inhibitors of DNA replication and expression could potentially be raised significantly by an associated dietary regime. This should include supplementation daily, per or, with antioxidant isoflavones (or other bioflavonoids) in selected cases of unresponsive cancer of the bowel, to possibly seek to trigger the pathway of apoptosis (programmed cell death) in the tumour cells preferentially.

The inhibitory effect of quercetin on IL-6 production by LPS-stimulated neutrophils.

Site Editor — Fri, 09 Jun 2006 04:23:02 -0700

The inhibitory effect of quercetin on IL-6 production by LPS-stimulated neutrophils.: Cell Mol Immunol. 2005 Dec;2(6):455-60 Authors: Liu JJ, Li X, Yue Y, Li J, He T, He YZ

Quercetin is a herbal flavonoid derived from various foods of plant origin and plays a role in anti-inflammation. Although a number of researches in the field have been done, the mechanism of anti-inflammatory effect of quercetin should be further clarified. In the present study, we investigated the effects of quercetin on IL-6 production by LPS-stimulated neutrophils in human. Neutrophils were were pre-treated with quercetin at the final concentrations of ranging from 0-80 uM for 30 min, or not treated, and then incubated in the presence or absence of lipopolysaccharide (LPS) at a final concentration of 100 ng/ml for indicated time. The secretion level of IL-6 in the culture supernatants was assayed by ELISA, the intracellular level of IL-6 was detected by flow cytometry and the expression of IL-6 mRNA was analyzed by RT-PCR. The experiment results showed that neutrophils cultured with medium or quercetin alone did not express IL-6, but LPS (100 ng/ml) induced IL-6 expression of neutrophils. However, after pre-treatment of neutrophils with quercetin (40 uM) for 30 min, the inducible effects of LPS on the increase of IL-6 secretion, intracellular IL-6 level and IL-6 mRNA expression by neutrophils were abrogated. IL-6 is one of the important pro-inflammatory factors, especially in early phage of inflammation. Thus, our data suggested that quercetin might exert its anti-inflammatory effect through negatively modulating pro-inflammatory factors, such as IL-6. The inhibitory effects of quercetin on IL-6 production by neutrophils may provide a theoretical basis on future therapy of inflammation.

Randomized placebo-controlled trial of a flavonoid-rich plant extract-based cream in the treatment of rosacea.

Site Editor — Fri, 09 Jun 2006 04:06:59 -0700

Randomized placebo-controlled trial of a flavonoid-rich plant extract-based cream in the treatment of rosacea.: J Eur Acad Dermatol Venereol. 2005 Sep;19(5):564-8 Authors: Rigopoulos D, Kalogeromitros D, Gregoriou S, Pacouret JM, Koch C, Fisher N, Bachmann K, Brown M, Schwarz E, Camel E, Katsambas A

BACKGROUND: Biological research suggests that vascular changes may play a major role in rosacea pathogenesis. Chrysanthellum indicum is a plant-based extract containing a unique combination of phenylpropenoic acids, flavonoids and saponosids, and has a well-documented effect on vascular wall permeability and increase of the mechanical resistance of capillaries. OBJECTIVE: To determine the efficacy and safety of a cream containing 1%C. indicum extract with vitamin P properties in the treatment of rosacea. METHODS: This study included 246 patients diagnosed clinically as having moderate rosacea. Patients were randomly allocated to C. indicum extract-based cream (n = 125) and placebo (n = 121) groups. Patients were advised to apply the products on their face twice a day for a 12-week period. The patients were examined at the end of each 4-week period. Severity of erythema (graded by reference to six photographs), surface of erythema and rosacea overall severity scores were recorded at each visit on days 0, 28, 56 and 84. Investigators carried out a final efficacy assessment at the end of week 12. Volunteers' final overall efficacy assessment was recorded in a self-administered questionnaire. Adverse events were identified through examination, interview and collection of comments in patients' questionnaires. RESULTS: Treatment with the C. indicum extract-based cream resulted in significant improvement (P < 0.05) in severity of erythema, overall rosacea severity compared to baseline and placebo, and investigator and patient overall efficacy assessment scores (P = 0.046 and P = 0.001, respectively) compared with placebo scores. Adverse reactions were mild, and did not differ between the C. indicum extract-based cream and the placebo groups. CONCLUSION: Chrysanthellum indicum extract-based cream is an effective and well-tolerated topical agent for the treatment of moderate rosacea. The mode of action of the active ingredient suggests that additional efficacy might be expected from combination with other topical treatments.

Chocolate and Prevention of Cardiovascular Disease: A Systematic Review

Site Editor — Fri, 09 Jun 2006 04:01:04 -0700

Chocolate and Prevention of Cardiovascular Disease: A Systematic Review:

Background:
Consumption of chocolate has been often hypothesized to reduce the risk of cardiovascular disease (CVD) due to chocolate's high levels of stearic acid and antioxidant flavonoids. However, debate still lingers regarding the true long term beneficial cardiovascular effects of chocolate overall.
MethodWe reviewed English-language MEDLINE publications from 1966 through January 2005 for experimental, observational, and clinical studies of relations between cocoa, cacao, chocolate, stearic acid, flavonoids (including flavonols, flavanols, catechins, epicatechins, and procynadins) and the risk of cardiovascular disease (coronary heart disease (CHD), stroke). A total of 136 publications were selected based on relevance, and quality of design and methods. An updated meta-analysis of flavonoid intake and CHD mortality was also conducted.

Results:
The body of short-term randomized feeding trials suggests cocoa and chocolate may exert beneficial effects on cardiovascular risk via effects on lowering blood pressure, anti-inflammation, anti-platelet function, higher HDL, decreased LDL oxidation. Additionally, a large body of trials of stearic acid suggests it is indeed cholesterol-neutral. However, epidemiologic studies of serum and dietary stearic acid are inconclusive due to many methodologic limitations. Meanwhile, the large body of prospective studies of flavonoids suggests the flavonoid content of chocolate may reduce risk of cardiovascular mortality. Our updated meta-analysis indicates that intake of flavonoids may lower risk of CHD mortality, RR=0.81 (95% CI: 0.71-0.92) comparing highest and lowest tertiles.

Conclusions:
Multiple lines of evidence from laboratory experiments and randomized trials suggest stearic acid may be neutral, while flavonoids are likely protective against CHD mortality. The highest priority now is to conduct larger randomized trials to definitively investigate the impact of chocolate consumption on long-term cardiovascular outcomes.

Flavonoids from Theobroma cacao down-regulate inflammatory mediators.

Site Editor — Fri, 09 Jun 2006 03:53:10 -0700

Flavonoids from Theobroma cacao down-regulate inflammatory mediators.: J Agric Food Chem. 2005 Nov 2;53(22):8506-11 Authors: Ramiro E, Franch A, Castellote C, Pérez-Cano F, Permanyer J, Izquierdo-Pulido M, Castell M

In the present study, we report the effects of a cocoa extract on the secretion and RNA expression of various proinflammatory mediators by macrophages. Monocyte chemoattractant protein 1 and tumor necrosis factor alpha (TNFalpha) were significantly and dose-dependently diminished by cocoa extract, and this effect was higher than that produced by equivalent concentrations of epicatechin but was lower than that produced by isoquercitrin. Interestingly, cocoa extract added prior to cell activation resulted in a significantly greater inhibition of TNFalpha secretion. Both cocoa extract and epicatechin decreased TNFalpha, interleukin (IL) 1alpha, and IL-6 mRNA expression, suggesting that their inhibitory effect on cytokine secretion is produced, in part, at the transcriptional level. Cocoa extract also significantly decreased NO secretion in a dose-dependent manner and with a greater effect than that produced by epicatechin. In conclusion, our study shows that cocoa flavonoids not only inhibit NO release from macrophages but also down-regulate inflammatory cytokines and chemokines.

Inhibition of collagenase by naturally-occurring flavonoids.

Site Editor — Fri, 09 Jun 2006 03:51:36 -0700

Inhibition of collagenase by naturally-occurring flavonoids.: Arch Pharm Res. 2005 Oct;28(10):1152-5 Authors: Sin BY, Kim HP

We examined the inhibitory activities of various flavonoids, including the flavanones, flavones/isoflavones and flavonols, on collagenase from Clostridium histolyticum to establish their therapeutic potential against skin inflammation and photoaging. In general, the flavonols were stronger inhibitors than the flavones/isoflavones, and this indicated the importance of the C-3 hydroxyl substitution. Quercetin was the most active flavonoid among those tested, and it showed an IC50 of 286 microM. These novel results suggest that certain flavonoids, particularly the flavonols, may prevent collagen breakdown by inhibiting collagenase in inflamed skin as well as photoaged skin.

Protective effects of lycopene and tomato extract against doxorubicin-induced cardiotoxicity.

Site Editor — Fri, 09 Jun 2006 03:45:22 -0700

Protective effects of lycopene and tomato extract against doxorubicin-induced cardiotoxicity.: Phytother Res. 2005 Oct;19(10):912-4 Authors: Karimi G, Ramezani M, Abdi A

The protective effect of tomato extract and lycopene on acute doxorubicin (DOX) myocardial toxicity was evaluated in mice. DOX toxicity, induced by a single intraperitoneal injection (15 mg/kg), was revealed by an elevated serum CPK(MB) and histopathological observations. Tomato extract (1.2 and 2.4 g/kg, i.p.) and lycopene (1.7 and 3.5 mg/kg, i.p.) prevented the rise in serum CPK(MB) and ameliorated cardiac cell injury. These results suggest that tomato extract and lycopene inhibit DOX cardiotoxicity and might serve as a novel combination chemotherapeutic agent with DOX to limit free radical-mediated organ injury.

Effect of three flavonoids isolated from Japanese Polygonum species on superoxide generation in human neutrophils.

Site Editor — Fri, 09 Jun 2006 03:44:25 -0700

Effect of three flavonoids isolated from Japanese Polygonum species on superoxide generation in human neutrophils.: Planta Med. 2005 Oct;71(10):933-7 Authors: Liu G, Wang W, Masuoka N, Isobe T, Yamashita K, Manabe M, Kodama H

Three flavonoids, quercetin 3- O-glucoside-2''-gallate (QGG), quercetin 3- O-rhamnoside-2''-gallate (QRG) and kaempferol 3- O-glucoside-2''-gallate (KGG) were isolated from Japanese Polygonum species. The effect of these flavonoids on stimulus-induced superoxide generation in human neutrophils was assayed by measuring the reduction of cytochrome c. The tyrosyl or serine/threonine phosphorylation of neutrophil proteins and the translocation of p4(phox) and p67(phox) to the cell membrane were detected using specific monoclonal antibodies. The flavonoids used in this experiment significantly suppressed stimulus-induced superoxide generation in a concentration-dependent manner. FMLP-induced tyrosyl phosphorylation or PMA-induced serine/threonine phosphorylation and the translocation of the cytosolic proteins p47(phox) and p67(phox) to the cell membrane were suppressed in parallel to the suppression of the stimulus-induced superoxide generation.

Therapeutic potential of wogonin: a naturally occurring flavonoid.

Site Editor — Fri, 09 Jun 2006 03:43:59 -0700

Therapeutic potential of wogonin: a naturally occurring flavonoid.: CNS Drug Rev. 2005;11(2):141-50 Authors: Tai MC, Tsang SY, Chang LY, Xue H

The search for flavonoids with novel therapeutic effects has been intense. Wogonin, as a naturally existing monoflavonoid, has been shown to have therapeutic potential in vitro and in vivo. Methods for its extraction from herbs and its chemical synthesis have been developed. Pharmacokinetic studies have shown a rapid tissue distribution and prolonged plasma elimination phase of wogonin. It has been shown experimentally that wogonin exerts anti-oxidant activity, which may, in part, underlie its antiinflammatory, anti-cancer, antiviral and neuroprotective actions. The recent discovery of its anxiolytic activity suggests a new mechanism of action, involving interaction with the benzodiazepine (BZD) binding site of the GABA(A) receptor and modulation of this receptor activity. Although the safety record of wogonin is remarkable and voluminous literature about its pharmacological effects is available, it has not been used in Western medicine in the form of a pure chemical. In this article we review its therapeutic effects, its sources and pharmacokinetic profile to highlight its therapeutic potential.

Micellar electrokinetic chromatography for separation of a mixture of coptis alkaloids, scute flavonoids...

Site Editor — Fri, 09 Jun 2006 03:27:14 -0700

Micellar electrokinetic chromatography for separation of a mixture of coptis alkaloids, scute flavonoids, and rhubarb anthraquinones and bianthrones.: J Pharm Biomed Anal. 2005 Nov 15; Authors: Chang LC, Sun SW

Coptidis Rhizoma, Scutellariae Radix, and Rhei Rhizoma are three common Chinese herbs. There are many herbal formulas which contain either two or all three of the herbs mentioned above. Their bioactive components have already been identified, respectively. However, there is no report about separation of the 13 bioactive constituents of the three herbs at the same time. In order to assess these constituents of related Chinese herbal preparations, a micellar electrokinetic chromatography method was developed. While buffer pH and surfactant concentration affected the resolution of separation, acetonitrile percentage was found to significantly influence the resolution, peak shape, and elution window. Optimum separation of 13 compounds was achieved at pH 7.3 using a buffer mixture of 70% (v/v) 3mM di-sodium tetraborate, 10mM sodium dihydrogen phosphate, and 50mM sodium deoxycholate with 30% (v/v) acetonitrile. When applying the developed method to analyze a model preparation, San-huang-xie-xin-tang, which contains all three herbs, 8 of the 13 bioactive constituents, could be determined. The present study proposed a method to assess San-huang-xie-xin-tang within short analysis time and also provided a possible starting point to evaluate related herbal preparations containing Coptidis Rhizoma, Scutellariae Radix, and Rhei Rhizoma.

Inhibition of gastric H(+),K(+)-ATPase activity by flavonoids, coumarins and xanthones isolated from Mexican medicinal plants.

Site Editor — Fri, 09 Jun 2006 03:11:59 -0700

Inhibition of gastric H(+),K(+)-ATPase activity by flavonoids, coumarins and xanthones isolated from Mexican medicinal plants. - J Ethnopharmacol. 2005 Nov 25; Authors: Reyes-Chilpa R, Baggio CH, Alavez-Solano D, Estrada-Muñiz E, Kauffman FC, Sanchez RI, Mesia-Vela S

Medicinal plants are commonly used in Latin American folk medicine for the treatment of gastric problems. In order to understand the properties of some of their chemical constituents, four natural xanthones, an acetylated derivative, two coumarins (mammea A/BA and mammea C/OA) isolated from Calophyllum brasiliense Cambess and two flavonoids (minimiflorin and mundulin) isolated from Lonchocarpus oaxacensis Pittier, and the chalcone lonchocarpin isolated from Lonchocarpus guatemalensis Benth were tested for their activities on gastric H(+),K(+)-ATPase isolated from dog stomach. All the compounds tested inhibited H(+),K(+)-ATPase activity with varied potency. The xanthones inhibited the H(+),K(+)-ATPase with IC(50) values ranging from 47muM to 1.6mM. Coumarins inhibited H(+),K(+)-ATPase with IC(50) values of 110 and 638muM. IC(50) values for the flavonoids ranged from 9.6 to 510muM among which minimiflorin was the most potent. The results suggest that H(+),K(+)-ATPase is sensitive to inhibition by several types of structurally different natural compounds. The potency of the effects on gastric H(+),K(+)-ATPase depends on the presence, position and number of hydroxyls groups in the molecule. Collectively, these results suggest a potential for important pharmacological and toxicological interactions by these types of natural products at the level of H(+),K(+)-ATPase which may explain, at least in part, the gastroprotective properties, indicated by traditional medicine, of the plants from which these compounds were isolated.

Dietary flavonoids: Effects on xenobiotic and carcinogen metabolism.

Site Editor — Fri, 09 Jun 2006 03:04:35 -0700

Dietary flavonoids: Effects on xenobiotic and carcinogen metabolism. - Toxicol In Vitro. 2005 Nov 10; Authors: Moon YJ, Wang X, Morris ME

Flavonoids are present in fruits, vegetables and beverages derived from plants (tea, red wine), and in many dietary supplements or herbal remedies including Ginkgo Biloba, Soy Isoflavones, and Milk Thistle. Flavonoids have been described as health-promoting, disease-preventing dietary supplements, and have activity as cancer preventive agents. Additionally, they are extremely safe and associated with low toxicity, making them excellent candidates for chemopreventive agents. The cancer protective effects of flavonoids have been attributed to a wide variety of mechanisms, including modulating enzyme activities resulting in the decreased carcinogenicity of xenobiotics. This review focuses on the flavonoid effects on cytochrome P450 (CYP) enzymes involved in the activation of procarcinogens and phase II enzymes, largely responsible for the detoxification of carcinogens. A number of naturally occurring flavonoids have been shown to modulate the CYP450 system, including the induction of specific CYP isozymes, and the activation or inhibition of these enzymes. Some flavonoids alter CYPs through binding to the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, acting as either AhR agonists or antagonists. Inhibition of CYP enzymes, including CYP 1A1, 1A2, 2E1 and 3A4 by competitive or mechanism-based mechanisms also occurs. Flavones (chrysin, baicalein, and galangin), flavanones (naringenin) and isoflavones (genistein, biochanin A) inhibit the activity of aromatase (CYP19), thus decreasing estrogen biosynthesis and producing antiestrogenic effects, important in breast and prostate cancers. Activation of phase II detoxifying enzymes, such as UDP-glucuronyl transferase, glutathione S-transferase, and quinone reductase by flavonoids results in the detoxification of carcinogens and represents one mechanism of their anticarcinogenic effects. A number of flavonoids including fisetin, galangin, quercetin, kaempferol, and genistein represent potent non-competitive inhibitors of sulfotransferase 1A1 (or P-PST); this may represent an important mechanism for the chemoprevention of sulfation-induced carcinogenesis. Importantly, the effects of flavonoids on enzymes are generally dependent on the concentrations of flavonoids present, and the different flavonoids ingested. Due to the low oral bioavailability of many flavonoids, the concentrations achieved in vivo following dietary administration tend to be low, and may not reflect the concentrations tested under in vitro conditions; however, this may not be true following the ingestion of herbal preparations when much higher plasma concentrations may be obtained. Effects will also vary with the tissue distribution of enzymes, and with the species used in testing since differences between species in enzyme activities also can be substantial. Additionally, in humans, marked interindividual variability in drug-metabolizing enzymes occurs as a result of genetic and environmental factors. This variability in xenobiotic metabolizing enzymes and the effect of flavonoid ingestion on enzyme expression and activity can contribute to the varying susceptibility different individuals have to diseases such as cancer. As well, flavonoids may also interact with chemotherapeutic drugs used in cancer treatment through the induction or inhibition of their metabolism.