Anti-inflammatory activity of myricetin-3-O-beta-D-glucuronide and related compounds

Traditional uses, phytochemistry, pharmacology and current uses of underutilized Xanthoceras sorbifolium bunge: A review

ETHNOPHARMACOLOGICAL RELEVANCE

The Plant Xanthoceras sorbifolium Bunge (X. sorbifolia) has a long history of medicinal use as a traditional Chinese herbal medicine to deal with sterilizing, killing sperm, stabilizing capillary, hemostasis, lowering cholesterol, rheumatism, and pediatric enuresis. Additionally, X. sorbifolia is an oil crop for the production of edible oil due to the health-promotion effect. In recent years, X. sorbifolia has attracted worldwide attention as an important economic crop with low investment and high-income potential.

AIM OF THE REVIEW

This review aims to provide a comprehensive appraisal of X. sorbifolia, including the traditional uses, nutrients, phytochemical data, biological activities, and current applications. The natural compounds of X. sorbifolia and potential utilization in pharmacology are highlighted. The aim of this review is to inspire the research enthusiasm to X. sorbifolia and promote the comprehensive utilization of X. sorbifolia.

MATERIALS AND METHODS

The research information of X. sorbifolia was collected via Elsevier, American Chemical Society (ACS), PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), Baidu scholar, and Google scholar. Additionally, some information was collected from Ph.D. and Master's dissertations, as well as local books.

RESULTS

The identification of approximately 195 major phytochemical compounds from different parts of X. sorbifolia is presented in this review, including triterpenoids, flavonoids, phenolic acids, coumarins, lignans, meroterpenoids, monoterpene, alkaloids, and sterol. Among them, triterpenoids, flavonoids, and phenolic acids are the major compounds. Extracts from X. sorbifolia exhibited a wide range of biological activities, such as antioxidant, antibacterial, anti-tumor, anti-neuroinflammatory, anti-adipogenesis, anti-obesity, anti-HIV, gastroprotective, immunoregulatory, and anti-inflammatory activities.

CONCLUSIONS

Modern pharmacological studies have been well supported and clarified the traditional medicinal uses of X. sorbifolia, which brought a promising prospect for the pharmaceutical value of this plant. However, the related mechanisms between the structure and pharmacological effects were seldom reported. Also, at present, effective and in-depth research on X. sorbifolia is still relatively lacking. Moreover, there is little research on toxicological experiments. Further clinical trials should also be performed to accelerate the drug research and development.

Cosmetic and Dermatological Properties of Selected Ayurvedic Plant Extracts

Due to the constantly growing interest in ingredients of natural origin, this study attempts to evaluate the possibility of using extracts from three Ayurvedic plants in preparations for the care and treatment of skin diseases. Therefore, studies of antioxidant properties were carried out using DPPH and ABTS radicals, obtaining 76% and 88% of these radical scavenging, respectively. A significant decrease in the intracellular level of free radicals and an increase in the activity of the antioxidant enzyme-superoxide dismutase by almost 60% were also observed. In addition, the extracts were assessed for anti-inflammatory and anti-aging properties, obtaining over 70% inhibition of lipoxygenase activity and almost 40% of collagenase. Additionally, the cytoprotective properties of the obtained extracts on skin cells, keratinocytes and fibroblasts, were demonstrated. To assess the content of biologically active compounds, HPLC-electrospray ionization (ESI)-MS/MS multiple reaction monitoring (MRM) analyses were performed. The obtained results show that all three analyzed plants are a valuable source of biologically active substances with desired properties in the context of skin cell protection. Particularly noteworthy is the extract of Epilobium angustifolium L., for which the most promising results were obtained.

Myricetin protects pancreatic β-cells from human islet amyloid polypeptide (hIAPP) induced cytotoxicity and restores islet function

The aberrant misfolding and self-assembly of human islet amyloid polypeptide (hIAPP)-a hormone that is co-secreted with insulin from pancreatic β-cells-into toxic oligomers, protofibrils and fibrils has been observed in type 2 diabetes mellitus (T2DM). The formation of these insoluble aggregates has been linked with the death and dysfunction of β-cells. Therefore, hIAPP aggregation has been identified as a therapeutic target for T2DM management. Several natural products are now being investigated for their potential to inhibit hIAPP aggregation and/or disaggregate preformed aggregates. In this study, we attempt to identify the anti-amyloidogenic potential of Myricetin (MYR)- a polyphenolic flavanoid, commonly found in fruits (like Syzygium cumini). Our results from biophysical studies indicated that MYR supplementation inhibits hIAPP aggregation and disaggregates preformed fibrils into non-toxic species. This protection was accompanied by inhibition of oxidative stress, reduction in lipid peroxidation and the associated membrane damage and restoration of mitochondrial membrane potential in INS-1E cells. MYR supplementation also reversed the loss of functionality in hIAPP exposed pancreatic islets via restoration of glucose-stimulated insulin secretion. Molecular dynamics simulation studies suggested that MYR molecules interact with the hIAPP pentameric fibril model at the amyloidogenic core region and thus prevents aggregation and distort the fibrils.

Myricetin Inhibition of Peptidoglycan-Induced COX-2 Expression in H9c2 Cardiomyocytes

Peptidoglycan (PGN) is a cell wall constituent in dental plaque bacteria that triggers inflammatory responses. PGN binds Toll-like receptors, leading to increases in prostaglandin E2 and interleukin-1β, which play crucial roles in the inflammatory response and tissue destruction. Dental surgery can give plaque bacteria access to blood circulation, thereby creating a risk of septic inflammation of the endocardium. Plant-derived flavonoids have been reported to reduce inflammatory cytokine secretion by host cells. In the present study, we investigated the effects of flavonoid myricetin on expression of cyclooxygenase 2 (COX-2) in the H9c2 cells treated with PGN from Streptococcus sanguinis, a bacterial constituent of dental plaque associated with infective endocarditis. Myricetin exposure resulted in dose-dependent suppression of PGN-induced COX-2 expression, diminished phosphorylation of p38, extracellular signal regulated kinase 1/2, and c-Jun N-terminal kinase, and reduced IκB-α degradation, consistent with decreased COX-2 activity. In conclusion, the aforementioned results suggest that myricetin is useful for moderating the inflammatory response in infective endocarditis.

Flavonoids Alleviating Insulin Resistance through Inhibition of Inflammatory Signaling

During the past 20 years, many studies have focused on polyphenol compounds for their potential beneficial health effects. Flavonoids represent a large class of phenolic compounds found in fruits, vegetables, nuts, grains, cocoa, tea, and other beverages. Flavonoids have shown antioxidant and anti-inflammatory activities. Given the putative relationship between inflammation and insulin resistance, the consumption of flavonoids or flavonoid-rich foods has been suggested to reduce the risk of diabetes by targeting inflammatory signals. This is the first comprehensive review summarizing the current research progress on the inhibition of inflammation and alleviation of insulin resistance by flavonoids as well as the mechanistic link between these disorders. Laboratory and human studies on the activities of major flavonoids (flavones, isoflavones, flavonols, etc.) are discussed.

Raging the War Against Inflammation With Natural Products

Over the last few decade Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are the drugs of choice for treating numerous inflammatory diseases including rheumatoid arthritis. The NSAIDs produces anti-inflammatory activity via inhibiting cyclooxygenase enzyme, responsible for the conversation of arachidonic acid to prostaglandins. Likewise, cyclooxegenase-2 inhibitors (COX-2) selectively inhibit the COX-2 enzyme and produces significant anti-inflammatory, analgesic, and anti-pyretic activity without producing COX-1 associated gastrointestinal and renal side effects. In last two decades numerous selective COX-2 inhibitors (COXIBs) have been developed and approved for various inflammatory conditions. However, data from clinical trials have suggested that the prolong use of COX-2 inhibitors are also associated with life threatening cardiovascular side effects including ischemic heart failure and myocardial infection. In these scenario secondary metabolites from natural product offers a great hope for the development of novel anti-inflammatory compounds. Although majority of the natural product based compounds exhibit more selectively toward COX-1. However, the data suggest that slight structural modification can be helpful in developing COX-2 selective secondary metabolites with comparative efficacy and limited side effects. This review is an effort to highlight the secondary metabolites from terrestrial and marine source with significant COX-2 and COX-2 mediated PGE2 inhibitory activity, since it is anticipated that isolates with ability to inhibit COX-2 mediated PGE2 production would be useful in suppressing the inflammation and its classical sign and symptoms. Moreover, this review has highlighted the potential lead compounds including berberine, kaurenoic acid, α-cyperone, curcumin, and zedoarondiol for further development with the help of structure-activity relationship (SAR) studies and their current status.

Nonsteroidal Anti-Inflammatory Therapy: A Journey Toward Safety

The efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) against inflammation, pain, and fever has been supporting their worldwide use in the treatment of painful conditions and chronic inflammatory diseases until today. However, the long-term therapy with NSAIDs was soon associated with high incidences of adverse events in the gastrointestinal tract. Therefore, the search for novel drugs with improved safety has begun with COX-2 selective inhibitors (coxibs) being straightaway developed and commercialized. Nevertheless, the excitement has fast turned to disappointment when diverse coxibs were withdrawn from the market due to cardiovascular toxicity. Such events have once again triggered the emergence of different strategies to overcome NSAIDs toxicity. Here, an integrative review is provided to address the breakthroughs of two main approaches: (i) the association of NSAIDs with protective mediators and (ii) the design of novel compounds to target downstream and/or multiple enzymes of the arachidonic acid cascade. To date, just one phosphatidylcholine-associated NSAID has already been approved for commercialization. Nevertheless, the preclinical and clinical data obtained so far indicate that both strategies may improve the safety of nonsteroidal anti-inflammatory therapy.

Molecular Mechanisms of the Anti-Obesity and Anti-Diabetic Properties of Flavonoids

Obesity and diabetes are the most prevailing health concerns worldwide and their incidence is increasing at a high rate, resulting in enormous social costs. Obesity is a complex disease commonly accompanied by insulin resistance and increases in oxidative stress and inflammatory marker expression, leading to augmented fat mass in the body. Diabetes mellitus (DM) is a metabolic disorder characterized by the destruction of pancreatic β cells or diminished insulin secretion and action insulin. Obesity causes the development of metabolic disorders such as DM, hypertension, cardiovascular diseases, and inflammation-based pathologies. Flavonoids are the secondary metabolites of plants and have 15-carbon skeleton structures containing two phenyl rings and a heterocyclic ring. More than 5000 naturally occurring flavonoids have been reported from various plants and have been found to possess many beneficial effects with advantages over chemical treatments. A number of studies have demonstrated the potential health benefits of natural flavonoids in treating obesity and DM, and show increased bioavailability and action on multiple molecular targets. This review summarizes the current progress in our understanding of the anti-obesity and anti-diabetic potential of natural flavonoids and their molecular mechanisms for preventing and/or treating obesity and diabetes.

Content of phenolic compounds in wild populations of Epilobium angustifolium growing at different altitudes

CONTEXT

Flavonoids are regarded as essential ingredients for the anti-inflammatory activity of Epilobium angustifolium L. (Onagraceae). The metabolic profiles of medicinal plants vary aside from genetic determination due to the influence by external factors.

OBJECTIVES

This study evaluates the influence of altitudinal variation on the content of flavonoids in E. angustifolium in two consecutive growing periods.

MATERIALS AND METHODS

Aerial and herbaceous plant materials were collected at three different altitudes (800, 1000, and 1500 m) during two collection periods. Plant samples (11-13 samples per altitude and year) were extracted with methanol using accelerated solvent extraction (ASE). Identification and quantification of the constituents were achieved by chromatographic means of HPLC-PDA and LC-PDA-MS analyses.

RESULTS

Rising concentrations of flavonol 3-O-glycosides could be detected with increasing altitude. The content of the major compound, quercetin 3-O-glucuronide, ranged from 4.4 ± 2.05 (800 m) to 4.9 ± 1.03 (1000 m) and up to 6.6 ± 1.14 mg/g (1500 m). The total amount of flavonol 3-O-glycosides in 73 analyzed samples ranged from 10.7 ± 1.37 up to 17.3 ± 1.99 mg/g.

DISCUSSION

Quercetin-3-O-glucuronide can be considered as a potential marker for the increased production of flavonols in herbal parts of E. angustifolium at higher altitudinal levels.

CONCLUSION

The study confirms that environmental factors at higher altitude result in elevated levels of flavonols in aerial plant tissues of E. angustifolium. Specific factors for influencing the flavonoid content have to be clarified in further studies.

Phytochemistry, pharmacology and traditional uses of different Epilobium species (Onagraceae): a review

ETHNOPHARMACOLOGICAL RELEVANCE

The Epilobium genus (willowherb) comprises of ca. 200 species of herbaceous plants distributed around the world. Infusions prepared form willowherbs have been traditionally used externally in skin and mucosa infections and in the treatment of benign prostate hyperplasia. Nowadays extracts from different Epilobium species are widely used by patients, however the lack of clinical studies does not allow to fully establish their efficacy. The present review summarizes published data on phytochemistry, ethnopharmacological use and pharmacological studies concerning willowherb species investigated throughout past few decades.

MATERIALS AND METHODS

Literature survey was performed using Scopus, PubMed, Web of Science and Reaxys databases looking for papers and patents focused on chemical composition and bioactivity of Epilobium species. Systematic research in ethnopharmacological literature in digitalized sources of academic libraries was also carried out.

RESULT

The chemical composition of different Epilobium species and their bioactivities are described. The detailed information on constituents isolated and detected by chromatographic methods is given. The studies show that polyphenols are main compounds occurring in Epilobium herb among which flavonoids, phenolic acids and tannins (oenothein B and oenothein A) are dominating constituents. The extracts and some isolated compounds from Epilobium sp. were shown to possess antimicrobial, anti-proliferative, anti-inflammatory, analgesic and antioxidative activities. Because many studies suggest that oenothein B as dominating constituent may be responsible for Epilobium sp. pharmacological effects, its documented bioactivities were also described.

CONCLUSIONS

The pharmacological studies performed on Epilobium justify the traditional use of this species in external and in gastrointestinal inflammations. As far as the treatment of benign prostate hyperplasia (BPH) is considered, in the literature, there are some reports indicating that Epilobium extracts have a beneficial effect for this disorder, but the number of in vitro studies is not sufficient and the in vivo studies are not conclusive or too preliminary to draw a final conclusion about the efficacy of Epilobium preparations. More in vitro, in vivo and clinical studies to confirm this mode of action are strongly needed. Epilobium's extracts have also documented antioxidative and potential anti-inflammatory properties. Oenothein B can be considered as responsible for some of Epilobium pharmacological properties. Because of the lack of clinical data further studies are needed to provide an evidence base for traditional uses of plant materials belonging to the Epilobium genus.

Antinociceptive activity of Syzygium cumini leaves ethanol extract on orofacial nociception protocols in rodents

CONTEXT

Syzygium cumini (L.) Skeels (Myrtaceae) is a tree with dark purple fruits, popularly known as "jambolão" or "jambolan". In folk medicine, this plant is used for the treatment of diabetes and inflammatory conditions.

OBJECTIVE

We investigated the antinociceptive effect of ethanol extract (EE) from S. cumini leaves on orofacial nociception.

MATERIAL AND METHODS

The antinociceptive effects of the EE obtained from the leaves of S. cumini were evaluated in mice using formalin- and glutamate-induced orofacial nociception.

RESULTS

ESI-MS/MS analyses demonstrated that major constituents in the analyzed samples coincided with the mass of the phenolic acids and flavonoids. In pharmacological approach, pre-treatment with EE (100, 200, or 400 mg/kg, p.o.) significantly reduced (p<0.05 or p<0.01) the percentage of paw licks time during phase 2 (43.2, 47.1, and 57.4%, respectively) of a formalin pain test when compared to control group animals. This effect was prevented by pretreatment with glibenclamide and N(G)-nitro-l-arginine (l-NOARG). The extract, all doses, also caused a marked inhibition (p<0.01 or p<0.001) of glutamate-induced orofacial nociception (38.8, 51.7, and 54.7%) when compared with the control group. No effect was observed with the rota-rod model.

CONCLUSIONS

We can suggest that the antinociceptive effect of the EE is mediated by peripheral mechanisms, possibly involving KATP channels and the nitric oxide pathways. These effects appear to be related to the presence of flavonoids compounds, such as quercetin.

A convenient semisynthesis of myricetin-3-O-β-d-glucuronide

Myricetin-3-O-β-d-glucuronide, a bioactive flavonol glycoside, was synthesized effectively starting from myricetrin in a total yield of 49.2%. The structures of all synthetic compounds were confirmed by (1)H, (13)C NMR, and HR-MS techniques.

Chemical composition, antioxidative and anti-inflammatory activity of extracts prepared from aerial parts of Oenothera biennis L. and Oenothera paradoxa Hudziok obtained after seeds cultivation

In the present study we investigated the chemical composition of extracts prepared from aerial parts of Oenothera paradoxa Hudziok and Oenothera biennis L. and their antioxidative and anti-inflammatory activities. Ultra high pressure liquid chromatography (UHPLC)-DAD-MS/MS studies showed that both extracts contain a wide variety of polyphenols (39 identified constituents) among which macrocyclic ellagitannin turned out to be the main constituent. During the in vitro studies, using noncellular models, both extracts scavenged reactive oxygen species (ROS) in a concentration-dependent manner, and the lowest SC(50) values were obtained for O(2)(-) and H(2)O(2). Both extracts inhibited ROS production by stimulated human neutrophils. The stronger activity in the case of formyl-met-leu-phenylalanine stimulation suggests that both extracts may act through the receptor-dependent pathway. O. paradoxa extract and O. biennis extract exhibited anti-inflammatory activity by the inhibition of hyaluronidase and lipoxygenase in a concentration-dependent manner. The stronger activity of O.biennis extract toward lipoxygenase may be explained by its higher oenothein B content.

Analysis of Flavonoids from Eugenia uniflora Leaves and Its Protective Effect against Murine Sepsis

Eugenia uniflora, referred to as Pitanga cherry shrub, is largely distributed in tropical and subtropical America. This plant is cultivated in many countries and it is suitable for the production of juice, frozen pulp, and tea. Besides, it can be used as treatment for inflammatory diseases. We reported that a flavonoid-rich fraction (HE-Bu) obtained from leaves decreased the lethality induced by cecal ligation and puncture (CLP), a clinically relevant model of sepsis. The oral administration of HE-Bu reduced the late mortality rate by 30%, prevented neutrophil accumulation in lungs, decreased TNF-α and IL-1β serum levels, and markedly decreased iNOS and COX-2 protein expression by ileum cells. Chemical investigation showed myricetin and quercetin rhamnosides as the major components of this fraction. The results showed that HE-Bu protected mice from sepsis and indicated that this edible plant produces compounds that could be considered as potential adjuvants for sepsis treatment.

Novel insight into qualitative standardization of Polygoni avicularis herba (Ph. Eur.)

Polygonum aviculare L. (Common Knotrgrass) (Polygonaceae Juss.) is an annual from which pharmacopoeial (Ph. Eur.) plant material Polygoni avicularis herba is obtained. Although its main active constituents are flavonoids and its standardization is based on their total content, no profound qualitative analysis has been performed, yet. The use of hyphenated analytical methods: UHPLC-DAD coupled with ion trap or time of flight mass detectors together with acidic hydrolysis products analysis allowed for a comprehensive determination of flavonoid composition. Among dominating compounds, myricetin, kaempferol, isorhamnetin and kaempferide glucuronides, which were not previously reported in P. avicularis herba, were discovered. The developed method can be used as a suitable tool for a more insightful, metabolome-based standardization of flavonoid rich pharmacopoeial plant material -P. avicularis herba.

Oenothein B's contribution to the anti-inflammatory and antioxidant activity of Epilobium sp

Willow herb tea or preparation are available and relatively popular in the European market, and claimed to be effective inter alia because of their anti-inflammatory activity. The present study is therefore aimed at comparing the anti-inflammatory and antioxidant activity of extracts of the three most popular Epilobium species (E. angustifolium, E. hirsutum and E. parviflorum) and at juxtaposing this activity against the dominating compounds from the following extracts: oenothein B (OeB), quercetin-3-O-glucuronide and myricetin-3-O-rhamnoside. The phytochemical analysis of the extracts has shown that OeB quantities vary between 20% and 35%, while flavonoids content does not exceed 2%. All extracts have inhibited the activity of hyaluronidase and lipoxygenase with IC₅₀ around 5 μg/ml and 25 μg/ml. The inhibition of hyaluronidase is related with the presence of OeB, a strong inhibitor of this enzyme (IC₅₀) 1.1 μM). Additionally, the extracts inhibited myeloperoxidase (MPO) release from stimulated neutrophils. OeB inhibited MPO release similarly to the anti-inflammatory drug indomethacin with IC₅₀ 7.7 μM and 15.4 μM, respectively. Tested extracts significantly reduced the production of reactive oxygen species (ROS) from f-MLP and PMA induced neutrophils with IC₅₀ 5 μg/ml and 25 μg/ml, respectively. The flavonoids content seems to exert little influence on extracts' activity, contrary to OeB, whose high concentration explains the activity of extract obtained from Epilobium. Tested currently marketed Epilobium preparations are often wrongly assigned, but we should stress that the level of OeB in all tested herbs was high and always exceeded 2% in raw material.

Quercetin enhances intestinal barrier function through the assembly of zonula [corrected] occludens-2, occludin, and claudin-1 and the expression of claudin-4 in Caco-2 cells

Dietary flavonoids provide various beneficial effects for our health. We investigated the promotive effects of quercetin and myricetin on the intestinal barrier function in human intestinal Caco-2 cell monolayers. Transepithelial electrical resistance (TER) across the monolayers increased rapidly during incubation with quercetin, peaking at 6 h. Lucifer yellow flux, a paracellular marker, was dose-dependently lower after quercetin and myricetin treatments, although quercetin exhibited a more potent effect. Immunoblot analysis of tight junction (TJ) proteins revealed that zonula occludens (ZO)-2, occludin, and claudin-1 were distributed to the actin cytoskeleton fraction by quercetin without increasing their respective whole-cell levels and this distribution was correlated with the increases in TER. The claudin-4 level was elevated by quercetin in both the cytoskeleton fraction and whole cells after 12 h. Confocal microscopy showed the assembly of claudin-1 and -4 at the TJ by quercetin. An inhibitor of protein kinase Cdelta (PKCdelta), rottlerin, enhanced the barrier function with changes in the distribution and expression of TJ proteins in a manner very similar to that of quercetin. Phosphorylation of PKCdelta indicating the enzymatic activity in the cells was decreased by quercetin after 1 h. In the kinase assay, quercetin exhibits direct inhibition of the PKCdelta isoform. This study demonstrates that quercetin enhances the intestinal barrier function through the assembly of ZO-2, occludin, and claudin-1 by inhibiting PKCdelta and the increase in claudin-4 expression has an additional role after 12 h.

Lipoxygenase inhibitors from natural plant sources. Part 1: Medicinal plants with inhibitory activity on arachidonate 5-lipoxygenase and 5-lipoxygenase[sol ]cyclooxygenase

Arachidonate 5-lipoxygenase is the key enzyme in leukotriene biosynthesis and catalyses the initial steps in the conversion of arachidonic acid to biologically active leukotrienes. Leukotrienes are considered as potent mediators of inflammatory and allergic reactions and regarding their pro-inflammatory properties the inhibition of 5-lipoxygenase pathway is considered to be interesting in the treatment of a variety of inflammatory diseases. Besides 5-lipoxygenase inhibitors, drugs able to block the 5-lipoxygenase as well as the cyclooxygenase metabolic pathway are also of therapeutic value. A potential source for new 5-lipoxygenase inhibitors is undoubtedly provided by the abundance of medicinal plants used in traditional medicine. The present review article reports the results from a comprehensive literature search of plants that have been tested for 5-lipoxygenase inhibitory activity over the past 15 years. The obtained information is summarized in a tabular format and promising plant species and chemical classes of compounds are presented. Relevant in vitro tests are also described in this article.

Combining ethnopharmacology and virtual screening for lead structure discovery: COX-inhibitors as application example

Virtual screening of large libraries of organic compounds combined with pharmacological high throughput screening is widely used for drug discovery in the pharmaceutical industry. Our aim was to explore the efficiency of using a biased 3D database comprising secondary metabolites from antiinflammatory medicinal plants as a source for the virtual screening. For this study pharmacophore models of cyclooxygenase I and II (COX-1, COX-2), key enzymes in the inflammation process, were generated with structure-based as well as common feature based modeling, resulting in three COX hypotheses. Four different multiconfomational 3D databases limited in molecular weight between 300 and 700 Da were applied to the screening in order to compare and analyze the obtained hit rates. Two of them were created in-house (DIOS, NPD). The database DIOS consists of 2752 compounds from phytochemical reports of antiinflammatory medicinal plants described by the ethnopharmacological source 'De material medica' of Pedanius Dioscorides, whereas NPD contains almost 80,000 compounds gathered arbitrarily from natural sources. In addition, two available multiconformational 3D libraries comprising marketed and development drug substances (DWI and NCI), mainly originating from synthesis, were used for comparison. As a test of the pharmacophore models' capability in natural sources, the models were used to search for known COX inhibitory natural products. This was achieved with some exceptions, which are discussed in the paper. Depending on the hypothesis used, DWI and NCI library searches produced hit rates in the range of 6.6% to 13.7%. A slight increase of the number of molecules assessed for binding was achieved with the database of natural products (NPD). Using the biased 3D database DIOS, however, the average increase of efficiency reached 77% to 133% compared to the hit rates resulting from WDI and NCI. The statistical benefit of a combination of an ethnopharmacological approach with the potential of computer aided drug discovery by in silico screening was demonstrated exemplified on the applied targets COX-1 and COX-2.

Induction of tumor necrosis factor production and antitumor effect by cabbage extract

The effect of cabbage extract on the production of tumor necrosis factor and its implication in the antitumor effect were examined in vitro and in vivo. Cabbage extract stimulated the production of tumor necrosis factor by rat spleen cells and showed cytotoxic activity in a rat ascites hepatoma cell line (AH109A) when hepatoma cells were cultured with cabbage-stimulated spleen cells. When the extract was adminstered orally to AH109A-bearing rats in combination with lipopolysaccharide injection, the hepatoma weights were reduced to one-half of the vehicle control. The cytotoxic activity of tumor-infiltrating macrophages was induced by simultaneous treatment with cabbage extract and lipopolysaccharide. These results indicate that cabbage extract contains macrophage-stimulating component(s) and can implement the antitumor effect by stimulating the cytotoxicity of tumor-infiltrating macrophages.

Bioavailability in humans of the flavanones hesperidin and narirutin after the ingestion of two doses of orange juice

OBJECTIVE

Flavanones are polyphenols specific of citrus fruits, where they are present in high amounts. Although citrus fruits and juices are widely consumed in the world, little information has been published on flavanone bioavailability in humans. The aim of the present study was to determine the nature of the circulating metabolites, the plasma kinetics and the urinary excretion patterns of the flavanones, hesperidin and narirutin.

DESIGN

After an overnight fast, five healthy volunteers ingested 0.5 or 1 l of a commercial orange juice providing 444 mg/l hesperidin and 96.4 mg/l narirutin, together with a polyphenol-free breakfast. Blood was sampled at 10 different timepoints over a 24 h period. Urine was collected for 48 h, in five fractions.

RESULTS

Flavanones metabolites appeared in plasma 3 h after the juice ingestion, reached a peak between 5 and 7 h, then returned to baseline at 24 h. The peak plasma concentration of hesperetin was 0.46+/-0.07 micro mol/l and 1.28+/-0.13 micro mol/l after the 0.5 and 1 l intake, respectively. It was lower for naringenin: 0.20+/-0.04 micro mol/l after the 1 l dose. The circulating forms of hesperetin were glucuronides (87%) and sulphoglucuronides (13%). For both flavanones, the urinary excretion was nearly complete 24 h after the orange juice ingestion. The relative urinary excretion was similar for hesperetin and naringenin and did not depend on the dose: values ranged from 4.1+/-1.2 to 7.9+/-1.7% of the intake.

CONCLUSIONS

In case of a moderate or high consumption of orange juice, flavanones may represent an important part of the pool of total polyphenols present in plasma.

Free radical scavenging action of medicinal herbs from Mongolia

In the present study we evaluated the free radical scavenging action of some medicinal herbs growing in Mongolia. The aqueous extract of nine herbs Chamenerion angustifolium (Ch.ang), Equisetum arvense (Eq.arv), Gentiana decumbens (Gn.dec), Geranium pratense (Gr.pra), Lomatogonium carinthiacum (L.car), Nonea poulla (N.pl), Phodococcum vitis-idaea (Ph.v), Sphallerocarpus gracilis (Sph.gr), Stellera chamaejasme (St.cha) were used in the present experiment. The free radical scavenging action was determined in vitro and ex vivo by using electron spin resonance (ESR) spectrometer and chemiluminescence (CL) analyzer. The results showed that extracts of Ch.ang, Gn.dec, Gr.pra, L.car, N.pl, Ph.v, Sph.gr and St. cha possess strong scavenging action of 1,1-diphenyl-2-picrylhydrazyl, superoxide and hydroxyl radicals. On the other hand, the radical scavenging action of Eq.arv was low. Extracts of N.pl and Ph.v markedly inhibited the CL generated from rat liver microsomal cytochrome P450 system whereas the CL was moderately inhibited by Eq.arv, Gn.dec, Gr.pra, L.car and St.cha. The extracts of Ch.ang and Sph.gr did not decrease the CL generation. Ch.ang, Gr.pra, L.car, N.pl, Ph.v and St.cha also depressed reactive oxygen production from polymorphonuclear leukocytes stimulated by phorbol-12-myristate acetate ex vivo. Thus it was confirmed that the medicinal herbs from Mongolia possess high antioxidant potency in vitro and ex vivo.