Inhibitory effects of flavonoids from Hypericum perforatum on nitric oxide synthase

Hypericum perforatum: a comprehensive review on pharmacognosy, preclinical studies, putative molecular mechanism, and clinical studies in neurodegenerative diseases

The herb Hypericum perforatum, also referred to as St. John's wort, has drawn a lot of interest because of its potential therapeutic benefits in treating neurodegenerative illnesses. Due to the absence of effective therapies, illnesses like Alzheimer's and Parkinson's disease pose an increasing worldwide health concern. Because of its wide variety of phytochemicals, especially hyperforin, and hypericin, Hypericum perforatum is well known for its neuroprotective properties. These substances have proven to be able to affect different cellular processes linked to neurodegeneration. They can act as anti-inflammatory, antioxidant, and neurotransmitter system regulators, which may help halt neurodegenerative illnesses' progression. The use of Hypericum perforatum extracts and its contents has shown encouraging results in research on animal models of neurodegenerative disorders. These advantages include higher nerve cell survival, lowered oxidative stress, and higher cognitive performance. Underscoring its versatile potential to combat neurodegeneration, Hypericum perforatum has neuroprotective mechanisms that modulate neuroinflammation and prevent apoptotic pathways. In conclusion, Hypericum perforatum shows tremendous promise as a potential treatment for neurological illnesses due to its wide variety of phytochemicals. To completely comprehend its specific mechanisms of action and turn these discoveries into efficient clinical therapies, additional research is needed. Investigating Hypericum perforatum's function in neurodegenerative disorders may present new opportunities for the advancement of ground-breaking therapeutic strategies.

Therapeutic potential of dietary flavonoid hyperoside against non-communicable diseases: targeting underlying properties of diseases

Non-communicable diseases (NCDs) are a global epidemic with diverse pathogenesis. Among them, oxidative stress and inflammation are the most fundamental co-morbid features. Therefore, multi-targets and multi-pathways therapies with significant anti-oxidant and anti-inflammatory activities are potential effective measures for preventing and treating NCDs. The flavonol glycoside compound hyperoside (Hyp) is widely found in a variety of fruits, vegetables, beverages, and medicinal plants and has various health benefits, especially excellent anti-oxidant and anti-inflammatory properties targeting nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor-κB (NF-κB) signaling pathways. In this review, we summarize the pathogenesis associated with oxidative stress and inflammation in NCDs and the biological activity and therapeutic potential of Hyp. Our findings reveal that the anti-oxidant and anti-inflammatory activities regulated by Hyp are associated with numerous biological mechanisms, including positive regulation of mitochondrial function, apoptosis, autophagy, and higher-level biological damage activities. Hyp is thought to be beneficial against organ injuries, cancer, depression, diabetes, and osteoporosis, and is a potent anti-NCDs agent. Additionally, the sources, bioavailability, pharmacy, and safety of Hyp have been established, highlighting the potential to develop Hyp into dietary supplements and nutraceuticals.

Hypericum perforatum L. prevents the acquisition of and promotes resilience against stress-induced reinstatement of the conditioned place preference induced by cocaine

Cocaine use disorder is a serious problem worldwide, and there are no approved medications for its treatment. A novel approach to the treatment of drug addiction is the use of natural products, and, in this context, preclinical evidence suggests that Hypericum perforatum L. (Hypericum) is effective against alcohol and other substance use disorders. We hypothesised that Hypericum could also be useful as a treatment for cocaine use disorder, and so we set out to test its effectiveness in a mice model of cocaine addiction. In the first experiment we evaluated its effects on the acquisition of cocaine-induced conditioned place preference (CPP). Adult male mice were conditioned with cocaine (25 mg/kg), cocaine with Hypericum (75, 150 or 300 mg/kg) or the plant extract alone (300 mg/kg). In the second experiment, we tested the effects of Hypericum on stress-induced reinstatement of cocaine CPP. All the mice were conditioned with cocaine (25 mg/kg) and, after extinction of CPP, the reinstating effects of social defeat (alone or with 75, 150 or 300 mg/kg of Hypericum) were evaluated. All the doses of Hypericum prevented the acquisition of cocaine-induced CPP. Furthermore, the plant extract dose-dependently reduced the reinstating effects of social defeat. Therefore, Hypericum is effective in reducing the rewarding effects of cocaine and prevents the stress-induced reinstatement of cocaine CPP in mice. The mechanisms underlying these positive effects of Hypericum perforatum L. need to be determined by future research. Our results endorse Hypericum as a natural treatment for cocaine dependence.

Camelina sativa Methanolic and Ethanolic Extract Potential in Alleviating Oxidative Stress, Memory Deficits, and Affective Impairments in Stress Exposure-Based Irritable Bowel Syndrome Mouse Models

Camelina sativa is mainly used as an oilseed crop; its edible oil is being also used as a traditional home remedy for the treatment of ulcers, wounds, and eye inflammations, due to the antioxidant activities. In the present study, the chemically characterized alcoholic extracts of Camelina sativa var. Madalina defatted seeds (5 g/kg body weight p.o., suspended in CMC-Na 0.1%) were administered to stress-induced animal models of irritable bowel syndrome (based on combinations of contention stress and multifactorial stress and maternal stress) and evaluated for the behavioural (short-term memory by the Y maze test, the anxious behaviour using the elevated plus maze test, and the antidepressant effect using the forced swimming test) and brain and bowel tissue oxidative status (superoxide dismutase and glutathione peroxidase enzymes activities and malondialdehyde and total soluble protein levels) improving effects. According to the chemical characterization, the extracts were rich in sinapine, glucosinolates, and flavonol glycosides. Moreover, this study showed the beneficial effects of Camelina sativa seed methanolic and ethanolic extracts on the behaviour and brain and bowel tissues oxidative stress status of stress exposure-based IBS mouse models. Despite the slight differences in the chemical composition of the methanolic and ethanolic extracts, the results suggested that the Camelina sativa extracts could reverse the short-term memory impairments caused by stress exposure and also could decrease the intensity and frequency of the anxiety and depressive-like behaviours observed in the stress-exposed animal models of IBS. Furthermore, the Camelina sativa extracts showed a significant effect on the oxidative stress markers in the brain and bowel tissues of the studied animal model by decreasing the superoxide dismutase activity and increasing the glutathione peroxidase activity. However, the results suggested that the extracts could also increase lipid peroxidation in bowel tissues. In this way, this study provides additional evidence that the administration of Camelina sativa seed alcoholic extracts could improve cognitive performances and mood and exhibit the antioxidant capacity in both the brain and bowel tissues.

Antioxidant Capacity and Behavioral Relevance of a Polyphenolic Extract of Chrysanthellum americanum in a Rat Model of Irritable Bowel Syndrome

Chrysanthellum americanum L. (Vatke) is a medicinal plant from the Compositae family used in west-African traditional medicine, known for its flavonoid and saponin richness and for its strong antioxidant potential. In the present study, we assessed the effects of Chrysanthellum americanum polyphenolic extract in the psychological stress-induced rat model of irritable bowel syndrome (IBS), a chronic functional digestive tract disorder marked by immune and inflammatory-related disturbances of central nervous and peripheral intestinal systems, which is often associated with mood disorders including depression and anxiety. Consequently, memory impairment, anxiety and depression behavioral indicators, and cerebral oxidative stress biomarker dynamics were evaluated in a multifactorial heterotypic stress-exposed IBS rats after 6-day gavage with polyphenolic C. americanum extract (100 mg/kg body weight). Y-maze, elevated plus maze, and forced swimming tests were used for assessing behavioral responses. Administration of the extract exhibited significant anxiolytic and antidepressant-like effects coupled with significantly increased temporal lobe antioxidant enzyme specific activity (superoxide dismutase and glutathione peroxidase) and decreased malondialdehyde levels, a well-known lipid peroxidation marker. Furthermore, linear regression statistical analyses showed significant correlations between the oxidative stress parameters and behavioral tests. In conclusion, our results suggest that the administration of Chrysanthellum americanum polyphenolic extract could ameliorate mood and cognitive disturbances related to stress-induced in an IBS rat model. This could be also related to cerebral oxidative stress status attenuation.

Distribution of total phenols, flavonoids and hypericin in different plant organs of wild-growing St. John’s-wort (Hypericum perforatum L., Hypericaceae) from North Macedonia

Hypericum perforatum L. (Hypericaceae) contains secondary metabolites that show noteworthy pharmacological activities. Therefore, the content of total phenols, flavonoids and hypericin from whole herb, flowers and leafs from St. John’s-wort collected over four consecutive seasons (2014-2017) from three different locations in western part of North Macedonia (Tetovo, Debar and Mavrovo) were investigated by three different spectrophotometric methods (using Folin-Ciocalteu reagent, NaNO2-AlCl3-NaOH and mixture of water/tetrahydrofuran). The quantity of total phenols obtained from different plant organs (leafs, whole herb and flowers) were 35.15-83.08 mg GAE/g, 55.41-98.52 mg GAE/g and 75.44-121.19 mg GAE/g, respectively. Afterword the total flavonoids contents were: 61.64-106.86 mg CE/g, 73.04-117.57 mg CE/g and 108.65-125.35 mg CE/g in leafs, whole herb and flowers, respectively, while the hypericin amounts were: 0.03-0.17 mg/g, 0.04-0.29 mg/g and 0.07-0.60 mg/g in leafs, whole herb, and flowers, respectively. Significant differences were observed in the quantities of total phenols, flavonoids and hypericin between the locations of harvesting, while the collection seasons were found not to be significant. Additionally, it can be seen that the flowers are characterized by higher amounts of total phenols, total flavonoids and hypericin compared to total herb and leaf in all three locations, therefore harvesting of St. John’s-wort should be made in a manner of obtaining larger quantities of flowers as harvesting material which could increase the bioactive compounds in the herbal row material. Keywords: Hypericum perforatum, plant organs, total phenols, flavonoids, hypericin, statistical analysis

Effect of (-)-epicatechin, a flavonoid on the NO and NOS activity of Raillietina echinobothrida

(-)-Epicatechin, a natural flavonoid reportedly has huge pharmacological properties. In this study the cestocide effect of (-)-epicatechin is demonstrated in Raillietina echinobothrida. Although the antiparasitic activity of (-)-epicatechin has been demonstrated against protozoa, helminths and ectoparasites, in the present study the cestocide activity of (-)-epicatechin is shown to be related to a decrease in nitric oxide synthase (NOS) activity and nitric oxide (NO) production. On exposure to 0.53mg/ml each of epicatechin, reference drug praziquantel and Ѡ Nitro-l- Arginine Methyl Ester (NOS inhibitor), the parasites attained paralysis at 10.15, 0.27 and 11.21h followed by death at 30.15, 1.21 and 35.18h respectively. Biochemical analysis showed a significant decrease in activity of NOS (57.360, 36.040 and 44.615%) and NO (41.579, 19.078 and 24.826%) in comparison to the controls. NADPH-diaphorase histochemical staining (a selective marker for NOS in neuronal tissue) demonstrated a pronounced decline in the visible staining activity in the tegument, subtegument and the peripheral nerve regions following exposure to the treatments. Strong binding affinity of (-)-epicatechin with NOS protein was also revealed through docking studies. The results strongly define the probable anthelmintic activity of our compound through its influence on the NOS activity.

THE BIOLOGICAL ACTIVITIES OF HYPERICUM PERFORATUM L

BACKGROUND

Mastitis reduces milk yield and alters milk composition. Antibiotics are widely used in the treatment of the disease. However, this widespread use of antibiotics causes both antibiotic residues in milks and antibiotic resistance developed in bacteria. Today's researches are focused on discovering and using new antibiotics against bacteria.

OBJECTIVE

The aim of this work was to discover the antibacterial effects of Hypericum perforatum L. extracts against mastitis pathogens, and its other biological activities.

MATERIAL AND METHODS

Kirby-Bauer assay was applied to the extracts. The other antibacterial activity was MIC for plant extracts. The non-enzymatic antioxidant activity was found using 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH).

RESULTS

The extract was showed maximum inhibition zone against two bacteria (Coagulase-negative Staphylococci-33 and 37; CNS 33 and 37), and the zone was 17 mm. A bacterium (CNS - 22) showed the lowest sensitivity to 812.5 μg/mL concentration. In addition, the extract was tried against the stable DPPH for antioxidant activity. As a result, the extract showed a strength antioxidant activity. Trolox equivalent is 0.83 mM.

CONCLUSION

The extract of Hypericum perforatum have antibacterial, antioxidant and antimutagenic potentials.

Neuroprotective Activity of Hypericum perforatum and Its Major Components

Hypericum perforatum is a perennial plant, with worldwide distribution, commonly known as St. John's wort. It has been used for centuries in traditional medicine for the treatment of several disorders, such as minor burns, anxiety, and mild to moderate depression. In the past years, its antidepressant properties have been extensively studied. Despite that, other H. perforatum biological activities, as its neuroprotective properties have also been evaluated. The present review aims to provide a comprehensive summary of the main biologically active compounds of H. perforatum, as for its chemistry, pharmacological activities, drug interactions and adverse reactions and gather scattered information about its neuroprotective abilities. As for this, it has been demonstrated that H. perforatum extracts and several of its major molecular components have the ability to protect against toxic insults, either directly, through neuroprotective mechanisms, or indirectly, through is antioxidant properties. H. perforatum has therefore the potential to become an effective neuroprotective therapeutic agent, despite further studies that need to be carried out.

An effective homogenate-assisted negative pressure cavitation extraction for the determination of phenolic compounds in pyrola by LC-MS/MS and the evaluation of its antioxidant activity

A novel extraction method was designed for the extraction and determination of the main phenolic compounds of Pyrola incarnata Fisch.

Investigation of the Antioxidant and Hepatoprotective Potential of Hypericum mysorense

Background:Hypericum is a well-known plant genus in herbal medicine. Hypericum mysorense (Family: Hypericaceae), a plant belonging to the same genus, is well known in folklore medicine for its varied therapeutic potential. Objective: The aim of the present study was to investigate the different parts of the plant for antioxidant and hepatoprotective properties. Materials and Methods: The methanol extracts of Hypericum mysorense prepared from various parts of the plant were tested in vitro for their free radical scavenging activity against ABTS^• (diammonium salt), DPPH^• (1,1-diphenyl-2-picrylhydrazyl), NO^•, O₂^•− and ^•OH radicals, using standard systems of assays. The total antioxidant capacity, total phenolic and total flavonoid content of the extracts were analyzed. Further, the leaf and flowering top extracts were tested for their in vivo antioxidant and hepatoprotective activities on Wistar rats using a carbon tetrachloride-induced hepatic injury model. Results: The leaf and flowering top extract showed potent antioxidant activity and also possessed highest total phenolic and flavonoid content. The antioxidant activity and the total phenolic and flavonoid content present in these extracts showed a good correlation. The leaf and flowering top extracts at 200 mg/kg restored aspartate amino transferase (ASAT), alanine amino transferase (ALAT), alkaline phosphatase (ALP), total bilirubin and protein levels significantly in CCl₄-intoxicated rats. The tested extracts also showed a significant (p < 0.001) reduction in 2-thiobarbituric acid reactive substance (TBARS) levels with an increase in SOD and CAT levels. The histopathology of liver did not show any toxicity after the treatment with the extracts. The active extracts were standardized using two marker compounds, hyperoside and rutin, which were isolated from the plant by HPLC. HPLC studies revealed that the maximum concentration of hyperoside and rutin is present in the flowering top extract.

The effect of hyperoside on the functional recovery of the ischemic/reperfused isolated rat heart: potential involvement of the extracellular signal-regulated kinase 1/2 signaling pathway

One of the leading causes of death in the world is ischemia/reperfusion (I/R)-mediated acute myocardial infarction. There are a lot of Chinese traditional patent medicines, such as Xin'an capsules, Xin Xuening tablets, and so on, which have protective effects against myocardial I/R injury and have been routinely used in treating cardiac diseases for a long time in China. Hyperoside (Hyp) is the chief component of these medicines. This study investigated the action of Hyp in isolated myocardial I/R injury, as well as its possible mechanisms. Using the Langendorff model, isolated Sprague-Dawley rat hearts were subjected to 30 min of global ischemia and 50 min of reperfusion. Cardiac function was measured, and infarct size was evaluated by triphenyltetrazolium chloride staining at the end of the reperfusion. Coronary effluent was analyzed for lactate dehydrogenase (LDH) and creatine kinase (CK). Myocardium was also measured for total superoxide dismutase (SOD) activity and malondialdehyde (MDA) content. Phosphorylation of extracellular signal-regulated protein kinase (ERK) was analyzed by Western blotting. We report for the first time that administration of Hyp before/after I/R significantly improved heart contraction and limited the infarct size and CK and LDH leakage from the damaged myocardium after I/R. The activity of SOD and the MDA content remarkably changed in the presence of Hyp as well. Phosphorylation of ERK was significantly increased in Hyp-treated hearts compared to controls (p<0.01). Hyp-induced ERK phosphorylation was inhibited by PD98059. We therefore conclude that Hyp can protect cardiomyocytes from I/R-induced oxidative stress through the activation of ERK-dependent signaling.

Comparative analysis of the chemical composition and antioxidant activity of red (Psidium cattleianum) and yellow (Psidium cattleianum var. lucidum) strawberry guava fruit

Strawberry guava (Psidium cattleianum Sabine) is a native fruit of Brazil widely consumed fresh and used in the food industry. In this context, the present study deals with the chemical characterization and the antioxidant activity of the red (Psidium cattleianum) and yellow (P. cattleianum var. lucidum Hort.) strawberry guava fruits, cultivars Irapuã and Ya-Cy, respectively. Knowledge of chemical composition is fundamental to human nutrition, contributing to the quality of foods. Phenolic compounds in both fruits were analyzed by HPLC-DAD and the total flavonoid content was determined by the Folin-Ciocalteu assay. The antioxidant activity was evaluated by the total reactive antioxidant (TRAP) method. Psidium cattleianum presented a higher content of polyphenolic compounds than P. cattleianum var. lucidum (501.33 and 292.03 mg/100 g, respectively), with hyperoside being one of the major flavonoids identified for both cultivars. In addition to flavonoids, P. cattleianum presented an anthocyanin, identified as cyanidin. The antioxidant activity varied in a concentration-dependent manner for both strawberry guava species. The volatile oils in fruits and fatty acids in seeds were quantified by GC-EM. The analysis of the essential oil of yellow strawberry guava was compared with a previous study on the red cultivar, revealing β-caryophyllene as the main component in both oils. The fatty acid composition was also quite similar and was especially characterized by the presence of unsaturated fatty acids (86.25% and 76%, respectively), among which linoleic acid as the most abundant.

PRACTICAL APPLICATION

In this study, the chemical characterization and the antioxidant activity of the red (Psidium cattleianum) and yellow (P. cattleianum var. lucidum Hort.) strawberry guava fruits were investigated. This is important for potential application of strawberry guava as functional food. Moreover, it may be the experimental basis for further development and use in food industry.

Protective effects of hyperoside against human umbilical vein endothelial cell damage induced by hydrogen peroxide

ETHNOPHARMACOLOGICAL RELEVANCE

Hyperoside (Hyp) is a flavonoid compound isolated from Rhododendron ponticum L. leaves that elicits vascular protective effects in vitro. Treatment with Hyp has been found to attenuate endothelial cell damage induced by oxidative stress, but its mechanisms of action remain unclear. This study investigated the action of Hyp in an endothelial injury model induced by hydrogen peroxide (H(2)O(2)), as well as its possible mechanisms.

MATERIALS AND METHODS

Human umbilical vein endothelial cells (HUVECs) were treated with H(2)O(2) alone or in combination with Hyp. The protective effects of Hyp against H(2)O(2) were evaluated, and the activation of extracellular signal-regulated protein kinase (ERK) in Hyp was assayed in HUVECs.

RESULTS

Loss of cell viability as well as excessive cell apoptosis and death were observed in HUVECs after 18 h of challenge with H(2)O(2) (400μM); however, both cell apoptosis and death were attenuated in the Hyp-pretreated cells. Western blot analysis revealed that Hyp increased the expression of Bcl-2 but decreased that of Bax. In addition, Hyp induced the phosphorylation of ERK1/2 in HUVECs.

CONCLUSION

These observations provide preliminary evidence that Hyp protects HUVECs against H(2)O(2) damage, at least partially, by activating the ERK signaling pathway.

Antioxidant activity relationship of phenolic compounds in Hypericum perforatum L

BACKGROUND

The St John's Wort (Hypericum perforatum; Clusiaceae) has been used in traditional and modern medicine for a long time due to its high content of biologically active phenolics. The purpose of this work was to develop a method for their fractionation and identification, and to determine the most active antioxidant compounds in plant extract.

RESULTS

An LC-MS method which enables fast qualitative and semiquantitative analysis was developed. The composition determined is in agreement with the previous results, where 6 flavonoids, 4 naphthodianthrones and 4 phloroglucinols have been identified. Significant antioxidant activity was determined for most of the fractions by DPPH assay (the lowest IC50 of 0.52 μg/ml), NO scavenging (6.11 μg/ml), superoxide scavenging (1.86 μg/ml), lipid peroxidation (0.0079 μg/ml) and FRAP (the highest reduction capacity of 104 mg Fe equivalents/g) assays.

CONCLUSION

LC-MS technique has been successfully applied for a quick separation and identification of the major components of H. perforatum fractions. Majority of the fractions analyzed have expressed a very high antioxidative activity when compared to synthetic antioxidants. The antioxidant activity could be attributed to flavonoids and phenolic acids, while phloroglucinols and naphthodianthrones showed no significant activity. It is demonstrated that it is possible to obtain, by fractionation, H. perforatum preparations with significantly increased phloroglucinols-to-naphthodianthrones ratio (up to 95:5).

Protective effects of hyperoside against carbon tetrachloride-induced liver damage in mice

In this study, the hepatoprotective effects of hyperoside (1), a flavonoid glycoside isolated from Artemisia capillaris, have been examined against carbon tetrachloride (CCl4)-induced liver injury. Mice were treated intraperitoneally with vehicle or 1 (50, 100, and 200 mg·kg(-1)) 30 min before and 2 h after CCl4 (20 μL·kg(-1)) injection. Levels of serum aminotransferases were increased 24 h after CCl4 injection, and these increases were attenuated by 1. Histological analysis showed that 1 prevented portal inflammation, centrizonal necrosis, and Kupffer cell hyperplasia. Lipid peroxidation was increased and hepatic glutathione content was decreased significantly after CCl4 treatment, and these changes were reduced by administration of 1. Protein and mRNA expression of tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and heme oxygenase-1 (HO-1) and nuclear protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2) significantly increased after CCl4 injection. Compound 1 suppressed TNF-α, iNOS, and COX-2 protein and mRNA expression and augmented HO-1 protein and mRNA expression and Nrf2 nuclear protein expression. These results suggest that 1 has protective effects against CCl4-induced acute liver injury, and this protection is likely due to enhancement of the antioxidative defense system and suppression of the inflammatory response.

Effects of Lycopene, Indole-3-Carbinol, and Luteolin on Nitric Oxide Production and iNOS Expression are Organ-Specific in Rats

Natural compounds are known to modify NO content in tissues; however, the biological activity of polyphenol-rich food often does not correspond to the effects of individual polyphenols on NO synthase activity. The aim of this study was to see how natural compounds luteolin, indole-3-carbinol, and lycopene modify NO production in rat tissues and change the expression of the iNOS gene and protein. Indole-3-carbinol produced multiple effects on the NO level; it significantly decreased NO concentration in blood, lungs, and skeletal muscles and increased it in the liver. Indole-3-carbinol enhanced lipopolyssaccharide (LPS)-induced NO production in all rat organs. It decreased iNOS gene expression in the brain cortex of animals that did not receive LPS and up-regulated it in the LPS-treated animals. Lycopene increased the iNOS gene transcription rate in the brain cortex of LPS-treated animals. Luteolin did not modify NO production in any organ of LPS-untreated rats, nor did it affect gene expression in the liver. In the brain it slightly decreased iNOS gene expression. Luteolin decreased NO production in the blood of LPS-treated animals and the number of iNOS-positive cells in these animals. Our results suggest that changes in tissue NO levels caused by natural compounds cannot be predicted from their effect on NOS expression or activity obtained in model systems. This stresses the importance of direct measurements of NO and NOS expression in animal tissues.

A comparison study on the interaction of hyperoside and bovine serum albumin with Tachiya model and Stern-Volmer equation

The interaction between hyperoside and bovine serum albumin (BSA) was examined by fluorescence spectroscopy at 298, 304, and 310K. The spectroscopic data were analyzed using Tachiya model and Stern-Volmer equation to determine the binding sites and apparent binding constant between hyperoside and BSA. For Tachiya model, both binding sites and apparent binding constants increased with the increasing of temperature, whereas for Stern-Volmer equation, the corresponding binding constants decreased as temperature increasing and the binding sites were independent of temperature. The positive sign of enthalpy change (DeltaH) and entropy change (DeltaS) suggested that hydrophobic forces played a major role in the interaction. Synchronous fluorescence spectra indicated that the conformation of protein was perturbed by the interaction of hyperoside with BSA. Moreover, the presence of metal ion affected the hyperoside-BSA binding.

Variation of bioactive substances in Hypericum montbretii during plant growth

The present study was conducted to determine phenologic and morphogenetic variation of chlorogenic acid and flavonoids, as rutin, hyperoside, apigenin-7-O-glucoside, quercitrin, quercetin and viteksin content of Hypericum montbretii growing in Turkey. Wild growing plants were harvested at vegetative, floral budding, full flowering, fresh fruiting and mature fruiting stages and dissected into stem, leaf and reproductive tissues and assayed for bioactive compounds by HPLC method. Accumulation of rutin and quercetin was not detected in plant parts of H. montbretii during plant growth. Chlorogenic acid and hyperoside content in whole plant was decreased linearly with advancing of development stages and reached their highest level at vegetative stage. On the contrary, apigenin-7-O-glucoside, quercitrin and viteksin content in whole plant increased during the course of seasonal development and the highest level of those compounds was observed at the stage of full flowering. Leaves did not produce apigenin-7-O-glucoside, while viteksin was not detectable in stem and reproductive tissues. Depending on development stages, reproductive parts had the highest level of apigenin-7-O-glucoside and leaves produced major amount of chlorogenic acid, hyperoside and viteksin whereas accumulation of quercitrin was prevailed in stem tissue. Such kind of data could be useful for elucidation of the chemotaxonomical significance of these compounds and medicinal evaluation of this species.

Topical anti-inflammatory activity of extracts and compounds from Hypericum perforatum L

Three preparations of Hypericum perforatum L. (a hydroalcoholic extract, a lipophilic extract and an ethylacetic fraction) and the pure compounds hypericin, adhyperforin, amentoflavone, hyperoside, isoquercitrin, hyperforin dicyclohexylammonium (DHCA) salt and dicyclohexylamine were evaluated for their topical anti-inflammatory activity. H. perforatum preparations provoked a dose-dependent reduction of Croton-oil-induced ear oedema in mice, showing the following rank order of activity: lipophilic extract > ethylacetic fraction > hydroalcoholic extract (ID50 (dose that inhibited oedema by 50%) 220, 267 and >1000 microg cm(-2), respectively). Amentoflavone (ID50 0.16 micromol cm(-2)), hypericin (ID50 0.25 micromol cm(-2)), hyperforin DHCA salt (ID50 0.25 micromol cm(-2)) and adhyperofrin (ID50 0.30 micromol cm(-2)) had anti-inflammatory activity that was more potent or comparable to that of indometacin (ID50 0.26 micromol cm(-2)), whereas isoquercitrin and hyperoside were less active (ID50 about 1 micromol cm(-2)). As dicyclohexylamine alone was inactive, the effect of hyperforin DHCA salt can be attributed completely to the phloroglucinol moiety. The pharmacological activity and phytochemical profile of the tested extracts and fraction suggest that different constituents are involved in the topical antiphlogistic property of H. perforatum in-vivo.

Extract of Hypericum perforatum blocks caffeine-induced locomotor activity in mice: a possible role of nitric oxide

The present study investigated the effects of HPE on caffeine-induced locomotor activity in mice. Caffeine (4-16 mg/kg) or saline were given to adult male Swiss-Webster mice, and the locomotor activity was immediately measured for 30 min. HPE (6-48 mg/kg) and saline were injected to another group of mice and the locomotor activity was measured 20 min later. HPE (6-24 mg/kg) was also administered to another group of mice 20 min before caffeine (16 mg/kg) injections and the locomotor activity was recorded for 30 min immediately after caffeine administrations. Finally l-arginine (1 g/kg) was administered i.p. 20 min before HPE (6 mg/kg) and the locomotor activity was measured as mentioned above. Each group of mice was used only once. Caffeine produced some significant increases in locomotor activity of the mice. HPE (6-24 mg/kg) significantly blocked the caffeine-induced locomotor hyperactivity. Pretreatment of l-arginine (1 g/kg) reversed the inhibitory effect of HPE (6 mg/kg) on caffeine-induced locomotor activity without producing any significant effect on locomotor activity of the mice when it was administered alone. The results suggest that HPE blocks caffeine-induced locomotor hyperactivity in mice. Furthermore, the inhibitory effect of HPE on caffeine-induced locomotor activity may be related to its NOS inhibitory property.

Attenuation of ethanol withdrawal syndrome by extract of Hypericum perforatum in Wistar rats

The effects of Hypericum perforatum (St John's wort) on ethanol withdrawal syndrome have been investigated in ethanol-dependent rats. Adult male Wistar rats were subjects. Ethanol (7.2% v/v) was given to rats by a liquid diet for 15 days. Hypericum perforatum extract (HPE) (25-200 mg/kg) and saline were injected to rats intraperitoneally just before ethanol withdrawal. After second, fourth and sixth hour of ethanol withdrawal, rats were observed for 5 min, and withdrawal signs that included locomotor hyperactivity, stereotyped behavior and tremors were recorded or rated. A second series of injections was given at 6 h after the first one, and subjects were then tested for audiogenic seizures. HPE (25-200 mg/kg) produced some dose-dependent and significant inhibitory effects on locomotor hyperactivity at second and sixth hour of ethanol withdrawal. In addition, it significantly reduced the number of stereotyped behaviors at the same dose range. HPE (50 and 100 mg/kg) produced some significant inhibitory effects on tremor and audiogenic seizures during withdrawal period. These results suggest that HPE has some beneficial effects on ethanol withdrawal syndrome in rats.

Radioprotective effects of hawthorn fruit extract against gamma irradiation in mouse bone marrow cells

The radioprotective effect of hawthorn (Crataegus microphylla) fruit extract against genotoxicity induced by gamma irradiation has been investigated in mouse bone marrow cells. A single intraperitoneal (ip) administration of hawthorn extract at doses of 25, 50, 100 and 200 mg/kg 1h prior to gamma irradiation (2 Gy) reduced the frequencies of micronucleated polychromatic erythrocytes (MnPCEs). All four doses of hawthorn extract significantly reduced the frequencies of MnPCEs and increased the PCE/PCE+NCE ratio (polychromatic erythrocyte/ polychromatic erythrocyte + normochromatic erythrocyte) in mice bone marrow compared with the non drug-treated irradiated control (p < 0.02-0.00001). The maximum reduction in MnPCEs was observed in mice treated with extract at a dose of 200 mg/kg. Administration of amifostine at dose 100 mg/kg and hawthorn at dose 200 mg/kg reduced the frequency of MnPCE almost 4.8 and 5.7 fold; respectively, after being exposed to 2 Gy of gamma rays, compare with the irradiated control group. Crataegus extract exhibited concentration-dependent activity on 1,1-diphenyl 2-picrylhydrazyl free radical showing that Crataegus contained high amounts of phenolic compounds and the HPLC analysis determined that it contained chlorogenic acid, epicatechin and hyperoside. It appeared that hawthorn extract with antioxidant activity reduced the genotoxicity induced by gamma irradiation in bone marrow cells.

Protective effects of polysaccharide from Euphorbia kansui (Euphorbiaceae) on the swimming exercise-induced oxidative stress in mice

The present study examined the effects of derivatives of galactosides and glucosides in a polysaccharide extract from Euphorbia kansui (Euphorbiaceae) on exercise-induced oxidative stress in mice. Exhaustive swimming exercise significantly increases the degree of lipid peroxidation in terms of malondialdehyde content and reduces the antioxidant activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Our findings revealed that chronic oral treatment with the extract elevates enzymatic activities of SOD and GPx accompanied by a corresponding decrease in malondialdehyde. The antioxidative activities of these compounds against exercise-induced oxidative stress are correlated with various activities such as reducing the production of superoxide and hydroxyl radicals, inhibiting lipid peroxidation, enhancing antioxidative defenses, and increasing the production of SOD and GPx activity and expression in different tissues. These compounds may be involved in glycogen metabolism to meet the requirement of working skeletal muscles and act as antioxidants by terminating the chain reaction of lipid peroxidation to maintain the morphological stability of mitochondria in spinal motor neurons. These observations suggest that E. kansui has antioxidative and antifatigue properties and can be given as prophylactic and (or) therapeutic supplements for increasing antioxidant enzyme activities and preventing lipid peroxidation during strenuous exercise.

Application of high-speed counter-current chromatography coupled with high-performance liquid chromatography–diode array detection for the preparative isolation and purification of hyperoside from Hypericum perforatum with online purity monitoring

Following preparative isolation and purification by high-speed counter-current chromatography (HSCCC), the collected fractions were generally analyzed by high-performance liquid chromatography (HPLC) to determine the relative purities of each fraction. Our paper reports for the first time a preparative isolation-purity detection hyphenated system: online coupling of HSCCC with high-performance liquid chromatography-diode array detection (HSCCC-HPLC-DAD). The introduction of online purity analysis in HSCCC has dramatically improved the efficiency of this technique by overcoming the drawbacks of post analysis in HSCCC isolation. The effluent from the outlet of HSCCC was splitted into two parts: one was collected, while the other was introduced directly into an HPLC-DAD system for purity analysis through a switch valve. Therefore, the purities of the obtained fractions from HSCCC were monitored, and fractions with high purities were collected. This strategy has been successfully demonstrated with the preparative isolation and purification of hyperoside from Hypericum perforatum (St. Jone's Wort); a model of TBE-300A HSCCC was used to isolate and separate hyperoside from H. perforatum with a two-phase solvent system composed of ethyl acetate-ethanol-water at the volume ratio of 5:1:5 (v/v) using online detection technique. The isolation was done in less than 3.5 h, and a total of 83.0-mg hyperoside at over 99.0% purity was yielded from 300 mg of the partially purified extract. This new strategy possesses general utility in the preparation of bioactive compounds from traditional Chinese medicine (TCM).

Antispasmodic and bronchodilator activities of St John's wort are putatively mediated through dual inhibition of calcium influx and phosphodiesterase

The crude extract of aerial parts of St John's wort (Hypericum perforatum) (Hp.Cr) and its fractions were studied in vitro for its possible spasmolytic and bronchodilator activities to rationalize some of its medicinal uses. In rabbit jejunum preparations, Hp.Cr caused a concentration-dependent relaxation of both spontaneous and K+ (80 mm)-induced contractions at a similar concentration range (0.1-1.0 mg/mL), similar to that produced by papaverine, whereas verapamil was relatively potent against K+-induced contractions. Hp.Cr shifted the Ca2+ concentration-response curves (CRCs) to the right, similar to that caused by papaverine or verapamil and also caused leftward shift of isoprenaline-induced inhibitory CRCs, similar to papaverine. In guinea-pig tracheal preparations, Hp.Cr caused relaxation of carbachol and K+-induced contractions at similar concentrations (0.01-0.3 mg/mL) and also shifted the isoprenaline-induced inhibitory CRCs to the left, similar to that caused by papaverine. In rabbit aorta preparations at rest, Hp.Cr produced a moderate vasoconstriction, while exhibited vasodilator effect against phenylephrine and K+-induced contractions. Papaverine and verapamil also produced similar non-specific vasodilation, but were devoid of any vasoconstrictor effect. Hp.Cr caused suppression of atrial force of contractions at concentrations about 20 times higher than those that produced inhibitory effect in smooth muscle preparations, similar to papaverine. These results suggest that the spasmolytic effects of Hp.Cr are mediated through dual inhibition of calcium influx and phosphodiesterase (PDE)-like mechanisms, which might explain the medicinal use of St John's wort in the disorders of gastrointestinal and respiratory tracts. Furthermore, the presence of Ca2+ antagonist and PDE inhibitory-like constituents might also be contributing to some extent in the well established use of plant in depression.

Protective effects of hyperoside (quercetin-3-o-galactoside) to PC12 cells against cytotoxicity induced by hydrogen peroxide and tert-butyl hydroperoxide

Reactive oxygen species are believed to play a very significant role in the pathogenesis of several diseases including Alzheimer's disease and Parkinson's disease. It is reported that the crucial balance between reactive oxygen species generation and antioxidant defense is regarded as a force in a wide variety of chronic diseases. In this paper, PC12 cells were used to study the antioxidative effect of hyperoside. The results indicated that hyperoside could effectively protect PC12 cells against cytotoxicity induced by hydrogen peroxide and tert-butyl hydroperoxide at 160 microg/ml and 100 microg/ml, respectively. The study also showed that hyperoside was no harmful within the tested concentration range and could easily enter into the PC12 cells. With the increasing concentration of hyperoside, cytotoxicity induced by hydrogen peroxide and tert-butyl hydroperoxide was significantly attenuated and the corresponding extracellular lactate dehydrogenase levels decreased concurrently by pretreatment with hyperoside. The results were proved by flow cytometric detection of apoptotic cells. All the above results showed hyperoside could efficiently prevent the PC12 cells from shrinking and turning against apoptosis induced by hydrogen peroxide and tert-butyl hydroperoxide.

Characterization of lipophilicity and antiproliferative activity of E-2-arylmethylene-1-tetralones and their heteroanalogues

A molecular library based on E-2-arylmethylene-1-tetralone has been designed and synthesized. A reversed phase high performance liquid chromatographic (RP-HPLC) method has been developed and applied to separate them and to characterize their lipophilicity. The chromatographic method applied here was suitable to separate the structural (ortho and para) isomers of compounds and was sensitive enough to differentiate their lipophilicities. The measured (k') and computer calculated (CLOGP) lipophilicity values has been compared. Good linear correlation has been found in the case of these structurally related molecules. In vitro biological assay has been performed with Methylene blue dying to investigate the antiproliferative potency of the compounds synthesized in this work. The measured (k') and calculated (CLOGP) lipophilicities of the compounds were compared with the antiproliferative activities and an optimum value of lipophilicity has been found for these compounds.

Trends in ethnopharmocology

The use of plants, plant extracts or plant-derived pure chemicals to treat disease is a therapeutic modality, which has stood the test of time. Indeed today many pharmacological classes of drugs include a natural product prototype. Aspirin, atropine, ephedrine, digoxin, morphine, quinine, reserpine and tubocurarine are a few examples of drugs, which were originally discovered through the study of traditional cures and folk knowledge of indigenous people. There is a revival of interest in herbal products (botanicals) at a global level and the conventional medicine is now beginning to accept the use of botanicals once they are scientifically validated. Ispaghula, Garlic, Ginseng, Ginger, Ginkgo, St. John's Wort, and Saw palmetto are a few examples of botanicals which are gaining popularity amongst modern physicians and this trend is likely to continue partly due to high cost involved in the development of patentable chemical drugs. There is growing evidence to show that medicinal plants contain synergistic and/or side-effects neutralizing combinations. Ethnopharmacology has already played important role in the development of conventional medicine and is likely to play more significant role in the years to come. A team work amongst ethnobotanists, ethnopharmacologists, physicians and phytochemists is essential for the fruitful outcome on medicinal plants research. While the ethnopharmacologists have a greater role to play in the rationalization of combination of activities, the phytochemist's role will slightly shift towards standardization of botanicals.

EFFECTS OF THE ANTIDEPRESSANT ST. JOHN′S WORT (HYPERICUM PERFORATUM) ON RAT AND HUMAN VAS DEFERENS CONTRACTILITY

PURPOSE

Since sexual dysfunction related to vas deferens smooth muscle contractility is a possible side effect of St. John's wort (SJW) (Hypericum perforatum) we evaluated the effect of this herbal antidepressant on rat and human vas deferens contractility.

MATERIALS AND METHODS

The effect of SJW was evaluated on contractions induced by electrical field stimulation or exogenous agonists (alpha,beta-methylene adenosine triphosphate and phenylephrine) in isolated rat and human vas deferens.

RESULTS

SJW (1 to 300 microM) decreased in a concentration dependent manner the amplitude of electrical field stimulation and agonist induced contractions with the same potency, suggesting direct inhibition of rat vas deferens smooth muscle. Of the chemical constituents of SJW tested hyperforin but not hypericin or the flavonoids quercitrin, rutin and kaempferol inhibited phenylephrine induced contractions. SJW and hyperforin also inhibited phenylephrine induced contractions in human vas deferens

CONCLUSIONS

The results of our study demonstrate that SJW directly inhibits rat and human vas deferens contractility. If confirmed in vivo, these results suggest that SJW might affect sexual function in humans. These results might explain delayed ejaculation described in patients receiving SJW.