chrysin and pinocembrin

The angiotensin-converting enzyme (ACE)-related carboxypeptidase, ACE-II, is a type I integral membrane protein of 805 amino acids that contains 1 HEXXH-E zinc binding consensus sequence. ACE-II has been implicated in the regulation of heart function and also as a functional receptor for the coronavirus that causes the severe acute respiratory syndrome (SARS). In this study, the potential of some flavonoids presents in propolis to bind to ACE-II receptors was calculated with in silico. Binding constants of ten flavonoids, caffeic acid, caffeic acid phenethyl ester, chrysin, galangin, myricetin, rutin, hesperetin, pinocembrin, luteolin and quercetin were measured using the AutoDock 4.2 molecular docking program. And also, these binding constants were compared to reference ligand of MLN-4760. The results are shown that rutin has the best inhibition potentials among the studied molecules with high binding energy - 8.04 kcal/mol, and it is followed by myricetin, quercetin, caffeic acid phenethyl ester and hesperetin. However, the reference molecule has binding energy of - 7.24 kcal/mol. In conclusion, the high potential of flavonoids in ethanolic propolis extracts to bind to ACE-II receptors indicates that this natural bee product has high potential for COVID-19 treatment, but this needs to be supported by experimental studies.

Topics: Angiotensin-Converting Enzyme 2; Animals; Bees; Caffeic Acids; COVID-19 Drug Treatment; Flavanones; Flavonoids; Hesperidin; Humans; Luteolin; Molecular Docking Simulation; Phenylethyl Alcohol; Plant Extracts; Propolis; Quercetin; Rutin

Propolis is a natural bee product with various beneficial biological effects. The health-promoting properties of propolis depend on its chemical composition, particularly the presence of phenolic compounds. The aim of this study was to evaluate the relationship between extraction solvent (acetone 100%, ethanol 70% and 96%) and the antifungal, antioxidant, and cytoprotective activity of the extracts obtained from propolis. Concentrations of flavonoids and phenolic acids in the propolis extracts were determined using ultrahigh-performance liquid chromatography. The antioxidant potential of different extracts was assessed on the basis of 2,2-diphenyl-1-picrylhydrazyl (DPPH·) free-radical-scavenging activity, Fe

Topics: Acetone; Animals; Antifungal Agents; Antioxidants; Bees; Cell Membrane; Chromatography, High Pressure Liquid; Coumaric Acids; Drug Evaluation, Preclinical; Erythrocytes; Ethanol; Flavanones; Flavonoids; Humans; Hydroxybenzoates; Liquid-Liquid Extraction; Oxidative Stress; Phenols; Propolis; Solvents

Propolis, a resinous substance produced by the Apis mellifera bee, contains a number of flavonoids sourced from plants found in the surrounding region. Whilst bees use this substance to seal off and protect the beehive, humans have used propolis therapeutically for centuries, making use of its antibacterial, antiseptic, antipyretic and wound healing properties, among others. South African propolis is rich in the flavonoids pinocembrin, galangin, and chrysin and very little previous research has been conducted on the antimicrobial effects of these compounds.. To obtain an understanding of the antimicrobial activity of the compounds pinocembrin, galangin, and chrysin, both independently and in combination.. The compounds pinocembrin, galangin and chrysin were investigated for interactive antimicrobial activity by determining the minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC), anti-quorum sensing activity, biofilm studies, and toxicity studies (brine shrimp lethality assay).. Minimum inhibitory concentration results demonstrated that combinations of compounds showed better inhibitory activity than single compounds. When the flavonoids were tested in combination using the MIC assay, synergy was noted for 22% of the 1:1 ratio combinations and for 66% of the triple 1:1:1 ratio combinations. Similarly, MBC results showed bactericidal activity from selected combinations, while the compounds on their own demonstrated no cidal activity. Quorum sensing studies showed that compound combinations are more effective at inhibiting bacterial communication than the individual compounds. Biofilm assays showed that the highest percentage inhibition was observed for the triple combination against E. coli at 24 h. Finally, brine shrimp lethality studies revealed that combinations of the three compounds had reduced cytotoxicity when compared to the individual compounds.. The results obtained in this study demonstrate that the compounds found in South African propolis work synergistically to achieve an optimal antimicrobial effect, whilst simultaneously minimizing cytotoxicity.

Topics: Animals; Anti-Infective Agents; Artemia; Biofilms; Candida albicans; Flavanones; Flavonoids; Gram-Negative Bacteria; Gram-Positive Bacteria; Microbial Sensitivity Tests; Propolis; Quorum Sensing; South Africa

Flavonoids are natural compounds that have been extensively studied due to their positive effects on human health. There are over 4000 flavonoids found in higher plants and their beneficial effects have been shown in vitro as well as in vivo. However, data on their pharmacokinetics and influence on metabolic enzymes is scarce. The aim of this study was to focus on possible interactions between the 30 most commonly encountered flavonoid aglycones on the metabolic activity of CYP3A4 enzyme. 6β-hydroxylation of testosterone was used as marker reaction of CYP3A4 activity. Generated product was determined by HPLC coupled with diode array detector. Metabolism and time dependence, as well as direct inhibition, were tested to determine if inhibition was reversible and/or irreversible. Out of the 30 flavonoids tested, 7 significantly inhibited CYP3A4, most prominent being acacetin that inhibited 95% of enzyme activity at 1 µM concentration. Apigenin showed reversible inhibition, acacetin, and chrysin showed combined irreversible and reversible inhibition while chrysin dimethylether, isorhamnetin, pinocembrin, and tangeretin showed pure irreversible inhibition. These results alert on possible flavonoid⁻drug interactions on the level of CYP3A4.

Topics: Apigenin; Chromatography, High Pressure Liquid; Cytochrome P-450 CYP3A; Cytochrome P-450 CYP3A Inhibitors; Drug Interactions; Flavanones; Flavones; Flavonoids; Humans; Quercetin; Testosterone

In the search of new alternatives for neurocysticercosis treatment, the cysticidal activity of organic extracts of Teloxys graveolens was evaluated. The in vitro activity of hexane, ethyl acetate and methanol extracts against Taenia crassiceps cysts was tested and the selectivity index relative to human fibroblasts was determined. Subsequently, the in vivo efficacy of the methanolic extract at doses of 200 and 500 mg/kg in the murine cysticercosis model was evaluated. The ultrastructural effects in vitro and in vivo of the methanolic extract were also investigated using scanning electron microscopy. Additionally, a bioassay-guided fractionation for the isolation of the cysticidal components was performed. Our in vitro findings revealed that all extracts exhibited good cysticidal activity with EC50 values from 44.8 to 67.1 µg/mL. Although the ethyl acetate and methanolic extracts displayed low cytotoxicity, the methanolic extract was the most selective. The methanolic extract also showed in vivo efficacy which was similar to that obtained with ABZ. Significant alterations were found on the germinal layer of the cysts, with a high accumulation of granules of glycogen and vacuoles. The bioguided fractionation of methanolic extract led to the isolation of three flavonoids: chrysin, pinocembrin and pinostrobin; among them, pinocembrin was the compound that displayed cysticidal activity. This is the first study which reveals that T. graveolens could be a potential source for cysticidal and non-toxic compounds.

Topics: Amaranthaceae; Animals; Biological Assay; Cysticercosis; Cysticercus; Female; Fibroblasts; Flavanones; Flavonoids; Gingiva; Humans; Mice; Mice, Inbred BALB C; Microscopy, Electron, Transmission; Plant Components, Aerial; Plant Extracts

The total flavonoids (TFs) were isolated from the leaves of Carya cathayensis Sarg. (LCC), a well-known Chinese medicinal herb commercially cultivated in Tianmu Mountain district, a cross area of Zhejiang and Anhui provinces in China. Five flavonoids, i.e. cardamonin, pinostrobin chalcone (PC), wogonin, chrysin, and pinocembrin were the main components of the TFs. The TFs and these pure compounds suppressed vascular endothelial growth factor (VEGF)-induced angiogenesis as detected in the mouse aortic ring assay, and cardamonin showed the best effect among them. To further elucidate the mechanisms for suppressing angiogenesis of these flavonoids, assays of VEGF-induced proliferation and migration in human umbilical vein endothelial cells (HUVECs) were performed. The TFs, cardamonin, pinocembrin, and chrysin obviously suppressed both VEGF-induced HUVEC proliferation and migration. However, PC and wogonin not only slightly inhibited VEGF-induced proliferation but also remarkably suppressed those of migration in HUVECs. Our further study showed that cardamonin decreased the phosphorylation of ERK and AKT induced by VEGF with a dose-dependent manner in HUVECs. Our findings indicate that the TFs and these pure flavonoids may become potential preventive and/or therapeutic agents against angiogenesis-related diseases.

Topics: Angiogenesis Inhibitors; Animals; Carya; Cell Movement; Cell Proliferation; Chalcones; Drugs, Chinese Herbal; Extracellular Signal-Regulated MAP Kinases; Flavanones; Flavonoids; Human Umbilical Vein Endothelial Cells; Humans; Male; Mice; Plant Leaves; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Vascular Endothelial Growth Factor A

Total phenolic content (TPC), total anthocyanin content (TAC), free and total ellagic acid content, sugars, minerals, and radical-scavenging activity were determined in nine berries harvested in Serbia. More than 30 phenolic compounds were identified; among them, 11 polyphenols and cis,trans-abscisic acid were quantified using UHPLC coupled with an LTQ-Orbitrap XL mass analyzer. For the first time chrysin, naringenin, pinocembrin, and galangin were quantified in some of the investigated berry species. The extraction efficiency of the two extraction systems, methanol and acetone, was investigated. It was found that acetone is a better extracting solvent for TPC, whereas more TAC was extracted by methanol. TPC in acetone extracts ranged from 177.51 to 459.71 mg gallic acid equiv/100 g frozen weight. TAC ranged from 5.39 to 96.94 mg cyanidin-3-glucoside/100 g frozen weight in methanol extracts. The amounts of both free and total ellagic acid were found to be higher in the acetone extract in comparison to the methanol extract.

Topics: Anthocyanins; Carbohydrates; Ellagic Acid; Flavanones; Flavonoids; Free Radical Scavengers; Fruit; Glucosides; Phenols; Plant Extracts; Polyphenols; Rosaceae; Serbia; Trace Elements

Aqueous and ethanol extracts of propolis were analysed phytochemically and examined for their antiviral activity in vitro. Different polyphenols, flavonoids and phenylcarboxylic acids were identified as major constituents. The antiviral effect of propolis extracts and selected constituents, e.g. caffeic acid (1), p-coumaric acid (2), benzoic acid (3), galangin (4), pinocembrin (5) and chrysin (6) against herpes simplex virus type 1 (HSV-1) was analysed in cell culture. The 50% inhibitory concentration (IC(50)) of aqueous and ethanol propolis extracts for HSV-1 plaque formation was determined at 0.0004% and 0.000035%, respectively. Both propolis extracts exhibited high levels of antiviral activity against HSV-1 in viral suspension tests, plaque formation was significantly reduced by >98%. In order to determine the mode of antiviral action of propolis, the extracts were added at different times during the viral infection cycle. Both propolis extracts exhibited high anti-HSV-1 activity when the viruses were pretreated with these drugs prior to infection. Among the analysed compounds, only galangin and chrysin displayed some antiviral activity. However, the extracts containing many different components exhibited significantly higher antiherpetic effects as well as higher selectivity indices than single isolated constituents. Propolis extracts might be suitable for topical application against herpes infection.

Topics: Animals; Antiviral Agents; Benzoic Acid; Caffeic Acids; Cell Line; Coumaric Acids; Dose-Response Relationship, Drug; Flavanones; Flavonoids; Herpesvirus 1, Human; Inhibitory Concentration 50; Molecular Structure; Propionates; Propolis

The ethanolic extract from Flourensia oolepis aerial parts showed strong antifeedant activity against the pest larvae, Epilachna paenulata, with an antifeedant index (AI%) of 99.1% at 100 microg/cm(2). Based on chromatographic fractionation of the extract, guided by bioassays on E. paenulata, the flavanone pinocembrin (1) was isolated as the most active principle. In a choice assay, compound 1 showed strong antifeedant activity against E. paenulata, Xanthogaleruca luteola and Spodoptera frugiperda with an AI% of 90, 94 and 91% (p<0.01) respectively, at 50 microg/cm(2). The dosages necessary for 50% feeding inhibition of the insects (ED(50)) were 7.98, 6.13 and 8.86 microg/cm(2), respectively. The feeding inhibitory activity of 1 against E. paenulata was compared with the activity of other structurally related flavonoids like naringenin, which was inactive up to 100 microg/cm(2), catechin which was nearly 6 times less active than 1, and quercetin which was equally active as 1. The effect of these on the feeding behavior of E. paenulata was also studied.

Topics: Animals; Asteraceae; Biological Assay; Biotechnology; Ethanol; Flavanones; Host-Parasite Interactions; Insecticides; Models, Chemical; Pest Control, Biological; Plant Extracts; Plant Leaves; Plant Oils; Quercetin; Spodoptera

Thin-layer chromatography of ethanolic extract of propolis (EEP) from the continental and Adriatic regions of Croatia showed that 72.2% of propolis samples contain galangin, 88.8% of samples contain kaempferol, naringenin and apigenin and 66.6% of samples contain caffeic acid. Caffeic acid, pinocembrin, galangin, chrysin and naringenin were analyzed by HPLC. In all samples, pinocembrin was the dominant flavonoid. In samples from the Adriatic region, concentration of pinocembrin ranged from 0.03 to 6.14% (x = 2.87%) and in the continental region samples from 0 to 4.74% (x = 2.84%). Chrysin was found in all propolis samples in a concentration ranging from 0.22 to 5.32% (x = 1.86%) in the continental region samples and from 0.03 to 3.64% (x = 1.96%) in samples from the Adriatic region. Chrysin was followed by naringenin, ranging from 0 to 1.14% (x = 0.42%) in samples from the Adriatic region and from 0.22 to 2.41% (x = 0.60%) in the continental region samples. Concentration of caffeic acid ranged from 0 to 10.11% (x = 2.69%) in the Adriatic region samples and from 0.27 to 2.67% (x = 1.37%) in samples from the continental region of Croatia. Results of HPLC analyses suggest that propolis samples collected from various parts of Croatia do not differ markedly in contents of chrysin, pinocembrin, naringenin and galangin but differ in the concentration of caffeic acid. All EEPs significantly inhibited the growth of Bacillus subtilis in comparison with the control (80% ethanol) (p < 0.05), showing inhibition zones of 16 +/- 2 mm for samples from the continental region, and of 18 +/- 3 mm for samples from the Adriatic region. There was no significant difference in antimicrobial activity of EEPs from the continental and Adriatic regions of Croatia, suggesting that bactericidal activity depends on synergism of all phenolic compounds.

Topics: Animals; Anti-Infective Agents; Apigenin; Bacillus subtilis; Bees; Caffeic Acids; Croatia; Flavanones; Flavonoids; Kaempferols; Microbial Sensitivity Tests; Propolis

The antimutagenicity of 14 naturally occurring flavonoids (20 mumol/l) on ofloxacin (43 mumol/l and 86 mumol/l)-induced bleaching (mutagenicity) was studied in Euglena gracilis. The flavonoids chrysin, techtochrysin, chrysin-5-methylether galangin, galangin-5-methylether, pinocembrin and pinobanksin possess considerable antimutagenic properties against ofloxacin-induced bleaching of E. gracilis. Apigenin and isalpinin had only weak antimutagenic potency. Pinobanksin-5-methylether and pinobanksin-3-acetate showed very weak or no antimutagenic effect. However, kempferol, quercetin-3-methylether and quercetin-3,3'-dimethylether showed co-mutagenic or no antimutagenic effect depending on the concentration of ofloxacin. Two possible modes of action of the flavonoids on ofloxacin-induced bleaching of E. gracilis are discussed.

Topics: Animals; Antimutagenic Agents; Chloroplasts; Euglena gracilis; Flavanones; Flavonoids; Mutagens; Ofloxacin