Bioactive Terpenoids and Flavonoids from Daucus littoralis Smith subsp. hyrcanicus Rech.f,an Endemic Species of Iran

Background

Daucus littoralis Smith subsp. hyrcanicus Rech.f. (Apiaceae) is an endemic species in northern parts of Iran where it is commonly named Caspian carrot. The fruits have been used as condiment.

Methods

In a series of in vitro assays, antioxidant (DPPH and FRAP assays), cytotoxic and antimicrobial activities of different extracts of roots and fruits were evaluated for the first time. The separation and purification of the compounds were carried out on the most potent extracts using various chromatographic methods and identified by spectroscopic data (¹H and ¹³C NMR).

Results

The results showed that among the extracts only fruit methanol extract (FME) has significant antioxidant activity (IC₅₀ = 145.93 μg.ml^-1 in DPPH assay and 358 ± 0.02 mmol FeII/g dry extract in FRAP assay). The radical scavenging activity of FME at 400 μg.ml^-1 was comparable with α-tocopherol (40 μg.ml^-1) and with BHA (100 μg.ml^-1) (p > 0.05). FME did not show any toxicity against cancerous and normal cell lines. Fruit ethyl acetate extract (FEE) had cytotoxic activity against breast carcinoma and hepatocellular carcinoma cells (IC₅₀ 168.4 and 185 μg.ml^-1, respectively), while it did not possess antioxidant activity in comparison with α-tocopherol and BHA as standard compounds. Ethyl acetate and methanol extract of fruits showed antimicrobial activity against Staphylococcus aureus (MIC: 3.75 mg.ml^-1) and Candida albicans (MIC: 15.6 and 7.8 mg.ml^-1, respectively). Four terpenoids were isolated form FEE including: β-sitosterol (1), stigmasterol (2), caryophyllene oxide (3), β-amyrin (4). Also, three flavonoids namely quercetin 3-O-β-glucoside (5), quercetin 3-O-β-galactoside (6) and luteolin (7) were isolated from FME.

Conclusion

This study showed that FEE and FME of D. littoralis Smith subsp. hyrcanicus Rech.f. had the highest biological activities which may be correlated with in vitro cytotoxic, antimicrobial and antioxidant activities of terpenoids and flavonoids components of the extracts.     

Temperature-dependent studies on the total phenolics,flavonoids, antioxidant activities,and sugar content in six onion varieties

Heating effect on total phenol, flavonoids, antioxidant activity, and sugar content of six onion varieties has been quantitatively investigated to explore the effect of different temperatures. The onion varieties comprised one red-skinned variety, two white-skinned varieties, and three yellow-skinned varieties. The heating temperature was scanned at 80°C, 100°C, 120°C, and 150°C for 30 minutes each, and quantitative analysis was performed relative to the powdered onion at ambient temperature. Quercetin, glucosides and sugar content were analyzed using high-performance liquid chromatography. The total phenolic and antioxidant content increased in all six varieties. The total flavonoid levels showed a considerable change. On heating the onion samples at 120°C for 30 minutes, the red-skinned variety showed the highest level of total phenolic content [13712.67 ± 1034.85 μg of gallic acid equivalent/g dry weight (μg GAE/g DW)] and total flavonoids [3456.00 ± 185.82 μg of quercetin equivalents/g dry weight (μg Q/g DW)], whereas the content of total phenolics and total flavonoids were 13611.83 ± 341.61 μg GAE/g DW and 3482.87 ± 117.17 μg Q/g DW, respectively, for the yellow-skinned (Sunpower) variety. Quercetin and its glucoside contents increased up to 120°C and then decreased at 150°C, whereas the sugar content continuously decreased with heating. All cultivars showed the same pattern in the heating effect, and the predominant flavonoids were destroyed at higher temperatures. Therefore, it is improper to expose onion powder to a temperature higher than 120°C.     

Investigation of Phytochemical and Antioxidant Properties of Methanol Extract and Fractions of Ballota limbata (Lamiaceae)

Ballota limbata (Lamiaceae) has been used for its antispasmodic, antiulcer, diuretic, vermifuge and sedative effects in folk medicine. However, little is known about how does it work to produce these therapeutic actions. Present research investigated phytochemical components and antioxidant properties of methanol extract and different fractions of Ballota limbata. In this study, phytochemical investigation was done by performing different chemical tests. Here, antioxidant property of the extract and fractions was investigated by using 1,1-diphenyl-2-picryl hydrazyl radical scavenging activity, total antioxidant activity by the phosphomolybdenum method, linoleic acid peroxidation, ferric thiocyanate analysis and ferric-reducing antioxidant power. Methanol extract and fractions showed presence of numerous chemical principles including alkaloids, cardiac glycosides, tannins and flavonoids. The ethyl acetate fraction exhibited higher scavenging activity compared to the other fractions under investigation. This fraction displayed 84.16±1.02% 1,1-diphenyl-2-picryl hydrazyl radical inhibition at a dose of 60 μg/ml. IC₅₀ for 1,1-diphenyl-2-picryl hydrazylradical-scavenging activity was 13.53±0.22 μg/ml, relative to the standard, butylatedhydroxytoluene, having IC₅₀ of 12.33±0.88 μg/ml. Thus, Ballota limbata showed significant antioxidant activity, which may contribute in the mechanism of above pharmacological actions.     

Biological activity and microscopic characterization of Lythrum salicaria L

Background

There are several plants have been used worldwide in the folk medicine with high incidence for treatment of human disorders, of which Lythrum salicaria belongs to the Lythraceae family has traditionally reputation for some medicinal usage and recently many biological and pharmacological activity of the plant have been studied.

Methods

In this study, microscopic characterizations of the aerial parts of the plant were determined. Moreover, the plant extract (aqueous methanol 80%) was subjected to an anti-diabetic activity test (in a rat model of streptozocin induced diabetes), anti-Helicobacter pylori (using disc diffusion method) along with antioxidant activity against DPPH (stable free radical) tests. Besides, total flavonoids, phenols, tannins, as well as polysaccharides contents have been assessed using spectroscopic methods.

Results

The microscopic properties of the plant fragments revealed anomocytic stomata, conical shape trichomes, and abundant spherical pollen grains as a characteristic pattern for the aerial parts of the plant. The extract of the plant at concentration of 15 g/kg showed mild lowering activity on blood glucose level to 12.6% and 7.3% after 2 and 3 h of administration. Additionally, clinically isolated H. pylori strain was inhibited with the plant extract at concentration of 500 mg/mL (zone of inhibition: 17 ± 0.08 mm). Moreover, IC₅₀ values for DPPH inhibition of the plant extract, vitamin E, BHA were examined as 13.5, 14.2, and 7.8 μg/mL, respectively. Total flavonoids, phenols, tannin, and polysaccharides contents of the extract were successfully evaluated as 5.8 ± 0.4 μg QE/mg EXT, 331 ± 3.7 μg GAE/mg EXT, 340 ± 2.3 μg TAE/mg EXT, 21 ± 0.2 μg GE/mg EXT, respectively.

Conclusions

The results suggested that L. salicaria has low anti-diabetic and anti-Helicobacter pylori effects, but high antioxidant activity, just the same as positive standard (vitamin E), which might be attributed to the high content of phenolic compounds in the extract.     

Antioxidant,antimicrobial, antitumor,and cytotoxic activities of an important medicinal plant (Euphorbia royleana) from Pakistan

The aim of present study was to evaluate antioxidant, antimicrobial, and antitumor activities of methanol, hexane, and aqueous extracts of fresh Euphorbia royleana. Total phenolic and flavonoid contents were estimated as gallic acid and querectin equivalents, respectively. Antioxidant activity was assessed by scavenging of free 2,2′-diphenyl-1-picrylhydrazyl radicals and reduction of ferric ions, and it was observed that inhibition values increase linearly with increase in concentration of extract. The results of ferric reducing antioxidant power assay showed that hexane extract has maximum ferric reducing power (12.70 ± 0.49mggallic acid equivalents/g of plant extract). Maximum phenolic (47.47 ± 0.71 μg gallic acid equivalents/mg of plant extract) and flavonoid (63.68 ± 0.43 μg querectin equivalents/mg of plant extract) contents were also found in the hexane extract. Furthermore, we examined antimicrobial activity of the three extracts (methanol, hexane, aqueous) against a panel of microorganisms (Escherichia coli, Bacillus subtillis, Pasteurella multocida, Aspergillus niger, and Fusarium solani) by disc-diffusion assay, and found the hexane extract to be the best antimicrobial agent. Hexane extract was also observed as to be most effective in a potato disc assay. As hexane extract showed potent activity in all the investigated assays, it was targeted for cytotoxic assessment. Maximum cytotoxicity (61.66%) by hexane extract was found at 800 μg/mL. It is concluded that investigated extracts have potential for isolation of antioxidant and antimicrobial compounds for the pharmaceutical industry.     

In vitro Antioxidant and Antibacterial Activities of Methanol Extract of Kyllinga nemoralis

The present study was designed to evaluate the antioxidant and antibacterial activity of methanol extract of Kyllinga nemoralis. Six different in vitro antioxidant assays including 2,2-diphenyl-1-picrylhydrazyl, hydroxyl radical, superoxide anion radical, hydrogen peroxide radical, ferric reducing antioxidant power assay and reducing power were carried out to ensure the scavenging effect of the plant on free radicals. In addition, total antioxidant capacity assay, total phenolic contents, tannins, flavonoids and flavonol contents of the plant were also analysed by the standard protocols. Kyllinga nemoralis exhibited high antioxidant activity on 2,2-diphenyl-1-picrylhydrazyl assay (IC₅₀= 90 μg/ml), superoxide radical scavenging assay (IC₅₀= 180 μg/ml) and hydrogen peroxide radical scavenging assay (IC₅₀= 200 μg/ml), compared with standards. These observations provide comprehensible supporting evidence for the antioxidant potential of the plant extract. Reducing power (IC₅₀= 213.16 μg/ml) and hydroxyl radical scavenging activity (IC₅₀= 223 μg/ml) of the plant extract was remarkable. The methanol extract of K. nemoralis exhibited significant antimicrobial activity against Gram-positive human pathogenic bacteria. Standard in vitro antioxidant assays assessed the electron donating ability of the plant extract in scavenging free radicals. The inhibitory effect of the plant extract against bacterial pathogens may be due to the presence of phytochemicals. Thus, the results suggest that Kyllinga nemoralis is a potential source of antioxidants and could serve as the base for drug development.     

Evaluation of In Vitro Antioxidant Potential of Cordia retusa

The present study was carried out to investigate the antioxidant potential, total flavonoid and phenolic content in extracts of aerial parts of Cordia retua (Vahl.) Masam. The samples such as ethyl acetate and ethanol extracts were tested using six in vitro models such as 2,2-diphenyl-1-picrylhydrazyl, nitric oxide radical, iron chelating, hydroxyl radical, superoxide radical scavenging activity and total antioxidant activity to evaluate the in vitro antioxidant potential of C. retusa by spectrophotometrically. Total flavonoid and phenolic content in samples were estimated using aluminum chloride colorimetric and Folin-Ciocalteu method. The results were analyzed statistically by the regression method. Half maximal inhibitory concentration (IC₅₀) of the ethanol extract was found to be 596 μg/ml for DPPH, 597 μg/ml for nitric oxide radical, 554 μg/ml for iron chelating, 580 μg/ml for hydroxyl radical, 562 μg/ml for superoxide radical and 566 μg/ml for total antioxidant capacity. Furthermore, the total flavonoid content and total phenolic content of the ethanol extract were found to be 2.71 mg gallic acid equivalent per gram of extract and 1.86 mg quercetin equivalent per gram of extract, respectively. In all the testing, a significant correlation existed between concentrations of the extract and percentage inhibition of free radicals. The results of the present comprehensive analysis demonstrated that C. retusa possess potent antioxidant activity, high flavonoid and phenolic content. The antioxidant property may be related to the polyphenols and flavonoids present in the extract. These results clearly indicated that C. retusa is effective against free radical mediated diseases as a natural antioxidant.     

UPLC-PDA-ESI-QTOF-MS/MS fingerprint of purified flavonoid enriched fraction of Bryophyllum pinnatum; antioxidant properties,anticholinesterase activity and in silico studies

ContextBryophyllum pinnatum (Lam.) Oken (Crassulaceae) is used traditionally to treat many ailments.ObjectivesThis study characterizes the constituents of B. pinnatum flavonoid-rich fraction (BPFRF) and investigates their antioxidant and anticholinesterase activity using in vitro and in silico approaches.Materials and methodsMethanol extract of B. pinnatum leaves was partitioned to yield the ethyl acetate fraction. BPFRF was isolated from the ethyl acetate fraction and purified. The constituent flavonoids were structurally characterized using UPLC-PDA-MS². Antioxidant activity (DPPH), Fe²⁺-induced lipid peroxidation (LP) and anticholinesterase activity (Ellman’s method) of the BPFRF and standards (ascorbic acid and rivastigmine) across a concentration range of 3.125–100 μg/mL were evaluated in vitro for 4 months. Molecular docking was performed to give insight into the binding potentials of BPFRF constituents against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE).ResultsUPLC-PDA-MS² analysis of BPFRF identified carlinoside, quercetin (most dominant), luteolin, isorhamnetin, luteolin-7-glucoside. Carlinoside was first reported in this plant. BPFRF significantly inhibited DPPH radical (IC₅₀ = 7.382 ± 0.79 µg/mL) and LP (IC₅₀ = 7.182 ± 0.60 µg/mL) better than quercetin and ascorbic acid. Also, BPFRF exhibited potent inhibition against AChE and BuChE with IC₅₀ values of 22.283 ± 0.27 µg/mL and 33.437 ± 1.46 µg/mL, respectively compared to quercetin and rivastigmine. Docking studies revealed that luteolin-7-glucoside, carlinoside and quercetin interact effectively with crucial amino acid residues of AChE and BuChE through hydrogen bonds.Discussion and conclusionsBPFRF possesses an excellent natural source of cholinesterase inhibitor and antioxidant. The material could be further explored for the potential treatment of oxidative damage and cholinergic dysfunction in Alzheimer’s disease.     

Effects of blending wheatgrass juice on enhancing phenolic compounds and antioxidant activities of traditional kombucha beverage

Traditional kombucha is a fermented black tea extract and sugar. Sweetened black tea (10% w/v) and wheatgrass juice (WGJ) were mixed in various ratios and used as fermentation substrate for enhancing phenolic compounds and antioxidant activity. Starter, comprising of yeast (Dekkera bruxellensis) and acetic acid bacteria (Gluconacetobacter rhaeticus and Gluconobacter roseus), was inoculated at 20% (v/v), and fermented statically at 29 ± 1°C for 12 days. The results showed that the total phenolic and flavonoid contents and antioxidant activity of the modified kombucha were higher than those of traditional preparations. All WGJ-blended kombucha preparations were characterized as having higher concentrations of various phenolic compounds such as gallic acid, catechin, caffeic acid, ferulic acid, rutin, and chlorogenic acid as compared to traditional ones. Addition of WGJ resulted in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability of kombucha being > 90%, while the oxygen radical absorbance capacity increased from 5.0 μmol trolox equivalents/mL to 12.8 μmol trolox equivalents/mL as the ratio of WGJ increased from 0% to 67% (v/v). The highest antioxidant activity was obtained using a 1:1 (v/v) black tea decoction to WGJ ratio and 3 days of fermentation, producing various types of phenolic acids. These results suggest that intake of fermented black tea enhanced with wheatgrass juice is advantageous over traditional kombucha formulas in terms of providing various complementary phenolics and might have more potential to reduce oxidative stress.     

Antioxidant capacity of calendula officinalis flowers extract and prevention of radiation induced oropharyngeal mucositis in patients with head and neck cancers: a randomized controlled clinical study

This study was designed to determine the effect of Calendula officinalis flowers extract mouthwash as oral gel on radiation-induced oropharyngeal mucositis (OM) in patients with head-and-neck cancer. Forty patients with neck and head cancers under radiotherapy or concurrent chemoradiotherapy protocols were randomly assigned to receive either 2% calendula extract mouthwash or placebo (20 patients in each group). Patients were treated with telecobalt radiotherapy at conventional fractionation (200 cGy/fraction, five fractions weekly, 30–35 fractions within 4–7 weeks). The oropharyngeal mucositis was evaluated by two clinical investigators (a radiation oncologist and a dentist), using the oral mucositis assessment scale (OMAS). Trying to find out the possible mechanism of action of the treatment, total antioxidant, polyphenol and flavonoid contents, and quercetin concentration of the mouth wash were measured. Calendula mouthwash significantly decreased the intensity of OM compared to placebo at week 2 (score: 5.5 vs. 6.8, p = 0.019), week 3 (score: 8.25 vs. 10.95, p < 0.0001) and week 6 (score: 11.4 vs. 13.35, p = 0.031). Total antioxidant, polyphenol and flavonoid contents and quercetin concentration of the 2% extract were 2353.4 ± 56.5 μM, 313.40 ± 6.52 mg/g, 76.66 ± 23.24 mg/g, and 19.41 ± 4.34 mg/l, respectively. Calendula extract gel could be effective on decreasing the intensity of radiotherapy- induced OM during the treatment and antioxidant capacity may be partly responsible for the effect.     

Total Phenolic Content and Antioxidant Activity of Morinda tinctoria Leaves

The antioxidant activity and total phenolic content of Morinda tinctoria leaves was evaluated. The successively extracted leaves of Morinda tinctoria using various solvents was analyzed for their total phenolic content. The extracts were subjected to column chromatography for the isolation of bioactive molecules. In vitro antioxidant activity was evaluated by employing different assays, including 2,2-diphenyl-1-picrylhydrazyl, nitric oxide scavenging assay and phosphomolybdenum reducing power assay. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging efficacy of hexane extract is significant at higher concentration (500 μg/ml-91.2±0.05%) and the efficacy at lower concentration is more significant for ethyl acetate extract (100 μg/ml - 65.1±0.05%). The total phenolic content was highest in methanol extract (5.30±0.011 μg/mg). Cynarin, a hydroxy cinnamic acid was isolated from chloroform extract; oleuropein, a polyphenolic iridoid was isolated from methanol extract. The results obtained suggeted that Morinda tinctoria leaf extracts possessed antioxidant properties and might offer protection from free radicals. Two compounds, cynarin and oleuropein were reported for the first time from Morinda tinctoria leaves.     

In vitro Screening for Antioxidant,Antimicrobial, and Antidiabetic Properties of Some Korean Native Plants on Mt. Halla,Jeju Island

In this study, Prunus padus, Lonicera caerulea, Berberis amurensis, and Ribes maximowiczianum, which are mainly distributed on Mt. Halla, Jeju Island, have been investigated for their antioxidant, antimicrobial, and antidiabetic activities. The methanol extracts of R. maximowiczianum leaves and P. padus branches exhibited significant and dose-dependent antioxidant activity including electron-donation ability and reducing power. To analyze the antimicrobial activity, each extract was tested by a serial two-fold dilution method against five selected gram-positive bacteria and four gram-negative bacteria, and this suggested that P. padus branches possessed the maximum antimicrobial activity against most of the gram-positive bacteria tested. In addition, the methanol extracts of P. padus branches exhibited the highest α-glucosidase inhibitory activity with an IC₅₀ value of 1.0±0.1 μg/ml, indicating that P. padus is a promising source as a herbal medicine.     

Antioxidant capacity and bioactive compounds of four Brazilian native fruits

The purpose of this study was to evaluate the bioactive compounds and antioxidant activity of extracts from araçá (Psidium cattleianum), butiá (Butia eriospatha), and pitanga (Eugenia uniflora) fruits with different flesh colors (i.e., purple, red, and orange), and blackberries (Rubus sp.; cv. Xavante and Cherokee) collected in the southern region of Brazil. The content of ascorbic acid, total carotenoids, and phenolics were determined. The profile of the phenolic compounds was assessed by high-performance liquid chromatography combined with diode array detection (HPLC-DAD). The antioxidant activity was determined using the ferric-reducing antioxidant power (FRAP) assay, 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) assay, total reactive antioxidant potential (TRAP) assay, and total antioxidant reactivity (TAR) assay. The Xavante blackberry and purple-fleshed pitanga showed the highest total phenolic content [816.50 mg gallic acid equivalents (GAE)/100g and 799.80 mg GAE/100g, respectively]. The araçá and red-fleshed pitanga showed the highest carotenoid content (6.27 ug β-carotene/g and 5.86 ug β-carotene/g, respectively). The fruits contained several phenolic compounds such as quercetin derivatives, quercitrin, isoquercitrin, and cyanidin derivatives, which may contribute differentially to the antioxidant capacity. The highest scavenging activity in the DPPH assay was found for purple-fleshed pitanga (IC₅₀ 36.78 mg/L), blackberries [IC₅₀ 44.70 (Xavante) and IC₅₀ 78.25 mg/L (Cherokee)], and araçá (IC₅₀ 48.05 mg/L), which also showed the highest FRAP, followed by orange- and red-fleshed pitanga. Our results revealed that some fruits grown in southern Brazil such as purple-fleshed pitanga, blackberries, and araçá are rich sources of phenolic compounds and have great antioxidant activity.     

Emodin,an 11β-hydroxysteroid dehydrogenase type 1 inhibitor,regulates adipocyte function in vitro and exerts anti-diabetic effect in ob/ob mice

Aim:

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a potent and selective inhibitor of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) with the ability to ameliorate metabolic disorders in diet-induced obese mice. In the present study, we investigated the effects of emodin on adipocyte function and the underlying mechanisms in vitro, and its anti-diabetic effects in ob/ob mice.

Methods:

3T3-L1 adipocytes were used for in vitro studies. 11β-HSD1A activity was evaluated with a scintillation proximity assay. The adipogenesis, glucose uptake, lipolysis and adiponectin secretion were investigated in 3T3-L1 adipocytes treated with emodin in the presence of active (corticosterone) or inactive glucocorticoid (11-dehydrocorticosterone). For in vivo studies, ob/ob mice were administered emodin (25 and 50 mg·kg⁻¹·d⁻¹, ip) for 26 d. On the last day of administration, the serum was collected and the mesenteric and perirenal fat were dissected for analyses.

Results:

Emodin inhibited the 11β-HSD1 activity in 3T3-L1 adipocytes in concentration- and time-dependent manners (the IC₅₀ values were 7.237 and 4.204 μmol/L, respectively, after 1 and 24 h treatment. In 3T3-L1 adipocytes, emodin (30 μmol/L) suppressed 11-dehydrocorticosterone-induced adipogenesis without affecting corticosterone-induced adipogenesis; emodin (3 μmol/L) reduced 11-dehydrocorticosterone-stimulated lipolysis, but had no effect on corticosterone-induced lipolysis. Moreover, emodin (3 μmol/L) partly reversed the impaired insulin-stimulated glucose uptake and adiponectin secretion induced by 11-dehydrocorticosterone but not those induced by corticosterone. In ob/ob mice, long-term emodin administration decreased 11β-HSD1 activity in mesenteric adipose tissues, lowered non-fasting and fasting blood glucose levels, and improved glucose tolerance.

Conclusion:

Emodin improves the inactive glucocorticoid-induced adipose tissue dysfunction by selective inhibition on 11β-HSD1 in adipocyte in vitro and improves glycemic control in ob/ob mice.     

Quercetin Inhibits ��3��4 Nicotinic Acetylcholine Receptor-Mediated Ion Currents Expressed in Xenopus Oocytes

Quercetin mainly exists in the skin of colored fruits and vegetables as one of flavonoids. Recent studies show that quercetin, like other flavonoids, has diverse pharmacological actions. However, relatively little is known about quercetin effects in the regulations of ligand-gated ion channels. In the previous reports, we have shown that quercetin regulates subsets of homomeric ligand-gated ion channels such as glycine, 5-HT_3A and α7 nicotinic acetylcholine receptors. In the present study, we examined quercetin effects on heteromeric neuronal α3β4 nicotinic acetylcholine receptor channel activity expressed in Xenopus oocytes after injection of cRNA encoding bovine neuronal α3 and β4 subunits. Treatment with acetylcholine elicited an inward peak current (I_ACh) in oocytes expressing α3β4 nicotinic acetylcholine receptor. Co-treatment with quercetin and acetylcholine inhibited I_ACh in oocytes expressing α3β4 nicotinic acetylcholine receptors. The inhibition of I_ACh by quercetin was reversible and concentration-dependent. The half-inhibitory concentration (IC₅₀) of quercetin was 14.9±0.8 µM in oocytes expressing α3β4 nicotinic acetylcholine receptor. The inhibition of I_ACh by quercetin was voltage-independent and non-competitive. These results indicate that quercetin might regulate α3β4 nicotinic acetylcholine receptor and this regulation might be one of the pharmacological actions of quercetin in nervous systems.     

18β-Glycyrrhetinic acid preferentially blocks late Na current generated by ΔKPQ Nav1.5 channels

Aim:

To compare the effects of two stereoisomeric forms of glycyrrhetinic acid on different components of Na⁺ current, HERG and Kv1.5 channel currents.

Methods:

Wild-type (WT) and long QT syndrome type 3 (LQT-3) mutant ΔKPQ Nav1.5 channels, as well as HERG and Kv1.5 channels were expressed in Xenopus oocytes. In addition, isolated human atrial myocytes were used. Two-microelectrode voltage-clamp technique was used to record the voltage-activated currents.

Results:

Superfusion of 18β-glycyrrhetinic acid (18β-GA, 1–100 μmol/L) blocked both the peak current (I_Na,P) and late current (I_Na,L) generated by WT and ΔKPQ Nav1.5 channels in a concentration-dependent manner, while 18α-glycyrrhetinic acid (18α-GA) at the same concentrations had no effects. 18β-GA preferentially blocked I_Na,L (IC₅₀=37.2±14.4 μmol/L) to I_Na,P (IC₅₀=100.4±11.2 μmol/L) generated by ΔKPQ Nav1.5 channels. In human atrial myocytes, 18β-GA (30 μmol/L) inhibited 47% of I_Na,P and 87% of I_Na,L induced by Anemonia sulcata toxin (ATX-II, 30 nmol/L). Superfusion of 18β-GA (100 μmol/L) had no effects on HERG and Kv1.5 channel currents.

Conclusion:

18β-GA preferentially blocked the late Na current without affecting HERG and Kv1.5 channels.     

Antioxidant and anti-inflammatory effects of Marrubium alysson extracts in high cholesterol-fed rabbits

The antioxidant and anti-inflammatory effects of hexane (HEXA), chloroform (CHLORO), ethyl acetate (EA) and total alcoholic (T. ALCOH) extracts of Marrubium alysson in hypercholesterolemic-fed rabbits were evaluated. Hypercholesterolemia was induced in male rabbits by high cholesterol diet (HCD) (350 mg/kg) for 8 weeks. Hypercholesterolemic rabbits were allocated into groups, treated with simvastatin (SIM 5 mg/kg), different extracts of M. alysson at two doses of 250, 500 mg/kg. A normal control group and an HCD control one were used for comparison. Lipid profile, as well as oxidized low density lipoprotein-cholesterol (ox-LDL-C), myeloperoxidase activity (MPO) and superoxide anion production (O₂•⁻), C-reactive protein (CRP) and monocyte chemoattractant protein-1 (MCP-1) were also evaluated. In addition, histological examination of ascending aorta was performed. We found dyslipidemia associated with significant increases in ox-LDL-C 123.5 ± 9.8 nmol MDA/mg non-HDL, MPO activity 0.08 ± 0.05 U/100 mg tissue and O₂•⁻ production 3.5 ± 0.3 nmol cytochrome C reduced/min/g tissue × 10⁻⁴ in hypercholerterolemic rabbits. In addition, there was a significant increase in CRP 6.6 ± 0.49 μmol/L and MCP-1 190.9 ± 6.4 pg/ml and its mRNA expression in HCD. Intima appeared thick with thick plaques surrounding the intima and luminal narrowing. SIM, EA and HEXA extracts of M. alysson had lipid lowering effect, decrease in ox-LDL-C, MPO, O₂•⁻, CRP and MCP-1 mRNA expression with improvement of the pathological picture. M. alysson enhanced the stability of plaque, had lipid lowering, anti-inflammatory and antioxidant activities.     

Discovery of new angiotensin converting enzyme (ACE) inhibitors from medicinal plants to treat hypertension using an in vitro assay

Background and purpose of the study

Angiotensin converting enzyme (ACE) inhibitors plays a critical role in treating hypertension. The purpose of the present investigation was to evaluate ACE inhibition activity of 50 Iranian medicinal plants using an in vitro assay.

Methods

The ACE activity was evaluated by determining the hydrolysis rate of substrate, hippuryl-L-histidyl-L-leucine (HHL), using reverse phase high performance liquid chromatography (RP-HPLC). Total phenolic content and antioxidant activity were determined by Folin-Ciocalteu colorimetric method and DPPH radical scavenging assay respectively.

Results

Six extracts revealed > 50% ACE inhibition activity at 330 μg/ml concentration. They were Berberis integerrima Bunge. (Berberidaceae) (88.2 ± 1.7%), Crataegus microphylla C. Koch (Rosaceae) (80.9 ± 1.3%), Nymphaea alba L. (Nymphaeaceae) (66.3 ± 1.2%), Onopordon acanthium L. (Asteraceae) (80.2 ± 2.0%), Quercus infectoria G. Olivier. (Fagaceae) (93.9 ± 2.5%) and Rubus sp. (Rosaceae) (51.3 ± 1.0%). Q. infectoria possessed the highest total phenolic content with 7410 ± 101 mg gallic acid/100 g dry plant. Antioxidant activity of Q. infectoria (IC₅₀ value 1.7 ± 0.03 μg/ml) was more than that of BHT (IC₅₀ value of 10.3 ± 0.15 μg/ml) and Trolox (IC₅₀ value of 3.2 ± 0.06 μg/ml) as the positive controls.

Conclusions

In this study, we introduced six medicinal plants with ACE inhibition activity. Despite the high ACE inhibition and antioxidant activity of Q. infectoria, due to its tannin content (tannins interfere in ACE activity), another plant, O. acanthium, which also had high ACE inhibition and antioxidant activity, but contained no tannin, could be utilized in further studies for isolation of active compounds.     

Phytochemical,Antioxidant and Anticancer Activities of Extracts of Seven Fruits Found in the Southern Brazilian Flora

Methanol extracts of seven edible fruits found in southern Brazil: Garcinia achachairu, Rubus imperialis, Rubus rosaefolius, Solanum quitoense, Solanum sessiliflorun, Diospyros inconstans and Plinia glomerata, were evaluated for their total phenol content and antioxidant activity in different in vitro free radical scavenging models. In addition, studies were performed on cell viability of extracts of the seeds of G. achachairu against murine melanoma cells. The fruits peel and seeds of G. achachairu were very promising in terms of total phenol content (data in gallic acid equivalent per gram), as assessed by the Folin-Ciocalteu method, with values of 9.70±3.2 and 8.40±1.1, respectively. On the other hand, antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl scavenging assay showed that the fruit pulp and peel of P. glomerata presented the best profile, with values of the 16.3±1.8 and 15.9±2.4 μg/ml, respectively. Regarding the cytotoxic effect of methanol extract and guttiferone A from G. achachairu, we have observed that both inhibit the growth of B16F10 tumor cells, with calculated IC₅₀ values of 49.6±2.1 mg/ml and 48.6±5.4 mM, respectively.     

The Effect of Polyphenols Isolated from Cynanchi wilfordii Radix with Anti-inflammatory,Antioxidant, and Anti-bacterial Activity

Recently, Cynanchi wilfordii Radix has gained wide use in Asian countries as a functional food effective for relieving fatigue, osteoporosis, and constipation, particularly in menopausal disorders. However, its anti-inflammatory and anti-microbial activities have not been explored in detail to date. The anti-inflammatory, antioxidant, and anti-bacterial properties of the Cynanchi wilfordii Radix extracts obtained with water, methanol, ethanol, and acetone were compared. All 4 polyphenol-containing extracts exhibited anti-inflammatory and antioxidant effects. The ethanol extract was found to elicit the most potent reduction of nitric oxide (NO), prostaglandin E₂ (PGE₂), and cytokine (IL-1β, IL-6, IL-10, and TNF-α) levels, as well as inhibit the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in a concentration-dependent manner. The evaluation of antioxidant activity also revealed the ethanol extract to have the highest free radical scavenging activity, measured as 85.3±0.4%, which is equivalent to 99.9% of the activity of α -tocopherol. In the assessment of anti-bacterial activity, only ethanol extract was found to inhibit the growth of the Bacillus species Bacillus cereus and Bacillus anthracis. These results show that polyphenols of Cynanchi wilfordii Radix have anti-inflammatory, antioxidant, and anti-bacterial properties that can be exploited and further improved for use as a supplementary functional food, in cosmetics, and for pharmaceutical purposes.