Zühal Güvenalp

Isolation of some luteolin derivatives from Mentha longifolia (L.) Hudson subsp. longifolia and determination of their genotoxic potencies

This study was designed to evaluate the mutagenic and antimutagenic activities of luteolin derivatives (luteolin 7-O-glucoside, luteolin 7-O-rutinoside and luteolin 7-O-glucuronide) isolated from Mentha longifolia (L.) Huds. subsp. longifolia by using Ames Salmonella test (TA 1535 and TA1537 strains). In the antimutagenicity assays, luteolin 7-O-glucoside, luteolin 7-O-rutinoside and luteolin 7-O-glucuronide showed antimutagenic effects on TA1537 and TA1535 strains. The highest inhibition rates for luteolin 7-O-glucoside, luteolin 7-O-rutinoside and luteolin 7-O-glucuronide on TA1537 strain were 84.03%, 87.63% and 67.77%, respectively. Similarly, in the antimutagenicity assays performed with the TA1535 strain, the inhibition rates for luteolin 7-O-glucoside and luteolin 7-O-rutinoside were 23.86% and 23.76% respectively. Our findings showed that the antimutagenic properties of luteolin derivatives on TA1537 and TA1535 strains have been found to be structure dependent. The clarification of differences in antimutagenic potency of these luteolin derivatives based on their structures has been demonstrated in this study.

Isolation of 3 Flavonoids from Mentha longifolia (L.) Hudson subsp. longifolia and Determination of Their Genotoxic Potentials by Using the E. coli WP2 Test System

UNLABELLED Flavonoids, abundant in most of plant species, are widely used in medicine and development studies on phytotherapeutic drugs due to their various biological activities. In the present study, 3 flavonoids, apigenin-7-O-glucoside, apigenin-7-O-rutinoside, and apigenin-7-O-glucuronide, were isolated from Mentha longifolia (L.) Hudson subsp. longifolia by using E. coli WP2 genotoxicity assay guided fractionation procedures. Later, the mutagenic and antimutagenic properties of each flavonoid were evaluated by using the same genotoxicity assay. The results showed that all the test compounds have significant antimutagenic activity at tested concentrations with or without S9 activation. The inhibition rates were between 25.3% (apigenin-7-O-glucoside with S9-2.0 μM/plate) and 59.0% (apigenin-7-O-rutinoside without S9-2.0 μM/plate). In conclusion, the results revealed that the 3 flavonoids from Mentha longifolia (L.) Hudson subsp. longifolia have significant antimutagenic activity, and the findings of the present study are valuable for further investigations, focus on the phytotherapeutic drug discovery. PRACTICAL APPLICATION Apigenin derivatives can be thought as genetically safe at tested concentrations because they did not show mutagenic activity. Furthermore, they have also significant antimutagenic activity. These are valuable for further research focus on phytotherapeutic drug discovery and development.

Investigation on Anti-Inflammatory and Antiulcer Activities of Anchusa azurea Extracts and their Major Constituent Rosmarinic Acid

This study investigated the anti-inflammatory and antiulcer activities of different extracts from the aerial parts and the roots of Anchusa azurea Miller var. azurea (Boraginaceae), as well as their major constituent, rosmarinic acid. The extracts were water (AWa, RWa) and methanol (AMe, RMe) extracts prepared from the aerial parts and the roots of A. azurea, respectively. The AMe extract was found to exert anti-inflammatory effects; so it was evaporated to dryness and the residue was dissolved in distilled water (AMeWa) and then further fractionated with n-hexane (AMeHe) and n-butanol (AMeBu). Anti-inflammatory activity was investigated in rats using carrageenan-induced acute inflammation, and antiulcer activity was investigated using indomethacin-induced gastric damage. The methanolic extract from the aerial parts, its n-butanol fraction, and rosmarinic acid, which was isolated from the n-butanol fraction of the AMe extract, showed signifi cant dose-dependent antiinflammatory activity. During the acute phase of inflammation, the anti-inflammatory activity of rosmarinic acid was comparable to that of ibuprofen. No antiulcer activity was observed. The experimental data demonstrate that A. azurea Miller var. azurea and rosmarinic acid display significant anti-inflammatory activity.

In vitro effects of rosmarinic acid on glutathione reductase and glucose 6-phosphate dehydrogenase

Context: Glutathione reductase (GR, NADPH:oxidized glutathione oxidoreductase, E.C 1.6.4.2) is a flavoprotein that catalyzes the NADPH-dependent reduction of oxidized glutathione (GSSG). GR is a crucial enzyme in the antioxidant system by maintaining reduced glutathione (GSH). Glucose 6-phosphate dehydrogenase (G6PD, glucose 6-phosphate (G6P):NADP+ oxidoreductase, EC 1.1.1.49) is the key regulatory enzyme of the pentose phosphate pathway and maintains NADPH for reductive reactions. Objective: Rosmarinic acid (RA; α-O-caffeoyl-3,4-dihydroxyphenyl lactic acid) is an ester of caffeic acid (CA) and 3,4-dihydroxyphenyllactic acid. It has a number of interesting biological activities. The inhibiting activities of the RA on GR and G6PD are investigated here for the first time. Materials and methods: GR and G6PD were purified from tissues, then the effects of RA are investigated. Results: This study reports that RA, which was isolated from Echium vulgare L. (Boraginaceae), inhibits purified GR and G6PD in a concentration-dependent manner. Kinetic characterizations and inhibition constants are investigated. Discussion and conclusion: Because of their importance in the antioxidative defense system, investigation of the inhibitors of these enzymes is important for drug development.

Iridoids from Centranthus longiflorus subsp. longiflorus

An investigation of the extracts from Centranthus longiflorus subsp. longiflorus has led to the isolation of seven substances. A new iridolactone has been isolated from the aerial parts of this plant and was elucidated by analysis of the spectroscopic data and named longiflorone. The constitution of the previously described valtrate hydrine B8 was elucidated via 2D NMR analysis for the first time. Additional compounds isolated were patrinoside, kanokoside A, oleanolic acid, sitosterol and quercetin 3-O-rutinoside.

Determination of antimutagenic properties of apigenin-7-O-rutinoside, a flavonoid isolated from Mentha longifolia (L.) Huds. ssp. longifolia with yeast DEL assay

Lamiaceae is an important plant family that has been investigated for its medicinal properties due to its large amounts of phenolic acids and flavonoids. Flavonoids have been shown to have antioxidant and antimutagenic activities in different test systems, but their certain mechanisms are still unclear. This study was designed to evaluate the mutagenic and antimutagenic activities of apigenin 7-O-rutinoside, a flavonoid isolated from Mentha longifolia (L.) Huds. ssp. longifolia. The possible antimutagenic potential of apigenin 7-O-rutinoside (A7R) was examined against mutagens ethyl methanesulfonate (EMS) and acridine (AC) in a eukaryotic cell system Saccharomyces cerevisiae RS112. The results showed that A7R has different inhibition rates against EMS and AC-induced mutagenicity. Thus, the properties of A7R are of great pharmacological importance and might be beneficial for reducing the risk of reactive oxygen species–related diseases.

Isolation of a flavonoid, apigenin 7-O-glucoside, from Mentha longifolia (L.) Hudson subspecies longifolia and its genotoxic potency.

Mentha is a medicinal and aromatic plant belonging to the Lamiaceae family, which is widely used in food, flavor, cosmetic and pharmaceutical industries. Recently, it has been found that the use of Mentha as a pharmaceutical source is based on its phytochemical constituents that have far been identified as tannins, saponins, phenolic acids and flavonoids. This study was designed to evaluate the mutagenic and antimutagenic activities of apigenin 7-O-glucoside (A7G), a flavonoid isolated from Mentha longifolia (L.) Hudson subspecies longifolia (ML). The possible antimutagenic potential of A7G was examined against mutagens ethyl methanesulfonate and acridine in an eukaryotic cell system Saccharomyces cerevisiae and sodium azide in Salmonella typhimurium TA1535 and 9-aminoacridine in S. typhimurium TA1537. According to our findings, any concentrations of the A7G used did not show mutagenic activity but exerted strong antimutagenic activities at tested concentrations. The inhibition rates for the Ames test ranged from 27.2% (S. typhimurium TA1535: 0.4 μM/plate) to 91.1% (S. typhimurium TA1537: 0.2 μM/plate) and for the yeast deletion assay from 4% to 57.7%. This genotoxicological study suggests that a flavonoid from ML owing to antimutagenic properties is of great pharmacological importance and might be beneficial to industries producing food additives, cosmetics and pharmaceuticals products.

β-Hydroxydihydrochalcone and flavonoid glycosides along with triterpene saponin and sesquiterpene from the herbs of Pimpinella rhodantha Boiss.

A new β-hydroxydihydrochalcone glycoside named ziganin (1) and a new acylated flavonol glycoside named isorhamnetin-3-O-α-L-(2″,3″-di-O-trans-coumaroyl)-rhamnopyranoside) (2), along with two known flavonoid glycosides, a β-hydroxydihydrochalcone glycoside, a hydroxybenzoic acid derivative, a trinorguaiane type sesquiterpenoid, a triterpenic saponin and a polyol were isolated from the herbs of Pimpinella rhodantha Boiss. Their structures were elucidated on the basis of spectroscopic analyses including 1D-and 2D-NMR, UV, IR, CD, ESI-MS, APCI-MS, HR-ESI-MS techniques. The isolated compounds were evaluated for their antioxidant capacity through the DPPH free-radical scavenging assay and ferrous ion-chelating power test.

Bioguided Fractionation of Polygonum alpinum and Isolation and Structure Elucidation of Active Compounds

Abstract Bioguided fractionation of the methanol extract of aerial parts from Polygonum alpinum. L. (Polygonaceae) was investigated using the exudation phase of inflammation in aseptic arthritis model, which is produced by carrageenan and radical-scavenging properties. Flavonoid-containing fractions showed anti-inflammatory and radical-scavenging activities. Therefore, isolation and structure elucidation of flavonoids were carried out. The eight flavonol glycosides, which were quercetin 3-O.-arabinofuranoside (= avicularin) (1), quercetin 3-O.-β.-glucuronopyranoside (2), quercetin 3-O.-α.-rhamnopyranosyl (1 → 6)-β.-glucopyranoside (3), quercetin 3-O.-β.-galacturonopyranoside (4), quercetin 3-O.-β.-glucopyranoside (5), kaempferol 3-O.-β.-galactopyranoside (6), quercetin 3-O.-β.-galactopyranoside (= hyperoside) (7), and myricetin 3-O.-β.-galactopyranoside (8), were isolated from the methanol herb extract of Polygonum alpinum.. The structures were established by spectroscopic methods.

α-Amylase and α-glucosidase inhibitory activities of the herbs of Artemisia dracunculus L. and its active constituents

A new phenylpropanoid named 4-(1′,1′,2′,2′-tetramethylpropyl)-1,2-benzenediol (1) with a known phenylpropanoid: 3-(p-methoxyphenyl)-1,2-propanediol (2), a coumarin: herniarin (3), and a flavonol glycoside: rutin (4) were isolated from the aerial parts of Artemisia dracunculus L. Their structures were elucidated by detailed analyses of 1D and 2D nuclear magnetic resonance, IR, ESI–MS and HR–ESI–MS data. Methanol extract of aerial parts of the plant, different polarity fractions of methanol extract and the isolated compounds from these fractions were evaluated for their alpha amylase and alpha glucosidase inhibitory effects. Phenylpropanoids containing fraction had a significantly higher α-glucosidase inhibitory activity (90.4%) when compared with the standart compound acarbose (26.0%) at 1 mg/mL. However none of the tested extracts or compounds were found to be active on α-amylase inhibition.