Fatma Ergun

Hypoglycemic activity and antioxidant potential of some medicinal plants traditionally used in Turkey for diabetes.

Cydonia oblonga Mill. (Rosaceae) leaves, Helianthus tuberosus L. (Asteraceae) tubers, and Allium porrum L. (Liliaceae) bulbs are used as a folk remedy for the treatment of diabetes and they are also consumed as food in Turkey. In the present study, the antidiabetic and antioxidant activities of the ethanol extracts of these plants were studied in normal and streptozotocin-induced diabetic rats for 5 days. All extracts were administrated orally to rats at the doses of 250 and 500 mg/kg. Blood glucose level was measured according to glucose oxidase method. In order to determine antioxidant activity, thiobarbituric acid reactive substance (TBARS) and reduced glutathione (GSH) levels in liver, kidney, and heart tissues were measured by using spectrophotometric methods. Oral administration of Cydonia oblonga (500 mg/kg) and Allium porrum (500 mg/kg) extracts for 5 days in diabetic rats caused a decrease in blood glucose levels by 33.8% and 18.0%, respectively. Moreover, Allium porrum and Cydonia oblonga extracts induced significant alleviation on only heart tissue TBARS levels (44.6 and 45.7%), Helianthus tuberosus and Allium porrum extracts showed an inhibitory effect on kidney tissue TBARS levels (24.5 and 14.8%). None of the extracts restored GSH levels in kidney, liver, and heart tissues of diabetic rats.

Evaluation of hepatoprotective effect of Gentiana olivieri herbs on subacute administration and isolation of active principle

Hepatoprotective effect of Gentiana olivieri Griseb. (Gentianaceae) flowering herbs on subacute administration were studied using in vivo models in rats. For the activity assessment on carbon tetrachloride-induced hepatic damage following biochemical parameters were evaluated; plasma and hepatic tissue malondialdehyde formation, and liver tissue glutathione level, as well as plasma transaminase enzyme levels (aspartate transferase and alanine transferase). Results of biochemical tests were also confirmed by histopathological examination. Through bioassay-guided fractionation procedures isoorientin, a known C-glycosylflavone, was isolated from the ethyl acetate fraction as the active antihepatotoxic constituent by silica gel column chromatography. Isoorientin exhibited significant hepatoprotective effect at 15 mg/kg b.w. dose.

Hepatoprotective effects of Turkish folk remedies on experimental liver injury.

Seven plants which are used in Turkish folk medicine were studied for possible hepatoprotective effects. These plants are Carduus acanthoides and C. nutans (Asteraceae), Cichorium intybus (Asteraceae), Fumaria asepalae and F. vailantii (Fumariaceae), Gentiana olivieri (Gentianaceae) and Plantago lanceolata (Plantaginaceae). Stems, bracts and receptaculum of Cynara scolymus were used as natural reference drugs. Effects of the ethanolic extracts were studied using the carbon tetrachloride-induced hepatotoxicity model in rats. The extracts of F. vailantii and G. olivieri significantly prevented the elevation of plasma and hepatic malondialdehyde formation (evidence of lipid peroxidation) as well as enzyme levels (AST and ALT) in acute liver injury, which might be ascribed to their potent hepatoprotective activity. Liver sections were also studied histopathologically to confirm the biochemical results.

Anti-inflammatory and antinociceptive activity of flavonoids isolated from Viscum album ssp. album.

Abstract Viscum album L. has been used in the indigenous systems of medicine for treatment of headache and some inflammatory diseases. In order to evaluate this information, antinociceptive and anti-inflammatory activities of the five flavonoids (5,7-dimethoxy naringenin or 4′,6′- dimethoxy chalcononaringenin) derivatives, isolated from the ethyl acetate fraction of the extract from V. album ssp. album, were investigated, namely 5,7-dimethoxy-flavanone-4′-O- β-ᴅ-glucopyranoside (1), 2′-hydroxy-4′,6′-dimethoxy-chalcone-4-O-β-ᴅ-glucopyranoside (2), 5,7-dimethoxy-flavanone-4′-O-[2″-O-(5‴-O-trans-cinnamoyl)-β-ᴅ-apiofuranosyl]-β-ᴅ-glucopyranoside (3), 2′-hydroxy-4′,6′-dimethoxy-chalcone-4-O-[2″-O-(5‴-O-trans-cinnamoyl)-β-ᴅ-apiofuranosyl]- β-ᴅ-glucopyranoside (4), 5,7-dimethoxy-flavanone-4′-O-[β-d-apiofuranosyl- (152)]-β-ᴅ-glucopyranoside (5). For the antinociceptive activity assessment the p-benzoquinone- induced writhing test and for the anti-inflammatory activity the carrageenan-induced hind paw edema model in mice were used. The ethyl acetate fraction in a dose of 250 mg/kg as well as compounds 2 and 5 in a 30 mg/kg dose were shown to possess remarkable antinociceptive and anti-inflammatory activities per os without inducing any apparent acute toxicity as well as gastric damage

Insights into cholinesterase inhibitory and antioxidant activities of five Juniperus species.

In vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory and antioxidant activities of the aqueous and ethanol extracts of the leaves, ripe fruits, and unripe fruits of Juniperus communis ssp. nana, Juniperus oxycedrus ssp. oxycedrus, Juniperus sabina, Juniperus foetidissima, and Juniperus excelsa were investigated in the present study. Cholinesterase inhibition of the extracts was screened using ELISA microplate reader. Antioxidant activity of the extracts was tested by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging, ferrous ion-chelating, and ferric-reducing antioxidant power (FRAP) assays. Total phenol and flavonoid contents of the extracts were determined spectrophotometrically. The extracts had low or no inhibition towards AChE, whereas the leaf aqueous extract of J. foetidissima showed the highest BChE inhibition (93.94 ± 0.01%). The leaf extracts usually exerted higher antioxidant activity. We herein describe the first study on anticholinesterase and antioxidant activity by the methods of ferrous ion-chelating, superoxide radical scavenging, and ferric-reducing antioxidant power (FRAP) assays of the mentioned Juniperus species.

Effects of the Turkish subspecies of Viscum album on macrophage-derived cytokines.

Viscum album L. herbs are used for the treatment of various diseases. Apart from their immunostimulatory, antitumor, and hypotension inducing activities, anti-inflammatory effects has also been recorded in the literature. Since the immunostimulatory activity of mistletoe is mainly attributed to a stimulation of the mononuclear phagocytic system and to an induction of inflammation by macrophage-derived cytokines, utilization based on anti-inflammatory activity seems in contrast with its use as immunostimulant. The inhibitory effects of 80% ethanol extracts and subfractions obtained by petroleum ether, diethylether, ethylacetate and n-butanol from three Turkish subspecies of V. album L. (ssp. album, ssp. abietis, ssp. austriacum) against interleukins (IL-1alpha and IL-1beta) and tumor necrosis factor-alpha were studied. Ethanolic (80%) extracts of all three subspecies exhibited almost no significant inhibitory activity on the proinflammatory cytokines, at least in the concentrations applied in this study. In contrast, they induce a concentration dependent stimulation of these cytokines. On the other hand, moderate to weak, dose dependent inhibitory effects were observed on fractionation, which may be attributed to the existence of less polar components with anti-inflammatory activity. Based on our results, it was concluded that the utilization of ethanol extracts for anti-inflammatory purposes would not be beneficial probably due to the partial extraction of the low-molecular-weight polypeptides, i.e. viscotoxins, which induce an inflammatory response. Moreover, for anti-inflammatory effects, extracts of Viscum album ssp. austriacum may be preferred, since higher inhibitory ratios were obtained against inflammatory cytokines than with the other two subspecies.

A bioactivity guided study on the antidiabetic activity of Juniperus oxycedrus subsp. oxycedrus L. leaves.

ETHNOPHARMACOLOGICAL RELEVANCE Juniperus (Cupressaceae) species are widely used as folk medicine in spreading countries. Decoction of Juniperus oxycedrus subsp. oxycedrus L. leaves is used internally to lower blood glucose levels in Turkey. AIM OF THE STUDY To determine hypoglycaemic and antidiabetic activities of Juniperus oxycedrus subsp. oxycedrus leaves and to identify active compounds through bioactivity guided isolation technique. MATERIALS AND METHODS Ethanol and water extracts of Juniperus oxycedrus subsp. oxycedrus (Joso), leaves on oral administration were studied using in vivo models in normal, glucose-hyperglycemic and streptozotocin-induced diabetic rats. Through in vivo bioactivity-guided fractionation processes, a nonpolar fraction was separated from the n-hexane subextract by silica gel column chromatography as the main active fraction. Subfractions of this fraction was found to possess antidiabetic activity and their chemical composition was investigated by GC-FID and GC-MS, simultaneously. RESULTS This is the first report on the antidiabetic constituents of Joso leaves. Fatty acids, such as palmitic, linoleic and linolenic acid were found as the major compounds in subfractions. CONCLUSION Results indicated that Joso leaf extract and its active constituents might be beneficial for diabetes mellitus.

Effects of Juniperus oxycedrus ssp. oxycedrus on tissue lipid peroxidation, trace elements (Cu, Zn, Fe) and blood glucose levels in experimental diabetes.

ETHNOPHARMACOLOGICAL RELEVANCE Juniperus oxycedrus L. (Cupressaceae) fruits and leaves are used internally and pounded fruits are eaten for diabetes in Turkey. AIM OF THE STUDY To evaluate the interrelationships between the levels of chosen trace elements (copper, iron, and zinc) and hepatic, renal lipid peroxidation (TBARS) in streptozotocin-induced diabetic rats treated with Juniperus oxycedrus ssp. oxycedrus (J.o.s.o.) leaf and fruit extracts for 10 days. MATERIALS AND METHODS J.o.s.o. fruit and leaf extracts were administered in STZ-induced diabetic rats, at doses of 500 and 1000 mg/kg. The blood glucose levels were measured in the 1st, 4th, 7th and 10th day of experiment. Fe, Cu, and Zn contents and lipid peroxidation levels of liver and kidney tissues were determined by atomic absorption spectrophotometry and ultraviolet spectrophotometry, respectively. RESULTS Treatment of diabetic rats with the J.o.s.o. fruit and leaf extracts decreased the blood glucose levels and both the levels of lipid peroxidation in liver and kidney tissues. J.o.s.o. extracts have augmented Zn concentrations in liver of STZ-induced diabetic rats. CONCLUSIONS Results indicated that J.o.s.o. fruit and leaf extracts might be beneficial for diabetes and its complications.

Iridoids from Galium aparine

The isolation and UV, IR, 1 H- and 13 C-NMR data of asperulosidic acid, 10-deacetylasperulosidic acid from Galium aparine L. aerial parts are reported.

Identification of hypoglycaemic compounds from berries of Juniperus oxycedrus subsp. oxycedrus through bioactivity guided isolation technique

ETHNOPHARMACOLOGICAL RELEVANCE Decoction of Juniperus oxycedrus subsp. oxycedrus L. (Cupressaceae) berries is used internally as tea and pounded fruits are consumed to lower blood glucose levels in Turkey. AIM OF THE STUDY To evaluate hypoglycaemic and antidiabetic activity of J. oxycedrus subsp. oxycedrus berries and to identify active compounds through bioactivity guided isolation technique. MATERIAL AND METHODS Hypoglycaemic effect of J. oxycedrus subsp. oxycedrus (Joso) berry extracts on oral administration was studied using in vivo models in normal, glucose-hyperglycaemic rats. Streptozotocin induced diabetic rats were used to examine antidiabetic activity of Joso extracts, subextracts, fractions, subfractions and shikimic acid (SA). RESULTS Through in vivo bioactivity-guided fractionation processes, shikimic acid, 4-O-β-d-glucopyranosyl ferulic acid and oleuropeic acid-8-O-β-d-glucopyranoside were isolated from the n-butanol subextract by silica gel and reverse phase column chromatography as the main active ingredient of the active subfraction. After 8 days administration of the major compound shikimic acid, blood glucose levels (24%), malondialdehyde levels in kidney tissues (63-64%) and liver enzymes (AST, ALT, ALP) of diabetic rats were decreased. CONCLUSION Results indicated that Joso berry extract and its active constituents might be beneficial for diabetes and its complications.