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Analysis of saponins and phenolic compounds as inhibitors of ?-carbonic anhydrase isoenzymes
(Informa Healthcare, 2014) Koz Ö.; Ekinci D.; Perrone A.; Piacente S.; Alankus-Caliskan Ö.; Bedir E.; Supuran C.T.
A series of phenolic and saponin type natural products such as quercetin, rutin, catechin, epicatechin, silymarin, trojanoside H, astragaloside IV, astragaloside VIII and astrasieversianin X, were investigated for their inhibitory effects against the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1). We here report inhibitory effects of these compounds against five ?-CA isozymes (hCA I, hCA II, bCA III, hCA IV and hCA VI). Most of the phenolic and saponin type compounds inhibited the isoenzymes quite effectively at low micromolar KI-s ranging between 0.1 and 4 µM, whereas a few derivatives were ineffective (KI-s > 100 µM). The results were remarkable which might lead to design of novel CAIs with a diverse inhibition mechanism compared to sulfonamide/sulfamate inhibitors. © 2013 Informa UK, Ltd.
An analytical approach based on ESI-MS, LC-MS and PCA for the quali-quantitative analysis of cycloartane derivatives in Astragalus spp.
(2013) Napolitano A.; Akay S.; Mari A.; Bedir E.; Pizza C.; Piacente S.
Astragalus species are widely used as health foods and dietary supplements, as well as drugs in traditional medicine. To rapidly evaluate metabolite similarities and differences among the EtOH extracts of the roots of eight commercial Astragalus spp., an approach based on direct analyses by ESI-MS followed by PCA of ESI-MS data, was carried out. Successively, quali-quantitative analyses of cycloartane derivatives in the eight Astragalus spp. by LC-ESI-MSn and PCA of LC-ESI-MS data were performed. This approach allowed to promptly highlighting metabolite similarities and differences among the various Astragalus spp. PCA results from LC-ESI-MS data of Astragalus samples were in reasonable agreement with both PCA results of ESI-MS data and quantitative results. This study affords an analytical method for the quali-quantitative determination of cycloartane derivatives in herbal preparations used as health and food supplements. © 2013 Elsevier B.V.
Antihyperglycemic and antihyperlipidemic effects of ferula assa-foetida and ferula tenuissima extracts in diabetic rats
(Asian Network for Scientific Information, 2015) Yusufoglu H.S.; Soliman G.A.; Abdel-Rahman R.F.; Abdel-Kader M.S.; Ganaie M.A.; Bedir E.; Erel Ş.B.; Öztürk B.
The present study was carried to explore the potential antihyperglycemic and antihyperlipidemic activity of Ferula assa-foetida L. and Ferula tenuissima Hub-Mor & Pesmen extracts in streptozotocin (STZ) induced diabetic rats. Furthermore, phytochemical screening, in vitro antioxidant activity and acute toxicity study of both plants were performed. Both extracts showed considerable antioxidant potential in vitro. In diabetic rats, F. assa-foetida (200 and 400 mg kg-1) and F. tenuissima (400 mg kgG1) showed significant elevation in plasma insulin level, total hemoglobin (Hb) and decrease in Fasting Blood Glucose (FBG) and glycosylated hemoglobin (HbA1c) levels. Significant elevations in the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and level of reduced glutathione (GSH) in liver and pancreas homogenates were observed in diabetic animals following F. assa-foetida (200 and 400 mg kg-1) and F. tenuissima (400 mg kg-1) treatments. The antihyperlipidemic effect of F. assa-foetida extract was demonstrated by a significant reduction in plasma triglycerides (TG), Total Cholesterol (TC), Low Density Lipoprotein Cholesterol (LDL-C) and the increase of High Density Lipoprotein Cholesterol (HDL-C). Plasma activities of alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) and levels of Total Protein (TP) and bilirubin (BIL) in diabetic rats were recovered significantly after F. assa-foetida and F. tenuissima treatment in comparison with diabetic controls. The present data suggest that F. assa-foetida have both antihyperglycemic and antihyperlipidemic effects with enhancement of insulin-secreting activity. © 2015 Asian Network for Scientific Information.
Antimicrobial and antimalarial activities of some endemic Turkish Verbascum species
(2004) Akdemir Z.Ş.; Tatli I.I.; Bedir E.; Khan I.A.
The antimicrobial activities of ethyl acetate and methanol extracts of five Verbascum species were studied. The dried extracts of the aerial parts of Verbascum chionophyllum Hub.-Mor., V. cilicicum Boiss., V. pterocalycinum var. mutense Hub.-Mor., V. pycnostachyum Boiss. & Helder. and V. splendidum Boiss. were tested in vitro against Candida albicans (ATCC 90028), Cryptococcus neoformans (ATCC 90113), Staphylococcus aureus (ATCC 29213), methicillin-resistant S. aureus (ATCC 43300), Pseudomonas aeruginosa (ATCC 27853), Aspergillus fumigatus (ATCC 90906) and Mycobacterium intracellulare (ATCC 23068) using a 96-well microplate assay. Amphotericin B, ciprofloxacin and rifampin were used as positive controls. The antimalarial activities of the same extracts were also tested to Plasmodium falciparum clone [Sierra Leone D6 (chloroquine-sensitive)]. The antimalarial agents chloroquine and artemisinin were used as positive controls. None of the tested extracts showed important antimicrobial or antimalarial activities.
Antioxidant and antihyperglycemic effects of ferula durdeana and ferula huber-morathii in experimental diabetic rats
(Asian Network for Scientific Information, 2015) Yusufoglu H.S.; Soliman G.A.; Abdel-Rahman R.F.; Abdel-Kader M.S.; Genaie M.A.; Bedir E.; Erel Ş.B.; Öztürk B.
In the present study, DPPH radical scavenging assay and ferric-reducing antioxidant assay were used to estimate the potential in vitro antioxidant effect of the methanol extracts of Ferula durdeana Korovin (F. durdeana) and Ferula huber-morathii Peşmen (F. huber-morathii). The antidiabetic activity of both extracts was evaluated in streptozotocin (STZ)-induced diabetic rats. Glibenclamide was taken as the standard drug. Both extracts showed considerable antioxidant potential in the DPPH radical scavenging assay and minimum reducing power in ferric-reducing antioxidant assay. Oral administration of F. durdeana (400 mg kg-1) and F. huber-morathii (200 and 400 mg kg-1) extracts to diabetic rats produced a marked reduction in Fasting Blood Glucose (FBG) and elevation in insulin levels after 14 and 28 days of treatment. A meaningful reduction in the concentrations of glycosylated hemoglobin (HbA1c), triglycerides (TG), Total Cholesterol (TC), Low Density Lipoprotein (LDL) in plasma and elevations in the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and glutathione (GSH) in liver and pancreas homogenates were observed in diabetic animals medicated with F. durdeana (200 and 400 mg kg-1) and F. huber-morathii (400 mg kgG1) extracts. Levels of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), bilirubin, total protein and High Density Lipoprotein (HDL) in plasma and malondialdehyde (MDA) in liver and pancreas homogenates were recovered significantly in F. durdeana and F. huber-morathii-medicated diabetic rats. Besides, biochemical results were supported by histopathological findings. These findings showed the significant antioxidant and hypoglycemic activities of F. durdeana and F. huber-morathii extracts in diabetic rats. © 2015 Asian Network for Scientific Information.
Antioxidant flavonoids from Verbascum salviifolium boiss
(2004) Akdemir Z.S.; Tatli I.I.; Bedir E.; Khan I.A.
Phenolic natural products such as flavonoids are known as potential antioxidant compounds. The aim of this study was the isolation, structure elucidation and determination of radical scavenging properties of flavonoids which were guided by DPPH autographic assay from the methanolic extract of the aerial parts of Verbascum salviifolium. From the titled plant, four flavonoid glucosides, apigenin-7-O-ß-glucopyranoside (1), luteolin-7-O-ß- glucopyranoside (2), luteolin-3'-O-ß-glucopyranoside (3), and chrysoeriol-7-O-ß-glucopyranoside (4), were isolated. The structures of the compounds were established on the basis of the spectroscopic evidence. Compounds 1-4 demonstrated scavenging properties toward the 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical in TLC autographic assays.
Antioxidant lignans from Larrea tridentata
(2004) Abou-Gazar H.; Bedir E.; Takamatsu S.; Ferreira D.; Khan I.A.
Three lignans, (7S,8S,7'S,8'S)-3,3',4'-trihydroxy- 4-methoxy-7,7'-epoxylignan and meso-(rel 7S,8S,7'S,8'S)-3,4, 3',4'-tetrahydroxy-7,7'-epoxylignan with significant antioxidant properties, and (E)-4,4'-dihydroxy-7,7'-dioxolign- 8(8')-ene, were isolated from the leaves of Larrea tridentata. The structures of the new compounds were determined primarily from 1D and 2D NMR analysis. Their antioxidant activities were evaluated on intracellular reactive oxygen species in HL-60 cells. Three lignans, (7S,8S,7'S,8'S)-3, 3',4'-trihydroxy-4-methoxy-7,7'-epoxylignan, meso-(rel 7S,8S,7'R,8'R)-3,4,3',4'-tetrahydroxy-7, 7'-epoxylignan, and (E)-4,4'-dihydroxy-7,7'-dioxolign- 8(8')-ene, together with 10 known compounds, were isolated from the leaves of Larrea tridentata. The structures of the new compounds were determined primarily from 1D and 2D NMR spectroscopic analysis. Their antioxidant activities against intracellular reactive oxygen species were evaluated in HL-60 cells. © 2004 Published by Elsevier Ltd.
Astragaloside IV and cycloastragenol production in in vitro produced Astragalus trojanus Stev.
(National Institute of Science Communication and Information Resources (NISCAIR), 2015) Nartop P.; Gürel A.; Akgün I.H.; Bedir E.
In the present paper, an efficient method for clonal propagation of an endemic plant, Astragalus trojanus Stev., was described. Effect of sucrose and 6-benzyladenine (BA) concentrations on shoot proliferation and rooting was studied. Woody plant medium (WPM) supplemented with two different concentrations of BA (S1 medium with 0.5 mg/L BA&S2 medium with 1 mg/L BA) was used, where S2 medium resulted in higher rates in both shoot elongation and multiple shoot proliferation of clonally propagated A. trojanus shoot cultures. Of 27 clones, 3 were selected for further studies based on the highest regeneration capacity (Clones 1, 12&15). A total of 340 shoots were obtained from Clone 1 in S1 medium. In this medium, the rooting ratio of shoots for Clone 15 was 11.67%. The highest shoot elongation (1.99 cm), multiple shoot proliferation ratio (4.35) and multiple shoot proliferation percentage (91.67%) were obtained from Clone 1 in S2 medium. Two media, WPM medium supplemented with 15 g/L (K1 medium) and 30 g/L (K2 medium) sucrose were used for rooting. The root formation of Clone 1 was 26.67% in K2 medium. The highest astragaloside IV (0.5486 µg/mg) and cycloastragenol (0.1263 µg/mg) contents were detected in roots grown in K1 medium.
Bioactive constituents from Turkish Pimpinella species
(2005) Tabanca N.; Bedir E.; Ferreira D.; Slade D.; Wedge D.E.; Jacob M.R.; Khan S.I.; Kirimer N.; Can Baser K.H.; Khan I.A.
A new 'phenylpropanoid', 4-(3-methyloxiran-2-yl)phenyl 2-methylbutanoate (1), a new trinorsesquiterpene, 4-(6-methylbicyclo[4.1.0]hept-2-en-7-yl)butan-2-one (2), and eight known compounds (3-10) were isolated from the essential oils of several Pimpinella species growing in Turkey. The structures of the new compounds were determined by 1D- and 2D-NMR analyses. The absolute configuration of 1 was established via comparison of its optical rotation with that of 'epoxypseudoisoeugenyl 2-methylbutyrate' (11), the absolute configuration of which was determined by chemical degradation and an appropriate Mosher ester formation. Direct bioautography revealed antifungal activity of 1 and 11 against Colletotrichum acutatum, C. fragariae, and C. gloesporioides. Subsequent evaluation of antifungal compounds in a 96-well microtiter assay showed that compounds 1 and 11 produced the most-significant growth inhibition in Phomopsis spp., Colletotrichum spp., and Botrytis cinerea. Compounds 1 and 6 displayed antimicrobial activities against Mycobacterium intracellulare, with IC50 values of 2.78 and 1.29 µM, respectively. © 2005 Verlag Helvetica Chimica Acta AG, Zürich.
Bioassay-guided isolation of antibacterial and cytotoxic compounds from the mesophilic actinomycete M-33-5
(2010) Urgen M.; Kocabaş F.; Nalbantsoy A.; Kocabas E.H.; Uzel A.; Bedir E.
One hundred and twenty-six mesophilic Actinomycete cultures were isolated from the Aegean region of Turkey. The antimicrobial activities of pure isolates were tested using the agar-plaque method. Based on high antimicrobial activity against methicillin resistant Staphylococcus aureus (MRSA) and Escherichia coli O157-H7 (E. coli), the isolate M-33-5 was selected for bioactivity-guided isolation. Fermentation, followed by solvent partition (H2O-EtOAc, H2O-n-BuOH), showed that the highest activity was present in the EtOAc extract. By using chromatographic methods, two bioactive compounds were isolated and their structures were determined by spectral methods to be 4'-deacetyl griseusin A and griseusin A. The MIC values of griseusin A and 4'-deacetyl griseusin A against MRSA and E. coli were ? 1.0 µg/mL. The cytotoxicities of the EtOAc extract and 4'-deacetyl griseusin A were also evaluated against two cancer cell lines (human servical cancer: HeLa; murine fibroblastic cells: L-929). The EtOAc extract showed strong cytotoxic activity against HeLa and L-929 lines with IC50 values of 1.57 and 2.43 µg/mL, respectively, whereas 4'-deacetyl griseusin A was very potent with IC50 values of 0.43 versus HeLa, and 0.12 µg/mL against L-929. The active strain M-33-5 was identified as Streptomyces griseus by 16SrDNA sequence data.
Cycloartane-type glycosides from Astragalus schottianus
(2012) Karabey F.; Khan I.A.; Bedir E.
Three new cycloartane-type triterpene glycosides were isolated from the roots of Astragalus schottianus Boiss. Their structures were established as 20(R),25-epoxy-3-O-ß-d-xylopyranosyl-24-O-ß-d-glucopyranosyl-3ß, 6?,16ß,24?-tetrahydroxycycloartane (1), 20(R),25-epoxy-3-O- [ß-d-glucopyranosyl(1 › 2)]-ß-d-xylopyranosyl-24-O-ß-d- glucopyranosyl-3ß,6?,16ß,24?-tetrahydroxycycloartane (2), 3-O-ß-d-xylopyranosyl-3ß,6?,16ß,20(S),24(S), 25-hexahydroxycycloartane (3) by the extensive use of 1D and 2D-NMR techniques and mass spectrometry. © 2012 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.
Cycloartane-type sapogenol derivatives inhibit NF?B activation as chemopreventive strategy for inflammation-induced prostate carcinogenesis
(Elsevier Inc., 2018) Debeleç-Bütüner B.; Öztürk M.B.; Tağ Ö.; Akgün İ.H.; Yetik-Anacak G.; Bedir E.; Korkmaz K.S.
Chronic inflammation is associated to 25% of cancer cases according to epidemiological data. Therefore, inhibition of inflammation-induced carcinogenesis can be an efficient therapeutic approach for cancer chemoprevention in drug development studies. It is also determined that anti-inflammatory drugs reduce cancer incidence. Cell culture-based in vitro screening methods are used as a fast and efficient method to investigate the biological activities of the biomolecules. In addition, saponins are molecules that are isolated from natural sources and are known to have potential for tumor inhibition. Studies on the preparation of analogues of cycloartane-type sapogenols (9,19-cyclolanostanes) have so far been limited. Therefore we have decided to direct our efforts toward the exploration of new anti-tumor agents prepared from cycloastragenol and its production artifact astragenol. The semi-synthetic derivatives were prepared mainly by oxidation, condensation, alkylation, acylation, and elimination reactions. After preliminary studies, five sapogenol analogues, two of which were new compounds (2 and 3), were selected and screened for their inhibitory activity on cell viability and NF?B signaling pathway activity in LNCaP prostate cancer cells. We found that the astragenol derivatives 1 and 2 as well as cycloastragenol derivatives 3, 4, and 5 exhibited strong inhibitory activity on NF?B signaling leading the repression of NF?B transcriptional activation and suppressed cell proliferation. The results suggested that these molecules might have significant potential for chemoprevention of prostate carcinogenesis induced by inflammatory NF?B signaling pathway. © 2018 Elsevier Inc.
Cycloartane-type sapogenol derivatives inhibit NF?B activation as chemopreventive strategy for inflammation-induced prostate carcinogenesis
(Elsevier Inc., 2018) Debeleç-Bütüner B.; Öztürk M.B.; Tağ Ö.; Akgün İ.H.; Yetik-Anacak G.; Bedir E.; Korkmaz K.S.
Chronic inflammation is associated to 25% of cancer cases according to epidemiological data. Therefore, inhibition of inflammation-induced carcinogenesis can be an efficient therapeutic approach for cancer chemoprevention in drug development studies. It is also determined that anti-inflammatory drugs reduce cancer incidence. Cell culture-based in vitro screening methods are used as a fast and efficient method to investigate the biological activities of the biomolecules. In addition, saponins are molecules that are isolated from natural sources and are known to have potential for tumor inhibition. Studies on the preparation of analogues of cycloartane-type sapogenols (9,19-cyclolanostanes) have so far been limited. Therefore we have decided to direct our efforts toward the exploration of new anti-tumor agents prepared from cycloastragenol and its production artifact astragenol. The semi-synthetic derivatives were prepared mainly by oxidation, condensation, alkylation, acylation, and elimination reactions. After preliminary studies, five sapogenol analogues, two of which were new compounds (2 and 3), were selected and screened for their inhibitory activity on cell viability and NF?B signaling pathway activity in LNCaP prostate cancer cells. We found that the astragenol derivatives 1 and 2 as well as cycloastragenol derivatives 3, 4, and 5 exhibited strong inhibitory activity on NF?B signaling leading the repression of NF?B transcriptional activation and suppressed cell proliferation. The results suggested that these molecules might have significant potential for chemoprevention of prostate carcinogenesis induced by inflammatory NF?B signaling pathway. © 2018 Elsevier Inc.
Effect of essential oils and isolated compounds from Pimpinella species on NF-?B: A target for antiinflammatory therapy
(2007) Tabanca N.; Ma G.; Pasco D.S.; Bedir E.; Kirimer N.; Baser K.H.C.; Khan I.A.; Khan S.I.
Pimpinella essential oils and isolated compounds were screened for their inhibitory activity against NF-?B mediated transcription in SW1353 cells. Twelve oils were effective in inhibiting NF-?B mediated transcription. Especially the roots of P. corymbosa, P. tragium and P. rhodanta showed potent activities with IC50 values of 2, 3 and 6 µg/mL, respectively. Five pure compounds, 7 (4-(2-propenyl)phenylangelate), 12 (4-(3-methyloxiranyl) phenyltiglate), 17 (4-methoxy-2-(3-methyloxiranyl)phenyl isobutyrate), 18 (4-methoxy-2-(3-methyloxiranyl)phenylangelate) and 21 (epoxy pseudoisoeugenol-2-methylbutyrate) inhibited NF-?B mediated transcription with IC50 values of 5.5, 1.2, 0.01, 3.6 and 11 µg/mL, respectively. None of the compounds were cytotoxic to mammalian cells. These findings add significant information to the pharmacological activity of Pimpinella species and their beneficial effects and use in disease prevention especially those related to inflammation. Copyright © 2007 John Wiley & Sons, Ltd.
Effects of Secondary Metabolites from the Fungus Septofusidium berolinense on DNA Cleavage Mediated by Human Topoisomerase II?
(American Chemical Society, 2016) Vann K.R.; Ekiz G.; Zencir S.; Bedir E.; Topcu Z.; Osheroff N.
Two metabolites from the ascomycete fungus Septofusidium berolinense were recently identified as having antineoplastic activity [Ekiz et al. (2015) J. Antibiot., DOI: 10.1038/ja.2015.84]. However, the basis for this activity is not known. One of the compounds [3,6-dihydroxy-2-propylbenzaldehyde (GE-1)] is a hydroquinone, and the other [2-hydroxymethyl-3-propylcyclohexa-2,5-diene-1,4-dione (GE-2)] is a quinone. Because some hydroquinones and quinones act as topoisomerase II poisons, the effects of GE-1 and GE-2 on DNA cleavage mediated by human topoisomerase II? were assessed. GE-2 enhanced DNA cleavage ~4-fold and induced scission with a site specificity similar to that of the anticancer drug etoposide. Similar to other quinone-based topoisomerase II poisons, GE-2 displayed several hallmark characteristics of covalent topoisomerase II poisons, including (1) the inability to poison a topoisomerase II? construct that lacks the N-terminal domain, (2) the inhibition of DNA cleavage when the compound was incubated with the enzyme prior to the addition of plasmid, and (3) the loss of poisoning activity in the presence of a reducing agent. In contrast to GE-2, GE-1 did not enhance DNA cleavage mediated by topoisomerase II? except at very high concentrations. However, the activity and potency of the metabolite were dramatically enhanced under oxidizing conditions. These results suggest that topoisomerase II? may play a role in mediating the cytotoxic effects of these fungal metabolites. © 2016 American Chemical Society.
Estrogenic activity of isolated compounds and essential oils of Pimpinella species from Turkey, evaluated using a recombinant yeast screen
(2004) Tabanca N.; Khan S.I.; Bedir E.; Annavarapu S.; Willett K.; Khan I.A.; Kirimer N.; Baser K.H.C.
Several plants and plant-derived pure compounds, designated as phytoestrogens, have been reported to cause estrogenic effects. They have been used for alleviation of menopausal symptoms, prevention of osteoporosis, heart disease and cancer. There is an increased interest in studying phytoestrogens such as isoflavones and lignans for their use as replacements for synthetic estrogens. In this study, the estrogenic activity of essential oils of eleven Pimpinella species and the compounds isolated from these species were evaluated using the yeast estrogen screen (YES) assay. The essential oils containing (E)-anethole as major compound showed estrogenic activity in the YES assay, except for the aerial parts without fruits of P. anisetum and P. flabellifolia. The percent maximal response produced by most anethole-containing oils was 30-50%. Fruits of P. isaurica and P. peucedanifolia were estrogenic in spite of the absence or trace amount of anethole, respectively. This study indicates that the estrogenic activity of Pimpinella oils is not solely due to the presence of anethole. Components other than anethole may be responsible for contributing towards the estrogenic activity. The essential oils from different species varied in their estrogenic potencies (relative potency from 8.3 × 10 -8 to 1.2 × 10-6 compared to 17ß-estradiol) and among the different plant parts, the fruit oils of most species were estrogenic followed by the aerial parts without fruits and the root oils and their EC 50 values varied from 45 µg/mL to 650 µg/mL.
Five new cardenolides transformed from oleandrin and nerigoside by Alternaria eureka 1E1BL1 and Phaeosphaeriasp. 1E4CS-1 and their cytotoxic activities
(Elsevier Ltd, 2021) Karakoyun Ç.; Küçüksolak M.; Bilgi E.; Doğan G.; Çömlekçi Y.E.; Bedir E.
Biotransformation of oleandrin (1) and nerigoside (2) by endophytic fungi; Alternaria eureka 1E1BL1 and Phaeospheria sp. 1E4CS-1, has led to the isolation of five new metabolites (3, 5, 6, 7 and 8) together with a known compound (4). The structures of the biotransformation products were elucidated by 1D-, 2D NMR and HR-MS. Phaeospheria sp. mainly provided monooxygenation reactions on the A and B rings, whereas A. eureka afforded both monooxygenated and desacetylated derivatives of the substrates. Cytotoxic activity of the compounds was tested against a non-cancerous (HEK-293) and four cancer (PANC-1, MIA PaCa-2, DU 145 and A549) cell lines by MTT cell viability assay. All compounds were less cytotoxic than oleandrin, which had IC50 values ranging between 2.7 and 41.9 nM. Two of the monohydroxylated metabolites, viz. 7(?)-hydroxy oleandrin (3) and 1(?)-hydroxy oleandrin (7), were also potent with IC50 values from 18.45 to 39.0 nM, while desacetylated + monohydroxylated, or dihydroxylated products had much lower cytotoxicity. Additionally, the lesser activity of 2 and its metabolite (6) possessing diginose as sugar residue inferred that oleandrose moiety is important for the toxicity of oleandrin as well as hydrophobicity of the steroid core. © 2020 Phytochemical Society of Europe
?-Glucosidase inhibitory constituents of Linaria kurdica subsp. eriocalyx
(2010) Aydogdu I.; Zihnioglu F.; Karayildirim T.; Gülcemal D.; Alankuş-Çalişkan Ö.; Bedir E.
Three known iridoid glycosides, antirrhide (1), antirrhinoside (2), and 5-O-ß-allosylantirrhinoside (3), and two known flavone glycosides, linariin (4?-O-acetylpectolinarin) (4) and linarin (acacetin-7-O-ß-D- rutinoside) (5) were isolated from Linaria kurdica Boiss & Hohen. subsp. eriocalyx The structures of the isolated compounds were established from spectroscopic evidence. Compounds 1-3 showed high inhibitory potential against ?-glucosidase.
Identification of hypoglycaemic compounds from berries of Juniperus oxycedrus subsp. oxycedrus through bioactivity guided isolation technique
(2012) Orhan N.; Aslan M.; Pekcan M.; Orhan D.D.; Bedir E.; Ergun F.
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-ß-d-glucopyranosyl ferulic acid and oleuropeic acid-8-O-ß-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. © 2011 Elsevier Ireland Ltd. All rights reserved.
Influence of supercritical carbon dioxide and methanolic extracts of rosemary on oxidation and sensory properties of wheat germ oil
(2009) Yesil-Celiktas O.; Isleten M.; Karagul-Yuceer Y.; Bedir E.; Vardar-Sukan F.
Both supercritical CO2 and methanolic extracts from the leaves of rosemary (Rosmarinus officinalis) harvested from three different locations of Turkey at four different times of the year were added at a concentration of 100 mg/kg to wheat germ oil. Wheat germ oil samples were stored in an incubator for 10 days at 50C in order to promote oxidation and for the efficacy of the extracts for stabilization purposes to be examined. Degree of oxidation was determined by peroxide and p-anisidine values, which were performed every 2 days. Extracts from Mersin and Canakkale regions performed better results. Additionally, June and September harvests had lower peroxide values. According to the descriptive sensory analysis, both locations and extraction methods were found to effect flavor. Some flavor attributes, such as wheatlike/starchy, fishy and rubbery/metallic changed during storage regardless of locations and extraction methods. Supercritical CO2 extracts performed better results in terms of both oxidation and sensory properties. © 2009 Wiley Periodicals, Inc.

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