Ilkay Erdogan Orhan

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.

Phytochemical contents and enzyme inhibitory and antioxidant properties of Anethum graveolens L. (dill) samples cultivated under organic and conventional agricultural conditions.

Inhibitory effect of the n-hexane, dichloromethane, ethyl acetate, and ethanol extracts from Anethum graveolens L. (dill) cultivated under organic (AG-O) and conventional (AG-C) conditions was tested against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase at 200 μg mL⁻¹. Their antioxidant activity was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), N,N-dimethyl-p-phenylendiamine (DMPD), and nitric oxide (NO) radical scavenging assays as well as ferric ion-chelation capacity, ferric-(FRAP), and phosphomolybdenum-reducing antioxidant power (PRAP). The phytochemical analyses have been performed on both of the plant samples. GC-MS analysis pointed out that α-phellandrene was the main component in both of the essential oils in varying amounts (47.75% for AG-O and 27.94% for AG-C), while oleic acid was the dominant in the fruit oils of two samples (36.39% for AG-O and 53.87% for AG-C). HPLC analysis showed that both of the extracts contained rosmarinic acid as the major phenolic acid. The extracts inhibited BChE at moderate level, while the ethanol extracts exerted remarkable NO scavenging effect. The results emphasize that cultivation conditions may have effect on bioactivity and phytochemical content on plant samples.

Profiling of in vitro neurobiological effects and phenolic acids of selected endemic Salvia species

The ethyl acetate and methanol extracts from 16 Salvia L. species were screened for their inhibitory activity against acetylcholinesterase, butyrylcholinesterase, lipoxygenase, and tyrosinase; the enzymes linked to neurodegeneration. Their antioxidant activity was also tested using DPPH radical scavenging, metal-chelation, and ferric-reducing antioxidant power (FRAP) assays. Total flavonoid content of the extracts was determined by AlCl3 reagent, while HPLC technique was applied for analysis of various phenolic acids in the extracts. The extracts exerted weak cholinesterase and tyrosinase inhibition, and remarkable inhibition against lipoxygenase (13.07±2.73-74.21±5.61%) at 100μgml-1. The methanol extracts showed higher antioxidant activity in DPPH radical scavenging and FRAP assays. The extracts were analyzed for their gallic, protocateuchic, p-hydroxy-benzoic, vanillic, caffeic, chlorogenic, syringic, o- and p-coumaric, ferulic, rosmarinic, and tr-cinnamic acid contents and the methanol extract of Salvia ekimiana (153.50mg100g-1) was revealed to be the richest in terms of rosmarinic acid.

Enzyme inhibitory and antioxidant activities of Viburnum tinus L. relevant to its neuroprotective potential

In vitro neuroprotective activity of the extracts of Viburnum tinus L. was investigated via inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), and tyrosinase (TYRO) by microtitre plate assays. Their antioxidant activity was tested using 2,2-diphenyl-1-picrylhydrazyl (DPPH), N,N-dimethyl-p-phenylendiamine (DMPD), super oxide (SO), and nitric oxide (NO) radical-scavenging activities, ferric ion-chelation capacity, ferric- (FRAP), and phosphomolybdenum-reducing antioxidant power (PRAP) assays. Total phenol and flavonoid content of the extracts was determined spectrophotometrically. The branch-ethyl acetate and fruit-methanol extracts exerted potent anticholinesterase effects (66.4 ± 0.65% to 97.7 ± 0.47%), while the fruit-methanol extract had the highest TYRO inhibition (47.0 ± 0.68%). The methanol extracts showed higher activities in most of the antioxidant tests. All the extracts displayed notable NO-scavenging effects (47.5 ± 5.03% to 74.5 ± 1.80%). Only the fruit-ethyl acetate extract quenched SO radical (38.4 ± 1.01%) at 500 μg ml(-1). Our data indicate that the fruit and branch extracts of V. tinus may provide potential neuroprotection.

Assessment of antimicrobial and antiprotozoal activity of the olive oil macerate samples of **Hypericum perforatum** and their LC-DAD-MS analyses

Twenty-one samples of traditionally-prepared (home-made) and ready-made (commercial) St. Johns Wort olive oil macerates were profiled for their in vitro antimicrobial and antiprotozoal activity. Their cytotoxic potential was evaluated on MRC-5 fibroblasts. In the antiprotozoal assays, ten of the oils inhibited Trypanosoma brucei rhodesiense (IC(50) 15.9-64.5 μg/mL), while only one oil exerted antimicrobial activity towards Staphylococcus aureus (IC(50)=88.7 μg/mL). LC-DAD-MS data revealed the presence of pseudohypericin (0.135-3.280 μg/g) and hypericin (0.277-6.634 μg/g) in all the oils, whereas chlorogenic acid (1.063 μg/g) was detected only in one oil sample. Hyperforin was detected in four (0.977-2.399 μg/g) and adhyperforin in six samples (0.005-3.165 μg/g). Hypericin and pseudohypericin were common in the active oils, whereas hyperforin, adhyperforin, and chlorogenic acid were absent in these samples. Our results indicated that if the correct plant material is used, the infused oils from Hypericum perforatum may contain active components.

UPLC-TOF-MS analysis of Galium spurium towards its neuroprotective and anticonvulsant activities

ETHNOPHARMACOLOGICAL RELEVANCE Galium species have been reported to be used against epilepsy in traditional Turkish folk medicine. AIM OF STUDY The present work was undertaken to evaluate the in vivo anticonvulsant and in vitro neuroprotective effects of Galium spurium L. and to determine the major constituents by UPLC-TOF-MS. MATERIALS AND METHODS Anticonvulsant activity of the aerial parts of Galium spurium was investigated using pentylenetetrazole, picrotoxin, and maximal electroshock-induced seizure animal models. In order to evaluate the safety, neurotoxicity (Rota rod test) of the ethanol extract was also determined. In vitro neuroprotective effect of the ethanol extract of Galium spurium was assessed by acetylcholinesterase and butrylcholinesterase inhibitions. Ultra Performance Liquid Chromatography-Time of Flight Mass Spectrometer (UPLC-TOF-MS) was used to identify the major compounds in the extract. RESULTS In pentylenetetrazole-induced seizure, the ethanol extract at doses of 250 and 1000mg/kg prolonged the onset of seizures. Similarly, Galium spurium (250 and 500mg/kg) significantly delayed the onset of picrotoxin-induced seizures in mice and these doses also exhibited 12.5% and 17% protection, respectively, against picrotoxin-induced seizures. Furthermore, Galium spurium extract showed a significant protective effect against maximal electroshock-induced seizures at doses of 250 and 1000mg/kg (50% and 37.5%, respectively) and also all tested doses prolonged the onset of seizures. No motor co-ordination was observed with intraperitoneal injection of Galium spurium extract at doses of 500 and 1000mg/kg. The extract exhibited 16.2% inhibition against butrylcholinesterase at 200μg/mL concentration, whereas it did not inhibit acetylcholinesterase. Phytochemical analysis of the extract based on the MS data by UPLC-TOF-MS, ten major compounds (phenolic and triterpenic acids, flavonoids and iridoids) were determined. CONCLUSIONS The results indicate that Galium spurium may have anticonvulsant activity against picrotoxin and maximal electroshock-induced seizures in mice. Phenolic acids, flavonoids and iridoids might be responsible for anticonvulsant activity. The results offer possible beneficial effects by the plants aerial parts and may suggest a realistic explanation for its traditonal usage in epilepsy.

Phytochemical Characterization of Phagnalon graecum Boiss. by HPLC and GC-MS with its Enzyme Inhibitory and Antioxidant Activity Profiling by Spectrophotometric Methods

In the current study, the n-hexane, chloroform, ethyl acetate, methanol, and water extracts of Phagnalon graecum Boiss. (Asteraceae), a spice plant, were investigated for their enzyme inhibitory activity against acetylcholinesterase, butyrylcholinesterase, lipoxygenase, tyrosinase, and antioxidant activities. Antioxidant activity of the extracts was determined by 2,2-diphenyl-1-picrylhydrazyl radical scavenging, ferric ion-chelation activity, and ferric-reducing antioxidant power tests. Total phenol (gallic acid equivalent) and flavonoid (quercetin equivalent) contents were calculated. Essential oil of the plant was analyzed by GC-MS, while the selected phenolic acids were analyzed by HPLC. The extracts had insignificant inhibition against the tested enzymes, whereas they displayed a remarkable antioxidant activity. Therefore, to the best of our knowledge, this study presents the first data on biological activity and phytochemical content of P. graecum and this species could be utilized as potential antioxidant applicable for food preservation.

Comparative antioxidant activity appraisal of traditional Sudanese kisra prepared from two sorghum cultivars

The effect of fermentation and heating on the antioxidant activity of the fermented and fermented baked (kisra) dough prepared from two Sorghum cultivars (Tabat and Wad Ahmed) was evaluated. Kisra prepared from Tabat cultivar showed higher DPPH (1,1-diphenyl-2-picrylhydrazyl radical) scavenging and ferric reducing/antioxidant power (FRAP) than that of the Wad Ahmed cultivar. Baking improves the DPPH and FRAP of the kisra prepared from two cultivars. Baking caused a variable effect on the total phenol, tannins and flavonoids content across different periods of fermentation where an increase was mainly observed for samples subjected to longer periods of fermentation. A positive high correlation between the total phenol and antioxidant activity, using the DPPH and FRAP assays, was obtained for kisra prepared from both cultivars. The same observation was obtained for tannin content. In conclusion, fermentation and heating improve the antioxidant capacity of the sorghum grains from Tabat and Wad Ahmed cultivars.

Anti-hepatitis B activity of isoquinoline alkaloids of plant origin

Hepatitis B virus (HBV) is the causative agent of B-type hepatitis in humans, a vaccine-preventable disease. Despite the availability of effective vaccines, globally, 2 billion people show evidence of past or current HBV infection, of which 350 million people are persistently infected, with an estimated annual increase of 1 million. There is no cure for chronic HBV infections, which are associated with cirrhotic liver failure and with an increased risk of developing hepatocellular carcinoma. Hepatitis antiviral research has focused primarily on the development of inhibitors of viral polymerase through the use of nucleoside analogues. Therefore, there is an urgent need for the development of non-nucleoside compounds to be used as an alternative or to complement the current therapy. To address this need, 18 isoquinoline alkaloids were evaluated for their potential antiviral activity against HBV in vitro.

Outstanding effect of the conformational restriction of isoquinolines: hints for the development of optimized antimicrobial agents

Conformational restriction constitutes a useful strategy of molecular modification for the design of new potential drug candidates. Herein we present the planning, antimicrobial evaluation, and establishment of structure–activity relationship (SAR) data for some isoxazole (3a–k, 8a–c, and 9a–c) and pyrazole (5a–h) derivatives. These derivatives were structurally designed by conformational restriction followed by bioisosteric exchange of previously described antimicrobial isoquinolines (1a–c). Some of these more conformationally restricted derivatives present improved properties as new antibacterial drug candidates.