Gülin Renda

Antimicrobial Activity and Analyses of Six Geranium L. Species with Headspace SPME and Hydrodistillation

Abstract A solid phase microextraction (SPME) method with gas chromatography-mass spectrometry (GC-MS) was used for analyses of the volatile compounds of six Geranium species; G. asphodeloides, G. psilostemon, G. purpureum, G. pyrenaicum, G. robertianum and G. sanguineum. The results were compared with those obtained by hydrodistillation. According to the results of the study, the major compounds identified in the SPME extracts were sabinen (33.5%) (G. asphodeloides), caryophyllene (34.1%, 21.7%, 11.2%) (G. psilostemon, G. purpureum and G. robertianum), germacrene D (25.2%) (G. pyrenaicum), and alloaromadendrene (19.8%) (G. sanguineum) whereas hydrodistillation (HD) essential oils were rich in benzene acetaldehyde (30%, 25.7%) (G. asphodeloides, G. sanguineum), caryophyllene (34.3%, 11.3%) (G. psilostemon and G. robertianum), hexadecanoic acid (36.2%, 15.1%) (G. purpureum and G. pyrenaicum). The oils were screened for antimicrobial activity against 10 microorganisms and showed antibacterial and antifungal activities against Staphylococcus aureus, Bacillus cereus, Mycobacterium smegmatis, Candida albicans and Saccharomyces cerevisiae.

Comparison of phenolic profiles and antioxidant activity of three Ornithogalum L. species

Abstract Background Aboveground parts and bulbs of Ornithogalum species are consumed as food and used in traditional medicine in worldwide. Objective It is aimed to report the antioxidant capacity and phenolic compounds content of Ornithogalum sigmoideum, Ornithogalum orthophyllum and Ornithogalum oligophyllum for the first time. Materials and methods Antioxidant activity of the crude methanol extracts of the aerial parts and the bulbs of the species were determined with 1,1-diphenyl-2-picryl-hydrazyl, superoxide radical scavenging, ferrous ion-chelating effect, phosphomolybdenum-reducing antioxidant power and ferric-reducing antioxidant power assay. The ethylacetate, diethylether and water subextracts from leaf and flower were analyzed to quantify selected phenolic compounds by HPLC-UV. Results Among the six extracts, the methanol extract of the aerial parts of O. orthophyllum contained the highest amount of phenolic compounds (GAE, 11.0 mg/g extract). The aerial parts of O. orthophyllum showed higher DPPH and SOD activities than the other extracts with the SC50 values of 0.39±0.05 mg/mL and 0.44±0.08 mg/mL, respectively. Protocatechuic acid, p-hydroxybenzoic acid, vanillic acid and p-coumaric acid were the most abundant compounds at all the subextracts. Conclusion The antioxidant activity is found to be in accordance with the levels of phenolic content in the extracts.

Evaluation of in vivo analgesic activity of Scrophularia kotscyhana and isolation of bioactive compounds through activity-guided fractionation

Abstract The present study was undertaken to evaluate the in vivo analgesic activities of the extracts prepared from the aerial parts and roots of Scrophularia kotscyhana and to isolate the bioactive metabolites from the most active extract. Analgesic activities of all extracts and subextracts at the doses of 5, 10 and 30 mg/kg (i.p.) were examined using hot plate test in mice. Among the tested extracts, MeOH extract prepared from the aerial parts and the n-butanol subextract prepared thereof displayed the best analgesic activity at all doses. Phytochemical studies on n-butanol subextract led to the isolation of two new iridoid glycosides as an inseparable mixture, 8-O-acetyl-4′-O-(E)-(p-coumaroyl)-harpagide (1) and 8-O-acetyl-4′-O-(Z)-(p-coumaroyl)-harpagide (2) along with five known secondary metabolites, β-sitosterol 3-O-β-glucopyranoside (3), apigenin 7-O-β-glucopyranoside (4), apigenin 7-O-rutinoside (5), luteolin 7-O-β-glucopyranoside (6) and luteolin 7-O-rutinoside (7). The iridoid mixture (1 and 2), 3 and 4 elicited significant inhibition of pain at 5 mg/kg dose.

In vitro Protective and Enzyme Inhibitory Effects of Crataegus microphylla Extracts Against Oxidative Damage

Objectives: Crataegus species have been used as food and also in folk medicine for the treatment of various diseases. The present study aimed to make investigations on the biologic properties of different extracts prepared from Crataegus microphylla C. Koch, which was collected from Turkey. Materials and Methods: Dried leaf, stem bark, and fresh fruit samples of C. microphylla were separated and ethanol extract, acidified (0.5% HCl, pH: 2.5) ethanol extract, ethanol:water (1:1) extract, methanol extract, acidified (0.5% HCl, pH: 2.5) methanol extract, methanol:water (1:1) extract, water extract, and acidified (0.5% HCl, pH: 2.5) water extract were prepared for each. Various biologic effects such as the prevention of oxidative DNA damage, acetylcholinesterase, tyrosinase, α-glucosidase inhibition, and antioxidant effects with 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, PRAP, and FRAP assays of these extracts at different concentrations were studied. Results: Acidified methanol extract of stem barks exhibited the highest acetylcholinesterase and tyrosinase inhibitions among the other extracts with IC50 values of 204.02±0.95 μg/mL and 37.30±0.27 μg/mL, respectively. Acidified ethanol extract of leaves was the most efficient extract against α-glucosidase, giving an IC50 of 15.78±0.14 μg/mL. The IC50 value of the acidified ethanol extract for DPPH was 9.89±0.09 µg/mL. Methanol extracts of leaves and stem barks at the dose of 125 µg/mL exhibited significant protective activity against DNA strand scission by hydroxyl radicals (.OH) on supercoiled pBR322 DNA. Conclusion: Acidified methanol or ethanol extracts prepared with stem bark and leaf from C. microphylla have potential antioxidant, hypoglycemic, and neuroprotective effects.

Carbonic Anhydrase and Urease Inhibitory Potential of Various Plant Phenolics Using in vitro and in silico Methods

Plant phenolics are known to display many pharmacological activities. In the current study, eight phenolic compounds, e.g., luteolin 5‐O‐β‐glucoside (1), methyl rosmarinate (2), apigenin (3), vicenin 2 (4), lithospermic acid (5), soyasaponin II (6), rubiadin 3‐O‐β‐primeveroside (7), and 4‐(β‐d‐glucopyranosyloxy)benzyl 3,4‐dihydroxybenzoate (8), isolated from various plant species were tested at 0.2 mm against carbonic anhydrase‐II (CA‐II) and urease using microtiter assays. Urease inhibition rate for compounds 1 – 8 ranged between 5.0 – 41.7%, while only compounds 1, 2, and 4 showed a considerable inhibition over 50% against CA‐II with the IC50 values of 73.5 ± 1.05, 39.5 ± 1.14, and 104.5 ± 2.50 μm, respectively, where IC50 of the reference (acetazolamide) was 21.0 ± 0.12 μm. In silico experiments were also performed through two docking softwares (Autodock Vina and i‐GEMDOCK) in order to find out interactions between the compounds and CA‐II. Actually, compounds 6 (30.0%) and 7 (42.0%) possessed a better binding capability toward the active site of CA‐II. According to our results obtained in this study, among the phenolic compounds screened, particularly 1, 2, and 4 appear to be the promising inhibitors of CA‐II and may be further investigated as possible leads for diuretic, anti‐glaucoma, and antiepileptic agents.