Records of Natural Products Articles

Fractionation of EtOAc and aqueous MeOH extracts of Ajuga remota underground part has led to the isolation of four new iridoid glycosides identified as 2', 3'-diacetyharpagide (1), 6'-O-rhamnosylharpagide (2), 6'-O-galloyl-7,8-dehydroharpagide (3) and 6-O-xylosylharpagoside-B (4). Together with these were known compounds 8-O-acetylharpagide(5), harpagide (6), cyasterone (7), 20-hydroecdysone (8), sengosterone (9), 3-O-β-glucopyranosylstigmasta-5, 25-diene (10), stigmasterol (11) and ergosterol-5, 8-endoperoxide (12). Their structures were determined using spectroscopic methods as well as comparison with data from known compounds. In the in vitro larvicidal tests using 2 nd instar Aedes aegypti larvae, the EtOAc extract was found to be toxic with LC 50 of 5.30 ± 1.3 µg/mL, while the MeOH extract exhibited weak toxicity with an LC 50 value of 65.94 ± 0.4 µg/mL. Among the pure isolates tested, compound 12 associated with EtOAc extract was the active principal with LC 50 value of 4.40 ± 0.2.

Medlar is the fruit of Mespilus germanica L. in the family of Rosaceae. The present study outlines that the native medlar (Mespilus germanica L.) fruits an extremely rich source of antioxidants. In this study, antioxidant and antiradical property of medlar fruits were evaluated. Total phenolics and flavonoids amounts in lyophilized extract of medlar (LEM) fruits were calculated as gallic acid and quercetin equivalents, respectively. Antioxidant and radical scavenging activity of LEM were investigated using different in vitro assays including 1,1-diphenyl-2-picryl-hydrazyl (DPPH∙), N,N-dimethyl-p-phenylenediamine (DMPD •+), and superoxide anion radicals (O 2 •-) scavenging activity, hydrogen peroxide (H 2O 2), ferric ions (Fe 3+) and cupric ions (Cu 2+) reducing ability, Fe 3+-TPTZ reducing ability, ferrous ions (Fe 2+) chelating activity as trolox equivalent. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α-tocopherol, pyrogallol, p-hydroxybenzoic acid, vanillin, p-coumaric acid, gallic acid and ascorbic acid in LEM were detected by high performance liquid chromatography and tandem mass spectrometry (LC-MS/MS). The presence of these antioxidant compounds can be considered as a quality parameter for edible medlar fruits.

Eight e ssential oil s of Chinese medicinal herbs ( Angelica sinensis , Curuma aeruginosa , Cyperus rotundus , Eucalyptus robusta , Illicium verum, Lindera aggregate , Ocimum basilicum , and Zanthoxylum bungeanum ) w ere obtained by hydrodistillation and the essential oil of Eucalyptus robustaleaves was analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 22 components of the essential oil of E. robusta were identified. The principal compounds in E . robusta essential oil were α- p inene (28.74%) and 1,8- c ineole (27.18%), spathulenol (6.63%), globulol (6.53%) and ρ - m enth-1-en-8-ol (5.20%). The 8 essential oil s and two main components, α -pinene and 1, 8-cineole of the essential oil of E. robusta were evaluated repellency against nymphs of the German cockroaches . Strong repellency (Class V) was obtained for Cyperus rotundus and Eucalyptus robusta essential oils and α- p inene and 1, 8- c ineole . However, Illicium verum essential oil possessed weak (Class I) repellency. At a concentration of 5 ppm, all the 8 essential oils and the two compounds showed repellent activity after one hour exposure. At 1 ppm concentration, essential oil of Cyperus rotundus showed strong repellency and Class IV repellency was obtained for essential oil of E. robusta and the two compounds after one hour exposure. However, essential oils of I . verum and Lindera aggregata showed strong attractiveness to the German cockroaches at a concentration of 1 ppm .

The composition of the essential oils obtained from the flowering aerial parts of two populations of Thymus pubescens, collected from Mishov-Dagh, was determined by the GC-MS analyses. A total of 18 compounds, representing about 95% of the total oils, were identified in both samples of the essential oils. The essential oils of these two populations showed the presence of high amounts of citronellol (42.0% and 42.6%), geranyl acetate (14.0 and 14.0%), geraniol (13.0 and 13.1%), citronellyl acetate (3.9 and 3.8%), L-linalool (7.8% and 7.9%), cis-nerodiol (5.9% and 5.5%) and citronellyl acetate (3.9% and 3.8%). However, in the published literature, carvacrol, thymol and p-cymene were reported to be the major compounds in T. pubescens. This significant difference in the composition of the essential oils was a clear evidence of chemical polymorphism with in the T. pubescens taxon, suggesting that these two populations of T. pubescens were in deed a new chemotype of this species, and the name Thymus pubescens Boiss. & Kotschy ex Celak chemotype Citronellol for this new chemotype has been proposed . The antibacterial and free-radical-scavenging properties of the essential oils of T. pubescens have also been evaluated.

In the current study, we examined anti-acetylcholinesterase (AChE) and antioxidant activities of the ethyl acetate, methanol, and water extracts from the bulbs of Turkish Sternbergia Waldst. & Kit. (Amaryllidaceae) species; S. candida, S. clusiana, S. fisheriana, S. lutea subsp. lutea, and S. lutea subsp. sicula. Anti-AChE activity was tested by spectrophotometric method of Ellman using ELISA microplate reader at 50, 100, and 200 μg mL -1 concentrations. Antioxidant activity of the extracts was evaluated by DPPH radical scavenging activity, ferrous ion-chelating capacity, ferric-reducing antioxidant power, and beta-carotene bleaching assays at 500, 1000, and 2000 μg mL -1. Total phenol and flavonoid contents of the extracts were determined via Folin-Ciocalteau’s and AlCl3 reagents, respectively. The ethyl acetate extract of S. fischeriana was the most active in anti-AChE assay (90.94% and 98.02% of inhibitions at 100 and 200 μg mL -1 concentrations, respectively. Antioxidant activity of the extracts was found to be not significant.

The volatile composition of different parts (whole fruit, peel and flesh) of a rare wild red apple named “Mela Rossa Val Metauro” was established by SPME (Solid Phase Micro-Extraction) sampling, followed by GC-MS analysis. The most prominent constituent in all the three parts was the sesquiterpene (E,E)-α-farnesene. The presence of the ester ethyl hexanoate particularly in the flesh (39.8%) gives a special exotic flavor to the fruit.

This study was designed to examine the in vitro antimicrobial and antioxidant activities of the essential oil of T. boveii and T. hyemalis. According to the results of GC-EIMS analysis, essential oils were found rich in phenols and hydrocarbons. p-cymene, thymol and carvacrol were mainly found as the major compounds for the essential oils. Both plant species showed remarkable antioxidant activity in all test systems except chelating effect. In the case of antimicrobial activity, the oils showed remarkable growth inhibition against the tested microorganism except K. pneumoniae, P. aeruginosa, L. monocytogenes, P. fluorescens.

The essential oil, obtained by steam distillation of flowers, leaves and stems from Wisteria brachybotrys Sieb.et Zucc, collected in Japan was analyzed by gas chromatography (GC) and GC-MS. The important aroma-active compounds were also detected in the oil using GC-MS/Olfactometry (GC-MS/O) and aroma extraction dilution analysis (AEDA). As a result, sixty-eight compounds from flowers of W. brachybotrys, accounting for 96.3%, were identified, and benzyl cyanide (31.7%), palmitic acid (8.7%), and (Z)- g -bisabolene (8.4%) as the main compounds. Thirty compounds from leaves, accounting for 97.3%, were identified, and phytol (46.0%), palmitic acid (8.2%), and nonanal (5.7%) as the main compounds. Twenty-eight compounds from stems, accounting for 98.7%, were identified, and geraniol (32.8%), linalool (22.1%), and nerol (10.4%) as the main compounds. A preliminary analysis by GC-MS and using Kovats’ retention indexes, lead to characterize and quantify the oil constituents, while GC-MS/O was then applied for the identification of the main odorants. By the incremental dilution method (AEDA), applied to the GC-MS/O technique, the flavor dilution (FD) factor was obtained. To our knowledge, the composition of these parts of essential oils is described here for the first time, both from the chemical and olfactometric viewpoints.

 The in vitro anti-listerial potential of essential oil and various organic extracts of Piper chaba Hunter (Piperaceae) were evaluated. The chemical composition of the essential oil was analyzed by the GC-MS. Fifty four compounds representing 95.4% of the total oil w ere identified, of which α-humulene (16.4%), caryophyllene oxide (12.2%), veridiflorol (8.1%), globulol (7.4%), β-selinene (7.1%), spathulenol (6.2%), trans-nerolidol (5.1%), linalool (4.5%), 3-pentanol (3.5%), tricyclene (2.2%) and p-cymene (1.6%) were the major compounds. The oil and organic extracts revealed a great potential anti-listerial effect against all five strains of Listeriamonocytogenes ATCC 19111, 19116, 19118, 19166 and 15313. Also the essential oil had a strong inhibitory effect on the viable cell count of the tested Listeria spp. Our findings demonstrate that the essential oil and extracts derived from the leaf of P. chaba might be a potential source of natural preservatives used in food industries.

Two sterols, stigmasterol (1) and β-sitosterol (2), two lignans, (+)-sesamin (3), new for the genus Stachys and (±)-paulownia (4), new in the Lamiaceae family, reported for the second time from a natural source, and one acetylated flavone glycoside isoscutellarein-7-O-(2''-O-6'''-O-acetyl-β-D-allopyranosyl-β-D-glucopyranoside (5), were isolated from the roots of Stachys mialhesi de Noé. Surprisingly, 3g of compound 5 are gathered from 5g of roots extract. The structures of compounds 1-5 were established on the basis of physical and spectroscopic analysis, and by comparison with the literature data. The free-radical-scavenging property of compound 5 was evaluated by the use of the ESR method in order to visualize the inhibition of the 1,1-diphenyl-2-1picrylhydrazyl (DPPH) free radical.

 β -caryophyllene oxide was isolated from the leaf of the Jeju guava (Psidium cattleianum Sabine) for the first time in this study. The chemical structure was confirmed with the help of various spectroscopic analyses, including NMR data, by comparison to that of the published data. An MTT assay was conducted against several cancer cell lines t o resolve an ongoing controversy regarding the cytotoxic effects of β-caryophyllene oxide. β-caryophyllene oxide evidenced potent cytotoxic activity against HepG2, AGS, HeLa, SNU-1, and SNU-16 cells, with IC 50 values of 3.95, 12.6, 13.55, 16.79, and 27.39 μM, respectively. The results also showed that β-caryophyllene oxide evidenced cytotoxicity in both a dose-dependent and time-dependent manner.