首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12篇
  免费   0篇
化学   12篇
  2022年   1篇
  2021年   5篇
  2013年   1篇
  2012年   1篇
  2011年   1篇
  2005年   2篇
  2001年   1篇
排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
Many of the essential oils obtained from medicinal plants possess proven antimicrobial activity and are suitable for medicinal purposes and applications in the food industry. The aim of the present work was the chemical analysis of 19 essential oils (EOs) from seven different Cymbopogon species (C. nardus, C. citratus, C winterianus, C. flexuosus, C. schoenanthus, C. martinii, C. giganteus). Five different chemotypes were established by GC/MS and TLC assay. The EOs, as well as some reference compounds, i.e., citronellol, geraniol and citral (neral + geranial), were also tested for their antimicrobial and antibiofilm activity against methicillin-resistant Staphylococcus aureus (MRSA) by the microdilution method and direct bioautography. The toxicity of EOs was evaluated by Danio rerio ‘Zebrafish’ model assay. All examined EOs showed moderate to high activity against MRSA, with the highest activity noted for C. flexuosus—lemongrass essential oil, both in microdilution and direct autobiography method. Significant difference in the toxicity of the examined EOs was also detected.  相似文献   
2.
JPC – Journal of Planar Chromatography – Modern TLC - The object of this study was determination of the content and composition of the essential oil of the fruits of three varieties of...  相似文献   
3.
High‐performance counter‐current chromatography was successfully used for the isolation and purification of terpenoid compounds from the essential oil of Pimpinella anisum L. A two‐phase solvent system composed of n‐heptane/methanol/ethyl acetate/water (5:2:5:2, v/v/v/v) was suitable for the purification of linalool, terpinen‐4‐ol, α‐terpineol, p‐anisaldehyde, while n‐heptane/methanol (1:1, v/v) was used for the isolation of anethole and foeniculin. A scale‐up process from analytical to preparative was developed. Additionally, a stepwise gradient elution was applied and instead of two different runs, 40 min each, one 80 min separation was performed; although the time of separation remains the same, it was possible to repeat the efficiency even if the water‐containing mobile phase was changed to a nonaqueous system. The obtained essential oil, as well as purified compounds, was analyzed by GC. A total of 0.64 mg of linalool, 0.52 mg of terpinen‐4‐ol, 0.10 mg of α‐terpineol, 0.62 mg of p‐anisaldehyde, 15 mg of anethole, and 2.12 mg of foeniculin were obtained from 210 mg of the essential oil of P. anisum L. in a short time with purities of 99, 98, 94, 93.54, 93, and 93.6%, respectively.  相似文献   
4.
The liverwort, Porella vernicosa complex produces a very hot tasting polygodial, a drimane-type sesquiterpene dialdehyde. The same compound has been isolated from two ferns, Thelypteris hispidula and Blechnum fluviatile, as well as from the higher plants Polygonum hydropiper, P. hydropiper f. purpurascens (Polygonaceae), Cinnamosma, Caspicodendron, Canella and Warburgia species (Canellaceae), and Pseudowintera colorata, Tasmannia lanceolata, Drimys and Zygogynum species (Winteraceae). In addition, the liverworts and higher plants which elaborate polygodial and its related pungent drimane dials contain a small amount of alpha-tocopherol, gamma-tocopherol or delta-tocotrienol. The present paper gives the results of a comparative study on the drimane-type sesquiterpenoids in some liverworts, ferns and higher plants, and the role of tocopherols in these plant groups.  相似文献   
5.
The taxonomy of the liverwort genus Porella based on plant morphology has been regarded as difficult. Recent DNA-based studies have brought new insights into the systematics of these liverworts and have uncovered some novel relationships that allowed the resolution of controversial treatments based on morphology. One of the outstanding features of these plants, in addition to their form, is their chemical composition, which is characterized by great diversity of secondary metabolites. In this paper the sesqui- and diterpenoids occurring in Porella species are described and their chemosystematic relevance is explored. On the basis of chemical data, the Porella species have been divided into six chemotypes: the drimane- (I), sacculatane- (II), pinguisane-sacculatane- (III), guaiane-germacrane- (IV), pinguisane- (V) and africane- (VI) types. Species belonging to type I are characterized by their hot taste, whereas the other chemotypes are comprised of non-pungent species. Consideration of recent DNA data shows striking correlations between molecular groups and their terpenoid chemistry. The chemical data suggest that the P. vernicosa complex (chemotype I) deserves recognition as a separate section of Porella and that terpenoids are important chemosystematic markers in the family Porellaceae.  相似文献   
6.
The chemical composition of the hydroethanolic extracts (60% v/v) from the aerial parts of Thymus marschallianus Willd (TM) and Thymus seravschanicus Klokov (TS) from Southern Kazakhstan flora was analyzed together with their hexane fractions. Determination of antibacterial, antifungal and antioxidant activities of both extracts was also performed. RP-HPLC/PDA and HPLC/ESI-QTOF-MS showed that there were some differences between the composition of both extracts. The most characteristic components of TM were rosmarinic acid, protocatechuic acid, luteolin 7-O-glucoside, and apigenin 7-O-glucuronide, while protocatechuic acid, luteolin 7-O-glucoside, luteolin 7-O-glucuronide, and eriodictyol predominated in TS. The content of polyplenols was higher in TS than in TM. The GC-MS analysis of the volatile fraction of both examined extracts revealed the presence of thymol and carvacrol. Additionally, sesquiterpenoids, fatty acids, and their ethyl esters were found in TM, and fatty acid methyl esters in TS. The antioxidant activity of both extracts was similar. The antibacterial activity of TS extract was somewhat higher than TM, while antifungal activity was the same. TS extract was the most active against Helicobacter pylori ATCC 43504 with MIC (minimal inhibitory concentration) = 0.625 mg/mL, exerting a bactericidal effect. The obtained data provide novel information about the phytochemistry of both thyme species and suggest new potential application of TS as a source of bioactive compounds, especially with anti-H. pylori activity.  相似文献   
7.
Ginseng saponins (ginsenosides) were extracted from the root and leaves of locally cultivated American ginseng (Panax quinquefolium L.). For the isolation of compounds from plant samples three different extraction methods were utilized: accelerated solvent extraction, the ultrasound-assisted solvent extraction and mechanical shaking assisted solvent extraction. The separation of compounds was achieved with a water–acetonitrile gradient system using a C18 reversed-phase column. Target compounds were identified in MS2 and MS3 experiments. The relative distribution of these ginsenosides in each root and leaf extract was established. The limit of detection of the method was less than 30 ng/ml. Recovery of ginseng saponins in spiked samples exceeded 80%, while the relative standard deviation ranged from 7.1 to 9.1%. The total concentrations of ginsenosides were 41 and 13 mg/g in root and leaves.  相似文献   
8.
Plants belonging to the Rosa genus are known for their high content of bioactive molecules and broad spectrum of healing and cosmetic activities. Rosa platyacantha Schrenk is a wild-type species abundant in the mountainous regions of Kazakhstan. The phytochemical composition as well as the bioactivity of R. platyacantha extracts have not been fully investigated to date. In this study, various parts of R. platyacantha plant, collected in Almaty region, Kazakhstan, were used to prepare five hydroalcoholic extracts (R1–R5). The extracts were compared for the content of phytochemicals and selected biological activities, which are important for the potential cosmetic application of R. platyacantha. Extract R3, prepared from flower buds, showed the most significant antioxidant and tyrosinase inhibitory potential, decreasing the monophenolase and diphenolase activities of tyrosinase. Extract R3 showed also collagenase inhibitory activity and cytotoxicity against human melanoma cells A375, being less cytotoxic for noncancerous skin keratinocytes HaCaT. Analysis of fractions E and F, obtained from R3 extracts, revealed that quercetin, kaempferol, rutin, and their derivatives are more likely responsible for the tyrosinase inhibitory properties of R. platyacantha extracts.  相似文献   
9.
10.
Liverwort endophytes could be a source of new biologically active substances, especially when these spore-forming plants are known to produce compounds that are not found in other living organisms. Despite the significant development of plant endophytes research, there are only a few studies describing liverwort endophytic microorganisms and their metabolites. In the presented study, the analysis of the volatile compounds obtained from thallose liverwort species, Marchantia polymorpha L., and its endophytes was carried out. For this purpose, non-polar extracts of plant material and symbiotic microorganisms were obtained. The extracts were analyzed using gas chromatography coupled to mass spectrometry. Compounds with the structure of diketopiperazine in the endophyte extract were identified. Liverwort volatile extract was a rich source of cuparane-, chamigrane-, acorane-, and thujopsane-type sesquiterpenoids. The cytotoxicity of ethyl acetate extracts from endophytic microorganisms was evaluated on a panel of cancer (FaDu, HeLa, and SCC-25) cell lines and normal (VERO), and revealed significant anticancer potential towards hypopharyngeal squamous cell carcinoma and cervical adenocarcinoma.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号