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Objective & Background: Emergence and spreading of antimicrobial resistance is one of the serious challenges of modern medicine. Many microorganisms acquired various resistance mechanisms, including mutations of the antimicrobial targets, adoption of resistance genes coding for enzymes degrading or modifying the antimicrobial molecules, protecting or modifying the antimicrobial targets, or coding for efflux systems that pumps the antimicrobials out of the cells. The spectrum and quantity of medically important microbial strains resistant to antimicrobials are steadily increasing. Nowadays, the antimicrobial resistance poses a real threat of the postantibiotic era, and increases mortality and morbidity of infected patients, as well as the cost of health care expenses. Conclusion: The effort of current pharmaceutical research is to search for new classes of active compounds with better antimicrobial activity and different target sites than antimicrobial drugs in current use. Alkaloids, essential oils and phenolic compounds such as tannins, phenolic acids and flavonoids are important groups of plants secondary metabolites that are not essential for plant survival but are significant for their defense, especially against microbial pathogens. Several studies investigated and approved their antimicrobial effects also in human medicine. These compounds are promising alternative natural antibacterial, antiviral and antifungal agents.

The investigation of a dichloromethane extract of flower heads of Achillea clypeolata collected in Bulgaria led to the isolation of one guaiane (4,10,11-trihydroxy-guaiane, 1), four eudesmanes (4(15)-eudesmene-1β ,11-diol, 2, clypeotriol, 3, 3-epi-clypeotriol, 4, cryptomeridiol, 5), one diterpene (sugeroside, 6) and two phenolic compounds (centaureidin, 7 and scopoletin, 8). Their structures were elucidated by UV/vis, EI- and CI-MS as well as by one- and two-dimensional NMR experiments. 4,10,11-Trihydroxy-guaiane (1) and 3-epi-clypeotriol (4) are reported here for the first time.

The investigation of a dichloromethane extract of flower heads of a Hungarian taxon of the Achillea millefolium group led to the isolation of three flavonoid aglycones, one triterpene, one germacranolide and five guaianolides. Their structures were elucidated by UV-VIS, EI- and CI-MS, 1H NMR and 13C NMR spectroscopic methods as well as by 2D-NMR studies and by selective 1D-NOE experiments. Besides apigenin, luteolin and centaureidin, ß-sitosterol, 3ß-hydroxy-11a,13-dihydro-costunolide, desacetylmatricarin, leucodin, achillin, 8a-angeloxy-leucodin and 8a-angeloxy-achillin were isolated. Both latter substances are reported here for the first time. Their NMR data were compared with those of the other guaianolides. The stereochemistry of 3ß-hydroxy-11a,13-dihydro-costunolide was discussed and compared with data of the literature.

AbstractThe chemical composition of the hydrodistilled essential oils obtained from the fresh (sample A) and air-dried flowers of Cynara cardunculusL. (sample B) was determined by GC/MS. In sample A, 25 compounds were identified of which hexadecanoic acid (27.6%), methyl hexadecanoate (9.3%) and methyl 9,12-octadecadienoate (12.6%) were the major components. In sample B, 21 compounds were identified, with hexadecanoic acid (51.8%), tetradecanoic acid (8.8%) and dodecanoic acid (8.7%) predominating.

Acidic extraction of the stem bark and roots of Chione venosa(SW.) URBAN var. venosa, purchased in Grenada under the vernacular name Bois Bandé, led to the isolation of two new substances of the oxynorneolignan-type. Moreover, TLC- and HPLC-systems were developed in order to determine these substances in crude extracts. Analytical data are indicated for the new compounds, as well as for those substances which were published recently. In the different Caribbean islands different plant sources are used to furnish the aphrodisiac Bois Bandé. On the basis of the presented analytical systems, 14 different samples of Bois Bandé (stem bark and/or root) that were either purchased from local traders or collected at different sites in the Grenadian forest were examined. In addition, an entire macroscopic and microscopic description of the drug is given which, in combination with the phytochemical data, provides a powerful tool to assess the quality of the drug material with regard to its botanical homogeneity.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.