Struktur der Sesquiterpene vonPetasites hybridus(L.)G. M.etSCH.: Petasol- und Isopetasol-Abkömmlinge

Cumulative Data of 1H and 13C NMR Signals and Specific Rotations of Eremophilane Sesquiterpenoids. 2. Bicyclic Eremophilanes (2)

1H and 13C NMR signals and specific rotations of eremophilane sesquiterpenoids are cumulated as a series of review articles. In the second chapter of this review, 124 bicyclic eremophilanes without furan or lactone rings (except for epoxides) and with 3-OR functionality (some have OH) are listed in 25 tables. Those bearing long chain acyloxy groups without 3-oxygen functions and some bi- or tri-cyclic compounds are also included in this chapter. These data may help chemists working in the area of natural products chemistry as well as synthetic scientists.

Lipophilic 9,10-Dehydrofukinone Action on Pathogenic and Non-Pathogenic Bacterial Biofilms. Why Is This Main Volatile Metabolite in Senecio?

The effect of a natural sesquiterpene ketone, 9,10-dehydrofukinone (DHF), on pathogenic Staphylococcus aureus and Pseudomonas aeruginosa strains isolated from chronic infectious processes, was the focus of the present study. Lipophilic DHF produced important antibacterial synergistic effects in association with ciprofloxacin (CPX) against two biofilm-forming strains of S. aureus HT1 (FIC=0.21) and P. aeruginosa HT5 (FIC=0.05). Hence, this mixture constitutes an excellent strategy to combat these biofilm-producing bacteria that overexpress drug efflux pumps as a resistance mechanism. Additionally, a substantial rise in beneficial Lactobacillus biofilm biomass was determined as a very significant finding of this association. Particularly, a non-pathogenic biofilm increment of 119 % was quantified when the mixture was added to a probiotic L. acidophilus ATCC SD-5212 culture. A surface activity enhanced in 71 % with respect to untreated L. acidophilus culture was also generated by the DHF and CPX association, and therefore, a glycoprotein synthesis induction mediated by the mixture is discussed. The results obtained could help in the development of new selective antibiotics. From an ecological standpoint, the present study strongly suggests that DHF is a polyfunctional organic molecule produced with a high yield in Senecio punae that exerts a positive impact on a non-pathogenic plant bacterium L. plantarum CE105.

Eremophilane-type sesquiterpenes from fungi and their medicinal potential

Eremophilanes are sesquiterpenes with a rearranged carbon skeleton formed both by plants and fungi, however, almost no plant eremophilanes are found in fungi. These eremophilanes possess mainly phytotoxic, antimicrobial, anticancer and immunomodulatory properties and in this review fungal eremophilanes with bioactivities of potential medicinal applications are reviewed and discussed. A special focus is set on natural products bearing highly functionalized fatty acids at C-1 or C-3 position of the eremophilane backbone. Many of these fatty acids seem to contribute to the bioactivity of the metabolites enhancing the activity of the sesquiterpene moieties. Several approaches for optimization of these natural products for clinical needs and testing of the resulting derivatives are presented and discussed. The combination of identification of bioactive natural products with their subsequent improvement using a variety of genetical or chemical tools and the pharmacokinetic assessment of the products is presented here as a promising approach to new drugs.

Eremophilane-type sesquiterpenes from cultured lichen mycobionts of Sarcographa tricosa

Spore-derived mycobionts of the crustose lichen Sarcographa tricosa were cultivated on a malt-yeast extract medium supplemented with 10% sucrose. Chemical investigation of the cultivated colonies led to isolation of three eremophilane-type sesquiterpenes, 3-epi-petasol (1), dihydropetasol (2) and sarcographol (3), together with six known eremophilanes and ergosterol peroxide. These structures were elucidated by spectroscopic and chemical methods. This is the first report of eremophilane-type sesquiterpenes from the cultured mycobionts of lichen.

The medical plant butterbur (Petasites): analytical and physiological (re)view

Butterbur (Petasites) is an ancient plant which has been used for medical and edible purposes with its spasmolytic agents. However, toxic alkaloid content of the plant limits its direct usage. The paper covers the pyrrolizidine alkaloids (PAs) and butterbur themes in detail in order to display the outline of alkaloid-free plant extract production for medical and edible purposes. The toxic PAs and medicinal constituents of the plant are described with emphasis on analytics, physiological effects and published patent data on alkaloid free extract production. The analytics is based on several commonly used analytical methods including liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry and enzyme linked immunoassay analysis of PAs and N-oxides based on published literature data of butterbur. The analyses of major medicinal constituents of butterbur are given and the physiological effects of these compounds have been discussed to attract attention to the importance of alkaloid-free extract production. The concentration distributions of the medicinal constituents and toxic PAs in different parts of the plant and the outcomes of the published patent data provide comprehensive information for proper plant raw-material selection and production of alkaloid-free butterbur extracts. The review is intended to guide researchers interested in medical plant extracts by providing comprehensive data on the medical plant butterbur and its chemical constituents.

Anti-allergic effects of total bakkenolides from Petasites tricholobus in ovalbumin-sensitized rats

The anti-allergic effect of total bakkenolides from the rhizome of Petasites tricholobus (BAPT) was evaluated in an ovalbumin-induced allergic rhinitis model in male Wistar rats. The major components of the bakkenolide fraction are bakkenolide-D, bakkenolide-B, bakkenolide-IIIa and bakkenolide-IVa, which account for 60.04% of the total. The rats were treated with 40 mg/kg, 20 mg/kg, 10 mg/kg or 5 mg/kg BAPT, and 0.942 mg/kg loratadine and 0.5% gum tragacanth were used as positive and negative controls, respectively. The frequency of nose rubbing and sneezing was observed, the number of eosinophils infiltrating into the nasal tissue was counted, and serum levels of IL-4 and histamine were determined by ELISA. The results showed that BAPT had a beneficial effect on allergic rhinitis in ovalbumin-sensitized Wistar rats, which was evidenced by a significant decrease in the frequency of sneezing, the number of eosinophils infiltrating into the nasal tissue, and the serum levels of IL-4 and histamine. BAPT may therefore be a potential antiallergic drug.

Sesquiterpene constituents in Petasites hybridus

The essential oil of the rhizomes of Petasites hybridus (Asteraceae) was investigated by gas chromatography, mass spectrometry, 1- and 2-dimensional NMR techniques and chemical correlations. Two new sesquiterpene hydrocarbons, petasitene and pethybrene, could be identified. Petasitene is the parent sesquiterpene hydrocarbon to the known norsesquiterpene albene. The absolute configuration of petasitene could be assigned by conversion of natural albene to petasitene by partial synthesis. Pethybrene is a tricyclic sesquiterpene hydrocarbon, which rearranges to the structurally related alpha-isocomene under acidic conditions. Several sesquiterpenes were isolated from the hydrodistillation products of Petasites hybridus and investigated by spectroscopic methods and chemical correlations

Petasites hybridus: a tool for interdisciplinary research in phytotherapy

The 3rd Petasites gathering took place in Romanshorn, Switzerland on March 29, 1996 and gave 16 European scientists the opportunity to transmit their latest considerable discoveries to interested researchers working in different scientific disciplines such as pharmacognosy, botany, chemistry, pharmacology, medicine or clinical pharmacy. The newest findings on Petasites hybridus as a significant plant drug showed very promising aspects of therapeutic utility. Great progress has been made in chemical analytical methods and the determination of pharmacological activities. Substantial advances have also occurred in the production of bioassay procedures and plant materials, particularly utilizing cell- and tissue-culture techniques.

Effects of pyrrolizidine alkaloids and sesquiterpenes on snail feeding

We determined in the laboratory the feeding response of two populations of the generalist herbivorous snail Arianta arbustorum (Helicidae) towards the composite Adenostyles alliariae and towards various allelochemicals. These were: a pyrrolizidine alkaloid (PA) extract of Adenostyles leaves; senecionine (a PA present in Adenostyles); retrorsine (a PA not present in Adenostyles) and two sesquiterpene (ST) fractions from Adenostyles: a mixture of the STs adenostylone and neoadenostylone, and deacyladenostylone. Tertiary PAs and PA N-oxides were tested separately. For each allelochemical, we tested whether it was deterrent or whether it induced changes of feeding behaviour (i.e. whether it had pre- or postingestive effects), and whether the effects were more pronounced with younger (smaller) snails. The tertiary PA extract from Adenostyles was deterrent, especially for young snails, but did not induce changes of feeding behaviour. Tertiary PA senecionine was deterrent for young snails only and induced changes of feeding behaviour. Also, consumption of untreated Petasites was higher after this treatment. Tertiary PA retrorsine was not deterrent, but induced changes of feeding behaviour. The PA N-oxides showed no activity against the snails. The mixture of adenostylone and neoadenostylone was deterrent and induced feeding aversions. Deacyladenostylone was highly deterrent, but did not induce changes of feeding behaviour. At the Jura site, PA content of Adenostyles was lower than at the Black Forest site. The snails from Jura consumed much less Adenostyles than the snails from Black Forest, and also ate a little less of the treated leaf discs. The PAs which are encountered by the snails in their natural food plants (PA extract and senecionine) were more deterrent than retrorsine (a novel compound). This suggests that the snails have mechanisms for the rejection of allelochemicals which they encounter in their natural food plants, but not for novel allelochemicals. The results suggest two hypotheses regarding the function of the allelochemicals in Adenostyles: (1) The allelochemicals act mainly on very young snails. (2) PAs render Adenostyles toxic, while STs act as feeding deterrents.