Sesquiterpene lactones development

Pollen allelopathy is phenomenon when pollen chemicals (e.g., phenols, terpenoids, sesquiterpene lactones, etc.) inhibit sexual reproduction in heterospecific individuals due to influencing of fertilization (Murphy 1992). The phenomenon includes excretion of signaling compounds from the donor cell (pollens, pistil stigma), recognition of a specific signal, transmission of information (pollen), and the development of a characteristic response in the acceptor cell. The possible mechanism of the effect was described in Roshchina (2001). 

A methodological approach for an effective and reliable quality control of Chinese star anise [I. verum Hook. F.) was developed and validated by Lederer et al. (2006). A combined method of TLC and HPLC-MS/MS was used for differentiation ofvarious Ulicium species, especially Chinese and Japanese star anise. Species can be distinguished by their TLC flavonoid pattern. A sensitive and selective HPLC/ESI-MS/MS method was developed for the detection and quantification of lower admixtures of I. anisatum and of further toxic Ulicium species at a low concentration range using the sesquiterpene, lactone anisatin, as a marker. This assay includes a solid-phase extraction clean-up procedure with a high recovery (> 90%). 

Encelin from Montanoa speciosa is inhibitory to growth and development of fungal cells of Mucor rouxii. Other cytotoxic sesquiterpene lactones from Montanoa tomentosa ssp. microcephala have been reported.45,46 A number of kaurane diterpenes and e/tf-kauranoids have been reported that are potentially useful because of their cytotoxicity against human tumor cells, anti-HIV activity, and trypanosomicidal activity.47 56 New structures are frequently discovered, and probably we will learn new effects in humans and animals in the future.57,58 Paradoxically, these plant natural products probably have specific and important effects in the plants, but we are still ignorant of these roles. 

Asteriscanolide (65) is a cyclooctane sesquiterpene lactone that has been synthesised by a number of groups who have employed a variety of different strategies. In 2001, Krafft and co-workers developed a strategy that utilised the intermolecular PK reaction as a key step in its synthesis (63- 64 - Scheme 23).71... 

Therefore, it may be possible to increase the resistance of cultivated sunflower to Hj. electellum by breeding for increased concentrations of sesquiterpene lactone-containing glandular trichomes on the anther tips. The development of new cultivated lines with high densities of glandular trichomes may prove to be an... 

Artemisinin is an antimalarial constituent isolated from Qinghao. It is a sesquiterpene lactone with an endoper-oxide bridge, structurally distinct from other classes of antimalarial agents. Several derivatives of the original compound have proved effective in the treatment of Plasmodium falciparum malaria and are currently available in a variety of formulations artesunate (intravenous, rectal, oral), artelinate (oral), artemisinin (intravenous, rectal, oral), dihydroartemisinin (oral), artemether (intravenous, oral, rectal), and artemotil (intravenous). Artemisinic acid (qinghao acid), the precursor of artemisin, is present in the plant in a concentration up to 10 times that of artemisinin. Several semisjmthetic derivatives have been developed from dihydroartemisinin (1). 

A positive patch test reaction to U. dioica has been obtained in a patient who had developed edematous gingivostomatitis following the regular use of stinging nettle tea as a tonic the patient also had positive reactions to chamomile (Anthemis nobilis) and its allergens (sesquiterpene lactones) (2). 

Matricaria chamomilla L. -camomila Nervous disturbances Flower (infusion) Afro-Brazilians (Northeast Brazil) [45,46] Flavonoids [104,105] essential oil [106] acylglycerols, linoleic and linolenic acids [107] coumarins [108,109] sesquiterpene lactone [110] inhibits both development of morphine dependence and expression of abstinence syndrome [255,256] anxiolytic effect [257] sedative as well as spasmolytic effects [258]... 

An example of the power of this method in structure elucidation is shown for the sesquiterpene lactone acetylisomontanolide (Fig. 5.74). The complete carbon skeleton of the molecule can be traced directly in the spectrum, with breakdown occurring only when heteroatom linkages arise. Unfortunately, it is rare indeed to have sufficient sample quantities at hand to consider employing this technique, and still it remains a little used method in its original form. However, greater potential exits for directly tracing carbon-carbon connectivities with recently developed methods based on proton excitation and observation combined with gradient selection see Section 5.8.4 below. 

B Arnicae flos (A, montana, A. chamissonis 5a-8a). The CHCt, extracts of Arnicae flos ( method see Sect. 7.1.1), developed in system PE, contain sesquiterpene lactones, detectable as violet-grey zones witlt ZM reagent (vis). 

Over the years, numerous plants have been used in folk medicine against gastroduodenal disorders. The development of phytochemical techniques has allowed the identification and isolation of numerous principles from some of them, such as alkaloids [70], sesquiterpen lactones [71, 72], or polyphenolic compounds [66-69]. 

Artemisinin (44) is a structurally complex cadinane sesquiterpene lactone bearing an endoperoxide group embedded in a 1,2,4-trioxane ring. With its unique juxtaposition of peracetal, acetal and lactone functionalities, it has very much to interest organic chemists. Totally synthetic routes to artemisinin have been developed [64], but their complexity suggests that they will very unlikely supplant the natural extract as drug source. 

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