Lactones, bioactive

C. Loustau Cazalet, Nouvelles voies de synthfese de lactones bioactives, These, University de Nancy (France) (1994). 

Zhang S, Won Y-K, Ong C-N, Shen H-M (2005) Anti-cancer potential of sesquiterpene lactones bioactivity and molecular mechanisms. Curr Med Chem Anticancer Agents 5 239-249... 

Bioactive polyphenol acids and lignans with 0-heterocyclic fragments and terpenoid 8-lactones as components of traditional Chinese drugs 98PAC547. 

Bioactive sesquiterpenic y-lactones and flavonoids in plants of Inula L. genus 97MI20. 

Pd-catalyzed intermolecular coupling reactions of allyl alkynoates with formation of bioactive y-lactones 98SL115. 

Both chiral lactones and ketones have been utilized in asymmetric synthesis of bioactive compounds like lipoic acid [175[ and natural products like various insect pheromones [176[. 

Microbial natural product chemistiy has generated a number of bioactive natural products. For instance cyclosporine A FK506 and rapamycin are used as immunosuppressants [16]. Other examples of microbial metabolites, having potential biomedical application include antihyperlipidemics, lovastatin and guggulsterone [17, 18]. The crude extracts of Mucor plumbeus exhibited acetylcholinesterase (AChE) enzyme inhibition activity. Our detailed chromatographic work on this crude extract resulted in the isolation of mucoralactone A (11), a novel steroid containing a lactone moeity incorporated in its structure. 

Andrographolide, a labdane-diterpenoid lactone, is the principal bioactive chemical constituent of Andrographis paniculata (Brum. F.) Nees (family Acanthaceae) this prime constituent is mainly concentrated in leaves and can easily be isolated from the crude plant extracts as crystalline... 

Osterhages work has led to further analysis of bioactive products from the marine fungus A. salicorniae. In addition to the novel tetramic acid derivatives (38, 39), this fungus also produces two new epimeric lactones, the cycloethers ascolactone A (43) and B (44), similar to known cephalosporide compounds, and ascochitine (45), ascochital (46), and halopyrone (47), which were previously known.Compound 45 exhibited moderate inhibition of a tyrosine phosphatase B from Mycobacterium tuberculosis. 

Sugar-derived a,(3-unsaturated lactones are relevant motifs considering their ability to act as functionalized substrates for a variety of transformations. Some of them are bioactive [218-222]. An early synthesis of the enantiomer of (+)-altholactone, a natural product with cytotoxic and antitumor activities (for a review on the bioactivity of styryUactones see [223, 224]), involves the preparation of a furanose-fused a,p-unsaturated 8-lactone intermediate 189 [225]. Starting from a a-D-xy/o-pentodialdofuranose derivative 187, aReformatsky reaction with ethyl bromoacetate introduces the carboxyhc side chain necessary for intramolecular lactonization (Scheme 46). 

Neonepetalactone, 61 (Fig. 1.2.3), a bioactive compound found to be quite attractive to cats [41], was isolated in 1965 from the leaves and galls of Actinidia polygama by T. Sakan et al. and its absolute configuration was determined in 1980 [41b]. As some syntheses of the racemic mixture or ex-chiral-pool syntheses had already been reported, we realized that our SAMP/RAMP hydrazone methodology would make it possible to develop a very short asymmetric synthesis of this bioactive 8-lactone. 

The tubulin-bound conformation of DDM in solution has been determined from tr-NOE data [112], Sample conditions were similar to those used previously to determine the bioactive conformation of EpoA. Distance restraints were obtained from a series of tr-NOE spectra recorded at several mixing times and were used in the structure calculation based on the complete relaxation matrix methodology [37], The NMR-derived bioactive conformation is quite similar to the crystal structure except for the conformation of the 8 lactone ring, that is close to a flattened chair in solution but a twisted boat in the crystal (Fig. 18). 

P h y t o c h e m i c a l investigations of plant species of Parthenium, Encelia and Pi coria (Asteraceae) from semi-arid and arid zones of the United States and Mexico has resulted in the isolation and identification of numerous sesquiterpene lactones and benzopyrans that are active insect feeding deterrents. The chemistry, biological effects and possible mode of action of bioactive pseudoguaianolides and chromenes are reviewed. 

One reason that dominant plants are successful in semi-arid and arid ecosystems is due to the high concentration of terpenoids and prenylated phenolics that repel and/or deter feeding by herbivorous insects. Compounds like sesquiterpene lactones and benzopyrans are present in high quantities in the leaves of species of Pjajl t h ij jn, E n c e l i a and D i c o r i a and have been demonstrated to be effective feeding deterrents against known economic insect pests. Ijt vivo experiments are still needed in the field with bioactive constituents to better understand their effects on native phytophagous insects. 

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