Sesquiterpene Lactones biological activities

Chemistry and biological activity of artemisinin (sesquiterpene y-lactone with oxepane fragment and transannular peroxide bridge) and related antimalari-als 99H(51)1681. 

Composites -have been reported (8) to contain a wide variety of sesquiterpene lactones and lactones of this type have been previously found in both Russian knapweed and yellow starthistle (9,10,11,12). The wide range of biological activity associated with sesquiterpene lactones, e.g., cytotoxicity, phytotoxicity, antineoplasticity, etc. (8) suggested the possibility that these compounds may play a role in the allelopathy of both Russian knapweed and yellow starthistle. 

One final comment on the biological activity of the sesquiterpene lactones in relation to ENE disease in horses. Unfortunately, horses are the only animal which contract this disease. Consequently, acquiring sufficient pure material to be fed to horses becomes a formidable task. At the present time, trial studies are being initiated with solstltlalln-A to observe its effect on horses. Insufficient material is available to permit the testing of the other sesquiterpene lactones. 

Effects of Sesquiterpene Lactones on Seed Germination. Sesquiterpene lactones are common constituents of the Asteraceae but are also found in other angiosperm families and in certain liverworts (31,32). These highly bitter substances exhibit a wide spectrum of biological activities (J 3) which include cytotoxicity, anti-tumor, anti-microbial, insecticidal (34) and molluscicidal (35) properties. Furthermore, they are known causes for livestock poisoning and contact dermatitis in humans (33). Structure-activity relationship studies on sesquiterpene lactones have demonstrated that biological activity frequently depend on the presence of the cr... 

Experiment 2. Effects of terpenoid allelochemicals on pollen germination The effects of the terpenoids found in many allelopathically active plants are dependent on the concentration of the active matter (Fig. 4). Linalool, cymol, citral, gaillardine and austricine excreted by many flowers, stimulated the pollen germination upto 10 7-1()" M concentrations and depress in higher ones. Rodriguez et.al (1976) described the biological effects of some sesquiterpene lactones, which are allelochemicals. 

There have been no reports on the chemical synthesis of parthenolide or indeed on the modification of the biological activity (see below) of parthenolide or the sesquiterpene lactones in general. However, routes for the synthesis of constunolide have been reported [23-25]. 

One of the first biological activities for which sesquiterpene lactones were screened was their possible anti-tumour activity. Studies have shown that... 

A different cychzation reaction of 460, by treatment with iodine and silver oxide, gave l,6-dioxaspiro[3.4]octanes 469 (Scheme 130). This heterocychc core present in a series of sesquiterpenic lactones has interesting biological activity and is isolated as secondary metabolites from species of the Compositae family . 

Terpenoids are a diverse group of conqiounds showing a wide spectrum of biological activities. Among the most biologically active terpenoids are the sesquiterpene lactones. Their biological activity has been reviewed (56, 57, 58). 

The biological activity and toxicity of terpenoids to herbivores has been discussed (56,84) and representatives of each major type of terpene are known to be active. Well known examples are sesquiterpene lactones, pyrethrins, and several classes of diter-penes and triterpenes. 

A number of sesquiterpenes have been demonstrated to have pronounced biological activity ( ) among the non-volatile compounds the sesquiterpene lactones are best known (M) but other oxygenated sesquiterpenes are also known to be active. For example, the role of gossypol, a dimeric sesquiterpene and structurally related compounds has been investigated (21,22). The oxygenated sesquiterpenes, shiromodiol monoacetate and diacetate, from Parabenzoin trilobum (=Lindera triloba Blume) possess potent anti feeding activity toward Spodoptera litura larvae (85). 

Pieman, A.K. Biological activities of sesquiterpene lactones. Biochem Syst Ecol 1986 4 255-281. 

Sesquiterpene lactones (SL) constitute a numerous group of compounds with several biological activities reported, usually related to the presence of an a, 3-unsaturated carbonyl system in the lactone ring.42 This is a very common chemical feature in these compounds, and their alkylating properties through Michael addition reactions are considered as responsible for such activity.16... 

The nucleophilic properties of groups such as -NHR and -SH have been reported in natural Michael acceptor systems present in many natural products. Typical examples are the addition of the sulfhydryl groups of glutathione to the exocyclic methylene of sesquiterpene lactones (Fig. 6.7).14,41 Such interactions have been considered as responsible for the biological activity observed in many natural products, and this is again the case in Zwanenburg s hypothesis for strigolactones. 

Jawad, A L.M., Dhahir, A.B.J., Hussain, A.M., Ali, K.F. and Saleh, H.M. (1985) Antimicrobial activity of sesquiterpene lactones extracted from Iraqi plants. Part II. Journal of Biological Sciences Research 16(2), 17-22. 

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. 

Since the importance of sesquiterpenes, sesquiterpene lactones and flavonoids from the chemosystematic and the biological point of views, especially the chemistry and the biological activities of these compounds will be reviewed in this chapter, while the essential oils and the acetylenic compounds will not be mentioned. 

Kalsi, S.R., Goyal, K.K., Talwar and Cabra, B.R. (1989). Sterostructures of two biologically active sesquiterpen lactones from Inula racemosa. Phytochemistry, 28 2093-2096. 

---