Biological antifeedant activity

Example A family of biologically active compounds Isolated from African trees include polygodial (39), an antifeedant which protects the tree against plagues of caterpillars. ... 

Sesquiterpenoids possessing the drimane skeleton (22) exhibit an impressive series of biological properties. Recently, all aspects relative to occurrence [76], biological activity [76], insect antifeedant properties [77] and synthesis [78] of these terpenoids have been exhaustively reviewed. 

Diterpenoids have a wide range of biological activities. Their role in plant-insect interactions, both as antifeedants and growth inhibitors, is reviewed. Four ent-kauranes, kaur-16-en-19-oic acid, (-)-kauran-l > -ol, 15 t-hydroxy-(-)-kaur-16-en-19-oic acid, and 17-hydroxy-(-)-kaur-15-en-19-oic acid, have recently been isolated from the leaves of Solidago nemoralis.These compounds were found to have antifeedant activity against Trirhabda canadensis. 

The diterpenoids of Isodon (Labiatae) species have been reviewed. The presence of an a-methylenecyclopentanone moiety in these diterpenoids is important for their anti-tumour and anti-bacterial activity. " Inflexin (79) is a cytotoxin and insect antifeedant which has been isolated from Isodon inflexus. Isodomedin (80) is another member of this series, isolated from /. shikokianus, which shows this type of biological activity. Its structure was assigned on the basis of its H and C n.m.r. spectra and on an interrelationship with kamebanin (81), isolated from /. kameba. 

Several non-volatile iridoid monoterpenes occur as glycosides and have been observed to have biological activity. For example, xylomolin, from the unripe fruits of Xylocarpus moluccensis Roem. (Meliaceae) has antifeedant activity against Spodoptera exempta an African armyworm at 100 ppm ( ) and crotepoxide from Croton macrostachys (Euphorbiaceae) possesses antifeedant activity against Spodoptera exempta (85). 

These natural substances are of great interest due to both their unusual structures and the potent wide-ranging spectrum of biological activities that they possess antitumor activity [10] in vitro and/or in vivo, antiinflammatory activity [7], fungicidal activity [11], herbivorous mammalian antifeedant activity [12], insecticide activity against house-fly larvae and other insects [13] and, lastly, a potent plant growth regulatory activity, both as inhibitors and as stimulants [14-15]. 

Many polyhalogenated monoterpenes have potent biological activity (7). In addition to cytotoxic activity, several compounds display insect repellent and antifeedant activity, and selective insect cell toxicity (480). To acquire sufficient quantities of these and other target metabolites for biological evaluation, the laboratory cultivation of marine algae - bioprocess engineering - is under intense exploration (481 483). 

Chicory (Cichorium intybus) is cultivated in cool regions such as Northern Europe. Recently, this vegetable has arisen out of claims that it is able to promote good health since no pesticides are used to cultivate chicory in the field, while the plant remains noticeably free from herbivore and microbial attack. The bitter substances, lactupicrin, 8-deoxylactucin and some phenolics had previously been shown to possess insect antifeedant properties in chicory (Rees and Harbome, 1985). Specifically, sesquiterpenoid lactones from chicory leaves, such as 8-deoxylactucin and lactupicrin (Figure 1), were identified as insect antifeedants against desert locust, Schistocerca gregaria. Similarly, we found some biologically active secondary metabolites in the... 

In spite of the many studies on isolation, activity, and synthesis of natural antifeedants, the number of compounds commercially available remains low, often due to their cost of isolation, availability of the plant source, or low persistence in field conditions. To overcome these drawbacks, much research is conducted on structure—activity relationships (SAR). The rationale behind these studies is to discover the correlation between biological activity and chemical structure and to draw from that optimum structures having both the activity, stability, and selectivity for maximum feeding deterrence.4 5 SAR are much used in drug design6 and have been applied to insecticides.7... 

The potent biological activity (insect antifeedant, antitumour, antifungal) of warburganal (35) has stimulated considerable synthetic interest in this compound. Three total syntheses of this compound have been recorded in the period under review. " The synthesis by Tanis and Nakanishi has additional flexibility since the key intermediate diol (34) can be used in the syntheses of cinnamolide (36), drimenin (37), and polygodial (38). Both norisoambreinolide (39 R = O) and isoambrox (39 R = H2) have been synthesized from (40), the product of the stannic chloride-catalysed cyclization of farnesyl phenyl sulphone. Yahazunol (41), a bicyclofarnesyl hydroquinone, has been identified in the brown seaweed... 

ABSTRACT The genus Tanacetum has been used as medicinal plants for over 2000 years. Interest in the genus has been stimulated by its biological activities, particularly as insect antifeedants, antitumor and antimicrobial activities due to its sesquiterpenoid constituents. The genus Tanacetum is represented by c.a.70 species in the world and by 44 in Turkey. It is an Asia centered genus which is widespread in the Northern Hemisphere and temperate regions. 

Moreover, the observation of an interesting antibiotic activity for some Lactarius extracts (3) stimulated the search of new biologically active compounds among those isolated from these mushrooms. In fact, simple bioassays (4) led to the identification of new products with antimicrobial, cytotoxic, antifeedant and other interesting activities. No less important was the observation that some species seem to withstand attack from parasites such as snails and insects better than others. In fact, it has been shown that resistant species are armed with a chemical defence system which protects the mushrooms from predators and invaders. 

Naturally occurring neolignans, represented by shizandrins and steganes, exhibit a variety of biological activities such as antifeedant against insects and antitumor activities. 

The diverse biological activity (e.g. insect antifeeding, plant growth regulation, molluscicidal) of a number of drimane sesquiterpenoids has stimulated considerable interest in their synthesis and the year under review has seen many new developments and improvements. Much of the synthetic work has centred around the key bicyclic diester (54) derived from 1-vinyl-2,6,6-trimethylcyclohexene and dimethyl acetylenedicarboxylate. In contrast to earlier results,34 Ley et al.8S... 

Source Tephrosia purpurea. Molecular formula C23 H22 O7. Molecular weight 334.4. Melting point 198 deg C. Biological activity Antifeedent. 

Bryophytes are divided into three classes, Musci, Hepaticae (liverwort) and Anthocerotae, which are known to include 14000,6000 and 300 species, respectively. Various kinds of biologically active compounds have been discovered from bryophytes. For instance there are compounds with hot or bitter taste, ichthyotoxicity, insect antifeedant, antiinflammatory, antimicrobial, antifungus and antitumor activities (1). In liverworts, there exist oil bodies, while in Musci, no oil bodies are present. This can help us to identify the liverworts. 

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