Biological activity terpene

Maimone TJ, Baran PS. Modem synthetic efforts toward biologically active terpenes. Nat. Chem. Biol. 2007 3(7) 396—107. 

Citrus fruits provide a diverse range of flavonoids [35] naringenin, a flavonone, has been shown to posses cholesterol-lowering and anticancer properties [36]. The naringin content of lime juice has been estimated to be -100 pg/g [37], and the lime is also a source of limonene, a biologically active terpene (see above). Other bioactive substances in lime (Table 4) include coumarins that possess anticoagulatory and anti-inflammatory properties. 

In addition to the QM structure of the natural terpene QMs, the reactive oxygen species (ROS) may also play a significant role in the observed biological activities. In the synthesis of taxodione and taxodone, QMs were formed from the catechol precursors through the spontaneous oxidation in the presence of silica gel.7, 8,49-51... 

In addition to terpenes (as described above), carbohydrates have also been used as substrates in domino metathesis reactions, the aim being to synthesize enan-tiopure polyhydroxylated carbocyclic rings. These structures are components of several biologically active compounds such as aminoglycoside antibiotics [254], inositol phosphates [255], and carbanucleosides [256]. An efficient entry to this skeleton was developed by Madsen s group using a domino RCM/CM of the carbohy-... 

The notion of action by specific allelochemical compounds is also unjustified. Detailed study of some allelochemicals in active species has shown the presence of phenolic acid mixtures and other phenolic derivatives or terpenes. I think that we can never talk about the action of a single substance everywhere many compounds having different biological activity act simultaneously, perhaps mutually increasing their activity. As a rule, such allelochemicals are the intermediate products of soil humus, synthesis, or the ground detritus in aquatic ecosystems (11). High concentrations of these substances are lethal, moderate ones inhibit growth processes, and low concentrations stimulate them. 

An entirely different, in fact opposite, effect on insect reproduction by terpenes occurs with the desert locust. In this case the monoterpenes a-pinene, -pinene, llmonene, and euge-nol evaporating from desert shrubs about to bloom, precipitates synchronised sexual maturation and mating activity in the locusts (14). The spruce budworm is also stimulated to increased fertility levels by host tree monoterpenes (R.G. Cates, personal communication). It is possible that even opposite effects on reproduction in insects could occur depending on the specialisation of the insect species to its environment, the diversity of the biological activities of the compounds, and the high level of complexity of the reproductive processes. 

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. 

Participation of Br in marine terpene biosynthesis (Section II.C) is reflected in the impressive number (several hundred) of halogenated terpenes, some with useful biological activities, that have been identified. For example, the poly halogenated sesquiterpenes isoobtusol (14) and isoobtusol acetate (15), isolated from the red alga Laurencia obtussa, showed potent activity against HeLa 229 human carcinoma cells1011. 

The inverse electron demand hetero Diels-Alder reaction of 1-oxa-l,3-butadienes and electron-rich dienophiles is an extremely versatile tool in natural product synthesis. This cycloaddition represents the key step of numerous approaches not only to carbohydrates, but also to terpenes, alkaloids, polyethers, steroid derivatives and various biologically active metabolites. 

High level compound purity is essential for a hit to become a genuine lead. For example, the terpene, ursolic acid, has shown inconsistent biological activity across a number of diverse assays. Recently, purity-activity studies of its antimycobacterial activity were performed using ursolic acid samples of varying purity. Ursolic acid showed enhanced antimycobacterial activity when impure.43... 

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