Diterpenes

They have 20 carbon atoms and are derived from geranylgeraniol pyrophosphate. They are of fungal or plant origin and are found in resins, gummy exudates, diterpenes, and in the resinous high-boiling fractions remaining after distillation of essential oils. However, unequivocal evidence was provided for de novo geranylgeraniol biosynthesis in mammals Shidoji Diterpenes et al, diterpenes.

Antimicrobial resistance has been posing an alarming threat to the treatment of infectious diseases over the years. Ineffectiveness of the currently available synthetic and semisynthetic antibiotics has led the researchers to discover new molecules with potent antimicrobial activities. To overcome the emerging antimicrobial resistance, new antimicrobial compounds from natural sources might be appropriate. Secondary metabolites from natural sources could be prospective candidates in the development of new antimicrobial agents with high efficacy and less side effects. Among the natural secondary metabolites, diterpenoids are of crucial importance because of their broad spectrum of antimicrobial activity, which has put it in the center of research interest in recent years.

Diterpenes

Diterpenes are a structurally diverse class of C 20 natural compounds, widely distributed in nature and originating by condensation of four isoprene units derived from mevalonate or deoxyxylulose phosphate pathways. The latter, recently discovered, originates the diterpene compounds in plants. Diterpenes can be classified as linear, bicyclic, tricyclic or tetracyclic, pentacyclic, and macrocyclic diterpenes depending on their skeletal core. In nature, they are commonly found in a polyoxygenated form with keto and hydroxyl groups, these last often esterified by small-sized aliphatic or aromatic acids. Diterpenes have attracted growing attention because of their interesting biological and pharmacological activities. Although thousands of diterpene compounds have been described in nature from terrestrial and marine organisms, only few of them became clinically effective. Overall, the anticancer drug taxol, used in therapy against ovarian, breast, and lung cancer, with its synthetic water-soluble analogue taxotere, is an example of unusual structure discovered from nature and used as medicine. Promising diterpenes are the ginkgolides showing potent and selective antagonistic activity toward platelet-activating factor increasing in conditions of shock, burns, ulceration, and inflammation skin diseases. Also used in therapy is the diterpene resiniferatoxin, an ultrapotent vanilloid, isolated from the Euphorbia resinifera latex, in clinical trials for bladder hyperiflexia and diabetic neuropathy. The diterpenes used in therapy will be described together with other promising bioactive diterpenes with particular attention to those isolated from plants. This is a preview of subscription content, log in via an institution. Dickschat JS Isoprenoids in three-dimensional space: the stereochemistry of terpene biosynthesis. Nat Prod Rep

The main metabolic reactions in all animals diterpenes hydroxylation in the ring system, S -oxidation and N -deethylation on the side chain, diterpenes. Five communic acids have been described to date, they differ in the location of the double bonds and the orientation of the carboxyl group, diterpenes.

The research, development and use of natural products as therapeutic agents, especially those derived from plants, have been increasing in recent years. There has been great deal of focus on the naturally occurring antispasmodic phytochemicals as potential therapy for cardiovascular diseases. Naturally occurring diterpenes exert several biological activities such as anti-inflammatory action, antimicrobial and antispasmodic activities. Several diterpenes have been shown to have pronounced cardiovascular effects, for example, grayanotoxin I produces positive inotropic responses, forskolin is a well-known activator of adenylate cyclase, eleganolone and deoxyandrographolide exhibit vasorelaxant properties and marrubenol inhibits smooth muscle contraction by blocking L-type calcium channels. In the last few years, we have investigated the biological activity of kaurane and pimarane-type diterpenes, which are the main secondary metabolites isolated from the roots of Viguiera robusta and V. Moreover, kaurane and pimarane-type diterpenes decreased mean arterial blood pressure in normotensive rats.

Terpenes are major biosynthetic building blocks. Comprising more than 30, compounds, these unsaturated hydrocarbons are produced predominantly by plants , particularly conifers. Other functions of terpenoids include cell growth modulation and plant elongation, light harvesting and photoprotection, and membrane permeability and fluidity control. Terpenes are classified by the number of carbons: monoterpenes C 10 , sesquiterpenes C 15 , diterpenes C 20 , as examples. The terpene alpha-pinene is a major component of the common solvent , turpentine. The one terpene that has major applications is natural rubber i. The possibility that other terpenes could be used as precursors to produce synthetic polymers has been investigated.

Diterpenes

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The diterpenoids salvic acid 60 , Figure 26 , acetylsalvic acid 61 , propanoylsalvic acid 62 , butanoylsalvic acid 63 , and isopentanoylsalvic acid 64 were evaluated against Botrytis cinerea. De Graan A. The bioconversion of andrographolide with Aspergillus ochraceus afforded similar metabolites [ 56 ]. The understanding of the metabolic pathways for both phase I and II biotransformation of new drug candidates is mandatory for toxicity and efficacy evaluation and part of preclinical studies [ 33 ]. Drug Metab. Li, Q. Liu J. Article Talk. Chemical transformation of xenobiotics by the human gut microbiota. Gracilins are diterpenoid compounds derived from Spongionella gracilis , a marine sponge. Bozov, P. Benth [Lamiaceae]. Biotransformation of agallochaexcoerin A 12 in agallochaexcoerin G Crassolide, a highly oxygenated diterpene from the soft coral lobophytum crassum. Buying options Chapter EUR

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XL were investigated against seven agricultural pathological fungal strains, Sclerotinia sclerotiorum , Helminthosporium maydis , Verticillium dahliae Kleb, Phytophthora parasitica , Gibberella saubinetii , Botrytis cinerea Pers. Furthermore, biotransformations can promote regio and stereoselective or regio and stereospecific reactions, leading to compounds that would be difficult, more expensive, or impossible to obtain by traditional organic synthesis [ 63 , 83 ]. Bioscience One of the great advantages of selective modifications is the need of fewer purification steps to obtain metabolites of interest. Both pathways are the natural routes for the synthesis of terpenoids and many other natural products that contain terpenoid elements in their molecules, in combination with carbon skeletons derived from the acetate and shikimate pathways [ 7 ]. Among the isolated diterpenes, compounds 32 — 34 were found to be active against the tested microorganisms. Microbial metabolism of atovaquone and cytotoxicity of the produced phase I metabolite. According to Liu et al. They are produced via the mevalonic acid biosynthetic pathway, by condensation reaction of isopentenyl pyrophosphate IPP with farnesyl pyrophosphate FPP , which yields geranylgeranyl pyrophosphate GGPP in a few consecutive reactions Singh and Sharma, Ocimene Myrcenes.