Kaurane

Kitajima, T. Komori and T. Kawasaki, Chem. Pharm. Bull. (Tokyo), 30(11), 3912 (1982). 

Source Vellozia aaput-ardeae L.B.Smith and Ayensu Mol. formula  

Source Helianthus annuus L. Mol. formula 20 2302 Mol. wt. 300 Solvent CDClo 

Source Tetradhyron orizdbaensis Sch. Bip ex Klatt Mol. formula 20 002 Mol. wt. 302 Solvent CDCl, 

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One of the most significant differences between Arabica and Robusta coffees is in the caffeine content. Robusta coffees contain almost twice the caffeine found in Arabica coffees. There are some other differences recognized thus far Robustas contain almost no sucrose and only very small amounts of the kaurane and furokaurane-type diterpenes they contain higher proportions of phenols, complex carbohydrates (both soluble and hydrolyzable), volatile fatty acids on roasting, and sulfur compounds, all in comparison with Arabicas. References to these distinctions can be found in Chapter 6 of this book. 

Several alicyclic compounds identifiable in roasted coffee are terpenes and these contribute presumably to the coffee oil. The kaurane and furokaurane type diterpenes are discussed in Section VIII.D. 

Some kaurane and kaurene compounds found in green coffee beans their glycosides are listed in Table 15. 

Richter, H., Obermann, H., Spiteller G., A new kauran-18-oic acid glucopyranosylester from green coffee beans, Chem. Ber., 110, 1963, 1977. (CA87 68579x)... 

The plant is used to treat leprosy the roots are used to heal ulcers and to cure ringworm infection. A decoction of the leaves is drunk to treat tuberculosis and to improve general weakness. In Cambodia, Laos, and Vietnam, an infusion of the bark is used to correct nervous affections. The plant is known to elaborate lupane triter-pene saponins and kaurane diterpenes including 16-aH, 17-isovalerate-ent-kauran-19-oic acid, which strongly inhibited the enzymatic activity of cyclooxygenase in vitro (76,77). 

Kiem PV, Cai XF, Minh CV, Lee JJ, Kim YH. Kaurane-type diterpene glycoside from the stem bark of Acanthopanax trifoliatus. Planta Med 2004 70 282-284. 

Malacria and coworkers346 prepared phyllocladane and kaurane types of diterpenes by means of [3 + 2]/[2 + 2 + 2]/[4 + 2] cascade reaction sequences. A representative example of such a reaction sequence has been outlined in equation 171. The five-membered ring of 598 was built by a 1,3-dipolar cycloaddition between 596 and an all-carbon 1,3-dipole generated from 597. The reaction of 598b with 568h afforded benzocyclobutene 599. The intramolecular [4 + 2] cycloaddition afforded diastereomers 600 and 601 in a 5 1 ratio. It is noteworthy that the exocyclic double bond in 598b neither participates in the [2 + 2 + 2] cycloaddition reaction nor isomerizes under the reaction conditions applied. 

The kaurane type of adduct 601 became the major product when the methylene group at C(12) was replaced by a carbonyl group and substituents were present at C(15). Repulsive steric interactions between the substituents at C(15) and H(l) prevented the formation of phyllocladane type of compounds like 600347. 

A series e t-kaurane diterpenoids isolated from Sideritis species were tested against A2780 ovarian cancer cell lines, and 7-e/>/candicandiol (Fig. 6.6) showed the highest cytotoxic potential with ICj , = 9.0 pg/mL, and sidol followed it (ICj , = 15.6 pg/mL). 

Mono-, sesqui-, and some diterpenoids are found in marine and terrestrial flora. They are, therefore, not always unambiguous tracers for higher plant sources. However, diterpenoids with the abietane and pimarane (Fig. 1), and less common phyllocladane and kaurane, skeletons are predominant constituents in resins and supportive tissue of coniferous vegetation (Coniferae), which evolved in the late Paleozoic (200—300 million years ago). Diterpenoid biomarkers have been characterized in... 

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. 

Isodon diterpenes. Highly oxygenated.- -seco-ent-kaurane diterpenoids, the isodons (Figure 7), isolated from species of Isodon (now Rhabdosia)... 

Figure 7. Kauranes that inhibit insect growth and development.

Solldago is a mostly North American genus of about 125 species. It belongs to the Asteraceae (Compositae), a family with a very distinctive chemistry (57, 58). The genus itself contains several different classes of secondary compounds including a number of diterpenes (59). During the 1960 s and 1970 s Anthonsen in Finland, and McCrindle and his coworkers in Canada, isolated about twenty-five different compounds from the roots of Solidago species, mainly clerodanes and labdanes. But in the last five years attention has turned to the aerial parts of the plant and compounds of several other classes of diterpenes, abietanes and kauranes, have been isolated (60-79) (Table II). 

Figure 8. Kauranes Isolated from the leaves of Solidago nemoralls.

Antifeedant activity of kauranes isolated from S. nemoralis... 

Most previous experiments with kauranes and closely related compounds have been concerned with their effects on Insect growth and development. However in this case the deterrent effects of the Isolated compounds to Trirhabda canadensis were investigated as a first step in understanding the feeding behavior of this insect in the field. 

Epoxy-kauran-2,3-dione 3-Dehydro-6-deoxoteasterone Ppsi58 3-Dehydroteasterone PpSl58 6-Deoxoteasterone Ppsi58 Abscisic acid ... 

Watanabe, M., Y. Sakai, T. Teraoka, OS026 et al. Novel C19-kaurane type of diterpenes (oryzalide A), a new antimicrobial compound isolated from healthy leaves of a bacterial leaf blight OS027 resistant cultivar of rice plant. Agr... 

A number of kauranoid diterpenoids have been isolated from the liverworts. (16i )-ent-Kauran-15-one, ent-15a-hydroxykaur-16-ene, and the corresponding 15-ketone have been isolated from the liverwort Jungermannia infusca and (16i )-ent-18-hydroxykauran-15-one, ent-kaur-16-en-18-oic acid, and ent- a-hydroxykaur-16-en-15-one have been found in another species, Porella densi-folia. The full paper on the crystal structure of enf-1 la,15or-dihydroxykaur-16-ene, which has been obtained from Jungermannia sphaerocarpa and Solenostoma trista, has appeared. ... 

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