Diterpenoids isolation

Since the discovery of the high anticancer activity of taxol, much attention has been drawn to its asymmetric synthesis. The total synthesis stood for more than 20 years as a challenge for organic chemists. The compound taxoids are diterpenoids isolated from Taxus species and have a highly oxidized tricyclic carbon framework consisting of a central eight-membered and two peripheral six-membered rings (see Fig. 7-2).21... 

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). 

Huang QR, Iwamoto M, Aoki S, Tanaka N, Tajima K, Yamahara J, Takaishi Y, Yoshida M, Tomimatsu T, Tamai Y. (1991). Anti-5-hydroxytryptamine3 effect of galanolactone, diterpenoid isolated from ginger. Chem Pharm Bull (Tokyo). 39(2) 397-9. 

Danshenol A (57), an abietane-type diterpenoid isolated from the dried roots and rhizomes of Salvia miltiorrhiza Bunge (family Labiatae),... 

Hayashibara, Y. Katagiri, Y. Kano, and K. Iwamoto. Pharmacokinetics of [6]-gingerol after intravenous administration in rats. Chem Pharm Bull (Tokyo) 1991 39(6) 1612-1614. Huang, Q. R., M. Iwamoto, S. Aoki, et al. Anti-5-hydroxytryptamine effect of galanolactone, diterpenoid isolated from ginger. Chem Pharm Bull (Tokyo) 1991 39(2) 397-399. Srinivasan, K., and K. Sambaiah. The effect of spices on cholesterol 7 alpha-hydroxylase activity and on serum and hepatic cholesterol levels in the rat. Int J Vitam Nutr Res 1991 61(4) 364-369. 

By virtue of its seven contiguous stereogenic centers, including two quaternary centers, and the presence of very sensitive functionalities such as the exocyclic epoxide and the acetal unit, clerodin 1 84 (Scheme 12.14) represents perhaps one of the most complex diterpenoids isolated. 

E-isolinaridial and E-isolinaridial methylketone are two neo-clerodane diterpenoids isolated from the aerial parts of Linaria saxatilis var. glutinosa (Schrophulariaceae). Benrezzouk et al. evaluated these compounds on multiple inflammation pathways and found that they were not COX-1/COX-2 inhibitors [139]. However, E-isolinaridial and E-isolinaridial methylketone were dual inhibitors against purified phospholipase A2 and 5-lipoxygenase. E-isolinaridial and E-isolinaridial methylketone showed potent inhibition of cell-free 5-LOX enzyme with IC50 values of 0.42 pM and 1.41 pM,... 

Fuscoside B is a lobane diterpenoid isolated from the Caribbean gorgonian Eunicea fusca. It has been evaluated for the inhibitory activities against COX-1, 5-LOX, 12-LOX, PLA2, and other eicosanoid biosynthesis pathways and found only to irreversibly inhibit the 5-LOX pathway with an IC50 value of 10 pM. [141,142]... 

The beyerene diterpenoids isolated from Sideritis pusilla possess a C-l 4a-hydroxy-group. The 7,18-diacetate of pusillatriol (78) was prepared75 by rearrangement of the 15,16-epoxide of 7,18-diacetoxysideridiol, thus interrelating the two... 

Montanin D is a new furanoid diterpenoid isolated from Teucrium montanum (Labiatae) to which the clerodane structure (44) has been assigned. The full paper has appeared on the teucrins Hi—H4, (45)—(48), which were isolated from T. hyrcanicum. The mass spectral fragmentation pattern of these diter-... 

Very recently, we ve established the antioxidant activity of six abietane diterpenoids isolated from the roots of the endemic species Salvia barrelieri namely, 12-methoxy-7-acetoxyroyleanone (or 7-acetoxybarrilierone) Al, 12-methoxy-7-oxoroyleanone (or 7-oxobarrilierone) A2, 14-hydroxycryptojaponol A3, 7-a-... 

CLASSIFICATION OF THE DITERPENOIDS ISOLATED FROM Salvia SPECIES... 

A fascinating group of diterpenoids isolated from soft coral have been identified as isoprenylogues of caryophyllene or secocaryophyllene cf. D. J. Vanderah, P. A. Steadier, L. S. Ciereszko, F. J. Schmitz, J. D. Ekstrand, and D. van der Helm, J. Amer. Chem. Soc., 1977,99,5780 A. Groweiss and Y. Kashman, Tetrahedron Letters, 1978, 2205 cf Chapter 3. 

Fig. (1). Structures of diterpenoids isolated from Scoparia dulcis L.

Generally, terpenoids have been believed to be biosynthesized via acetate-mevalonate pathway. Aphidicolin, a tetracyclic diterpenoid isolated from moulds, Cephalosporium aphidicola [47] and Nigrospora sphaerica [48], was also proved to be biosynthesized from mevanonic acid [49]. In this pathway, isopentenyl pyrophosphate (IPP), geranylgeranyl diphosphate (GGPP), labdane-type and pimarane-type diterpenoids were proposed to be intermediate precursors of aphidicolin [50]. 

Fig. (64). Structure of protozoocidal eo-clerodane diterpenoids isolated from Baccharis spp.

Zoapatanol. 9-[3-Hydroxy-6-i2-hydroxyethylid-ene )-2-me i h yt-2-oxepa nylJ-2,6-dim elhyl-2-n on en-S-on e. CaHMOt mol wt 338.49. C 70.97%, H 10.12%, O 18.91%. Oxepane diterpenoid isolated from the leaves of the zoapatle plant, Monlanoa tomentosa, Compositeae, which has been used by Mexican women to prepare "tea to induce menses and labor. Isoln and structure M. P. Wachter, R. M. 

Some microbiological reactions were attempted either on natural kaurane diterpenoids isolated from Sideritis or on their hemisynthetic derivatives, by incubating them with Gibberella fujikuroi. The purpose was the transformation of the products into gibberelline derivatives. However, epicandicandiol (7) yielded no gibbane compounds, only oxidation of the 19-Me occurred, with the formation of the CH2OH and COOH derivatives (A) and (B) [112]. 

In a recent paper [106], the antibacterial activity was investigated on 27 known diterpenoids isolated from five species of Sideritis growing in Turkey. A certain activity, expressed as MIC (minimum inhibitory concentration), was observed for epicandicandiol (7) against E. coli and for sideroxol (54) against B. subtilis. 

Fig. (3) Representative antimalarial diterpenoids isolated from the marine sponge Cymbastela hooperi...

Table 18. Diterpenoids Isolated from Aristolochia Species...

Various biological activities, such as antibacterial and antitumor ones, and inhibitory activities as to insect growth and oxidative phosphorylation in rat mitochondria, are known for Rabdosia diterpenoids [2]. During the past decade, the antitumor activity of diterpenoids isolated from R. trichocarpa [149. 150]... 

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