Diterpene, labdane

The plant is attracting a great deal of interest on account of its ability to elaborate labdane diterpenes vitexilactone, 6-acetoxy-9 hydroxy 13(14)-labden-16,15-olide, rotundifuran,... 

M.T. Calabuig, M. Cortes, C.G. Francisco, R. Hernandez, E. Suarez, Labdane diterpenes from Cistus symphytifolius, Phytochemistry, 20, 2255 2258 (1981). 

The plant Stevia rebaudiana bertoni has been studied in depth because it was discovered that this plant is the source of six sweet-tasting diterpene glycosides. They are stevioside, rebaudiosides A, C, D, E and dulcoside A. (Table 1). These sweet diterpene glycosides, as well as a complex mixture of organic compounds of which more than a hundred compounds have been identified, are found mainly in the leaves of the plant. The leaves contain a complex mixture of labdane diterpenes, triterpenes, stigmasterol, tannins and volatile oils. There is an abundance of reviews and patents relating to these sweet diterpene glycosides. 

Cuticular diterpenes-duvanes and labdanes. Cutler have found that the cuticular diterpenes of green tobacco have both allelopathic and insect-deterrent effects (38). Present in the cuticle are duvane and/or labdane diterpenes (Figure 3) The levels of these specific cuticular components are believed to be responsible for the observed resistance of some types of tobacco to green peach aphids Myzus persicae (Sulzer), tobacco budworm Heliothis virescens (F.), and tobacco hornworm Manduca sexta (L.) (39). 

Labdanum Cistus ladaniferus L. Labdane diterpenes and mono-terpene hydrocarbons ... 

Biologically active secondary metabolites from fungi. 12. Oidiolactones A-F, labdane diterpene derivatives isolated from Oidiodendron truncata. John, M. Krohn, K. Florke, U. Aust, H-J. Draeger, S. Schulz, B. J. Nat. Prod. 1999, 62, 1218-1221. 

A variety of biological activities have been associated with labdane diterpenes including antibacterial, antifungal, antiprotozoal, enzyme induction, anti-inflammatory modulation of immune cell functions, as well as cytotoxic and cytostatic effects against human leukemic cell lines. 

A series of other labdane diterpenes isolated from various sources have also been reported to exhibit antimicrobial activity. Aulacocarpinolide and aulacocarpines A and B, labdane diterpenes isolated from the Cameroonian spice Aframonum aulacocarpos (Zingiberaceae), exhibited weak antibacterial activity against B. subtilis and fungus Mucur miehei [166],... 

Based on off-resonance decoupling, lanthanoid shift studies, spectral comparison with different analogues and decalin models, signal assignments of pimaradienes [550], kaura-noid diterpenes [551, 552], podocarpane derivatives [553] and labdanic diterpenes [554] could be achieved (Table 5.6). 

Iliopoulou D, Mihopoulos N, Roussis V, Vaglas C (2003) New Brominated Labdane Diterpenes from the Red Alga Laurencia obtusa. J Nat Prod 66 1225... 

Aquatic plant ent-labdane diterpenes from Potamogetonaceae TBA A,I,I,I,I (Cangiano et al., 2002)... 

Cangiano, T., Dellagreca, M., Fiorentino, A., Isidori, M., Monaco, P. and Zarrelli, A. (2002) Effect of ent-labdane diterpenes from Potamogetonaceae on Selenastrum capricornutum and other aquatic organisms, Journal of Chemical Ecology 28 (6), 1091-1102. 

An intramolecular 2-alkylation was also observed in a sulfonyl free radical induced addition-cyclization <95SL763>. A key intermediate in a new synthesis of pallescensin A (a biologically active labdane diterpene) was prepared by a cationic cyclization reaction with a furan <95SYN1141>. The sonochemical Barbier reaction was extended to carboxylate salts. 2-Furanylketones 10 can be obtained by sonication of a mixture of furan, lithium carboxylate, an alkylchloride, and lithium in THF <95JOC8>. 

The plants were air dried and extracted with solvents of increasing polarity. Chromatographic processing of the extracts led to the isolation of twenty ent-labdane diterpenes, identified on the basis of their spectroscopic properties and by chemical correlation. 

Enf-Labdane-diterpenes isolated from Ruppia maritima. 

The biological activity of diterpenes is copiously reported in the literature. Singh et al. reviewed the biological activity of labdane diterpenes from 1987 to 1997.30 The antibacterial, antifungal, anti-inflammatory, cytotoxic and other... 

Gray, C. A., Davies-Coleman, M. T., and McQuaid, C., 1998. Labdane diterpenes from the South African marine pulmonate Trimusculus costatus. Nat. Prod. Lett. 12, 47-53... 

Azadirachtin (limonoid nortriterpene) 6-Desacetylnimbin (limonoid nortriterpene) 1,9- Dideoxyforskolin (labdane diterpene)... 

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