Occurrence, Biological Activities and Synthesis of Kaurane Diterpenes and their Glycosides

Abstract

This paper presents a review on kaurane diterpenes and their glycoside derivatives, covering aspects of their occurrence, biological activities and the synthesis of these natural products and their analogues. First, it shows and classifies diterpenes, in accordance with the already established structural criteria in the literature. Then, kaurane diterpenes are presented, focusing on their chemical structures, occurrence in the plant kingdom and their main, recently described, biological activities. Moreover, the most significant works, published between 1964 and November 2006, which describe the total synthesis or structural transformations of some kaurane diterpenes, including either semisynthetic and/or microbiological methodologies, are consisely reviewed. At this point, some general considerations on glycosides are introduced, and kaurane glycosides are presented and discussed on the basis of their toxic importance and occurrence in the plant kingdom, having focused on related aspects of their biological activities and the relationships between these activities and the structural factors of their molecules. Finally, the principal methods of glycosidation by enzymatic and chemical processes are both presented, and a few papers on the synthesis of kaurane glycosides are succinctly discussed. Molecules 2007, 12 456

Ent-kauren-19-oic acid derivatives from the stem bark of Croton pseudopulchellus Pax

“…The negative optical rotation of -55.9 indicated that compound 2a belonged to the ent series of kaurenoic acid-type diterpenoids (Garcia et al, 2007), as for all the diterpenoids isolated from this extract. The H-14 proton resonance displayed a correlation in the NOESY spectrum with the H-7α (1.58, m), H-11α (2.01, m), H-12α (1.32, dd, J = 3.5, 11.0 Hz) and H-13α resonances, thus the C-14 hydroxy group was assigned the β -configuration.…”

Cytotoxicity of Wedelia paludosa D.C. extracts and constituents

“…In addition, 1 and 2 were shown to be potent stimulators of uterine contraction, and their presence in Aspilia mossambicensis may explain why female chimpanzees consume such plant more frequently than males do (Page et al, 1992). Among more recently reported activities for 1, we can stand out the antimicrobial (Zgoda-Pols et al, 2002), anti-platelet aggregation (Yang et al, 2002), analgesic (Block et al, 1998a), antifungal (Sartori et al, 2003), smooth muscle relaxant (Cunha et al, 2003), hypoglycemic (Bresciani et al, 2004), cytotoxic and embryotoxic (Costa-Lotufo et al, 2002) effects, among others (García et al, 2007).…”

Potencial antiinflamatório de Annona glabra, Annonaceae

“…Uma vez que, após a instalação de um agente patogênico, o organismo reage para a eliminação do mesmo numa ação integrada entre os fagócitos, protagonistas da reação inflamatória, e as células do sistema imunológico, investigou-se também o seu potencial imunomodulador. Ainda, investigar simultaneamente o comportamento do ácido caurenóico dele purificado, uma vez que o mesmo tem sido alvo de estudos de modificações estruturais no esqueleto caurânico com o objetivo de se obter substâncias bioativas (Garcia et al, 2007). Machado-Jr. et al (2006) e Presibella (2006).…”