Cacalolides from Senecio madagascariensis

Abstract

14-Isovaleryloxy-O-methyl-1,2-dehydrocacalol (1) and cycloart-23-ene-3,25-diol, beta-sitosterol, and stigmasterol, along with five new cacalolides, 1-hydroxy-2-methoxy-1,2,3,4-dehydro-6-dehydroxycacalone (2), 1-hydroxy-2-methoxy-1,2,3,4-dehydrocacalone (3), 1,2-dimethoxy-1,2,3,4-dehydro-6-dehydroxycacalone (4), 1,2-dimethoxy-1,2,3,4-dehydrocacalone (5), and 2-methoxy-O-methyl-1-oxo-2,3-dehydrocacalol (6), were isolated from Senecio madagascariensis collected from Colombia. The structures of the new compounds were determined using one- and two-dimensional NMR techniques. In addition, the structure of 2 was corroborated by derivatizations and single-crystal X-ray diffraction studies.

Conformational evaluation and detailed 1H and 13C NMR assignments of eremophilanolides

“…Furanoeremophilanes with an ester group at C-6 are frequently found, whereas furanoeremophilanes with a hydroxyl group at C-6 are uncommon in nature. 1 As part of our chemical study of species of the genus Senecio, 6 we collected S. toluccanus from the mountain region of Morelia, Michoacan, Mexico. Their roots gave 1,10-epoxy-6-hydroxyeuryopsin (1), 7 6-hydroxyeuryopsin (3) 7 -9 and toluccanolide A (5), 7,10 and the corresponding acetyl derivatives 2, 7,11 4 7 and 6 10 were obtained by reaction with acetic anhydride.…”

Chemical and Pharmacological Research on Plants from the Genus Senecio

“…Cacalolides are biogenetic Wagner -Meerwein rearrangement products derived from furanoeremophilanes and derive their name from cacalol, a sesquiterpenoid isolated from the antihyperglycemic species Cacalia decomposita, also referred to as Psacalium decompositum and Odontorichum decompositum. Six new cacalolides 309 -314 were isolated from S. madagascariensis collected in Colombia [87]. From the roots of S. barba-johannis, the two new cacalolides 315 and 316, together with the known cacalolide 317, were isolated [3].…”

Antifeedant and Phytotoxic Activity of Cacalolides and Eremophilanolides

“…Natural products 4Ð7, 9, and 11, and the derivatives 1Ð3, 8, 10, and 12 were available from previous works (Burgueñ o-Tapia et al, 2001Burgueñ o-Tapia and Joseph-Nathan, 2003;Romo and Joseph-Nathan, 1964).…”

“…As part of our ongoing studies on the structural analysis (Burgueñ o-Tapia et al, 2001Burgueñ o-Tapia and Joseph-Nathan, 2003) and plant-defensive properties of cacalolides and eremophilanolides from Senecio species (Reina et al, 2001(Reina et al, , 2006, we selected S. madagascariensis, a plant of South African origin (Humbert, 1923;Scott et al, 1998) which has been the target of many efforts to control infestation levels in pastures (Sindel and Michael, 1992;Anderson and Panetta, 1995). This species is migrated in South America and is currently found in quite distant countries like Argentina and Colombia (Cabrera and Zardini, 1978).…”