Spiranoid

Cirigliano AM, Veleiro AS, Bonetto GM, Oberti JC, Burton G (1996) Spiranoid Withanolides from Jaborosa runcinata and Jaborosa araucaria. J Nat Prod 59 717... 

The presence of an oxygenated function at C-23 allows the formation of a y-lactone side chain (group B), these withanolides may be divided in five subgroups, spiranoid withanolides, trechonolides, subtriflora-y-lactones, ixocarpalactones and perulactones, Fig. (3)... 

The first withanolide with a spiranoid y-lactone side chain, jaborosalactone P (77), was isolated from plants of Jaborosa odonelliana collected in Salta province (Argentina) [43]. Lately six structurally related compounds were found in the same plant, jaborosalactones 10 (78), 14 (79) and 15 (80) in plants collected in summer and jaborosalactones 11 (81), 12 (82), 13 (83) and 14 (79) in plants collected in autumn [44]. 

Comparison of the structure of jaborosalactone 2 (85) with that of trechonolide A (64) indicated that both compounds may have closely related biosynthetic precursors. In the former withanolide, ring closure on C-12 has occurred with a C-22 hydroxyl as shown in Fig. (4) pathway a. Oxidation of this intermediate or a related compound to the 22-ketone would allow cyclization between C-23 and the C-12 ketone to give a spiranoid withanolide (Fig. (4) pathway b). The co-occurrence of trechonolide A (64) and jaborosalactone 2 (85) in J. araucana supports this hypothesis. 

Fig. (4). Proposed biosynthetic routes to trechonolides (pathway a) and spiranoid withanolides (pathway b) via a common precursor. The spiranoid intermediate could render both types of spiranoid withanolides either by reduction at C-22 or dehydration of the 20-hydroxyl.

The fragmentation process in the mass spectra of proaporphines is strongly dependent on the character of the spiranoid ring D, as well as on the substitution pattern in the aromatic ring A and the relative stereochemistry. Cleavage patterns should, therefore, be compared only among structurally close analogs. 

These withanolides are formed by the double oxidation of C-22, leading to the formation of an ether linkage between C-12 and C-22 and a spiranoid -lactone at C-22. Examples include jaborosalactones 27 (18) and 28 (19), isolated from Jaborosa rotacea [31]. 

Special isopiene rule, 2669 Specific doses, 2423 Specific symptrans, 2423 Spectral generalizatiSpectrophotometric methods, 2073 Sperm count, 2420, 2421 Spermidine, 1732 Spermine, 1732 Sperm production, 2418 Sphacelariaceae, 2900-2901 Sphacelariales, 2900-2901 Sphaerococcaceae, 2890 Sphaerococcus coronopifolius, 2890 Sphaerotrichia japonica (Sphaerotrichia divaricata), 2896 Spherisorb ODS2, 3393 Spheroidene, 3270, 3271 Spheromastigote, 845 Spinacea oleracea, 864 Spinacia oleracea, 3584 Spindle cell sarcoma 45, 992 Spinosin, 2163 Spiranoid 5-lactone, 3472 Spiranthera, 735 Spirilloxanthin, 3268, 3270, 3271 Spirilloxanthin pathways, 3268, 3270, 3271 Spirostanols, ilXl-ZXiO, il il, 3239,... 

Fig. 7.30 Acnistin E, a withanolide with a modified skeleton due to a functionalization of 21-methyl (for explanation see text), and two highly functionalized jaborosalactones with characteristic spiranoid partial structures (C-23 and C-22, respectively)...

Modifications Due to an Integration of C-12 into an Additional Ring System. Highly functionalized metabolites with characteristic spiranoid substructure have been discovered as constituents of Jaborosa spp., e.g., jaborosalactone 10 in J. odonelliana (Cirigliano et al. 2002 and references therein) and jaborosalactone 29 in J. rotacea (Nicotra et al. 2006) (structures Fig. 7.30). 

Cirigliano AM, Veleiro AS, Oberti 1C, Burton G (2002) Spiranoid withanolides from Jaborosa odenelliana. 1 Nat Prod 65 1049-1951... 

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