Abstract
Two triterpenoids, iripallidal and iriflorental, known irone precursors, were shown to be solubilized by phosphatidylcholine (PC). Elution of liposomes (containing PC + iridals) on a Sephadex column showed that iridals and PC were always associated in the same fractions with comparable PC/iridal molecular ratios. Moreover, the physical parameters of dimyristoyl-PC membranes, measured by electron spin resonance were specifically modified by the presence of cycloiridals, indicating that they are integrated within liposomal membranes. These effects on fluidity and phase-transition patterns were compared with those of cholesterol. The secondary plant products, iridals, seem to have a structural role within cells comparable to that of sterols. Possible ecophysiological implications of iridals are discussed.
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Abbreviations
- CNO:
-
25-doxyl, 27-nor-cholesterol
- DMPC:
-
dimyristoylphatidylcholine
- ESR:
-
electron spin resonance
- MLV:
-
multi-lamellar vesicle(s)
- PC:
-
phosphatidylcholine
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Bonfils, JP., Sauvaire, Y. & Maurin, L. Evidence of cycloiridals as membrane constituents: effects on fluidity patterns compared to those of cholesterol. Planta 200, 353–357 (1996). https://doi.org/10.1007/BF00200303
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DOI: https://doi.org/10.1007/BF00200303