This class contains glycosides composed of a single rhamnose moiety joined in an O-glycosidic linkage to a lipid moiety. The lipid moiety is mainly two (sometimes one or three) β-hydroxy fatty acid chains (represented here in part by R1 and R2) linked to each other through an ester bond between the β-hydroxyl group of the chain distal to the glycosidic bond with the carboxyl group of the chain proximal to the glycosidic bond. The carboxyl group of the distal chain is usually free, but in a few cases it is esterified with a short alkyl group. The fatty acid chains may be saturated, mono-unsaturated, or poly-unsaturated and the chain length may vary from C8 to C16. In rare cases the rhamnose 2-hydroxyl group distal to the glycosidic bond may be acylated with a long chain alkenoate. [SoberonChavez05, AbdelMawgoud10]. Also see a di-rhamnolipid and a 3-(3-hydroxyalkanoyloxy)alkanoate.
Lepine02: Lepine F, Deziel E, Milot S, Villemur R (2002). "Liquid chromatographic/mass spectrometric detection of the 3-(3-hydroxyalkanoyloxy) alkanoic acid precursors of rhamnolipids in Pseudomonas aeruginosa cultures." J Mass Spectrom 37(1);41-6. PMID: 11813309
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