Ipomoea operculata

Ipomoea operculata has afforded three resin glycosides containing this glyco-sidic acid, operculins VI (19), XI (20), and XII (21). The macrolactone site was located at C-2 of the first rhamnose unit for 19 while in compounds 20 and 21 the lactonization was placed at C-3, the same site for mammosides A (17) and B (18). Two dodecanoyl residues are the fatty acids present in these resin glycosides and located at C-2 of the second rhamnose and at C-4 of the third rhamnose for operculin VI (19). For operculins XI (20) and XII (21), they were placed at C-2 or C-3 of the second rhamnose and C-4 at the third rhamnose (27). 

Ono M, Kawasaki T, Miyahara K (1989) Resin Glycosides. V. Identification and Characterization of the Component Organic and Glycosidic Acids of the Ether-Soluble Crude Resin Glycosides ( Jalapin ) from Rhizoma Jalapae Brasiliensis (Roots of Ipomoea operculata). Chem Pharm Bull 37 3209... 

Wagner H, Kazmaier P (1977) Struktur der Operculinsaure aus dem Harz von Ipomoea operculata. Phytochemistry 16 711... 

Constit. of the capsular antigen of Klebsiella K12, K18, K41 type specific antigen of Streptococcus pneumoniae type 2, type 6A O-antigen of Serratia marces-cens extracellular polysaccharide from Mycobacterium album B-88 in operculinic acid (see 3,12-Dihydroxyhexadecanoic acid) formed from the resin of Ipomoea operculata. 

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