Structure of the ascarosides from Ascaris suum.

Six glycosides have been identified from the nematode Ascaris suum. The glycon part of all six glycosides is alpha L-3,6-dideoxymannose, previously known as ascarylose. The major components (4 and 5) and the minor components (8 and 9) have been shown by NMR and electrospray MS to involve a mixture of two homologous aglycons: the 2, omega-1 diols of hentriacontane and tritriacontane. Compounds 4 and 5 are glycosylated on only one of the hydroxy groups, while 8 and 9 are glycosylated on both. These compounds resemble ascarosides B and C previously isolated from Parascaris equorum. However, these aglycons are reported to be based on the 2,6-diol of hentriacontane. Compounds 6 and 7 are based on 2-hydroxy-nonacosane and 2-hydroxy-28-methylnonacosane glycosylated at C-2 with the same sugar. Although 6 and 7 are related to ascaroside A, previously isolated from P. equorum, these earlier reports suggest the chain in ascaroside A to be unbranched.