Occurrence, biosynthesis, biological activity and NMR Spectroscopy of D and B, D ring seco-limonoids of Meliaceae family

Limonoids are modified tetranortriterpenoids, classified on the basis of which of the four rings (A, B, C and D) in the intact triterpene nucleus have been oxidized. The order Rutales produces a variety of seco-limonoids, such as A, 13, C, D, AB, AD, and BD-ring seco-limonoids. The Meliaceae family, belonging to the order Rutales, has yielded several D-ring and B, D-ring seco-limonoids This review describes the occurrence, biosynthesis, biological activity and NMR spectroscopy of D ring seco-limonoids, such, as gedunin derivatives and B, D-ring seco-limonoids, such as methyl angolensates, xyloccensins, methyl meliacates, phragmalins and modified phragmalins. The literature from 1990 to 2005 is reviewed.