Iridoid Glycosides from Tabebuia avellanedae.

Five novel iridoid glycosides, avellanedaesides A-E (1 - 5) were isolated from the H2 O extract of Tabebuia avellanedae. Their structures were determined on the basis of NMR and MS analysis. Isolated compounds suppressed inflammatory cytokine, tumor-necrosis factor-α and interleukin-1β production in cultured human myeloma THP-1 cells co-stimulated with lipopolysaccharide (LPS). In addition, the study revealed iridoid glycosides inhibited the activity of cytochrome CYP3A4 enzyme.