Unusual Bicyclo[3.2.1]Octanoid Neolignans from Leaves of Piper crocatum and Their Effect on Pyruvate Dehydrogenase Activity

Three undescribed bicyclo[3.2.1]octanoid neolignan glucosides, along with a known neolignan, were isolated from the leaves of Piper crocatum Ruiz & Pav. Their chemical structures were elucidated using extensive spectroscopic analyses including 1D and 2D NMR experiments and HR-ESI-MS analysis, as well as through comparison with previously reported data. Two compounds were assessed for their inhibitory effect against pyruvate dehydrogenase E1 alpha S300 phosphorylation. The fluorescent image suggested that both compounds (60 mu M) revealed a stronger inhibition effect than the positive control (dichloroacetate, DCA 5 mM), with IC50 values of 99.82 mu M and 80.25 mu M, respectively.

Automated summary

Three undescribed bicyclo[3.2.1]octanoid neolignan glucosides, along with a known neolignan, were isolated from Piper crocatum leaves. Their chemical structures were elucidated through spectroscopic analyses and compared with previous data. Two compounds showed strong inhibitory effects against pyruvate dehydrogenase E1 alpha S300 phosphorylation in comparison to the positive control.