Four new amide alkaloids from the fruits of Piper longum and their anti-adipogenic activities.

Two pairs of previously unreported enantiomeric amide alkaloids (1a/1b, 2a/2b), together with twelve known compounds (3 - 14), were isolated from the fruits of Piper longum L. Their structures and absolute configurations were fully elucidated through a combination of comprehensive spectroscopic analyses and a comparison between experimental and calculated electronic circular dichroism (ECD) data. Furthermore, the anti-adipogenic potential of the isolates was evaluated using the MDIR-induced adipogenesis model in OP9 preadipocytes. Notably, compounds 3, 4, 10 and 14 demonstrated favorable anti-adipogenic activities, highlighting their potential as lead molecules for the development of anti-adipogenic agents.