Isolation and structure elucidation of anti-tyrosinase compounds from the seeds of Crotalaria pallida.

Three new compounds, crotalariapallins A-C (1-3), were isolated from the 95% EtOH extract of the seeds of Crotalaria pallida. Their structures were established based on extensive spectroscopic methods, including HRESIMS, UV, 1D and 2D NMR. All compounds were evaluated for their inhibitory activities to tyrosinase. These compounds showed different degrees of inhibitory activities, among them, compound 3 exhibited the strongest inhibition activity (IC50 = 0.42 mM).