Two new compounds from the seeds of Vernonia anthelmintica

Two new compounds, named benzoyl-vernovan (1) and 2-(4'-hydroxyphenyl)-6-methyl-4H-pyran-4-one (2), together with one biflavonoid (3), one aurone (4) and six flavonoids were isolated from the seeds of Vernonia anthelmintica. Their structures were elucidated by extensive spectroscopic analyses and comparison with published data, and their influence on melanin content in B16 melanoma cells were tested. 5 and 9 increased melanin content by 2.2% and 30.9% higher than positive control 8-methoxypsoralen.