Tenuistones A–H, Flavonoid Derivatives from Miliusa tenuistipitata with Anti-Proliferative and Anti-Migration Activities Against Triple-Negative Breast Cancer Cells (DRAFT: CAE92EC7)

Tenuistones A–H (1–8), eight undescribed flavonoid derivatives were isolated from the twigs and leaves of Miliusa tenuistipitata. Compound 1 is a flavonol-naphthoquinone hybrid contained a unique 2-isopentenyl-2-methoxyacetyl-6-methyl-1,4-naphthoquinone unit with new carbon skeleton. Compound 2 represent the first example of flavonol-homogentisic acid-monoterpene hybrid. Compounds 3–8 are six novel flavonol-sesquiterpene hybrids. Seven pairs of enantiomers [(+)/(-)-1–4, (+)/(-)-6–8] were further resolved by chiral HPLC resolution. Their structures were established by a combination analysis of the NMR and MS data, along with chemical calculations. A plausible biogenetic pathway of compound 1 was proposed. Enantiomer (–)-3 displays profound anti-proliferative and anti-migration activities against triple-negative breast cancer cells.