| Daylilies (Hemerocallis spp., Hemerocailidaceae) are widely consumed in eastern Asian as both a traditional food and medicine. In this study, Hemerocallis flowers and roots were examined in order to identify bioactive constituents that may exhibit antioxidant, anticancer, mosquitocidal, and schistosome inhibitory properties. An investigation of Hemerocallis cv. Stella de Oro flowers lead to the isolation of nine kaempferol, quercetin, and isorhamnetin 3-O-glycosides (1–9), phenethyl β-D-glucopyranoside (10), orcinol β-D-glucopyranoside ( 11), phloretin 2′-O-β- D-glucopyranoside (12), phloretin 2′- O-β-D-xylopyranosyl-(1 → 6)-β- D-glucopyranoside (13), a new napthalene-glycoside, stelladerol (14), and an amino acid (longitubanine A) (15). An examination of Hemerocallis fulva ‘Kwanzo’ Kaempfer roots lead to the isolation of seven new anthraquinones, kwanzoquinones A (16), B (17), C (19), D (20 ), E (21), F (22), and G (24), two known anthraquinones, 2-hydroxychrysophanol (18) and rhein (23), one new naphthalene glycoside, 5-hydroxydianellin ( 26), one known naphthalene glycoside, dianellin (25), one known flavone, 6-methylluteolin (27), and α-tocopherol.; Several new compounds such as kwanzoquinones A (16), B ( 17), C (19), E (21), and kwanzoquinone A and B monoacetates (16a and 17a, respectively) exhibited promising cancer cell growth inhibitory activity. In addition, the known compounds 2-hydroxychrysophanol (18) and rhein (23) inhibited cancer cell growth. Three compounds, kwanzoquinone D (20), stelladerol (14), and 5-hydroxydianellin (26), demonstrated remarkable antioxidant activity by inhibiting lipid oxidation more than 90% in an in vitro assay system. Three compounds, 2-hydroxychrysophanol ( 18) and kwanzoquinones C (19) and E (21), exhibited mosquitocidal properties against fourth instar Ades aegyptii larvae. Two compounds, 2-hydroxychrysophanol (18) and kwanzoquinone E (21), were discovered as novel agents for the prevention and treatment of schistosomiasis. These compounds were found to inhibit the motility and induce mortality in Schistosoma mansoni cercariae and adults. The bioactive constituents from daylilies are being further investigated in order to determine their modes of action and for development as new phytoceuticals. |
