Triterpene Saponins from the Aerial Parts of Ilex cornuta and Their Cytotoxic Activity

Four new triterpene saponins (1-4), together with 13 known triterpenoids (5-17), were isolated from the MeOH extract of Ilex cornuta Lindley (Aquifoliaceae).Their structures were elucidated on the basis of chemical and spectroscopic methods.The isolated compounds were tested for their cytotoxicities against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15) in vitro using the sulforhodamine B (SRB) assay.Ilex cornuta Lindley (the Chinese holly or horned holly) belongs to the family Aquifoliaceae, and this herb is native to eastern China and Korea. 1 This species have been used in traditional Chinese medicine for the treatment of intertrigo, headache, dizziness, and hypertension, and for purifying the blood. 2 The water extract from its leaves has been used as contraceptive and anti-bacterial agents. 3Previous phytochemical studies on this plant reported the isolation of various triterpene saponins as main constituents such as ilexside, zigu-glucoside, cornutaside, and cornutaoside. 3-7Some of these isolates have been reported to exhibit increase in coronary blood flow and anti-hematoblastic coagulation activity. 5 have recently reported the isolation of triterpene derivatives from the MeOH extract of I. cornuta. 8In continuing research on this source, four new triterpene saponins (1-4), together with 13 known triterpenoids (5-17) were isolated and identified (Figure .1).The structures were determined using HETEROCYCLES, Vol.91, No. 6, 2015 Compound (1): a colorless gum; [α] 25 D +35.0 (c=2.0,MeOH); IR (KBr) νmax 3359, 2945, 2833, 1666, 1452, 1032, 649 cm -1 ; 1 H-NMR data, see Table 2; 13 C-NMR data, see Table 1; FABMS m/z 643 [M + Na] + ; HRFABMS m/z 643.3825 [M + Na] + ; (calcd.for C35H56O9Na 643.3822).Compound (2): a colorless gum; [α] 25 D +20.5 (c=0.3,MeOH); IR (KBr) νmax 3383, 2944,