Molecular Characterization and Bioactivity of Coumarin Derivatives from the Fruits of Cucumis bisexualis.

Cucumis bisexualis (Cucurbitaceae) is known as "mapao egg" or "muskmelon egg", which has been widely used as a wild melon in Chinese folk. Nine new coumarin derivatives (1-9), named 7-hydroxy-3-(4',6'-dihydroxy-5'-isopropyl-3″,3″-dimethyl-2 H-chromen)-6-prenyl-2 H-chro-men-2-one (1), 7-hydroxy-3-(5'-prenyl-3″,3″-dimethyl-2 H-chromen)-6-prenyl-2 H-chromen-2-one (2), 3-(6'-hydroxy-5'-prenyl-3″,3″-dimethyl-2 H-chromen)-6-prenyl-2 H-chromen-2-one (3), 3-(5'-ethyl-3″,3″-dimethyl-2 H-chromen)-6-prenyl-2 H-chromen-2-one (4), 3-(4',6'-dihydroxy-5'-dimeth-ylallyl-3″,3″-dimethyl-2 H-chromen)-6-prenyl-2 H-chromen-2-one (5), 3-[4',6'-dihydroxy-5'-(2-pro-penyl)-3″,3″-dimethyl-2 H-chromen]-14,15-dimethyl-pyrano-chromen-2-one (6), 3-(6'-dihydroxy-5'-isopropanol-3″,3″-dimethyl-2 H-chromen)-14,15-dimethyl-pyrano-chromen-2-one (7), 3-(5'-iso-pentenol-3″,3″-dimethyl-2 H-chromen)-14,15-dimethyl-pyrano-chromen-2-one (8), 3-(4',6'-dihydr-oxy-5'-prenyl-3″,3″-dimethyl-2 H-chromen)-14,15-dimethyl-pyrano-chromen-2-one (9), together with 12 known compounds (10-21), were isolated and identified by spectroscopic analysis and references from the active site (EtOAc soluble fraction) of the fruits of C. bisexualis for the first time. Compounds (1-21) were evaluated for antiacetylcholinesterase (AChE) and hepatoprotective activities for the first time. Compounds 1, 3, 5, 6, 7, and 9 showed anti-AChE activities with IC50 values ranging from 11.23 to 89.69 µM, and compounds 2, 4, 12, 15, 17, 18, and 19 (10 µM) exhibited moderate hepatoprotective activities. These findings shed much light on a better understanding of the anti-AChE and hepatoprotective effects of these coumarin derivatives and provided new insights into developing better anti-AChE and hepatoprotective drugs in the future.

Characterization of Chalcones from Medicago sativa L. and Their Hypolipidemic and Antiangiogenic Activities.

Medicago sativa L. is the most important cultivated herbage, known as "the king of forage" and "feed queen", in the world. A total of 8 new chalcones (1-8), and 12 known chalcones (9-20) were isolated from the aerial parts of M. sativa for the first time. Their structures were identified by extensive spectral data and references. The hypolipidemic and antiangiogenic activities of compounds (1-20) were evaluated for the first time. Compounds 3, 4, 11, 12, and 20 (10 µM) exhibited significant hypolipidemic activities by measuring the triglyceride content in HepG2 cells, with simvastatin as the positive control. Moreover, compounds 6, 8, 18, and 19 exhibited moderate antiangiogenic activities, which inhibited vascular-endothelial-growth-factor-induced human umbilical vein endothelial cell proliferation in vitro, with IC50 values of 13.86 ± 0.43, 15.53 ± 0.19, 39.52 ± 0.24, and 45.04 ± 0.51 µM, respectively. These research results may guide the search for new natural products with hypolipidemic and antiangiogenic attributes.

Alkenes with antioxidative activities from Murraya koenigii (L.) Spreng.

Four new alkenes (1-4), and six known alkenes (5-12) were isolated from Murraya koenigii (L.) Spreng. Their structures were elucidated on the basis of spectroscopic analyses and references. Compounds (1-12) were evaluated for antioxidative activities. Among them, compounds 1, 2, 4, and 7 exhibited significant antioxidative activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay with IC50=21.4-49.5 µM. The known compounds (5-12) were isolated from this plant for the first time.

[Studies on flavonoids from Cirsium setosum].

To investigate the chemical constituents of ethyl acetate from Cirsium setosum, fifteen flavonoids were obtained by column chromatography on silica gel, MCI, Sephadex LH-20, and preparative HPLC. Their structures were identified as 4',5,6-trihydroxy-7-methoxyflavone(1), 4',5-dihydroxy-7,8-dimethoxyflavone(2), sorbifolin-6-O-ß-glucopyranoside(3), kaempferol-7-O-α-L-rhamnoside(4), kaempferol(5), quercetin-3-O-ß-D-glucosyl-7-O-α-L-rhamnoside(6), myricetin(7), myricetin-3-O-ß-D-glucoside(8), 5,7- dihydroxy -3',4'- dimethoxyflavone(9), 3',4',5- trihydroxy-3,7-dimethoxyflavone(10), 3',3,4',5-tetrahydroxy-7-methoxyflavone(11), 3'-hydroxy-4',5,7-trimethoxyflavone(12), 7-hydroxy-3',4',5-trimethoxyflavone(13), 4',5-dihydroxy-2',3',7,8-tetramethoxylflavone(14), and 5-hydroxy-2',3',7,8-tetramethoxylflavone(15) by spectroscopic data analysis. All compounds were isolated from this plant for the first time.Compounds(1-15) were evaluated for their hypoglycemic activities by PTP1B enzyme model. Among them, compounds 2, 12, and 14 showed significant PTP1B inhibitory activities with IC50 values of 2.54, 1.85, 2.11 µmol•L⁻¹, respectively.

Hepatoprotective sesquiterpenes and rutinosides from Murraya koenigii (L.) Spreng.

Three new sesquiterpenes (1-3) and two new rutinosides (4 and 5) along with 17 known compounds (6-22) were isolated from the leaves of Murraya koenigii (L.) Spreng. The new compounds were elucidated as (3R,5S,6R)-3,5,6-trihydroxy-1,1,5-trimethylcyclohexyl-8-butyn-9-one (1), (8E,9R)-ethyl-7-(3S,5R,6S)-3,6-dihydroxy-1,1,5-trimethylcyclohexyl-9-hydroxybut-8-enoate (2), (3R)-3-O-ß-D-glucoside-6'-D-apiose-ß-ionone (3), 4-O-ß-D-rutinosyl-3-methoxyphenyl-1-propanone (4), and 1-O-ß-D-rutinosyl-2(R)-ethyl-1-pentanol (5) based on their spectroscopic data. Compounds 1, 4, 5, 18, and 21 (10 µM) exhibited moderate hepatoprotective activities.