This study was carried out to investigate the potential of Korean red pine (Pinus densiflora) inner bark extracts as an antidiabetic agent. The ethyl acetate soluble fraction of the bark extracts was chromatographed on a Sephadex LH-20 column to yield five compounds, which structures were elucidated by NMR spectroscopy. The isolated compounds were (+)-catehin, (−)-epicatechin, taxifolin, taxifolin-3'-O-β-D-(+)-glucose and ñ-courmaric acid. The antidiabetic activity of the different fractions, including the crude extracts and isolated compounds, was evaluated by β-cells insulin secretion and glucose uptake in skeletal muscle cells. The insulin secretion was 128%for taxifolin at 25 µg/mL. However, the other samples had no effect on this test. For the glucose uptake activity assay, 1 µM insulin and 2 mM metformin were used as controls. Both the crude extract and taxifolin showed relatively low activity values, but the other samples yielded glucose uptake values over 260%. ρ-courmaric acid showed the highest uptake (270%). The results confirmed that Korean red pine extracts may be used as a hypoglycemic agent.

Japanese anise (Illicium anisatum L.) leaves were collected and ground after drying, then immersed with 50 % aqueous acetone for 3 days. After filtration, the extracts were fractionated with n-hexane, chloroform (CHCl 3 ), ethylacetate (EtOAc) and H 2 O, and then freeze dried after concentration. A portion of EtOAc (3.12 g) and H 2 O (6.08 g) soluble fractions were chromatographed on a Sephadex LH-20 column with various aqueous MeOH solution to isolate the compounds.Compound 1 ((+)-catechin) was isolated from EtOAc soluble fraction. Compounds 2 (quercetin), 3 (quercitrin) and 4 (2''-O-rhamnosylvitexin) were isolated from H 2 O soluble fraction.For the first time, quercitrin (3) and 2''-O-rhamnosylvitexin (4) of the isolated compounds were obtained from the extracts of japanese anise leaves.