Hyeong Kyu Lee

Anti-complementary activity of protostane-type triterpenes fromAlismatis rhizoma

Four protostane-type triterpenes, alisol B 23-acetate (1a), alisol C 23-acetate (2a), alisol B (3a), and alisol A 24-acetate (4a), were isolated from the rhizome ofAlismatis plantago-aquatica L. var.orientate Samuelson (Alismataceae) and eleven protostane derivatives (compounds1-11) were obtained by selective modification from alisol B 23-acetate (1a). These compounds were investigated for their anti-complement activity against the classical pathway of the complement system. Alisol B (3a) and alisol A 24-acetate (4a) exhibited anti-complement activity with IC50 values of 150 and 130 μM. Among the synthetic derivatives, the tetrahydroxylated protostane triterpene (9) showed moderate inhibitory activity with IC50 value of 97.1 μM. Introduction of an aldehyde group at C-23 (10; IC50 value, 47.7 μM) showed the most potent inhibitory effect on the complement systemin vitro

Inhibition of cytokine-induced vascular cell adhesion molecule-1 expression; possible mechanism for anti-atherogenic effect of Agastache rugosa

Adhesion molecules such as vascular cell adhesion molecule‐1 (VCAM‐1) play an important role during the early stages of atherogenesis. Agastache rugosa has an anti‐atherogenic effect in low density lipoprotein receptor −/− mice. Moreover, A. rugosa reduced macrophage infiltration and VCAM‐1 expression has been localized in aortic endothelium that overlies early foam cell lesions. This study ascertained that tilianin (100 μM), a major component of A. rugosa, inhibits the tumor necrotic factor‐α (TNF‐α)‐induced expression of VCAM‐1 by 74% in cultured human umbilical vein endothelial cells (HUVECs). Also, tilianin (100 μM) reduced TNF‐α‐induced activation of nuclear factor‐κB in HUVECs.

Magnone A and B, novel anti-PAF tetrahydrofuran lignans from the flower buds of Magnolia fargesii.

In a search for platelet-activating-factor (PAF) antagonists, two new lignan compounds were isolated from the Chinese crude drug shin-i, the flower buds of Magnolia fargesii. Their structures were elucidated as (2S,3R,4R)-tetrahydro-2-(3,4-dimethoxyphenyl)-4-(3, 4-dimethoxybenzoyl)-3-(hydroxymethyl)furan (magnone A, 1) and (2S,3R, 4R)-tetrahydro-2-(3,4,5-trimethoxyphenyl)-4-(3, 4-dimethoxybenzoyl)-3-(hydroxymethyl)furan (magnone B, 2). Magnones A and B showed antagonistic activity against PAF in the [3H]PAF receptor binding assay with the IC50 values of 3.8 x 10(-5) M and 2.7 x 10(-5) M, respectively.

Anti-human immunodeficiency virus-type 1 activity of constituents fromJuglans mandshurica

Three naphthalene glycosides (1-3), four flavonoids (4-7), and two galloyl glycosides (8-9) were isolated from the stem-bark ofJuglans mandshurica (Juglandaceae). Their structures were determined by chemical and spectral means, including to 2D-NMR (COSY, HMQC, and HMBC) experiments. Amongst the isolated compounds, taxifolin (4) showed the most potent HIV-induced cytopethic activity against MT-4 cells with complete inhibitory concentration (IC100) value of 25 μg/ml and maximum cytotoxic concentration (CC100) value of above 100 μg/ml. However, naphthalene glycosides (1-3), flavonoids (5-7)), and galloyl tannins (8-9) were inactive against anti-HIV-1 activity.

Oleanane-Type Triterpenoids from Aceriphyllum rossii and Their Cytotoxic Activity

The hexane-soluble fraction of the roots of Aceriphyllum rossii was used to isolate seven new oleanane-type triterpenoids, aceriphyllic acids C-I (1-7), together with seven known triterpenoids. The structures of aceriphyllic acids C-I were determined as 3alpha-hydroxyolean-12-en-23,29-dioic acid (1), 3beta-hydroxyolean-12-en-23,29-dioic acid (2), 3beta,23-dihydroxyolean-12-en-29-oic acid (3), 3alpha-O-acetylolean-12-en-23,27-dioic acid (4), 3alpha-O-caffeoylolean-12-en-27-oic acid (5), 3alpha-O-acetylolean-12-en-23,29-dioic acid (6), and 3alpha-hydroxyolean-12-en-23-al-27-oic acid (7) by spectroscopic analyses. In the evaluation of the in vitro cytotoxicity of these compounds against the MCF-7 and LLC cancer cell lines, compounds 10 and 13 exhibited cytotoxic activity against the LLC cancer cell line with IC(50) values of 7.63 and 6.56 microM, respectively.

A cytotoxic secocycloartenoid from Abies koreana.

Two triterpenoids, 24-methylene-3, 4-seco-cycloart-4(28)-en-3-oic acid (1) and 3-oxo-9ß-lanosta-7, 22Z, 24-trien-26, 23-olide (6) were isolated fromAbies koreana, together with ß-sitosterol (2), maltol (3), ß-sitosterol-O-ß-D-glucoside (4), and hexacosylferulate (5). The structures of the compounds were established based on the spectroscopic data. The cytotoxic activities of triterpenoids have been evaluated using the sulforhodamine B (SRB) method. Compound 1 showed moderate cytotoxicities against human lung carcinoma (A549), ovarian carcinoma (SK-OV-3), malignant melanoma (SK-MEL-2), and colon carcinoma (HCT-15) cell lines.

A potent anti-complementary acylated sterol glucoside fromOrostachys japonicus

In order to isolate substances that inhibit the hemolytic activity of human serum against erythrocytes, we have evaluated whole plants of theOrostachys japonicus species with regard to its anti-complement activity, and have identified its active principles following activity-guided isolation. A methanol extract of theO. japonicus, as well as itsn-hexane soluble fraction, exhibited significant anti-complement activity on the complement system, which was expressed as total hemolytic activity. A bioassay-guided chromatographic separation of the constituents resulted in the isolation of three known compounds1–3 from the activen-hexane fraction. The structure of these compounds were analyzed, and they were identified as hydroxyhopanone (1), β-sitosteryl-3-O-β-d-glucopyranosyl-6′-O-palmitate (2), and β-sitosteryl-3-O-β-d-glucopyranoside (3), respectively. Of these compounds, compound2 exhibited potent anti-complement activity (IC50=1.0±0.1 μM) on the classical pathway of the complement, as compared to tiliroside (IC50=76.5±1.1 μM), which was used as a positive control. However, compounds1 and3 exhibited no activity in this system.

Lignans from the Fruits of Forsythia suspensa (Thunb.) Vahl Protect High-Density Lipoprotein during Oxidative Stress

The objective of the present study was to investigate the beneficial properties lignan compounds obtained from the fruits of Forsythia suspensa (Thunb.) Vahl (Oleaceae) for protecting human high-density lipoprotein (HDL) against lipid peroxidation. The isolated compounds (1–8) inhibited the generation of thiobarbituric acid-reactive substances (TBARS) in a dose-dependent manner with IC50 values from 8.5 to 18.7 μM, since HDL oxidation mediated by catalytic Cu2+. They also exerted an inhibitory effect against thermo-labile radical initiator (AAPH)-induced lipid peroxidation of HDL with IC50 values from 12.1 to 51.1 μM. Compounds 1 and 5 exerted inhibitory effects against the Cu2+-induced lipid peroxidation of HDL, as shown by an extended lag time prolongation at the concentration of 3.0 μM. These results suggest that the antioxidative effects of F. suspensa are due to its lignans and that these constituents may be useful for preventing the oxidation of HDL.

Inhibitory constituents against HIV-1 protease fromAgastache rugosa

Two diterpenoid compounds, agastanol (1) and agastaquinone (2), were isolated from the roots ofAgastache rugosa (Labiatae). Compound1 and2 showed significant inhibitory effects against human immunodeficiency virus type 1 (HIV-1) protease activity with IC50 values of 360 and 87 μM, respectively.

Phenolic glycosides from Alangium salviifolium leaves with inhibitory activity on LPS-induced NO, PGE2, and TNF-α production

Three new phenolic glycosides, salviifosides A-C (13), and three known compounds salicin (4), kaempferol (5), and kaempferol 3-O-beta-d-glucopyranoside (6) were isolated from the leaves of Alangium salviifolium (L.f.) Wangerin (Alangiaceae). The structures of the new metabolites were determined on the basic of spectroscopic analyses including two dimensional NMR. The anti-inflammatory activities of new compounds (1-3) were investigated on lipopolysaccharide (LPS)-induced murine macrophage cells line, RAW 264.7. Salviifoside B (2) potentially inhibits the productions of nitric oxide (NO), prostaglandin E(2) (PGE(2)), and tumor necrosis factor-alpha (TNF-alpha).