Im Seon Lee

Anticomplementary activity of ginseng saponins and their degradation products

The anticomplementary activity of ginseng saponins and their degradation products obtained by chemical treatment of Korean red ginseng saponins was investigated. The total saponin and its major components showed strong anticomplementary activity and their structure-activity relationship was evaluated.

In vitro anticomplementary activity of hederagenin saponins isolated from roots ofDipsacus asper

Anticomplementary activity of hederagenin and related saponins isolated fromDipsacus asper was investigatedin vitro. HN saponin F (3) was most potent with IC50 value of 3.7×10−5 M followed by 3-O-β-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-β-L-arabinopyranosyl hederagenin 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyrano side (8), 3-O-β-L-arabinopyranosyl hederagenin 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyrano side (5) dipsacus saponin A (4), and hederagenin (1) on the classical pathway (CP) of complement system, while the saponins3–5, did not show the inhibition of hemolysis and rather increase the hemolysis on the alternative pathway (AP). However, all of C-3 monodesmosides [prosapogenin CP (2), dipsacus saponin B (6), and dipsacus saponin C (7)] evoked hemolysis directly on the erythrocytes.

Anticomplementary activity of ergosterol peroxide fromNaematoloma fasciculare and reassignment of NMR data

A very high content (at least 0.23%) of ergosterol peroxide was isolated fromNaematoloma fasciculare Karst. Not only ergosterol peroxide but also ergosterol showed very strong anticomplementary activity on the classical pathway, the IC50 values being 5.0 μM and 1.0 μM, respectively. The1H and13C NMR data of ergosterol peroxide were revised and completely assigned by DEPT,1H-1H COSY, HMQC and HMBC correlations.

Anticomplement activities of oleanolic acid monodesmosides and bisdesmosides isolated fromTiarella polyphylla

Seven known oleanolic acid glycosides (1–7) were isolated from the MeOH extract ofTiarella polyphylla. The structures were identified to be 3-O-(β-D-glucopyranosyl) oleanolic acid (1), 3-O-[β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl] oleanolic acid (2), 3-O-[β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl] oleanolic acid (3), 3-O-[β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl] oleanolic acid 28-O-β-D-glucopyranosyl ester (4), 3-O-[β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl] lleanolic acid 28-O-β-D-glucopyranosyl ester (5), 3-O-[a-L-rhamnopyranosyl-(1→3)-β-D-glucuronopyranosyl] oleanolic acid (6), and 3-O-[α-L-rhamnopyranosyl-(1→3)-β-D-glucuronopyranosyl] oleanolic acid 28-O-β-D-glucopyranosyl ester (7) on the basis of physicochemical and spectral data. These triterpene glycosides were tested for the anticomplement activity and hemolytic activity. Bisdesmosidic saponins,4, 5, and7, showed anticomplement activity; in contrast, monodesmosidic saponins,1–3, and6, showed direct hemolytic activity. Methyl esterified monodesmosidic saponins showed anticomplement activity at a low concentration and hemolytic activity at a high concentration.

Platelet-activating factor antagonistic activity and13C NMR assignment of pregomisin and chamigrenal fromSchisandra chinensis

In the course of searching for PAF receptor antagonists, pregomisin (1) and chamigrenal (2) were isolated from the fruits ofSchizandra chinensis Baill by the bioactivity-guided isolation. Both compounds showed PAF antagonistic activity and the IC50 values were 4.8×10−5 M and 1.2×10−4 M, respectively. In addition, the13C NMR assignments of1 and2 using DEPT, HMQC, COLOC and HMBC were reported for the first time.

Sesquiterpene components from the flower buds ofMagnolia fargesii

From the Chinese crude drugshin-i, the flower buds ofMagnolia fargesii, four sesquiterpene, oplopanone (1), oplodiol (2), homalomenol A (3) and 1β,4β,7α-trihydroxyeudesmane (4) were isolated. These structures were elucidated and the13C-NMR chemical, shifts of these compounds were revised by means of various 2D-NMR techniques.

Anticomplementary Activity of Stilbenes from Medicinal Plants

The anticomplementary activity of stilbenes from medicinal plants in Korea was investigatedin vitro. 3,5-Dihydroxy-4′-methoxystilbene (3) was most potent with IC50 value of 1.5×10−4 M followed by rhapontigenin (4), oxyresverastrol (2), 2,3,4′,5-tetrahydroxystilbene-2-O-β-glucoside (9), rhaponticin (8), resverastrol (1), and piceid (7). The activity was found to be increased by a methylation on a hydroxy group of C-4′ of1, but decreased by further methylation on hydroxy groups of C-3 and C-5 and glucosylation on any hydroxy group of1. Addition of hydroxy group on C-2′ of1 or C-3′ of3 was little affected on the anticomplementary activity but the activity was increased byO-glucosylation on C-2 of1.

5α,7α(H)-6,8-cycloeudesma-1β,4β-diol from the flower buds of Magnolia fargesii

Abstract From the Chinese crude drug shin-i, the flower buds of Magnolia fargesii, a new cycloeudesmane-type sesquiterpene, 5α,7α(H)-6,8-cycloeudesma-1β,4β-diol, was isolated. The structure was elucidated by means of various NMR techniques. This compound has biogenetic significance because it is a plausible intermediate of the oppositol-type compound such as homalomenol A reported from this plant.