A new pancreatic lipase inhibitor isolated from the roots of <Emphasis Type="Italic">Actinidia arguta</Emphasis>

A new coumaroyl triterpene, 3-O-trans-p-coumaroyl actinidic acid (1), as well as five known triterpenes, ursolic acid (2), 23-hydroxyursolic acid (3), corosolic acid (4), asiatic acid (5) and betulinic acid (6) were isolated from an EtOAc-soluble extract of the roots of Actinidia arguta. The structure of compound 1 was elucidated from interpretation of the spectroscopic data, particularly by extensive 1D and 2D NMR studies. All the isolates (1-6) were evaluated in vitro for their inhibitory activities on pancreatic lipase (PL). Of the isolates, the new compound 1 possessed the highest inhibitory activity on PL, with an IC(50) of 14.95 microM, followed by ursolic acid (2, IC(50) = 15.83 microM). The other four triterpenes (3-6) also showed significant PL inhibitory activity, with IC(50) values ranging from 20.42 to 76.45 microM.     

<Emphasis Type="Italic">Meso</Emphasis>-dihydroguaiaretic acid isolated from <Emphasis Type="Italic">Saururus chinensis</Emphasis> inhibits cyclooxygenase-2 and 5-lipoxygenase in mouse bone marrow-derived mast cells

Meso-dihydroguaiaretic acid (MDGA) is a medicinal herbal product isolated from the aerial parts of Saururus chinensis that inhibits the cyclooxygenase-2 (COX-2)-dependent phase of prostaglandin D(2) (PGD(2)) generation in bone marrow-derived mast cells (BMMC) (IC(50) 9.8 microM). However, this compound did not inhibit COX-2 protein expression in BMMC at concentrations up to 30 microM, indicating that MDGA directly inhibits COX-2 activity. In addition, this compound consistently inhibited the production of leukotriene C(4) (IC(50) 1.3 microM). These results demonstrate that MDGA inhibits both COX-2 and 5-lipoxygenase. Furthermore, this compound strongly inhibited the degranulation reaction in BMMC (IC(50) 11.4 microM). Therefore, this compound might provide a basis for novel anti-inflammatory drug development.     

Inhibitory effect of<Emphasis Type="Italic">Trans-N-p</Emphasis>-coumaroyl tryamine from the twigs of<Emphasis Type="Italic">Celtis chinensis</Emphasis> on the acetylcholinesterase

The methanolic extract of the twigs of Celtis chinensis was found to show inhibitory activity on acetylcholinesterase (AChE), an enzyme that plays a role in the metabolic hydrolysis of ACh. Bioassay-guided fractionation of the methanolic extract resulted in the isolation of N-p-coumaroyl tyramine, as an inhibitor on AChE. This compound inhibited AChE activity in a dose-dependent manner, and the IC50 value of trans-N-p-coumaroyl tyramine was 34.5 microg/mL (122 microM).     

A new lignan glycoside from the fruits of <Emphasis Type="Italic">Cornus kousa</Emphasis> Burg.

A new lignan glycoside, (7'S, 8'R)-dihydrodehydrodiconiferyl alcohol-4'-O-beta-D-xylopyranoside (1), named cornuskoside A, was isolated from the fruits of Cornus kousa. The structure of the compound was determined by spectroscopy, including FABMS, UV, IR, (1)H-and 13C-NMR, DEPT and 2D-NMR (COSY, HSQC, and HMBC). This new lignan glycoside, along with its aglycone, (7'S, 8'R)-dihydrodehydrodiconiferyl alcohol (3), and another lignan with a similar skeleton, (-)-balanophonin (2), which have been previously isolated from this plant, were evaluated for cytotoxicity in human cancer cell lines such as HeLa, MCF-7, SK-MEL-5, and SK-OV-3. Compounds 2 and 3 showed cytotoxicity against HeLa [IC50 = 29.1 microM (2), 45.5 microM (3)], MCF-7 [IC50 = 29.2 microM (2), 28.2 microM (3)], SK-MEL-5 [IC50 = 31.3 microM (2), 32.3 microM (3)], and SK-OV-3 [IC50 = 33.4 microM (2), 43.4 microM (3)] cell lines.     

The radical scavenging effects of stilbene glucosides from<Emphasis Type="Italic">Polygonum multiflorum</Emphasis>

The extract of the root of Polygonum multiflorum exhibited a significant antioxidant activity assessed by the DPPH radical scavenging activity in vitro. The bioassay-guided fractionation of the extract yielded a stilbene glucoside, (E)-2,3,5,4'-tetrahydroxystilbene-2-O-beta-d-glucopyranoside (1) as an active constituent responsible for the antioxidant property. Compound 1 demonstrated a moderate DPPH radical scavenging activity (IC50, 40 microM), while the corresponding deglucosylated stilbene 2 exhibited a much higher activity (IC50, 0.38 microM).     

<Emphasis Type="Italic">In Vitro</Emphasis> hepatoprotective compounds from <Emphasis Type="Italic">Suaeda glauca</Emphasis>

Bioassay-guided fractionation of the MeOH extract of Suaeda glauca yielded four phenolic compounds, methyl 3,5-di-O-caffeoyl quinate (1) and 3,5-di-O-caffeoyl quinic acid (2), isorhamnetin 3-O-beta-D-galactoside (3), and quercetin 3-O-beta-D-galactoside (4). Compounds 1 and 2 were hepatoprotective against tacrine-induced cytotoxicity in human liver-derived Hep G2 cells with the EC(50) values of 72.7+/-6.2 and 117.2+/-10.5 microM, respectively. Silybin as a positive control showed an EC(50) value of 82.4+/-4.1 microM.     

Two new phenolic constituents of<Emphasis Type="Italic">Humulus japonicus</Emphasis> and their cytotoxicity test<Emphasis Type="Italic">In Vitro</Emphasis>

Two new phenolic constituents (4 and 6), together with four known constituents, methyl ferulate (1), eugenyl-beta-D-glucopyranoside (2), apigenin-7-O-beta-D-glucopyranoside (3), and (E)-resveratrol-3-O-beta-D-glucopyranoside (5) were isolated from the MeOH extract of the aerial part sof Humulus japonicus. The structures of the new compounds were determined by spectroscopic methods to be divarin-3-O-beta-glucopyranoside (4), and lariciresinol-9-O-beta-xylopyranoside (6). Compounds 1 and 3 exhibited moderate cytotoxicity against two human cancer cell lines (SK-OV-3 and HCT15) with ED50 values ranging from 8.84 to 8.79 microM.     

Neuraminidase Inhibitors from<Emphasis Type="Italic">Reynoutria elliptica</Emphasis>

In the course of screening neuraminidase inhibitors from herbal medicines, Reynoutria elliptica exhibited high inhibitory activity. Four active compounds were isolated from the ethyl acetate soluble fraction by consecutive purification using sillica gel, Sephadex LH-20 chromatography, and recrystallization. The chemical structures of these compounds were identified as 1,3,8-trihydroxy-6-methylanthraquinone (emodin) 1,8-dihydroxy-3-methoxy-6-methylanthraquinone (emodin 3-methyl ether; physcion), 1,3,8-trihydroxy-6-hydoxymethylanthraquinone (omega-hydroxyemodin), and 3,5,4'-trihydroxystilbene (trans-resvertrol) by spectral data including MS, 1H-, and 13C-NMR. The IC50 values of emodin, emodin 3-methyl ether, omega-hydroxyemodin, and trans-resvertrol were 2.81, 74.07, 10.49, and 8.77 microM, respectively. They did not inhibit other glycosidase such as glucosidase, mannosidase, and galactosidase, indicating that they were relatively specific inhibitors of neuraminidase.     

Antioxidant constituents and a new triterpenoid glycoside from<Emphasis Type="Italic">Flos Lonicerae</Emphasis>

As a component of our continuing investigations into herb-derived antioxidant agents, we have evaluated the antioxidant effects of Flos Lonicerae (Lonicera japonica flowers), via 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, total reactive oxygen species (ROS), hydroxyl radical (*OH), and peroxynitrite (ONOO-) assays. Among the methanolic extract and the dichloromethane, ethyl acetate, n-butanol, and water fractions, the EtOAc fraction of Flos Lonicerae exhibited marked scavenging/inhibitory activities, as follows: IC50 values of 4.37, 27.58 +/- 0.71, 0.47 +/- 0.05, and 12.13 +/- 0.79 microg/mL in the DPPH, total ROS, ONOO-, and *OH assays, respectively. Via a bioactivity-guided fractionation approach, a new triterpenoid glycoside, oleanolic acid 28-O-alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-xylopyranosyl(1-->6)]-beta-D-glucopyranosyl ester (12), along with eleven known compounds, including chrysoeriol (1), luteolin (2), 5-hydroxymethyl-2-furfural (3), caffeic acid (4), protocatechuic acid (5), chrysoeriol 7-O-beta-D-glucopyranoside (6), isorhamnetin 3-O-beta-D-glucopyranoside (7), kaempferol 3-O-beta-D-glucopyranoside (8), quercetin 3-O-beta-D-glucopyranoside (9), hederagenin 3-O-alpha-L-arabinopyranoside (10), and luteolin 7-O-beta-D-glucopyranoside (11), were isolated from the EtOAc fraction. The structures of isolated compounds 1-12 were elucidated via spectroscopic analyses. Compound 12 was isolated from a natural source for the first time. Compounds 2, 4, 5, 7, 9, and 11 evidenced marked scavenging activities, with IC50 values of 2.08-11.76 microM for DPPH radicals, and 1.47-6.98 microM for ONOO-.     

Antioxidant and antiatherogenic activity of<Emphasis Type="Italic">cis</Emphasis>-hinokiresinol from<Emphasis Type="Italic">Trapa pseudoincisa</Emphasis>

cis-Hinokiresinol, also known as (+)-nyasol, was isolated for the first time from an aquatic herbaceous plant, Trapa pseudoincisa NAKAI, via silica gel and octadecyl silica gel column chromatographies. The chemical structure was determined via analyses of the spectroscopic data, including NMR, MS and IR. cis-Hinokiresinol was also found to exhibit antioxidant and antiatherogenic activities. The ICso values for the scavenging activities of cis-hinokiresinol on ABTS cation and superoxide anion radicals were 45.6 and 40.5 microM, respectively. The IC50 values for the inhibitory effects on Lp-PLA2, hACAT1, hACAT2 and LDL-oxidation were 284.7, 280.6, 398.9 and 5.6 microM, respectively.     

Monoamine oxidase inhibitory components from<Emphasis Type="Italic">Cayratia japonica</Emphasis>

Seven flavonoids were isolated from the whole plants and fruits of Cayratia japonica through the activity-guided isolation of a methanol extract using a monoamine oxidase (MAO) inhibition assay as a monitor. The chemical structures of the isolates were assigned as apigenin-7-O-beta-D-glucuronopyranoside (1), apigenin (2), luteolin (3), luteolin-7-O-beta-D-glucopyranoside (4), (+)-dihydroquercetin (taxifolin) (5), (+)-dihydrokaempferol (aromadendrin) (6) and quercetin (7). Among the isolated compounds, flavones such as apigenin (2) and luteolin (3), as well as the flavonol, quercetin (7) showed potent inhibitory effects against the MAO activity with IC50 values of 6.5, 22.6, and 31.6 microM, respectively. However, the flavone glycosides, apigenin-7-O-beta-D-glucuronopyranoside (1) and luteolin-7-O-beta-D-glucopyranoside (4), showed mild MAO inhibition (IC50 values: 81.7 and 118.6 microM, respectively). The flavanonol derivatives, taxifolin (5) and aromadendrin (6), also showed weak inhibition (IC50 values: 154.7 and 153.1 microM, respectively). Furthermore, quercetin (7) had a more potent inhibitory effect on MAO-A (IC50 value: 2.8 microM) than MAO-B (IC50 value: 90.0 microM). Apigenin (2) and luteolin (3) also preferentially inhibited MAO-A (IC50 values: 1.7 and 4.9 microM, respectively) compared with MAO-B (IC50 values: 12.8 and 59.7 microM, respectively).     

Acetylcholinesterase inhibitors from the aerial parts of<Emphasis Type="Italic">Corydalis speciosa</Emphasis>

In a bioassay-guided search for acetylcholinesterase inhibitors from Korean natural resources, four isoquinoline alkaloids, corynoxidine (1), protopine (2), palmatine (3), and berberine (4) have been isolated from the methanolic extract of the aerial parts of Corydalis speciosa. Structures of these compounds were elucidated on the basis of spectroscopic techniques. These compounds inhibited acetylcholinesterase activity in a dose-dependent manner, and the IC50 values of compounds 1-4 were 89.0, 16.1, 5.8, and 3.3 microM, respectively.     

Jacaranone: A cytotoxic constituent from<Emphasis Type="Italic">senecio ambiguus</Emphasis> subsp.<Emphasis Type="Italic">ambiguus</Emphasis> (Biv.) DC. Against renal adenocarcinoma achn and prostate carcinoma LNCaP cells

Senecio ambiguus subsp. ambiguus (Biv.) DC. extracts were able to inhibit the in vitro proliferation of renal cell adenocarcinoma ACHN and hormone dependent prostate carcinoma LNCaP. The potential cytotoxic property of the plant was revealed by the methanolic extract action against LNCaP (IC50 of 5.51 microg/mL) and ACHN (IC50 of 38.95 microg/mL). The most potent cytotoxic activity (IC50 of 5.34 microg/mL against the prostate carcinoma cell line) was exerted by the dichloromethane extract. Through bioassay-guided fractionation of the dichloromethane extract jacaranone was isolated as the major active constituent. This quinoid showed a very strong activity against ACHN and LNcaP with IC50 of 4.32 and 7.39 microg/mL, respectively. Its structure was established by GC/MS and NMR analysis. The n-hexane extract showed an interesting inhibition on the proliferation of tumor cell lines an IC50 value of 5.23 microg/mL against LNCaP. Three compounds identified in the n-hexane extract such as nerolidol, a-humulene and g-tocopherol were found to be active aginst LNCAP with IC50 values ranged from 11.24 to 15.56 microg/mL.     

Two New Triterpene Glycosides from the Vietnamese Sea Cucumber<Emphasis Type="Italic">Holothuria scabra</Emphasis>

Two new triterpene glycosides, namely holothurin A3 (1) and A4 (2) were isolated from the methanol extract of the sea cucumber, Holothuria scabra, with their structures elucidated from the spectroscopic evidence (1D NMR, 2D NMR, ESI-MS and HRESI-MS). Compounds 1 and 2 were found to be strongly cytotoxic to both cancer cell lines, KB and Hep-G2, with 50% inhibitory concentrations (IC50) of 0.87 and 0.32 microg/mL (for compound 1) and of 1.12 and 0.57 microg/mL (for compound 2), respectively.     

Isolation of constituents and anti-complement activity from<Emphasis Type="Italic">Acer okamotoanum</Emphasis>

A novel acylated sterol glucoside (1) along with four known compounds, beta-amyrin acetate (2), 3beta,24-dihydroxytaraxer-14-ene (3), cleomiscosin A (4), and cleomiscosin C (5), were isolated from the leaf and twig of Acer okamotoanum Nakai (Aceraceae). The structure of the new compound was determined to be beta-sitosterol glucoside-3'-O-hexacosanoicate based on chemical and spectroscopic analyses. In addition, the novel compound was found to exhibit a significant inhibitory effect (IC50 value of 0.2 microM) on the complement system activated by the classical pathway.     

Cytotoxic constituents of <Emphasis Type="Italic">Amanita subjunquillea</Emphasis>

As part of our systematic study of Korean toxic mushrooms, we have investigated the constituents of Amanita subjunquillea. The column chromatographic separation of the MeOH extract of A. subjunquillea led to the isolation of four ergosterols, two cerebrosides and four cyclopeptides. Their structures were determined by spectroscopic methods to be (22E,24R)-5alpha,8alpha-epidioxyergosta-6,9,22-triene-3beta-ol (1), (22E,24R)-5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol (2), (22E,24R)-5alpha,6alpha-epoxyergosta-8,22-diene-3beta,7beta-diol (3), (24S)-ergost-7-en-3beta-ol (4), 8,9-dihydrosoyacerebroside I (5), soyacerebroside I (6), beta-amanitin (7), phalloin (8), alpha-amanitin (9), and phalloidin (10). The compounds 1-6 and 8 were isolated for the first time from this mushroom. The isolated compounds were evaluated for the cytotoxicity against A549, SK-OV-3, SK-MEL-2 and HCT15 cells. Compound 9 exhibited significant cytotoxic activity against A549, SK-OV-3, SK-MEL-2 and HCT15 with ED(50) values of 1.47, 0.26, 1.57 and 1.32 microM, respectively.     

Gnidilatimonoein from<Emphasis Type="Italic">Daphne mucronata</Emphasis> induces differentiation and apoptosis in leukemia cell lines

Gnidilatimonoein is a new diterpene ester, recently isolated from the leaves of Daphne macronata with potent anti-tumoral and anti-metastastic activities (Yazdanparast et al., 2004). Promyeloblastic (KG1), promyelocytic (NB4) and promonocytic (U937) cells were cultured in the presence of various concentrations of the drug (0.5-3.0 microM) for 3 days. Herein, we report that gnidilatimonoein induces differentiation and apoptosis in KG1, NB4 and U937 cells. The drug inhibited growth and proliferation of KG1, NB4 and U937 cells with IC50 values of 1.5, 1.5 and 1.0 microM, respectively, after 72 h of treatment. Cell viability was also decreased by 18%, 20% and 23%, respectively, after 72 h treatment with the drug. NBT reducing assay revealed that the inhibition of proliferation is associated with differentiation especially toward monocytes-like morphology. Indeed, the drug at 0.5-1.5 microM induced differentiation by 5-50% in the cells. Acridine orange/ethidium bromide (AO/EtBr) double staining and DNA fragmentation assays revealed that apoptosis occurred after differentiation of the cells. Based on the present data, it seems that the new compound is a good candidate for further evaluation as an effective chemotherapeutic agent acting through induction of differentiation and apoptosis.     

Cholinesterase inhibitory activity of two farnesylacetone derivatives from the brown alga<Emphasis Type="Italic">Sargassum sagamianum</Emphasis>

Two known farnesylacetone derivatives (1 and 2) were isolated from the Korean brown alga Sargassum sagamianum off Jeju Island, Korea. Compounds 1 and 2 were identified as (5E,10Z)-6,10,14-trimethylpentadeca-5,10-dien-2,12-dione and (5E,9E,13E)-6,10,4-trimethyl-pentadeca-5,9,13-trien-2,12-dione, respectively, by comparison with the literature data. Compounds 1 and 2 showed moderate acetylcholinesterase and butyrylcholinesterase inhibitory activities with IC50 values of 65.0 approximately 48.0 and 34.0 approximately 23.0 microM, respectively.     

Anti-complementary activity of protostane-type triterpenes from<Emphasis Type="Italic">Alismatis rhizoma</Emphasis>

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 of Alismatis plantago-aquatice L. var. orientale Samuelson (Alismataceae) and eleven protostane derivatives (compounds 1-11) 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 microM. Among the synthetic derivatives, the tetrahydroxylated protostane triterpene (9) showed moderate inhibitory activity with IC50 value of 97.1 microM. Introduction of an aldehyde group at C-23 (10; IC50 value, 47.7 microM) showed the most potent inhibitory effect on the complement system in vitro.