Inhibitory effect of 2-arylbenzofurans from the Mori Cortex Radicis (Moraceae) on oxygen glucose deprivation (OGD)-induced cell death of SH-SY5Y cells

Three known 2-arylbenzofurans, moracin P (1), moracin O (2) and mulberrofuran Q (3) were isolated from the MeOH extract of the Mori Cortex Radicis. These compounds 1–3 enhanced cell viability in dose-dependent manner against oxygen-glucose deprivation (OGD)-induced cell death in neuroblastoma SH-SY5Y cells, which was measured by MTT reduction assay. (EC₅₀ values of 10.4, 12.6, and 15.9 μM, respectively). In addition, the compounds 1–3 were examined for their inhibitory effect on OGD-induced ROS production by FACS analysis. We observed these compounds reduced ROS production in OGD-induced cell death (IC₅₀ values of 1.9, 0.3 and 12.1 μM, respectively). Consequently, reactive oxygen species (ROS) were overexpressed in OGD-induced cells and all three compounds reduced ROS induced by OGD in dosedependent manner. Taken together, compounds 1–3 might protect neuronal cell death against the oxidative stress induced by OGD, though further studies in vitro and in vivo models are necessary.     

Two new non-glycosidic iridoids from the leaves of Campsis grandiflora

Two new non-glycosidic iridoids, which were named cachinol (1) and 1-O-methyl cachinol (2), were isolated from the methanol extract of the leaves of Campsis grandiflora together with a known iridoid cachineside I (3). The structures of compounds 1 and 2 were determined on the basis of spectroscopic methods including two dimensional NMR and high resolution mass spectrometry. All of the isolated compounds showed mild inhibitory activities on rat platelet aggregation. Compounds 1 and 3 (IC50 : 246 and 219 microM, respectively) showed about 2-fold higher inhibitory effects than acetylsalicylic acid (ASA, IC50: 412 microM) on collagen-induced aggregation. Compounds 1 and 2 (IC50: 43.2 and 38.4 microM, respectively) were about 2-fold more inhibitory than ASA (IC50: 75.2 microM), and about 4-fold more effective than their glycoside 3 (IC50: 189 microM) on AA-induced aggregation.     

Monoamine oxidase inhibitory coumarins from the aerial parts ofDictamnus albus

The methanol extract from the aerial parts of Dictamnus albus was active in inhibiting monoamine oxidase (MAO) from the mouse brain. Activity-guided fractionation led to the isolation of four known coumarins, 7-(6'R-hydroxy-3', 7'-dimethyl-2'E, 7'-octadienyloxy) coumarin (1), auraptene (2), umbelliferone (3), and xanthotoxin (4), as active compounds along with an inactive alkaloid, skimmianine (5). Compounds 1 and 2 inhibited MAO activity in a concentration-dependent manner with IC50 values of 0.7 and 1.7 microM, respectively. Compounds 1 and 2 showed a slight and potently selective inhibitory effect against MAO-B (IC50 0.5 and 0.6 microM, respectively) compared to MAO-A (IC50 1.3 and 34.6 microM, respectively). According to kinetic analyses derived by Lineweaver-Burk reciprocal plots, compounds 1 and 2 exhibited a competitive inhibition to MAO-B.     

长穗桑中的苯并呋喃类化合物

为了研究长穗桑中具有抗氧化活性的化学成分，采用硅胶、Sephadex LH-20、RP-C18等色谱方法从长穗桑茎皮的95%乙醇提取物中分离得到7个苯并呋喃类化合物：wittifuran D (1)、 wittifuran E (2)、 moracin C (3)、 moracin M (4)、 moracin P (5)、 2-(3,5-dihydroxyphenyl)-5,6-dihydroxybenzofuran (6)和mulberroside C (7)，并通过NMR、MS等波谱分析手段鉴定了化合物的结构。化合物1～7均为首次从该种植物中分离得到，其中化合物1和2为新化合物。对化合物3～7进行了抗氧化活性筛选，其中化合物3、4、6浓度在1×10^-5 mol·L^-1时对Fe²⁺-半胱氨酸诱导的肝微粒体脂质过氧化产生的丙二醛(malondialdehyde，MDA)的抑制率分别为73%、69%和89%。     

Monoamine oxidase inhibitory components from the roots ofSophora flavescens

In our search for monoamine oxidase (MAO) inhibitors from natural resources, we found that the methanol extract of the roots of Sophora flavescens showed an inhibitory effect on mouse brain monoamine oxidase (MAO). Bioactivity-guided isolation of the extract yielded two known flavonoids, formononetin (1) and kushenol F (2), as active compounds along with three inactive compounds, oxymatrine (3), trifolirhizin (4), and beta-sitosterol (5). Formononetin (1) and kushenol F (2) showed significant inhibitory effects on MAO in a dose-dependent manner with IC50 values of 13.2 and 69.9 microM, respectively. Formononetin (1) showed a slightly more potent inhibitory effect against MAO-B (IC50: 11.0 microM) than MAO-A (IC50: 21.2 microM). Kushenol F (2) also preferentially inhibited the MAO-B activity than MAO-A activity with the IC50 values of 63.1 and 103.7 microM, respectively.     

Protection of prenylated flavonoids from mori cortex radicis (Moraceae) against nitric oxide-induced cell death in neuroblastoma SH-SY5Y cells

Seven prenylated flavanoids, licoflavone C (1), cyclomulberrin (2), neocyclomorusin (3), sanggenon I (4), morusin (5), kuwanon U (6) and kuwanon E (7), and three 2-arylbenzofurans, moracin P (8), moracin O (9), and mulberrofuran Q (10) were isolated from the MeOH extract of Mori Cortex Radicis. Among these, compounds 2–7 enhanced cell viability in a dose-dependent manner against sodium nitroprusside-induced cell death in neuroblastoma SH-SY5Y cells, which was measured by MTT reduction assay (EC₅₀ values of 4.4, 5.6, 8.0, 6.4, 8.7, and 11.9 μg/mL, respectively). Among 10 compounds, C-3 prenylated flavones (2, 3, and 5) and prenylated flavanones (4, 6, and 7) showed cell protection. However, compound 1 which lacks the prenyl group at C-3 and three 2-arylbenzofurans (8–10) did not show protective effect. The order of cell protection was as follow: C-3 prenylated flavones (2, 3, and 5) > prenylated flavanones (4, 6, and 7) > 2-arylbenzofurans (8–10) and flavone (1). From this result, we show that some prenylated flavones and flavanones might protect neuronal cells against nitrosative stress-mediated cell death. Even though further evaluations are necessary in vitro and in vivo study, we carefully suggest that some prenylated flavonoids from Mori Cortex Radicis might protect neuronal cells from neurodegenerative diseases.     

Caffeic acid phenethyl ester (CAPE) analogues: potent nitric oxide inhibitors from the Netherlands propolis

The MeOH and water extracts of the Netherlands propolis were tested for their inhibitory activity toward nitric oxide (NO) production in lipopolysaccharide (LPS)-activated murine macrophage-like J774.1 cells. Both of the extract possessed significant NO inhibitory activity with IC(50) values of 23.8 and 51.5 microg/ml, respectively. Then 13 phenolic compounds obtained from the MeOH extract showing stronger NO inhibition were examined on their NO inhibitory activities. Caffeic acid phenethyl ester (CAPE) analogues, i.e., benzyl caffeate, CAPE and cinnamyl caffeate, possessed most potent NO inhibitory activities with IC(50) values of 13.8, 7.64 and 9.53 microM, respectively, which were two- to four-fold stronger than the positive control N(G)-monomethyl-L-arginine (L-NMMA; IC(50), 32.9 microM). Further study on the synthetic analogues of CAPE revealed that both of 3-phenylpropyl caffeate (18; IC(50), 7.34 microM) and 4-phenylbutyl caffeate (19; IC(50), 6.77 microM) possessed stronger NO inhibitory activity than CAPE (10) and that elongation of alkyl side chain of alcoholic parts of caffeic acid esters enhance the NO inhibitory activity. In addition, it was found that CAPE analogues having longer carbon chain (>C(5)) in alcoholic part showed toxic effects toward J774.1 cells. This NO inhibitory effect may directly correlate with antiinflammatory properties of the Netherlands propolis.     

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).     

Cucurbitacins from Trichosanthes kirilowii as the inhibitory components on tyrosinase activity and melanin synthesis of B16/F10 melanoma cells

Cucurbitacins 1 and 2 were isolated from the root of Trichosanthes kirilowii by tyrosinase inhibitory activity-guided fractionation. Spectroscopic analysis revealed that compounds 1 and 2 were cucurbitacin D and 23,24-dihydro-cucurbitacin D, respectively. Compounds 1 and 2 effectively inhibited the activity of tyrosinase (IC(50) = 0.18 microM and 6.7 microM, respectively), and the synthesis of melanin (IC(50) = 0.16 microM and 7.5 microM, respectively) in B16/F10 melanoma cells.     

Anthraquinones from the seeds of Cassia tora with inhibitory activity on protein glycation and aldose reductase

Nine anthraquinones, aurantio-obtusin (1), chryso-obtusin (2), obtusin (3), chryso-obtusin-2-O-beta-D-glucoside (4), physcion (5), emodin (6), chrysophanol (7), obtusifolin (8), and obtusifolin-2-O-beta-D-glucoside (9), isolated from an EtOAc-soluble extract of the seeds of Cassia tora, were subjected to in vitro bioassays to evaluate their inhibitory activity against advanced glycation end products (AGEs) formation and rat lens aldose reductase (RLAR). Among the isolates, compounds 6 and 8 exhibited a significant inhibitory activity on AGEs formation with observed IC(50) values of 118 and 28.9 microM, respectively, in an AGEs-bovine serum albumin (BSA) assay by specific fluorescence. Furthermore, compounds 6 and 8 inhibited AGEs-BSA formation more effectively than aminoguanidine, an AGEs inhibitor, by indirect AGEs-ELISA. N(epsilon)-Carboxymethyllysine (CML)-BSA formation was also inhibited by compounds 6 and 8. Whereas compounds 1, 4, and 6 showed a significant inhibitory activity on RLAR with IC(50) values of 13.6, 8.8, and 15.9 microM, respectively.     

Chalcomoracin and moracin C, new inhibitors of Staphylococcus aureus enoyl-acyl carrier protein reductase from Morus alba

Bacterial enoyl-acyl carrier protein (ACP) reductase has been confirmed as a novel target for antibacterial drug development. In the screening of inhibitors of Staphylococcus aureus enoyl-ACP reductase (FabI), we found that a methanol extract of leaves of Morus alba L. potently inhibited S. aureus FabI as well as growth of S. aureus. The active principles were identified as chalcomoracin and moracin C by MS and NMR analysis. Chalcomoracin and moracin C inhibited S. aureus FabI with IC(50) of 5.5 and 83.8 μM, respectively. They also prevented the growth of S. aureus with minimum inhibitory concentration (MIC) of 4 and 32 μg/mL, respectively. Consistent with their inhibition against FabI and bacterial growth, they prevented (14)C]acetate incorporation into fatty acid in S. aureus while didn't affect protein synthesis. In this study, we reported that chalcomoracin and moracin C, potent antibacterial compounds from Morus alba, inhibited FabI and fatty acid synthesis.     

Antioxidant effects of quinoline alkaloids and 2,4-di-tert-butylphenol isolated from Scolopendra subspinipes

The oxidized low-density lipoprotein (ox-LDL) plays a critical role at the early stages of atherosclerosis. Thus, the prevention of LDL-oxidation by antioxidants may arrest the progression of atherosclerosis. Two quinoline alkaloids, 3,8-dihydroxyquinoline (1) and 2,8-dihydroxy-3,4-dimethoxyquinoline (3), and 2,4-di-tert-butylphenol (2) were isolated from the dried body of Scolopendra subspinipes. Compounds 1-3 exhibited antioxidant activities on copper-mediated (1: IC50=2.6 microM, 2: IC50=8.2 microM, 3: IC50=63.0 microM), AAPH-mediated oxidation (1: IC50=3.9 microM, 2: IC50=9.9 microM, 3: IC50=71.8 microM), and SIN-1-mediated oxidation (1: 70%, 2: 52%, 3: 29% at 5.0 microM) in the TBARS assay. The antioxidant activities of compounds 1-3 were tested with respect to other parameters, such as the lag time of conjugated diene fromation, relative electrophoretic mobility (REM) of ox-LDL, and apoB-100 fragmentation on copper-mediated LDL-oxidation. In addition, compounds 1-3 showed 1,1-diphenyl-2-picrylhydrasyl (DPPH) radical scavenging activity and compound 1 also exhibited metal chelating activity.     

CAR-mediated up-regulation of CYP3A4 expression in LS174T cells by Chinese herbal compounds

The constitutive androstane receptor (CAR) is an orphan nuclear receptor which has been shown to participate in the activation of human CYP3A4, which metabolizes more than 50% of clinically used drugs. We investigated the effects of an array of compounds isolated from herbal medicines such as Rheum palmatum (Da Huang), Peucedanum praeruptorum Dunn (Qian Hu), Cortex Mori Radicis (Sang Bai Pi), Radix Asteris (Zi Wan), Salvia miltiorrhiza (Dan Shen), Polygonum cuspidatum Sieb. et Zucc (Hu Zhang), and Ginkgo biloba (Yin Xing) on the CAR-mediated transactivation of CYP3A4. The effect of herbal compounds on CYP3A4 expression was measured using a CYP3A4 luciferase reporter gene assay in transiently transfected human intestinal LS174T cells. The gene expression, protein expression, and catalytic activity of CYP3A4 in LS174T cells transfected with CAR were determined by using real-time PCR, Western blot analysis, and LC-MS/MS-based substrate assay. The study found that in CAR-transfected cells, praeruptorin A, C, and D significantly induced CYP3A4 luciferase activity, mRNA expression, and functional activity through the CAR-mediated pathway; conversely, induction was not found in untransfected cells. Our findings suggest that these herbal compounds can significantly up-regulate the CYP3A4 gene via the CAR-mediated pathway, which has important implications in herb-drug interactions.     

Xanthine oxidase inhibitors from the flowers of Chrysanthemum sinense

From the MeOH extract of the flowers of Chrysanthemum sinense, a new flavone glucoside, acacetin 7- O-(3- O-acetyl- beta- D-glucopyranoside), has been isolated together with 27 known compounds including flavonoids, caffeoylquinic acid derivatives, phenolics, and a monoterpenoid glucoside. Their structures were elucidated on the basis of spectroscopic data. Compounds and displayed significant xanthine oxidase inhibitory activity in a concentration-dependent manner, and compounds and showed more potent inhibitory activity, with IC50 values ranging from 0.13 to 2.31 microM, than that of a positive control allopurinol (IC50=2.50 microM). The kinetic study indicated that and displayed competitive-type inhibition like that of allopurinol, while displayed a mixed-type inhibition.     

Antiplasmodial phenolic compounds from Piptadenia pervillei

Piptadenia pervillei Vatke (Fabaceae) was selected from a screening programme devoted to the search of naturally-occuring antimalarial compounds from plants of Madagascar. Bioassay-guided fractionation of the ethyl acetate extract of the leaves led to the isolation of four phenolic compounds, (+)-catechin ( 1), (+)-catechin 5-gallate ( 2), (+)-catechin 3-gallate ( 3) and ethyl gallate ( 4). Structures were determined by NMR and mass spectroscopy. Compounds 2 and 3 displayed the highest in vitro activity against the chloroquine-resistant strain FcB1 of Plasmodium falciparum with IC (50) values of 1.2 microM and 1.0 microM, respectively, and no significant cytotoxicity against the human embryonic lung cells MRC-5 was measured (IC (50) values > 75 microM). Five analogues ( 5 - 9) of (+)-catechin 5-gallate ( 2) were synthesized and evaluated for their antiplasmodial activity.     

Activity of compounds from Chinese herbal medicine Rhodiola kirilowii (Regel) Maxim against HCV NS3 serine protease

Treatment of the chronic hepatitis C virus (HCV) infection is an unmet medical need, and the HCV NS3 serine protease (NS3-SP) has been used as an attractive target of antiviral screening against HCV. To find naturally chemical entities as lead compounds from which novel anti-HCV agents could be developed, bioassay-guided fractionation and isolation were performed on a crude ethanol extract from rhizomes of the Chinese medicinal herb Rhodiola kirilowii (Regel) Maxim using column chromatography (CC) techniques and in vitro inhibitory activity against HCV NS3-SP. The partition of the extract between water and different organic solvents led to the isolation and identification of 12 compounds in the ethyl acetate part which proved to be the most active. These compounds were tested for in vitro activity against HCV NS3-SP, among which four (-)-Epicatechin derivatives: 3,3'-Digalloylproprodelphinidin B2 (Rhodisin, 1); 3,3'-Digalloylprocyanidin B2 (2); (-)-Epigallocatechin-3-O-gallate (EGCG, 3); and (-)-Epicatechin-3-O-gallate (4, ECG) represented the most potent ones with IC(50) of 0.77, 0.91, 8.51, and 18.55 microM, respectively. Salidroside, the commonly known compounds, together with the other compounds showed no activity up to 100.0 microM. Methylation and acylation of the hydroxyl groups of 1-4 caused a decrease of activity. Cell viability and secreted alkaline phosphatase (SEAP) activity assays with 1-4 revealed little if any toxicity. These nonpeptide inhibitors of HCV NS3-SP might serve as potential candidate anti-HCV agents.     

Antioxidant activity of two phloroglucinol derivatives from Dryopteris crassirhizoma

The rhizome of Dryopteris crassirhizoma NAKAI exhibited significant antioxidant activity, as assessed by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in vitro. Two phloroglucinol derivatives, flavaspidic acids PB (1) and AB (2), were isolated from the rhizome of D. crassirhizoma by a bioassay-guided fractionation. 1H-, 13C-NMR, and UV analysis were used to determine the structures. Furthermore, the two compounds were tested for their antioxidant activities, such as their DPPH radical scavenging, superoxide radical scavenging, and lipid peroxidation (LPO) inhibitory activities. Compounds 1 and 2 exhibited potent antioxidant activity against the LPO inhibitory test with IC(50) values of 12.9 and 13.1 microM, respectively, compared with alpha-tocopherol (IC(50); 15.6 microM) and butylated hydroxy anisole (BHA, IC(50); 10.8 microM), while the two compounds had a moderated effect on the DPPH radical scavenging activity (IC(50); 71.7, 76.3 microM) as well as superoxide radical scavenging activity (IC(50); 58.6, 64.4 microM). The potent activity of the flavaspidic acids (1, 2) on inhibiting LPO might be due to possible stabilization as a result of chelating with iron.     

Inhibition of DNA topoisomerases by nidulalin A derivatives

Three cytotoxic dihydroxanthone derivatives, nidulalin A(1), F390B(2), and F390C(3) were evaluated for inhibitory activity against DNA topoisomerases. Compounds 1 and 2 inhibited DNA topoisomerase II with IC50 values of 2.2 microM and 16 microM, and 3 inhibited DNA topoisomerase I with an IC50 value of 5.9 microM.     

Anti-platelet pentacyclic triterpenoids from leaves of<Emphasis Type="Italic">campsis grandiflora</Emphasis>

Five pentacyclic triterpenoids, oleanolic acid (1), hederagenin (2), ursolic acid (3), tormentic acid (4) and myrianthic acid (5), were isolated from the methanol extract of the leaves of Campsis grandiflora, and structures of the compounds were established by the spectroscopic methods. Compounds 2, 3, 4, and 5 were isolated for the first time from the genus Campsis. All of the compounds (IC50: 45.3, 32.8, 82.6, 42.9 and 46.2 microM respectively) were as equivalently inhibitive as acetylsalicylic acid (IC50: 57.0 microM) on epinephrine induced platelet aggregation.