Withaperuvin O, a new withanolide from Physalis peruviana L

Physalis peruviana L. (Solanaceae) has been used in tropical and subtropical countries of the world as medicinal and fruit trees. In this study, a new withanolide named withaperuvin O (1) and seven known ones, including physalolactone B-3-O-β-D-glucopyranoside (2), withanolide J (3), physapruin A (4), physaperuvin G (5), withaperuvin (6), withaperuvin C (7) and 28-hydroxywithaperuvin C (8), were isolated from the whole plants of P. peruviana. Their structures were elucidated based on extensive spectroscopic analyses including NMR and HR-ESI-MS. The bioactivities of these compounds against lipopolysaccharide (LPS)-induced NO production in RAW264.7 cells and cytotoxicity against HepG2 were tested. Compound 3 showed strong anti-inflammatory activities with IC50 3.55 ± 0.12 µM (compared to positive control L-NMMA 7.72 ± 0.46 µM). Compounds 3 and 4 inhibited HepG2 cell line with the IC50 values of 2.01 ± 0.12 µM, 0.96 ± 0.05 µM, respectively (Ellipticine, 0.32 ± 0.02 µM). Our study indicated that compounds 3 and 4 could be new potential natural products for the development of anti-inflammatory and anti-cancer agents.

Alpha-Glucosidase Inhibitory Activity of Saponins Isolated from Vernonia gratiosa Hance

Species belonging to the Vernonia (Asteraceae), the largest genus in the tribe Vernonieae (consisting of about 1,000 species), are widely used in food and medicine. These plants are rich sources of bioactive sesquiterpene lactones and steroid saponins, likely including many as yet undiscovered chemical components. A phytochemical investigation resulted in the separation of three new stigmastane-type steroidal saponins (1 - 3), designated as vernogratiosides A-C, from whole plants of V. gratiosa. Their structures were elucidated based on infrared spectroscopy  (IR), one-dimensional (1D) and two-dimensional nuclear magnetic resonance (2D NMR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), and electronic circular dichroism analyses (ECD), as well as chemical reactivity. Molecular docking analysis of representative saponins with αglucosidase inhibitory activity was performed. Additionally, the intended substances were tested for their ability to inhibit α-glucosidase activity in a laboratory setting. The results suggested that stigmastane-type steroidal saponins from V. gratiosa are promising candidate antidiabetic agents.

Dihydrostilbene glycosides from Camellia sinensis var. assamica and their cytotoxic activity

Three undescribed dihydrostilbene glycosides, 3,5-dihydroxyldihydrostilbene 4'-O-[6''-O-(4'''-hydroxylbenzoyl)]-β-D-glucopyranoside (1), 3,5-dihydroxyldihydrostilbene 4'-O-(6''-O-galloyl)-β-D-glucopyranoside (2), and 3,5-dihydroxyldihydrostilbene 4'-O-[6''-O-(3''',4'''-dimethoxyl)galloyl]-β-D-glucopyranoside (3), and seven known compounds, kaempferol 3-O-β-D-glucopyranoside (4), isoquercitrin (5), kaempferol 3-O-α-L-rhamnoside (6), quercitrin (7), (6S,9R)-roseoside (8), (-)-epicatechin 3-O-gallate (9), and (-)-epigallocatechin 3-O-gallate (10) have been isolated from the methanol extract of the leaves of Camellia sinensis var. assamica (J.W.Mast.) Kitam. (synnonym of Camellia assamica (Mast.) H.T.Chang) (Theaceae). Their structures were elucidated by spectroscopic methods (1 D-, 2 D-NMR) and mass spectra. All compounds were evaluated for cytotoxic activity against human oral cancer (CAL27) and human breast cancer (MDAMB231) cell lines. Compound 10 showed significant cytotoxic activity against CAL27 and MDAMB231 cell lines with IC₅₀ values of 9.78 ± 0.25 and 3.27 ± 0.18 μM, respectively, compared to those of positive control, capecitabine (IC₅₀ values of 8.20 ± 0.75 and 5.20 ± 0.89 μM).

Five New Pregnane Glycosides from Gymnema sylvestre and Their α-Glucosidase and α-Amylase Inhibitory Activities

Gymnema sylvestre, a medicinal plant, has been used in Indian ayurvedic traditional medicine for the treatment of diabetes. Phytochemical investigation of Gymnema sylvestre led to the isolation of five new pregnane glycosides, gymsylosides A-E (1-5) and four known oleanane saponins, 3β-O-β-D-glucopyranosyl (1→6)-β-D-glucopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl ester (6), gymnemoside-W1 (7), 3β-O-β-D-xylopyranosyl-(1→6)-β-D- glucopyranosyl-(1→6)-β-D-glucopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl ester (8), and alternoside XIX (9). Their structures were identified based on spectroscopic evidence and comparison with those reported in the literature. All compounds were evaluated for their α-glucosidase and α-amylase inhibitory activities. Compounds 2-4 showed significant α-amylase inhibitory activity, with IC50 values ranging from 113.0 to 176.2 µM.

Cytotoxic sesquiterpene glucosides from Fissistigma pallens

Six undescribed sesquiterpene glucosides, fissispallins A-F, and one known sesquiterpene glucoside, fissispallin, were discovered in the leaves of Fissistigma pallens (Finet & Gagnep.) Merr. The structures were determined using spectroscopic methods, including 1D, 2D NMR, and MS. All compounds were evaluated for cytotoxic activity against three human cancer cell lines, HT-29, A-2058, and A-549. Fissispallin A showed potent activity with the IC₅₀ values less than 1.5 μM against all tested human cancer cell lines. Fissispallin also showed potent activity with IC₅₀ value of 0.4 ± 0.3 on the A-2058 cancer cell lines. Fissispallins B-D showed significant cytotoxic activity against all the tested cancer cell lines with IC₅₀ values ranging from 3.8 to 7.2 μM.

Three new flavonol glycosides from Fissistigma pallens

Three new flavonol glycosides, fissflavosides A-C (1-3), together with six known flavonol glycosides, kaempferol 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-galactopyranoside (4), kaempferol 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-galactopyranoside (5), kaempferol 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (6), rhamnetin 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (7), rutin (8), and isorhamnetin 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-galactopyranoside (9) were isolated from the methanol extract of the Fissistigma pallens leaves. Their chemical structures were determined by 1D-, 2D-NMR, and MS data as well as in comparison with reported data in the literature. Compounds 1-9 showed weak cytotoxic activity on three human cancer cell lines, HT-29, A-2058, A-549 with IC₅₀ ranging from 134.6 to 162.6 µM. In addition, the antioxidant capacities of compounds were also tested by ORAC assay. All compounds showed significant antioxidant with trolox equivalents ranging from 4.4 to 8.6 µM at the concentration of 1.0 µM. The results indicated 7 and 8 having meaningful reducing capacity of copper (I) ions of 2.7 to 6.9 µM at the concentrations of 1 and 2 µM.

Chemical Components from Phaeanthus vietnamensis and Their Inhibitory NO Production in BV2 Cells

Phaeanthus vietnamensis Bân is a well-known medicinal plant which has been used for the treatment of various inflammatory diseases in traditional medicine. Using various chromatographic methods, three new compounds, (7S,8R,8'R)-9,9'-epoxy-3,5,3',5'-tetramethoxylignan-4,4',7-triol (1), 8α-hydroxyoplop-11(12)-en-14-one (5), and (1R,2S,4S)-4-acetyl-2-[(E)-(cinnamoyloxy)]-1-methylcyclohexan-1-ol (12) along with twelve known compounds were isolated from the leaves of P. vietnamensis. Their chemical structures were elucidated by physical and chemical methods. All compounds were evaluated for the inhibitory activities of nitric oxide production in LPS-stimulated BV2 cells. As the results, compound 6 showed the most potent inhibitory activity on LPS-stimulated NO production in BV2 cells with the IC₅₀ values of 15.7 ± 1.2 μm. Compounds 2, 7, and 8 significantly inhibited inflammatory NO production with IC₅₀ values ranging from 22.6 to 25.3 μm.

Damarane-type Saponins from Gynostemma Longipes and their Cytotoxic Activity

Two new damarane- type saponins, named gylongiposides II-III (1 and 2), along with one known compound, (23 S)-3β,20ζ,21ζ-trihydroxy-19-oxo-21,23-epoxydammar-24-ene 3- O-α-L-rhamnopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-α-L-arabinopyranoside, were isolated from the leaves of Gynostemma longipes C.Y.Wu. Their structures were determined by 1D- and 2D-NMR and HR-ESI-MS spectra. Compounds 1–3 exhibited moderate activity against four human cancer cell lines, A-549, HT-29, OVCAR, and MCF-7, with IC50 values ranging from 9.8 ± 2.1 to 49.6 ± 2.6 μM.

Damarane-type Saponins from Gynostemma longipes and their Cytotoxic Activity

Two new damarane-type saponins, named gylongiposides II-III (1 and 2), along with one known compound, (23S)-3β,20ξ,21ξ-trihydroxy-19-oxo-21,23-epoxydammar-24-ene 3-O-α-L-rhamnopyranosyl-(1-->2)-[-D-xylopyranosyl-(1-->3)]-α-L-arabinopyranoside, were isolated from the leaves of Gynostemma longipes C.Y.Wu. Their structures were determined by 1D- and 2D-NMR and HR-ESI-MS spectra. Compounds 1-3 exhibited moderate activity against four human cancer cell lines, A-549, HT-29, OVCAR, and MCF-7, with IC50 values ranging from 9.8 +/- 2.1 to 49.6 +/- 2.6 μM.

A new coumarin and cytotoxic activities of constituents from Cinnamomum cassia

A new coumarin derivative, coumacasia (1) and eight known compounds, coumarin (2), cinnamaldehyde (3), 2-methoxycinnamaldehyde (4), 2-hydroxycinnamaldehyde (5), coniferaldehyde (6), cinnamic acid (7), 2-hydroxycinnamic acid (8), and cinnamic alcohol (9), were isolated from the methanol extract of Cinnamomum cassia. Their structures were elucidated by spectral data and by comparison with the reported literature. The cytotoxic activities of compounds 1-9 were evaluated with two human cancer cell lines, HL-60 and A-549. Compound 1 showed growth inhibitory effects in the HL-60 and A-549 cell lines with IC50 values of 8.2 +/- 0.5 and 11.3 +/- 1.1 microM, respectively. Compounds 3-6, and 8 exhibited moderate cytotoxicity with IC50 values ranging from 20.5 to 65.6 microM.

A New Coumarin and Cytotoxic Activities of Constituents from Cinnamomum cassia

A new coumarin derivative, coumacasia (1) and eight known compounds, coumarin (2), cinnamaldehyde (3), 2-methoxycinnamaldehyde (4), 2-hydroxycinnamaldehyde (5), coniferaldehyde (6), cinnamic acid (7), 2-hydroxycinnamic acid (8), and cinnamic alcohol (9), were isolated from the methanol extract of Cinnamomum cassia. Their structures were elucidated by spectral data and by comparison with the reported literature. The cytotoxic activities of compounds 1-9 were evaluated with two human cancer cell lines, HL-60 and A-549. Compound 1 showed growth inhibitory effects in the HL-60 and A-549 cell lines with IC50 values of 8.2 ± 0.5 and 11.3 ±1.1 μM, respectively. Compounds 3-6, and 8 exhibited moderate cytotoxicity with IC50 values ranging from 20.5 to 65.6 μM.

Anti-inflammatory properties of anthraquinones and their relationship with the regulation of P-glycoprotein function and expression

There is a growing interest in natural products that potentially have anti-inflammatory properties and inhibit P-glycoprotein (P-gp) function. In this report, we assessed the effects of anthraquinone derivatives from rhubarb on LPS-induced RAW 264.7 macrophages to determine their anti-inflammatory potential. The derivatives were also tested in Caco-2 cell lines to evaluate the inhibition of the drug efflux function of P-gp. The transport abilities were examined and the cellular accumulation of rhodamine-123 (R-123) was also measured. Electorphoretic mobility shift assay (EMSA) was performed to check the activator protein-1 (AP-1) DNA binding affinity. Five anthraquinones were tested to determine their inhibitory activities on NO production and the protein and mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Furthermore, the level of prostaglandin E(2) (PGE(2)) was determined in LPS-induced RAW264.7 macrophages. Emodin was found to be the most potent inhibitor, and it also reduced paw swelling in the mouse model of carrageenan-induced paw edema. In Caco-2 cells, emodin elevated the accumulation of R-123 and decreased the efflux ratio of R-123, which indicates the inhibition of P-gp function. The inhibition of COX-2 protein by emodin paralleled the decrease in P-gp expression. In addition, mitogen-activated protein kinase (MAPK) expression was decreased through the prevention of AP-1 DNA binding, which leads to downregulation in the expression of P-gp. Our data indicate that the decrease of P-gp expression is caused by the decreased expression of COX-2 through the MAPK/AP-1 pathway. Based on our results, we suggest that anti-inflammatory drugs with COX-2 inhibitory activity might be used to modulate P-gp function and expression.

Xanthine oxidase inhibitory activity of constituents of Cinnamomum cassia twigs

A methanol extract of the twigs of Cinnamomum cassia was found to inhibit xanthine oxidase. Purification of the methanol extract afforded three new phenolic glycosides, cinnacasolide A-C (11-13), together with 10 known compounds (1-10). The structures of the three new compounds were determined by interpretation of spectroscopic data. Cinnamaldehyde derivatives 1-5 and 7 were significant inhibitors of xanthine oxidase, with IC(50) values ranging from 7.8 to 36.3 μg/mL. The results indicate that the acyl group of these cinnamaldehyde derivatives plays an important role in the inhibition of xanthine oxidase.

Chemical-based species classification of rhubarb using simultaneous determination of five bioactive substances by HPLC and LDA analysis

INTRODUCTION

Rhubarb is a traditional Chinese medicine derived from the rhizome of three species: Rheum tanguticum, Rheum palmatum and Rheum officinale. There are several species that are often misidentified as rhubarb. Taxonomical identification of these various species can be challenging. We have developed an HPLC-based species classification to identify rhubarb.

OBJECTIVE

The objective of this study was to develop a simple HPLC method for the simultaneous determination of bioactive compounds and identification of medicinal rhubarb rhizome and non-medicinal species.

METHODOLOGY

Quantitative analysis was performed on a C₁₈-column using 0.05 M aqueous phosphoric acid and acetonitrile as the mobile phase under gradient conditions with ultraviolet detection at 280 nm. The method was validated with respect to linearity, accuracy, precision, and recovery. Statistical analysis was used to classify different groups of species.

RESULTS

All calibration curves showed good linearity (r ≥ 0.9995). The method showed good repeatability with intra- and inter-day standard deviations of less than 1.13% and 1.32%, respectively. The accuracy and recovery of all marker compounds were in the ranges of 98.0 to 102.6% and 99.21 to 102.04%, respectively. Seventeen peaks were selected, and 39 known and 57 unknown samples were classified into five species based on linear discriminant analysis with an accuracy of 100%.

CONCLUSION

A chemical-based species classification method of rhubarb using simultaneous determination of bioactive compounds by HPLC was developed with 39 known samples of five different species and successfully applied to identify 57 unknown samples collected from Korea and China.

Chrysophanol-8-O-glucoside, an anthraquinone derivative in rhubarb, has antiplatelet and anticoagulant activities

Rhubarb is a widely used traditional medicine and has been reported to elicit a number of biological effects including anti-inflammatory and antiplatelet effects. In the present study, we investigated the effects of anthraquinone derivatives isolated from rhubarb on platelet activity. Of four anthraquinone derivatives isolated from rhubarb examined, chrysophanol-8-O-glucoside (CP-8-O-glc) was found to have the most potent inhibitory effect on collagen- and thrombin-induced platelet aggregation. CP-8-O-glc-treated mice showed significantly prolonged bleeding times. Furthermore, CP-8-O-glc was found to have a significant inhibitory effect on rat platelet aggregation ex vivo and on thromboxane A(2) formation in vitro. In coagulation tests, CP-8-O-glc did not alter prothrombin time, and it prolonged the activated partial thromboplastin time. However, CP-8-O-glc only inhibited platelet phosphatidylserine exposure, but not exert direct inhibition on intrinsic factors. This study demonstrates the antiplatelet and anticoagulant effects of CP-8-O-glc and suggests that this compound might be of therapeutic benefit for the prevention of platelet-related cardiovascular diseases.

2-methoxycinnamaldehyde from Cinnamomum cassia reduces rat myocardial ischemia and reperfusion injury in vivo due to HO-1 induction

ETHNOPHARMACOLOGICAL RELEVANCE

Cinnamomum cassia Blume has been used as a traditional Chinese herbal medicine for alleviation of fever, inflammation, chronic bronchitis, and to improve blood circulation.

AIM OF THE STUDY

We addressed whether 2-methoxycinnamaldehyde (2-MCA), one of active ingredients of Cinnamomum cassia, reduces vascular cell adhesion molecule-1 (VCAM-1) expression in tumor necrosis factor-alpha (TNF-α)-activated endothelial cells and protects ischemia/reperfusion (I/R)-injury due to heme oxygenase (HO)-1 induction.

MATERIALS AND METHODS

Adult male rats were subjected to 30 min of ischemia by occlusion of the left anterior descending coronary artery followed by 24h of reperfusion. Rats were randomized to receive vehicle or 2-MCA (i.v.) 10 min before reperfusion.

RESULTS

Administration of 2-MCA significantly improved I/R-induced myocardial dysfunction by increasing the values of the first derivative (±dp/dt) of left ventricular pressure and decreased infarct size. In addition, 2-MCA reduced the expression of high mobility group box 1 (HMGB1), an activator of the inflammatory cascade when released into the extracellular space, and VCAM-1 in I/R myocardium along with increase of HO-1 induction. The reduced injury was accompanied by significantly reduction of neutrophils infiltration and increased SOD activity in ischemic tissues and reduced serum level of cardiac troponin I (cTnI). Furthermore, 2-MCA significantly increased HO-1 induction by translocation of Nrf-2 from cytosol to nucleus in endothelial cells. Inhibition of VCAM-1 expression by 2-MCA was reversed both by SnPPIX, a HO-1 inhibitor and siHO-1 RNA trasfection in TNF-α-activated cells. In addition, 2-MCA significantly inhibited NF-κB luciferase activity in TNF-α-activated endothelial cells. As expected, 2-MCA significantly inhibited monocyte (U937) adhesion to endothelial cells.

CONCLUSION

We concluded that 2-MCA protects of myocardial I/R-injury due to antioxidant and anti-inflammatory action possibly by HO-1 induction which can be explained why Cinnamomum cassia has been used in inflammatory disorders.

WITHDRAWN: Anti-proliferative effects of compounds from the fruit peel of Wisteria floribunda on vascular smooth muscle cells

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Selected compounds derived from Moutan Cortex stimulated glucose uptake and glycogen synthesis via AMPK activation in human HepG2 cells

AIM OF THE STUDY

To evaluate the effect of selected compounds derived from Moutan Cortex on glucose uptake and glycogen synthesis associated with AMPK activation in insulin-resistant human HepG2 cell.

MATERIALS AND METHODS

The effect of isolated compounds (1-16) on glucose uptake and glycogen synthesis was performed using HepG2 cells. The western blot was used to determine the expression of AMPK and its downstream substrates, ACC, p-ACC, and p-GSK-3beta.

RESULTS

The effects of the 16 compounds from Moutan Cortex on glucose metabolism in HepG2 cells under high glucose conditions were evaluated. Compounds 2, 3, and 6 displayed highly potent effects on the stimulation of glucose uptake and glycogen synthesis in human HepG2 cells under high glucose conditions. Compounds 2, 3, and 6 phosphorylate AMPK (AMP-activated protein kinase), and resulted in increased phosphorylation of GSK-3beta and suppression of lipogenic expression (ACC and FAS) in a dose-dependent manner. Compounds 2, 3, and 6 also demonstrated interesting, strong eNOS phosphorylation in human umbilical vein endothelial cells (HUVECs). Compounds 1, 4, 5-12, and 14 displayed considerable effects on hepatic glucose production, AMPK activation, and phosphorylation of GSK-3beta in HepG2 cells under high glucose conditions.

CONCLUSIONS

These effects may indicate that the activation of AMPK by the active compounds from Moutan Cortex has considerable potential for reversing the metabolic abnormalities associated with type-2 diabetes.

Antioxidant and lipoxygenase inhibitory activity of oligostilbenes from the leaf and stem of Vitis amurensis

ETHNOPHARMACOLOGICAL RELEVANCE

The root and stem of Vitis amurensis (Vitaceae) have popularly used as traditional medicine for treatment of cancer and various pains in Korea and Japan. Recent studies, its root and stem possess anti-inflammatory, anti-tumor activities, and protective effects against beta-amyloid-induced oxidative stress.

AIM OF THE STUDY

This study deals with the isolation, structural identification of the potent bioactive compounds from the leaf and stem, and their antioxidant capacity, as well as anti-inflammatory effect via lipoxygenase inhibitory assay.

MATERIALS AND METHODS

All isolated compounds yielded after using column chromatography were identified base on the physico-chemical properties and 1D, 2D NMR spectra. The scavenge ability against DPPH and ABTS(+) radicals, and to inhibit lipid peroxidation, as well as lipoxygenase type I inhibitory activity of all isolates were performed using in vitro assays.

RESULTS

Eleven resveratrol derivatives (1-11), including a new oligostilbene cis-amurensin B (9), whose structures were determined on the basis of extensively spectral analyses, were isolated from the leaf and stem of Vitis amurensis. The isolates (1-11) were examined for their antioxidant activities by evaluating scavenge ability against DPPH and ABTS(+) radicals, and to inhibit lipid peroxidation. Stilbenes 1 and 4, and oligostilbenes 5-10 displayed moderate anti-lipid peroxidation activities, but all the isolates exhibited strong ABTS(+) radical scavenging activity in the dose-dependent manner. In addition, the isolates showed stronger inhibitory capacity against soybean lipoxygenase type I than that of baicalein, a positive control. Of the isolates, r-2-viniferin (8) exhibited the strongest scavenging activity against ABTS(+) radical with TEAC value of 5.57, and the most potential inhibitory effect on soybean lipoxygenase with the IC(50) value of 6.39 microM.

CONCLUSION

This is the first report on the potential antioxidant and LOX-1 inhibitory effects of oligostilbenes isolated from the leaf and stem of Vitis amurensis. In addition, chemical compositions isolated from the leaf and stem are almost similar to those isolated from the root of Vitis amurensis. Therefore, the results may explain, in part, the uses of the leaf and stem, as well as the root of Vitis amurensis in the Korean traditional medicine.

Palbinone and triterpenes from Moutan Cortex (Paeonia suffruticosa, Paeoniaceae) stimulate glucose uptake and glycogen synthesis via activation of AMPK in insulin-resistant human HepG2 Cells

Moutan Cortex is a well-known herb in traditional Korean, Chinese, and Japanese anti-diabetic formulae. In the current study, we investigated the metabolic effects of isolated triterpenes (1-7) in HepG2 cells under high glucose conditions. These compounds remakably stimulated AMP-activated protein kinase (AMPK), GSK-3beta, and ACC phosphorylation. The compounds also increased glucose uptake and enhanced glycogen synthesis. Among these, compound 1 displayed the greatest potential anti-diabetic activity though the AMPK activation pathway. Compound 1 significantly increased the levels of phospho-AMPK, phospho-ACC, and phospho-GSK-3beta and stimulated glucose uptake and glycogen synthesis in a dose-dependent manner. In conclusion, our results suggest that these compounds, especially compound 1, may have beneficial roles in glucose metabolism via the AMPK pathway.

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.

Inhibitors of aldose reductase and formation of advanced glycation end-products in moutan cortex (Paeonia suffruticosa)

The methanol extract of Moutan cortex (Paeonia suffruticosa) afforded two new compounds, 8-O-benzoylpaeonidanin (1) and 5-hydroxy-3S-hydroxymethyl-6-methyl-2,3-dihydrobenzofuran (2), in addition to 4-O-butylpaeoniflorin (3) as an artifact of the separation, seven monoterpene glycosides (4-10), two monoterpenes (11, 12), four acetophenones (13-16), and two triterpenes (17, 18). The structures of the compounds were determined by spectroscopic methods, and the compounds were evaluated for inhibitory effects against rat lens aldose reductase (RLAR) and advanced glycation end-product (AGEs) formation. Compounds 17 and 18 showed the most potent inhibitory activity against RLAR, with IC(50) values of 11.4 and 28.8 microM, respectively. Compounds 3 and 6 also inhibited RLAR with IC(50) values of 36.2 and 44.6 microM, respectively. The positive control, 3,3-tetramethyleneglutamic acid, had an IC(50) value of 31.8 microM. Compounds 3 and 6 inhibited AGE formation with IC(50) values of 10.8 and 11.3 microM, respectively. Compound 2 had an IC(50) value of 177.0 microM, whereas the positive control, aminoguanidine, had an IC(50) value of 1026.8 microM.

Tyrosinase-inhibitory constituents from the twigs of Cinnamomum cassia

A methanol extract of the twigs of Cinnamomum cassia was found to possess inhibitory activity against tyrosinase. Purification of the MeOH extract afforded four new phenolics, cassiferaldehyde (6), icariside DC (9), cinnacassinol (10), and dihydrocinnacasside (13), together with 10 known compounds (1-5, 7-12, and 14). The structures of the new compounds were determined by spectroscopic data interpretation. Compounds 1-6 and 8-13 showed strong inhibitory activity against tyrosinase, with IC(50) values ranging from 0.24 to 0.94 mM.

Biphenylquinolizidine alkaloids from Lagerstroemia indica

Two new biphenylquinolizidine alkaloids, 5-epi-dihydrolyfoline (1) and its stereoisomer, dihydrolyfoline (2), along with lagerine (3) were isolated from the aerial parts of Lagerstroemia indica. The structures of compounds 1-3 were elucidated by extensive spectroscopic techniques.

Inhibition of human low density lipoprotein and high density lipoprotein oxidation by oligostilbenes from rhubarb

The objective of the present study was to elucidate the beneficial properties of ampelopsine B (1) and epsilon-Viniferin (2), two oligostilbenes isolated from rhubarb, toward cardiovascular disease by protecting human lipoproteins against lipid peroxidation. In low density lipoprotein (LDL) oxidation, both 1 and 2 exert an inhibitory activity against Cu(2+)-, 2,2'-azobis-(2-amidinopropane) hydrochloride (AAPH)-induced, as exhibited by prolongation of lag time from 52 to 118 and 136 min, respectively, and also increasing the lag time 38 to 105 and 128 min in high density lipoprotein (HDL) oxidation for 1 and 2, respectively, at the concentration of 3.0 microM. In generation of thiobarbituric acid reactive substances (TBARS), compounds 1 and 2 inhibited LDL oxidation mediated by either catalytic Cu(2+) or thermo-labile radical initiator (AAPH) in a dose-dependent manner with IC(50) values of 3.6 and 6.0 microM for 1, and 1.7 and 3.2 microM for 2, respectively. In addition, compounds 1-2 also showed strong ability to protect HDL oxidation induced by both Cu(2+) and AAPH with low IC(50) values. The results suggest that oligostilbenes 1-2 may have a role in preventing lipoprotein oxidation.

Cholinesterase inhibitory and anti-amnesic activity of alkaloids from Corydalis turtschaninovii

In the course of screening plants used in Korean folk medicine as memory enhancers, a 70% ethanol extract of tuber from Corydalis turtschaninovii Besser (Papaveraceae) showed significant acetylcholinesterase (AChE) inhibitory activity. Repeated column chromatography led to the isolation of a new aporphine alkaloid, oxoglaucidaline (9), and a new protoberberine, pseudodehydrocorydaline (13) together with 14 known compounds (1-8, 10-12, and 14-16). The chemical structures of isolated compounds were elucidated base on extensive 1D and 2D NMR spectroscopic data. Compounds 1-16 were investigated in vitro for their anti-cholinesterase activity using the mice cortex AChE enzyme. In further study, the anti-amnesic activities of pseudoberberine (16) in mice on the learning and memory impairments induced by scopolamine (1.0 mg/kg, i.p.) were examined. This alkaloid (5.0 mg/kg, p.o.) administration significantly reversed cognitive impairments in mice by passive avoidance test (P<0.05). It also reduced escape latencies in training trials and prolonged swimming times in the target quadrant during the probe trial in the water maze task (P<0.05). These results indicated that Corydalis turtschaninovii due to its alkaloids have anti-cholinesterase activity and pseudoberberine and other alkaloids have anti-amnesic activities that may be useful for cognitive impairment treatment.

Antioxidative activities of galloyl glucopyranosides from the stem-bark of Juglans mandshurica

Two phenolics, 1,2,6-trigalloylglucose (1) and 1,2,3,6-tetragalloylglucose (2), isolated from the stem-bark of Juglans mandshurica were evaluated for their antioxidative activities. The results showed that compounds 1 and 2 exhibited strong scavenging activities against 1,1'-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzenthiazoline-6-sulphonic) acid (ABTS(*+)), and superoxide radicals (O(2)(*-)), and also had a significant inhibitory effect on lipid peroxidation and low-density lipoprotein (LDL) oxidation. The strong superoxide radical scavenging of 1 and 2 resulted from the potential competitive inhibition with xanthine at the active site of xanthine oxidase (OX). In addition, compounds 1 and 2 displayed significant lipoxygenase inhibitory activity, the mode of inhibition also being identified as competitive. In comparison, the antioxidative activities of compounds 1 and 2, together with gallic acid, indicated that the number of galloyl moieties could play an important role in the antioxidative activity.

Lipoxygenase inhibitory constituents from rhubarb

Phytochemical study on the ethanol extract of rhubarb led to the isolation of fifteen compounds, including five anthraquinones: chrysophanol (1), physcion (2), emodin (7), chrysophanol-8-O-beta-D: -glucopyranoside (9) and emodin-8-O-beta-D: -glucopyranoside (15), and ten stilbenes: desoxyrhaponticin (3), rhaponticin (4), resveratrol (5), desoxyrhapotigenin (6), rhapontigenin (8), piceatannol-3'-O-beta-D: -glucopyranoside (10), piceid (11), epsilon-viniferin (12), ampelopsin B (13) and isorhaponticin (14). Their structures were identified by comparing the physicochemical data with those of published papers. Among the isolated compounds, stilbene derivatives (3-6, 8 and 10-14) showed remarkable inhibitory effect on lipoxygenase with IC(50) values ranging from 6.7 to 74.1 microM. The inhibition kinetics analyzed by Lineweaver-Burk plots found that they were competitive inhibitors with the linoleic acid at the active site of lipoxygenase. In addition, stilbenes exhibited significantly free radical scavenging activity against ABTS(.+) with trolox equivalent activity capacity (TEAC) values ranging from 1.16 to 4.64. Whereas, anthraquinone derivatives (1-2, 7, 9 and 15) neither inhibited lipoxygenase nor scavenged free radical ABTS(.+). These results indicated that stilbene derivatives were considerate to be mainly lipoxygenase inhibitor and free radical scavenger constituents of rhubarb.

Protective effect of magnoflorine isolated from coptidis rhizoma on Cu2+-induced oxidation of human low density lipoprotein

The aim of this study was to investigate the antioxidant activity of magnoflorine, an alkaloid isolated from Coptidis Rhizoma, against the oxidation of native low density lipoprotein (LDL) and modified LDL. Magnoflorine was found to inhibit the copper-mediated (Cu2+) oxidation of LDL, as well as of glycated and glycoxidated LDL by increasing the lag time of conjugated diene formation and preventing the generation of thiobarbituric acid reactive substances (TBARS). In addition, the results from the fluorescence emission spectra of tryptophan (Trp) supported that the antioxidant activity of magnoflorine could be associated with the protective effect on the structural modification of apolipoprotein B (apoB) required for LDL oxidation. These results suggest that magnoflorine may be useful for preventing the oxidation of various LDL forms.

Magnoflorine from Coptidis Rhizoma protects high density lipoprotein during oxidant stress

The objective of the present study was to investigate the beneficial properties of magnoflorine, an alkaloid isolated from coptidis rhizoma, on protecting human high density lipoprotein (HDL) against lipid peroxidation. Magnoflorine exerts an inhibitory effect against Cu2+-induced lipid peroxidation of HDL, as showed by prolongation of lag time from 62 to 123 min at the concentration of 3.0 microM. It also inhibits the generation of thiobarbituric acid reactive substances (TBARS) in the dose-dependent manners with IC50 values of 2.3+/-0.2 microM and 6.2+/-0.5 microM since HDL oxidation mediated by either catalytic Cu2+ or thermo-labile radical initiator (AAPH), respectively. Separately, Cu2+ oxidized HDL lost the antioxidant action but the inclusion of magnoflorine/Cu2+ oxidized HDL can protect LDL oxidation according to increasing magnoflorine concentration. The results suggest that magnoflorine may have a role to play in preventing the HDL oxidation.

Acetylcholinesterase inhibitory effect of lignans isolated fromSchizandra chinensis

The hexane extract of the fruit of Schizandra chinensis (Schisandraceae) was found to show significant inhibition of the activity of acetylcholinesterase enzyme (AChE). In further studies, fourteen lignans were isolated, and evaluated for their inhibitory effect on AChE. The compounds having both aromatic methylenedioxy and hydroxyl groups on their cyclooctadiene ring, such as gomisin C (6), gomisin G (7), gomisin D (8), schisandrol B (11) and gomisin A (13), entirely inhibited AChE in dose dependent manners, with IC50 values of 6.71 +/- 0.53, 6.55 +/- 0.31, 7.84 +/- 0.62, 12.57 +/- 1.07 and 13.28 +/- 1.68 microM, respectively. These results indicate that the lignans could potentially be a potent class of AChE inhibitors.

Anti-inflammatory activity of flavonoids from Populus davidiana

An in vitro bioassay-guide revealed that the methanol (MeOH) extract of the stem bark of Populus davidiana showed considerable inhibitory activity against cyclooxygenase (COX-1, COX-2). Continuous phytochemical study of the MeOH extract of this plant led to the isolation of ten flavonoids; sakuranetin (1), rhamnocitrin (2), 7-O-methylaromadendrin (3), naringenin (4), eriodictyol (5), aromadendrin (6), kaempferol (7), neosakuranin (8), sakuranin (9) and sakurenetin-5,4'-di-beta-D-glucopyranoside (10). Their structures were identified on the basis of their physicochemical and spectroscopic analyses. The isolated compounds, 1-10, were tested for their inhibitory activities against COX-1 and COX-2. Compound 7 was found to have potent inhibitory effect on COX-1 and a moderate effect on COX-2, meanwhile, compounds 1-6 showed moderate inhibition against COX-1 only. Moreover, compounds 5-8 exhibited suppressive effects on xanthine oxidase (XO). These results may explain, in part, the traditional uses of P. davidiana in ethnomedicine.

Phenolic glycosides with antioxidant activity from the stem bark of Populus davidiana

Phytochemical study on the EtOAc-soluble fraction of the stem bark of Populus davidiana resulted in the isolation of 10 phenolic glycosides (1-10), which were identified on the basis of physicochemical and spectroscopic analyses. Among these, three new compounds, populosides A-C (1-3), were determined to be 2-coumaroylmethyl-4-hydroxyphenyl-beta-D-glucopyranoside, 2-coumaroylmethylphenyl-beta-D-glucopyranoside, and 2-feruoylmethylphenyl-beta-D-glucopyranoside, respectively. Compounds 1-10 were tested for their radical scavenging activity against an azo radical, ABTS*+. Of these, populosides A-C (1-3), populoside (4), grandidentatin (8), salireposide (9), and coumaroyl-beta-D-glucoside (10) exhibited antioxidant activity in this assay.