Byeol Ryu

Antiviral activity of carnosic acid against respiratory syncytial virus

BackgroundHuman respiratory syncytial virus (hRSV) is a leading cause of severe lower respiratory infection and a major public health threat worldwide. To date, no vaccine or effective therapeutic agent has been developed. In a screen for potential therapeutic agents against hRSV, we discovered that an extract of Rosmarinus officinalis exerted a strong inhibitory effect against hRSV infection. Subsequent studies identified carnosic acid as a bioactive constituent responsible for anti-hRSV activity. Carnosic acid has been shown to exhibit potent antioxidant and anti-cancer activities. Anti-RSV activity of carnosic acid was further investigated in this study.MethodsEffects of extracts from various plants and subfractions from R. officinalis on hRSV replication were determined by microneutralization assay and plaque assay. Several constituents were isolated from ethyl acetate fraction of R. officinalis and their anti-RSV activities were assessed by plaque assay as well as reverse-transcription quantitative PCR to determine the synthesis of viral RNAs.ResultsAmong the tested bioactive constituents of R. officinalis, carnosic acid displayed the most potent anti-hRSV activity and was effective against both A- and B-type viruses. Carnosic acid efficiently suppressed the replication of hRSV in a concentration-dependent manner. Carnosic acid effectively suppressed viral gene expression without inducing type-I interferon production or affecting cell viability, suggesting that it may directly affect viral factors. A time course analysis showed that addition of carnosic acid 8 hours after infection still effectively blocked the expression of hRSV genes, further suggesting that carnosic acid directly inhibited the replication of hRSV.ConclusionsThe current study demonstrates that carnosic acid, a natural compound that has already been shown to be safe for human consumption, has anti-viral activity against hRSV, efficiently blocking the replication of this virus. Carnosic acid inhibited both A- and B- type hRSV, while it did not affect the replication of influenza A virus, suggesting that its antiviral activity is hRSV-specific. Collectively, this study suggests the need for further evaluation of carnosic acid as a potential treatment for hRSV.

Constituents of the stem barks of Ailanthus altissima and their potential to inhibit LPS-induced nitric oxide production.

Three new canthinone type alkaloids, canthin-6-one-1-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside (1), canthin-6-one-1-O-[6-O-(3-hydroxy-3-methylglutaryl)]-β-D-glucopyranoside (2) and canthin-6-one-1-O-[2-β-D-apiofuranosyl-6-O-(3-hydroxy-3-methylglutaryl)]-β-D-glucopyranoside (3) were isolated from the stem barks of Ailanthus altissima together with four quassinoids (4-7), seven phenylpropanoids (8-14) and a lignan of previously known structure (15). The inflammatory activities of the 15 isolates were screened on LPS-induced nitric oxide (NO), a proinflammatory mediator, in RAW 264.7 cells.

Swertisin, a C-glucosylflavone, ameliorates scopolamine-induced memory impairment in mice with its adenosine A1 receptor antagonistic property

Swertisin, a C-glucosylflavone isolated from Swertia japonica, has been known to have anti-inflammatory or antidiabetic activities. Until yet, however, its cognitive function is not investigated. In the present study, we endeavored to elucidate the effects of swertisin on cholinergic blockade-induced memory impairment. Swertisin (5 or 10mg/kg, p.o.) significantly ameliorated scopolamine-induced cognitive impairment in the several behavioral tasks. Also, single administration of swertisin (10mg/kg, p.o.) in normal naïve mice enhanced the latency time in the passive avoidance task. In addition, the ameliorating effect of swertisin on scopolamine-induced memory impairment was significantly antagonized by a sub-effective dose of N6-cyclopentyladenosine (CPA, 0.1mg/kg, i.p). The adenosine A1 receptor antagonistic property of swertisin was confirmed by receptor binding assay. Furthermore, the administration of swertisin significantly increased the phosphorylation levels of hippocampal or cortical protein kinase A (PKA, 5 or 10mg/kg) and CREB (10mg/kg), and co-administration of CPA (0.1mg/kg, i.p) blocked the increased phosphorylated levels of PKA and CREB in the both cortex and hippocampus. Taken together, these results indicate that the memory-ameliorating effects of swertisin may be, in part, mediated through the adenosinergic neurotransmitter system, and that swertisin may be useful for the treatment of cognitive dysfunction observed in several diseases such as Alzheimers disease.

Fulgidic Acid Isolated from the Rhizomes of Cyperus rotundus Suppresses LPS-Induced iNOS, COX-2, TNF-α, and IL-6 Expression by AP-1 Inactivation in RAW264.7 Macrophages

To identify bioactive natural products possessing anti-inflammatory activity, the potential of fulgidic acid from the rhizomes of Cyperus rotundus and the underlying mechanisms involved in its anti-inflammatory activity were evaluated in this study. Fulgidic acid reduced the production of nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in lipopolysaccharide (LPS)-induced RAW264.7 macrophages. Consistent with these findings, fulgidic acid suppressed the LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein level, as well as iNOS, COX-2, TNF-α, and IL-6 at mRNA levels. Fulgidic acid suppressed the LPS-induced transcriptional activity of activator protein-1 (AP-1) as well as the phosphorylation of c-Fos and c-Jun. On the other hand, fulgidic acid did not show any effect on LPS-induced nuclear factor κB (NF-κB) activity. Taken together, these results suggest that the anti-inflammatory effect of fulgidic acid is associated with the suppression of iNOS, COX-2, TNF-α, and IL-6 expression through down-regulating AP-1 activation in LPS-induced RAW264.7 macrophages.

New Flavonol Glucuronides from the Flower Buds of Syzygium aromaticum (Clove)

Repeated chromatography of the EtOAc-soluble fraction from the 70% EtOH extract of the flower buds of Syzygium aromaticum (clove) led to the isolation and characterization of four new flavonol glucuronides, rhamnetin-3-O-β-d-glucuronide (1), rhamnazin-3-O-β-d-glucuronide (2), rhamnazin-3-O-β-d-glucuronide-6″-methyl ester (3), and rhamnocitrin-3-O-β-d-glucuronide-6″-methyl ester (4), together with 15 flavonoids (5-19) having previously known chemical structures. The structures of the new compounds 1-4 were determined by interpretation of spectroscopic data, particularly by 1D- and 2D-NMR studies. Six flavonoids (6, 7, 9, 14, 18, and 19) were isolated from the flower buds of S. aromaticum for the first time in this study. The flavonoids were examined for their cytotoxicity against human ovarian cancer cells (A2780) using MTT assays. Among the isolates, pachypodol (19) showed the most potent cytotoxicity on A2780 cells with an IC50 value of 8.02 μM.

6-Acetoxy Cyperene, a Patchoulane-type Sesquiterpene Isolated from Cyperus rotundus Rhizomes Induces Caspase-dependent Apoptosis in Human Ovarian Cancer Cells

Cyperus rotundus (Cyperaceae) has been widely used in traditional medicine for the treatment of various diseases, including cancer. Although an anti‐tumour effect has been suggested for C. rotundus, the anti‐tumour effects and underlying molecular mechanisms of its bioactive compounds are poorly understood. The n‐hexane fraction of an ethanol extract of C. rotundus rhizomes was found to inhibit cell growth in ovarian cancer (A2780, SKOV3 and OVCAR3) and endometrial cancer (Hec1A and Ishikawa) cells. Among the thirteen sesquiterpenes isolated from the n‐hexane fraction, some patchoulane‐type compounds, but not eudesmane‐type compounds, showed moderate cytotoxic activity in human ovarian cancer cells. In particular, the patchoulane sesquiterpene 6‐acetoxy cyperene had the most potent cytotoxicity. In this regard, propidium iodide/Annexin V staining and terminal deoxynucleotidyl transferase dUTP (deoxynucleotide triphosphate) nick end labeling assay were performed to study cell cycle progression and apoptosis. 6‐acetoxy cyperene induced apoptosis, as shown by the accumulation of sub‐G1 and apoptotic cells. Furthermore, treatment with 6‐acetoxy cyperene stimulated the activation of caspase‐3, caspase‐8 and caspase‐9 and poly(ADP‐ribose)polymerase in a dose‐dependent manner. Pretreatment with caspase inhibitors neutralized the pro‐apoptotic activity of 6‐acetoxy cyperene. Taken together, these data suggest that 6‐acetoxy cyperene, a patchoulane‐type sesquiterpene isolated from C. rotundus rhizomes, is an anti‐tumour compound that causes caspase‐dependent apoptosis in ovarian cancer cells. Copyright

Constituents of the aerial parts of Eclipta prostrata and their cytotoxicity on human ovarian cancer cells in vitro

A new terthiophene, 3′-hydroxy-2,2′:5′,2″-terthiophene-3′-O-β-d-glucopyranoside (1) and a new oleanane-type saponin, echinocystic acid-3-O-(6-O-acetyl)-β-d-glucopyranoside (7) were isolated from the aerial parts of Eclipta prostrata L. Moreover, five thiophenes (2–6), seven triterpenoids (8–14), two coumestans (15 and 16), and four flavonoids (17–20) having previously known chemical structures were isolated during the same course of this study. All the isolates 1–20 were evaluated for their cytotoxicity against human ovarian cancer cells (SKOV3) using MTT assays.

A new acetophenone glycoside from the flower buds of Syzygium aromaticum (cloves).

A new acetophenone, 2,4,6-trihydroxy-3-methylacetophenone-2-O-β-d-glucoside (1), together with 21 known compounds; one acetophenone (2), four chromone glycosides (3-6), six phenylpropanoids (7-12), six sesquiterpenoids (13-18), two triterpenoids (19 and 20), one sterol (21), and one tannin (22) were isolated from the flower buds of Syzygium aromaticum (cloves). The structure of the new compound 1 was determined by spectroscopic analyses including 1D-, 2D-NMR and HRMS interpretation. Among the isolates, one acetophenone (2), three phenylpropanoids (10-12), and one sesquiterpenoid (13) were isolated from the flower buds of S. aromaticum for the first time in this study. All the isolates (1-22) were evaluated for their cytotoxicity against human ovarian cancer cells (A2780) using MTT assays. Some of the isolates (5, 6, 9, 15, 17, 19, 20, and 21) showed either moderate or weak cytotoxicity on A2780 cells.

Biflorin, Isolated from the Flower Buds of Syzygium aromaticum L., Suppresses LPS-Induced Inflammatory Mediators via STAT1 Inactivation in Macrophages and Protects Mice from Endotoxin Shock

Two chromone C-glucosides, biflorin (1) and isobiflorin (2), were isolated from the flower buds of Syzygium aromaticum L. (Myrtaceae). Here, inhibitory effects of 1 and 2 on lipopolysaccharide (LPS)-induced production of nitric oxide (NO) and prostaglandin E2 (PGE2) in RAW 264.7 macrophages were evaluated, and 1 (IC50 = 51.7 and 37.1 μM, respectively) was more potent than 2 (IC50 > 60 and 46.0 μM). The suppression of NO and PGE2 production by 1 correlated with inhibition of iNOS and COX-2 protein expression. Compound 1 reduced inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expression via inhibition of their promoter activities. Compound 1 inhibited the LPS-induced production and mRNA expression of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6. Furthermore, 1 reduced p-STAT1 and p-p38 expression but did not affect the activity of nuclear factor κ light-chain enhancer of activated B cells (NF-κB) or activator protein 1 (AP-1). In a mouse model of LPS-induced endotoxemia, 1 reduced the mRNA levels of iNOS, COX-2, and TNF-α, and the phosphorylation-mediated activation of the signal transducer and activator of transcription 1 (STAT1), consequently improving the survival rates of mice. Compound 1 showed a significant anti-inflammatory effect on carrageenan-induced paw edema and croton-oil-induced ear edema in rats. The collective data indicate that the suppression of pro-inflammatory gene expression via p38 mitogen-activated protein kinase and STAT1 inactivation may be a mechanism for the anti-inflammatory activity of 1.

Schisandrosides A–D, Dibenzocyclooctadiene Lignan Glucosides from the Roots of Schisandra chinensis

Four new dibenzocyclooctadiene lignan glucosides, schisandrosides A-D (1-4), as well as two known rare nortriterpenoids, micrandilactone C (5) and propindilactone Q (6), were isolated from the roots of Schisandra chinensis BAILLON (Schisandraceae). The structure of compounds 1-4 were elucidated by physical and spectroscopic data interpretation. To the best of our knowledge, schisandrosides A-D (1-4) represent the first example of a dibenzocyclooctadiene lignan glycoside.