Fungicidal effect of isoquercitrin via inducing membrane disturbance.

Isoquercitrin is a flavonoid isolated from Aster yomena, which has been used as a traditional medicinal herb. In the present study, we investigated the antifungal activity and the underlying mechanism of isoquercitrin. Isoquercitrin had a potent effect in the susceptibility test against pathogenic fungi and almost no hemolysis. Propidium iodide and potassium release assays were conducted in Candida albicans, and these studies confirmed that isoquercitrin induced membrane damage, thereby, increasing permeability. Membrane potential was analyzed using 3,3'-dipropylthiacarbocyanine iodide [DiSC3(5)], and the transition of membrane potential was indicated by an increased fluorescence intensity. To further analyze these results using model membranes, giant unilamellar vesicles and large unilamellar vesicles that encapsulated calcein were prepared and the detection of calcein leakage from liposomes indicated that membrane was disturbed. We further verified membrane disturbance by observing the disordered status of the lipid bilayer with 1,6-diphenyl-1,3,5-hexatriene fluorescence. Moreover, changes in size and granularity of the cell were revealed in flow cytometric analysis. All these results suggested the membrane disturbance and the degree of disturbance was estimated to be within a range of 2.3 nm to 3.3 nm by fluorescein isothiocyanate-dextran analysis. Taken together, isoquercitrin exerts its fungicidal effect by disturbing the membrane of cells.

Antifungal effect and mode of action of glochidioboside against Candida albicans membranes.

Glochidioboside was obtained from Sambucus williamsii and its biological effect has not been reported. Its antifungal activity against pathogenic fungi and the mode of action involved in its effect were examined. Glochidioboside exerted antifungal effect with almost no hemolytic effect against human erythrocytes. To understand its antifungal mechanisms, membrane studies were done. Using two dyes, 3,3'-dipropylthiacarbocyanine iodide [DiSC3(5)] and propidium iodide, membrane depolarization and permeabilization by glochidioboside were confirmed. Furthermore, the membrane-active mechanism was proven by synthesizing a model membrane, calcein-encapsulating large unilamellar vesicles (LUVs), and also by observing the influx of different sized fluorescent dyes, such as calcein, FD4 and FD10, into the fungal cells. The membrane-active action was pore-forming action with radii between 1.4 and 2.3 nm. Finally, three dimensional (3D) flow cytometric analysis showed the shrinkage of the fungal cells from the membrane damage. In conclusion, this study suggests that glochidioboside exerts an antifungal activity through a membrane-disruptive mechanism.

Three new lignan glycosides with IL-6 inhibitory activity from Akebia quinata.

Three new lignan glycosides, akeqintoside A [(7S,8S)-7,8-dihydro-8-hydroxymethyl-7-(4-hydroxy-3-methoxyphenyl)-1'-benzofuranpropanol 2'-O-ß-D-glucopyranoside] (1), akeqintoside B [(7R,8R)-7,8-dihydro-8-hydroxymethyl-7-(4-hydroxy-3-methoxyphenyl)-1'-(9'-methoxy-7'-propenyl) benzofuran 2'-O-ß-D-glucopyranoside] (2), and akequintoside C [7R*,8R*-dihydroxy-7-(4-hydroxy-3-methoxyphenyl)-glycerol 9-O-ß-D-(6'-O-caffeoyl)-glucopyranoside] (3) were isolated from Akebia quinata along with five known compounds, syringin (4), vanilloloside (5), salidroside (6), 3,4-dihydroxyphenylethyl alcohol 8-O-ß-D-glucopyranoside (7), and calceolarioside B (8). The structures of the compounds were identified based on one dimensional (1D)- and 2D-NMR, including (1)H-(1)H correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC) and nuclear Overhauser effect spectroscopy (NOESY) spectroscopic analyses. The inhibitory activity of these isolated compounds against interleukin-6 (IL-6) production in tumor necrosis factor-alpha (TNF-α) stimulated MG-63 cells was also examined.

Anti-melanogenic effects of extracellular vesicles derived from plant leaves and stems in mouse melanoma cells and human healthy skin.

Consumer interest in cosmetic industry products that produce whitening effects has increased demand for agents that decrease melanin production. Many such anti-melanogenic agents are associated with side effects, such as contact dermatitis and high toxicity, and also exhibit poor skin penetration. Considerable recent research has focused on plant-derived products as alternatives to chemotherapeutic agents that possess fewer side effects. In the current study, we investigated the anti-melanogenic effects of extracellular vesicles (EVs) extracted from leaves and stems of Dendropanax morbifera. Using spectrophotometric and biochemical approaches, we found that leaf-derived extracellular vesicles (LEVs) and stem-derived extracellular vesicles (SEVs) reduced melanin content and tyrosinase (TYR) activity in the B16BL6 mouse melanoma cell line in a concentration-dependent manner. An electron microscopy analysis further confirmed that LEVs and SEVs induce a concentration-dependent decrease in melanin content in melanoma cells. Both LEVs and SEVs exerted a greater whitening effect on melanoma cells than arbutin, used as a positive control, with LEVs producing the greater effect. Notably, neither LEVs nor SEVs induced significant cytotoxicity. We also examined the effects of plant-derived EVs on the expression of tyrosinase-related proteins (TRPs) in melanoma cells. LEVs inhibited expression of melanogenesis-related genes and proteins, including microphthalmia-associated transcription factor (MITF), TYR, TRP-1 and TRP-2. In a human epidermis model, LEVs exerted a stronger inhibitory effect on melanin production than arbutin. Collectively, our data suggest that LEVs from D. morbifera may be a novel candidate natural substance for use as an anti-melanogenic agent in cosmeceutical formulations.

Oleanane triterpenoids from Akebiae Caulis exhibit inhibitory effects on Aß42 induced fibrillogenesis.

Previous phytochemical investigations of Akebiae Caulis resulted in the isolation of triterpenes, triterpene glycosides, phenylethanoid glycosides and megastigmane glycoside. Amyloid beta (Aß), the main component of the senile plaques detected in Alzheimer's disease, induces cell death. However, only a limited number of studies have addressed the biological and pharmacological effects of Akebiae Caulis. In particular, the inhibitory activity of Akebiae Caulis against Aß42 fibrillogenesis remains unclear. Herein, a new triterpene glycoside, akequintoside F (1), along with nine known compounds pulsatilla saponin A (2), collinsonidin (3), akebonic acid (4), hederagenin (5), 1-(3',4'-dihydroxycinnamoyl) cyclopentane-2,3-diol (6), asperosaponin C (7), leontoside A (8), quinatic acid (9), and quinatoside A (10) were isolated from Akebiae Caulis using repeated column chromatography with silica gel, LiChroprep RP-18, and MCI gel. The chemical structures of compounds 1-10 were illustrated based on 1D and 2D NMR spectroscopy, including 1H-1H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Compound 1 a novel compound and known compounds 6 and 7 were isolated for the first time from this plant. Among these compounds, 1, 3, 4, 5 and 7 displayed significant inhibitory effects on Aß42 induced fibrillogenesis. We present the first report of new compound 1 and the inhibitory effects of components from Akebiae Caulis on Aß42 fibrillogenesis.

A new indole glycoside from the seeds of Raphanus sativus.

A new indole glycoside, ß-D-glucopyranosyl 2-(methylthio)-1H-indole-3-carboxylate, named raphanuside A (1), as well as eight known compounds, ß-D-fructofuranosyl-(2 â†’ 1)-(6-O-sinapoyl)-α-D-glucopyranoside (2), (3-O-sinapoyl)-ß-D-fructofuranosyl-(2 â†’ 1)-α-D-glucopyranoside (3), (3-O-sinapoyl)-ß-D-fructofuranosyl-(2 â†’ 1)-(6-O-sinapoyl)-α-D-glucopyranoside (4), (3,4-O-disinapoyl)-ß-D-fructofuranosyl-(2 â†’ 1)-(6-O-sinapoyl)-α-D-glucopyranoside (5), isorhamnetin 3,4'-di-O-ß-D-glucoside (6), isorhamnetin 3-O-ß-D-glucoside-7-O-α-L-rhamnoside (7), isorhamnetin 3-O-ß-D-glucoside (8) and 3'-O-methyl-(-)-epicatechin 7-O-ß-D-glucoside (9) were isolated from the seeds of Raphanus sativus. Furthermore, compounds 1-3 and 6-9, were isolated from this plant for the first time. The structures of compounds 1-9 were identified using 1D and 2D NMR, including (1)H-(1)H COSY, HSQC, HMBC and NOESY spectroscopic analyses. The inhibitory activity of these isolated compounds against interleukin-6 (IL-6) production in TNF-α stimulated MG-63 cells was also examined.

The memory-enhancing effect of erucic acid on scopolamine-induced cognitive impairment in mice.

Erucic acid is a monounsaturated omega-9 fatty acid isolated from the seed of Raphanus sativus L. that is known to normalize the accumulation of very long chain fatty acids in the brains of patients suffering from X-linked adrenoleukodystrophy. Here, we investigated whether erucic acid enhanced cognitive function or ameliorated scopolamine-induced memory impairment using the passive avoidance, Y-maze and Morris water maze tasks. Erucic acid (3mg/kg, p.o.) enhanced memory performance in normal naïve mice. In addition, erucic acid (3mg/kg, p.o.) ameliorated scopolamine-induced memory impairment, as assessed via the behavioral tasks. We then investigated the underlying mechanism of the memory-enhancing effect of erucic acid. The administration of erucic acid increased the phosphorylation levels of phosphatidylinositide 3-kinase (PI3K), protein kinase C zeta (PKCζ), extracellular signal-regulated kinase (ERK), cAMP response element-binding protein (CREB) and additional protein kinase B (Akt) in the hippocampus. These results suggest that erucic acid has an ameliorative effect in mice with scopolamine-induced memory deficits and that the effect of erucic acid is partially due to the activation of PI3K-PKCζ-ERK-CREB signaling as well as an increase in phosphorylated Akt in the hippocampus. Therefore, erucic acid may be a novel therapeutic agent for diseases associated with cognitive deficits, such as Alzheimer's disease.

Moracin M inhibits airway inflammation by interrupting the JNK/c-Jun and NF-κB pathways in vitro and in vivo.

The therapeutic effectiveness of moracins as 2-arylbenzofuran derivatives against airway inflammation was examined. Moracin M, O, and R were isolated from the root barks of Morus alba, and they inhibited interleukin (IL)-6 production from IL-1ß-treated lung epithelial cells (A549) at 101-00µM. Among them, moracin M showed the strongest inhibitory effect (IC50=8.1µM). Downregulation of IL-6 expression by moracin M was mediated by interrupting the c-Jun N-terminal kinase (JNK)/c-Jun pathway. Moracin derivatives inhibited inducible nitric oxide synthase (iNOS)-catalyzed NO production from lipopolysaccharide (LPS)-treated alveolar macrophages (MH-S) at 50-100µM. In particular, moracin M inhibited NO production by downregulating iNOS. When orally administered, moracin M (20-60mg/kg) showed comparable inhibitory action with dexamethasone (30mg/kg) against LPS-induced lung inflammation, acute lung injury, in mice with that of dexamethasone (30mg/kg). The action mechanism included interfering with the activation of nuclear transcription factor-κB in inflamed lungs. Therefore, it is concluded that moracin M inhibited airway inflammation in vitro and in vivo, and it has therapeutic potential for treating lung inflammatory disorders.

A new megastigmane glycoside from Akebia quinata.

A new megastigmane glycoside, 8S*,9R*-megastigman-3-one-4,6-diene-8,9-diol-9-O-ß-D-glucopyranoside, named akequintoside D (1), as well as six known compounds, roseoside II (2), 3-O-caffeoylquinic acid (3), methyl-3-O-caffeoylquinate (4), 3,4,5-trimethoxyphenyl-ß-D-glucopyranoside (5), cuneataside D (6), 3,4-dimethoxyphenyl-6-O-(α-L-rhamnopyranosyl)-ß-D-glucopyranoside (7) were isolated from the stem of Akebia quinata. The structures of compounds (1-7) were identified based on 1D and 2D NMR, including (1)H-(1)H COSY, HSQC, HMBC and NOESY spectroscopic analyses. The inhibitory activity of these isolated compounds against interleukin-6 (IL-6) production in TNF-α stimulated MG-63 cells was also examined.

Chemical constituents on the aerial parts of Artemisia selengensis and their IL-6 inhibitory activity.

Ten compounds, 1',3'-propanediol,2'-amino-1'-(1,3-benzodioxol-5-yl) (1), artanomaloide (2), canin (3), eupatilin (4), quercetin-3-O-ß-D-glucoside-7-O-α-L-rhamnoside (5), 1,3-di-O-caffeoylquinic acid (6), isoquercitrin (7), pinoresinol-4-O-ß-D-glucoside (8), scopolin (9), and isofraxidin-7-O-ß-D-glucopyranoside (10) were isolated from the aerial parts of A. selengensis. The structures of compounds (1-10) were identified based on 1D and 2D NMR, including (1)H-(1)H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Among them, compound 1 was isolated from this plant for the first time as a naturally occurring compound. The inhibitory activity of these isolated compounds against interleukin-6 (IL-6) production in TNF-α stimulated MG-63 cells was also examined.

Phenolic compounds with IL-6 inhibitory activity from Aster yomena.

A new biflavonoid, named asteryomenin (1), as well as six known phenolic compounds, esculetin (2), 4-O-ß-D-glucopyranoside-3-hydroxy methyl benzoate (3), caffeic acid (4), isoquercitrin (5), isorhamnetin-3-O-glucoside (6), and apigenin (7) were isolated from the aerial parts of Aster yomena. The structures of compounds (1-7) were identified based on 1D and 2D NMR, including (1)H-(1)H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Compounds 2-7 were isolated from this plant for the first time. For these isolates, the inhibitory activity of IL-6 production in the TNF-α stimulated MG-63 cell was examined. Among these isolates, compounds 4 and 7 appeared to have potent inhibitory activity of IL-6 production in the TNF-α stimulated MG-63 cell, while compounds 1-3 and 5-6 showed moderate activity.