13 research outputs found
Search for anti-inflammatory plant constituents by monitoring suppression of nitric oxide production in activated macrophages(活性化マクロファージの一酸化窒素産生の抑制を指標とする抗炎症性植物成分の探索研究)
Isolation of 4,5- O
There is a continual need to develop novel and effective melanogenesis inhibitors for the prevention of hyperpigmentation disorders. The plant Artemisia capillaris Thunberg (Oriental Wormwood) was screened for antipigmentation activity using murine cultured cells (B16-F10 malignant melanocytes). Activity-based fractionation using HPLC and NMR analyses identified the compound 4,5-O-dicaffeoylquinic acid as an active component in this plant. 4,5-O-Dicaffeoylquinic acid significantly reduced melanin synthesis and tyrosinase activity in a dose-dependent manner in the melanocytes. In addition, 4,5-O-dicaffeoylquinic acid treatment reduced the expression of tyrosinase-related protein-1. Significantly, we could validate the antipigmentation activity of this compound in vivo, using a zebrafish model. Moreover, 4,5-O-dicaffeoylquinic acid did not show toxicity in this animal model. Our discovery of 4,5-O-dicaffeoylquinic acid as an inhibitor of pigmentation that is active in vivo shows that this compound can be developed as an active component for formulations to treat pigmentation disorders
Search for anti-inflammatory plant constituents by monitoring suppression of nitric oxide production in activated macrophages(活性化マクロファージの一酸化窒素産生の抑制を指標とする抗炎症性植物成分の探索研究)
Flavone Tetraglycosides and Benzyl Alcohol Glycosides from the Mongolian Medicinal Plant <i>Dracocephalum ruyschiana</i>
From an extract of the aerial parts of <i>Dracocephalum
ruyschiana</i>, five new flavone tetraglycosides, five new benzyl
alcohol glycosides,
and 19 known compounds were isolated. The tetraglycosides contain
a 7-<i>O</i>-β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)]-β-d-glucopyranosyl moiety. The benzyl alcohol glycosides had acyl
groups on their glycosyl or aglycone moieties. The compounds were
tested for antioxidant activity using DPPH. Although the new compounds
were not active, phenylpropanoylquinic acid derivatives were revealed
as radical scavengers in <i>D</i>. <i>ruyschiana</i>
Antioxidant Constituents of Cotoneaster melanocarpus Lodd.
The aim of this study was the evaluation of the antioxidant capacity of Cotoneaster melanocarpus Lodd. and the identification of antioxidant active constituents of this plant. C. melanocarpus Lodd. is a shrub indigenous to Mongolia and used in Traditional Mongolian Medicine as a styptic. Before extraction, the plant material was separated into three parts: young sterile shoots, older stems and leaves. All these parts were extracted with water, methanol, ethyl acetate, dichloromethane and hexane, successively. The methanolic extract of the sterile shoots showed the highest antioxidant activity in the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay (IC50 30.91 ± 2.97 µg/mL). This active extract was further analyzed with chromatographic methods. TLC fingerprinting and HPLC indicated the presence of the flavonol glycosides quercetin-3-O-rutinoside (rutin), quercetin-3-O-galactoside (hyperoside) and quercetin-3-O-glucoside (isoquercetin), ursolic acid as well as chlorogenic acid, neochlorogenic acid and cryptochlorogenic acid. The findings were substantiated with LC-MS. All identified compounds have antioxidant properties and therefore contribute to the radical scavenging activity of the whole plant
Antioxidant Flavonols and Phenolic Compounds from <i>Atraphaxis frutescens</i> and Their Inhibitory Activities against Insect Phenoloxidase and Mushroom Tyrosinase
Chemical investigation of the aerial
parts of <i>Atraphaxis
frutescens</i> resulted in the isolation of five 7-methoxyflavonols
with pyrogallol B-ring moieties (<b>1</b>–<b>5</b>), a fisetinidol glucoside (<b>13</b>), and a benzyl glycoside
(<b>18</b>), together with 26 known compounds including flavonoids,
phenylpropanoid amides, anthraquinone glycosides, lignans, and a benzyl
derivative. The principal chemical structural feature of the isolated
compounds was either a pyrogallol or catechol B-ring moiety, and they
showed potent 1,1-diphenyl-2-picrylhydrazyl radical scavenging activities.
To assess the effects of these antioxidants on biological enzymes,
their inhibitory effects against an insect phenoloxidase and a mushroom
tyrosinase were evaluated. This study indicated that insect phenoloxidase
was inhibited by phenylpropanoid amides and that mushroom tyrosinase
was inhibited by the characteristic 7-methoxyflavonol 3-<i>O</i>-rhamnopyranosides
Evaluation of Mongolian compound library for potential antimalarial and anti-Toxoplasma agents
Trypanocidal Activity of 2,5-Diphenyloxazoles Isolated from the Roots of <i>Oxytropis lanata</i>
Eleven 2,5-diphenyloxazole derivatives
(<b>1</b>–<b>11</b>), together with six known isoflavonoid
derivatives, were
isolated from the roots of <i>Oxytropis lanata</i>. The
2,5-diphenyloxazole (<b>1</b>) obtained proved to be identical
to a standard sample used as a scintillator and liquid laser dye.
The other oxazole derivatives isolated were found to have one to four
hydroxy and/or <i>O</i>-methyl groups in their phenyl rings.
Seven of the oxazole derivatives obtained are new (<b>3</b>–<b>9</b>). The inhibitory activity of the isolated compounds was
evaluated against <i>Trypanosoma congolense</i>, the causative
agent of African trypanosomosis in animals. Oxazoles with di- and
trihydroxy groups showed trypanocidal activity, and 2-(2′,3′-dihydroxyphenyl)-5-(2″-hydroxyphenyl)oxazole
(<b>4</b>) exhibited the most potent inhibitory activity (IC<sub>50</sub> 1.0 μM)