A new single-reference quantitative method using liquid chromatography with relative molar sensitivity based on 1H-qNMR for khellactone esters from Peucedanum japonicum root extract.

Khellactone ester (KLE) quantification using the absolute calibration method is difficult owing to the unavailability of standard reagents that can guarantee purity. Herein, a new method was developed to quantify KLEs from Peucedanum japonicum root extracts using liquid chromatography (LC) without utilizing standards. This method used relative molar sensitivity (RMS) and 7-ethoxy-4-methylcoumarin as a single-reference (SR) compound instead of KLE standards. RMS is the sensitivity ratio of SR to analytes, determined using an offline combination of quantitative NMR and LC. LC was performed using a triacontylsilyl silica gel column of superficially porous particles with a ternary mobile phase. The range of the method was 2.60-509 µmol/L. The accuracy and precision were reasonable. This is the first study to apply the RMS method to both conventional LC and ultra-high-performance liquid chromatography using the same mobile phase and column. This method may aid the quality assurance of foods containing KLEs.

Efficient utilization of licorice root by alkaline extraction.

Compared to studies of water extracts of plants, those utilising alkaline extracts are limited. Both water and alkaline extracts from licorice root were compared regarding their biological activities. Licorice root was successively extracted first with water or alkaline solution (pH 9 or 12), and the alkaline (pH 12.0) extract was further separated into 50% ethanol-soluble and -insoluble fractions. Viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Antibacterial activity against Porphyromonas gingivalis 381 was determined by turbidity assay. Cytochrome P-450 (CYP)3A4 activity was measured by ß-hydroxylation of testosterone using human recombinant CYP3A4. Radical intensity of superoxide and hydroxyl radicals was determined by electron spin resonance spectroscopy. Alkaline extraction yielded slightly higher amounts of dried materials compared to water extraction. Alkaline extract showed higher anti-HIV and antibacterial activities, and similar magnitudes of CYP3A4 inhibitory and superoxide and hydroxyl radical-scavenging activities, compared to water extract. When alkaline extract was fractionated by 50% ethanol, anti-HIV activity was recovered from the insoluble fraction representing approximately 3% of the alkaline extract, whereas antibacterial activity was concentrated in the soluble fraction rich in glycyrrhizid acid, flavanones and chalcones. All extracts and sub-fractions led to bimodal hormetic dose-response (maximum hormetic response=238%) on the bacterial growth. The present study demonstrated the superiority of alkaline extraction over water extraction for preparing anti-HIV and antibacterial agents at higher yield from licorice root.

Evaluation of cytotoxiciy and tumor-specificity of licorice flavonoids based on chemical structure.

BACKGROUND: The mechanism of cytotoxicity induction by flavonoids has been studied by many investigators, but their tumor specificity is not clear. To address this point, 10 licorice flavonoids were subjected to quantitative structure-activity relationship (QASR) analysis with cytotoxicity assay with four human oral carcinoma and three normal cell lines. MATERIALS AND METHODS: Cytotoxicity was determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide method. Physico-chemical, structural, and quantum-chemical parameters were calculated based on the conformations optimized by the LowModeMD method. RESULTS: Licurazid and isoliquiritigenin had the highest cytotoxicity against tumor cells, and liquiritin, isoliquiritin and licurazid had the highest tumor specificity, suggesting an antitumor potential for licurazid. Chalcones had slightly higher cytotoxicity and tumor specificity than flavanones. The number of sugar units in the molecule was somewhat negatively-correlated with cytotoxicity, but not with tumor specificity. Parameters that reflect the three-dimensional structure, molecular volume and number of phenolic OH groups were significantly correlated with cytotoxicity, but not with tumor specificity. On the other hand, solvation energy was significantly correlated with tumor specificity, but not with cytotoxicity. CONCLUSION: These physicochemical descriptors may be useful to estimate cytotoxicity or tumor specificity of structurally-related compounds to these licorice flavonoids.

Hepatoprotective activity of tocha, the stems and leaves of Ampelopsis grossedentata, and ampelopsin.

Hepatoprotective effect of the leaves and stems of Ampelopsis grossedentata together with its main constituent, ampelopsin, were examined on D-galactosamine induced liver injury in rats. The diet containing 50% ethanolic extract (1%) and ampelopsin (0.1%) markedly suppressed the increase of LDH, ALT, AST, alpha-tocopherol levels and GSG/GSSH caused by GalN treatment. These results suggested that ampelopsin from Tocha acted to prevent the oxidative stress in vivo that may have been due to active oxygen species formed by a macrophage by the action of GalN.