Identification of Phenylethanoid Glycosides in Plant Extract of Plantago asiatica L. by Liquid Chromatography-Electrospray Ionization Mass Spectrometry

The present work describes a liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method for rapid identification of phenylethanoid glycosides in plant extract from Plantago asiatica L. By using a binary mobile phase system consisting of 0.2% acetic acid and acetonitrile under gradient conditions, a good separation was achieved on a reversed-phase C-18 column. The [M-H](-) ions, the molecular weights, and the fragment ions of phenylethanoid glycosides were obtained in the negative ion mode using LC-ESI-MS. The identification of the phenylethanoid glycosides (peaks 1-3) in the extract of P. asiatica L. was based on matching their retention time, the detection of molecular ions, and the fragment ions obtained by collision-induced dissociation (CID) experiments with those of the authentic standards and data reported in the literature.

Anti-HIV-1 activities of extracts from the medicinal plant Rhus chinensis

Rhus chinensis, a species used in folk medicine by Chinese native people, the anti-HIV-1 activities of the petroleum ether, ethyl acetate, butanol and aqueous extract of Rhus chinensis, named as RC-1, RC-2, RC-3 and RC-4, respectively, was evaluated. The

Antioxidative principals of Jussiaea repens: an edible medicinal plant

Jussiaea repens L. (JRL) is an edible medicinal plant and is also used as a vegetable by the local people in southwestern China. The crude extract and its four fractions derived from JRL were evaluated for the 1,1-diphenyl-2-picrylhydrazyl radical-scavenging ability, hydroxyl radical-scavenging capacity and the potassium ferricyanide reduction property. The ethyl acetate-soluble fraction (EAF) and EAF6 (a subfraction derived from EAF) were the most valuable fraction and subfraction, respectively. Furthermore, bioactivity-guided chromatographic fractionation revealed that three pure compounds greatly contributed to the antioxidant activities. Qualitative and quantitative analyses of the major antioxidant constituents in the extract were systematically conducted by NMR, mass spectral analyses and RP-HPLC. The result demonstrated that rosmarinic acid (2.00 mg g(-1) JRL dry weight) quercetin 3-O-beta-D-glucopyranoside (9.88 mg g(-1) JRL dry weight), and kaempferol 3-O-beta-D-glucopyranoside (1.85 mg g(-1) JRL dry weight) were the major antioxidative constituents in JRL. These compounds are reported for the first time from this plant.

An efficient combination of supercritical fluid extraction and high-speed counter-current chromatography to extract and purify homoisoflavonoids from Ophiopogon japonicus (Thunb.) Ker-Gawler

Supercritical fluid extraction (SFE) was used to extract homoisoflavonoids from Ophiopogon japonicus (Thunb.) Ker-Gawler. The optimization of parameters was carried out using an orthogonal test L-9 (3)(4) including pressure, temperature, dynamic extraction time and the amount of modifier. The process was then scaled up by 100 times with a preparative SFE system under the optimized conditions of 25 MPa, 55 degrees C, 4.0 h and 25% methanol as a modifier. Then crude extracts were separated and purified by high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of n-hexane/ethyl acetate/methanol/ACN/water (1.8:1.0:1.0:1.2:1.0 v/v). There three homoisoflavonoidal compounds including methylophiopogonanone A 6-aldehydo-isoophiopogonone A, and 6-formyl-isoophiopogonanone A, were successfully isolated and purified in one step. The collected fractions were analyzed by HPLC. In each operation, 140 mg crude extracts was separated and yielded 15.3 mg of methylophiopogonanone A (96.9% purity), 4.1 mg of 6-aldehydo-isoophiopogonone A (98.3% purity) and 13.5 mg of 6-formyl-isoophiopogonanone A (97.3% purity) respectively. The chemical structure of the three homoisoflavonoids are identified by means of ESI-MS and NMR analysis.