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Objective: To study the chemical constituents from the leaves of Platycladus orientalis, as well as their antioxidant and α-glucosidase inhibitory activities. Methods: The compounds were isolated and purified by silica gel, MCI, polyamide, and prep-HPLC chromatography, their structures were elucidated by spectral analysis. DPPH and ABTS methods were used to study the antioxidant activity, and pNPG method was used to study the α-glucosidase inhibitory activity. Results: Eleven compounds (1-11) were isolated from the 80% ethanol extract of the leaves of P. orientalis, and identified as 4-O-(1’,3’-dihydroxypropan-2’-yl)- dihydroconiferyl alcohol 9-O-β-D-glucopyranoside (1), myricetrin (2), 5,8,3’,4’-tetrahydroxy-flavone-7-O-β-D-xylopyranoside (3), isomassonianoside B (4), (-)-isopramine 9’-O-β-D-glucopyranoside (5), (7R,8S,7’S,8’R)-4,9,4’,7’-tetrahydroxy-3,3’-dimethoxy- 7,9’-epoxylignan 4-O-β-D-glucopyranoside (6), sugiol (7), totarol (8), 5,6-dehydrosugiol methyl ether (9), isopimara-8,15-dien-7-one (10) and ethanol α-L-rhamnopyranoside (11). Conclusion: Compound 1 is a new compound, named as platycloside A; In the known compounds, seven compounds (4-7, 9-11) are isolated from this plant for the first time, six compounds (4-6, 9-11) are isolated from the family Thujoideae for the first time, and four compounds (5, 6, 10, 11) are isolated from the family Cupresaceae for the first time. The compounds 2-6 showed a degree of antioxidant activities. The compounds 2 and 3 showed the α-glucosidase inhibitory activities.
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Objective: To study the chemical constituents of Urena lobata. Methods: Compounds were isolated and purified using various column chromatographies such as silica gel, Sephadex LH-20, and prep HPLC. Their structures were identified by physicochemical properties and various spectroscopic experiments, including HRESIMS, 1H-NMR, 13C-NMR, HSQC, and HMBC. Results: Fourteen flavonoids were obtained from the ethyl acetate extract of U. lobata, including apigenin-6-C-(6″-O-trans- caffeoyl)-β-D-glucopyranoside (1), tiliroside (2), kaempferol-3-O-(6″-O-cis-p-coumaroyl)-β-D-glucopyranoside (3), kaempferol-3- O-β-D-glucopyranosyl-(1→2)-β-D-galactopyranoside (4), rutin (5), astragalin (6), baicalin (7), myricetrin (8), isoquercitrin (9), baicalein (10), luteolin (11), apigenin (12), kaempferol (13), and quercetin (14). Conclusion: Compound 1 is a new compound named urenalobside A, compounds 3, 4, 7, and 8 are firstly obtained from the family Malvaceae, and compound 10 is firstly isolated from genus Urena Linn.
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To establish an HPLC method for the determination of myricetrin, quercitrin, myricetin, quercetin, kaempferol, amentoflavone and hinokiflavone in Cacumen Platycladi and processed Cacumen Platycladi, and compare the difference before and after the processing. Methods:The method described in Chinese pharmacopoeia was used in the processing. The chromato-graphic column was Welch Ultimate LP-C18 (250 mm × 4. 6 mm,5 μm),the mobile phase was methanol and 0. 2% phosphoric acid with gradient elution, the detection wavelength was 330 nm, and the flow rate was 1 ml·min-1 . The column temperatuhe was 35℃, the injection volume was 20μl. Results:The linear relationship respectively of myricetrin, quercitrin, myricetin, quercetin, kaempfer-ol, amentoflavone and hinokiflavone was good(r≥0. 999 0). The average recovery was within the range of 97. 6%-101. 1% (RSD≤1. 14%, n=6). The content of myricetrin, quercitrin, amentoflavone and hinokiflavone in Cacumen Platycladi was reduced after the processing, and the content of quercetin and kaempferol was increased after the processing. Conclusion: The method is simple,and can be used in the determination of Cacumen Platycladi and its processing product. The results of the content show that the flavones in Cacumen Platycladi can be changed by the processing.
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Objective To establish the RP-HPLC method for the determination of myricetrin and quercitroside in Euphorbia Hirta L.Methods The ZORBAX SB-C18 (250 mm × 4.6 mm,5 μn) column was used,the mobile phase consisted of acetonitrile:0.1％ H3PO4(21 ∶ 79),the flow rate was 0.8 ml/min,the column temperature was 30℃ the detecting wavelength was at 256 nm.Results The cablibration curve was linear within a range of 0.013～0.26 mg/ml and 0.008～0.16 mg/ml,the average recovery was 99.1％,98.9％and the RSD was 0.91％,1.55％,respectively.Conclusion The method is simple,repeatable and accurate,it can be applied in quantitative determination of myricetrin and quercitroside in Euphorbia Hirta L..
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Objective To establish the RP-HPLC method for the determination of myricetrin and quercitroside in Polygonum aviculare L.Methods The Agilent LC-C18 (250 mm×4.6 mm,5 μm) column was used,the mobile phase consisted of acetonitrile:0.1％ H3PO4(18 ∶ 82),the flow rate was 1.0 ml/min,the column temperature was 30℃ the detecting wavelength was at 256 nm.Results The calibration curve was linear within a range of 1.22～24.30 μg/ml and 0.77～15.40 μg/ml,the average recovery of this method was 98.9％,99.6％ and the RSD was 1.11％,1.09％,for the myricetrin and quercitroside respectively.Conclusion The method is simple,repeatable and accurate.It can be applied in quantitative determination of myricetrin and quercitroside in Polygonum aviculare L..