Flavonol glycosides and triterpenes from the leaves of Uncaria ...

Flavonol glycosides and triterpenes from the leaves of Uncaria rhynchophylla (Miq.) Jacks. / Asian Journal of TraditionalMedicines, 2009, 4 (3)HO6758OH1O9 2 1'104O3OR 22' 3'R 1OH1 R 1 =-OH, R 2 =- β Gal 6 - α Rha2 R 1 =-OH, R 2 =- β Glc 6 - α Rha3 R 1 =-OH, R2 =- β Gal4 R 1 =-H, R 2 =- β Gal 6 - α Rha5 R 1 =-H, R 2 =- β Gal6'5'4'HO232414 5R 11125 2610236 R 1 =-H, R 2 =-H7 R 1 =-H, R 2 =-OH8 R 1 =-OH, R 2 =-H96OH128729R 21813 171427153020 211916COOH2822R 1 O231411199510H612H8721 2220131418H17H1615239 R 1 =-H10 R 1 =- β Glc282429252627Fig. 1. The structures of compounds 1–10Fig.1 The structures of compounds 1–10General experimental proceduresMelting points were determined on a Yanacomicro melting-point apparatus (uncorrected) (Japan).UV spectra was obtained using a Shimadzu UV-2201spectrophotometer. 1 H NMR and 13 C NMR spectrawere recorded on a Bruker ARX-300 spectrometerwith TMS as the internal standard. ESI-MS datawere acquired on a Shimadzu QP8000α HPLC-Mass spectrometer. Preparative HPLC was carriedout using a Shimadzu LC-8A solvent delivery pumpand a Shimadzu SPD-10AVP detector. Silica-gel forchromatography was purchased from Qindao OceanChemicals Co., China, and polyamide was purchasedfrom the Zhejiang Plastics Plant, China. SephadexLH-20 was purchased from GE Healthcare, Sweden.Plant materialsLeaves of U. rhynchophylla were collected inOctober 2005 in Fujian Province, China. A voucherspecimen is held in the Department of TraditionalChinese Medicines, Shenyang PharmaceuticalUniversity. Species identification was confirmed byProfessor Zerong Jiang, Shenyang PharmaceuticalUniversity.Extraction and isolationThe air-dried leaves (2.5 kg) of U. rhynchophyllawere percolated with 75 % aqueous EtOH. The EtOHextract (670 g) was suspended in water and partitionedsuccessively with n-hexane (3 × 4 L), CHCl 3(3 × 4 L)and n-BuOH (3 × 4 L) to obtain the n-hexane extract(25 g), CHCl 3extract (55 g) and n-BuOH extract (250g), respectively. The n-BuOH extract was subjectedto silica-gel column chromatography (10 × 150 cm,200-300 mesh, Qindao Ocean Chemicals Co., China)involving elution with a CHCl 3-MeOH gradient.Several fractions (150 ml each) were collected,analyzed by TLC and grouped, accordingly.Three grams of the fraction eluted with CHCl 3-MeOH (20:1-10:1) (total 10 g) was subjected torepeated silica-gel column chromatography using aCHCl 3-MeOH solvent system and the eluates weregrouped on the basis of TLC analysis into six majorfractions (F1-F6). Fraction F2 was further subjectedto ODS open column chromatography (3.0×30 cm, 50μm, YMC Co., Ltd, Japan) eluting with MeOH-H 2O(50:50-100:0). The fraction eluted with MeOH-H 2O(85:15) was purified a further two times using ODSopen column chromatography to give compounds86