ABSTRACT
Objective: To establish an ultra-high performance liquid chromatography coupled with triple quadrupole mass for the determination of five biflavones. Method: Chromatographic separation was carried out on a ACQUITY UPLC BEH C18 column (2.1 mm×100 mm,1.7 μm) with gradient elution of acetonitrile and 0.10%formic acid at a flow rate of 0.3 mL·min-1,and the column temperature was set at 35℃. Result: Amentoflavone,bilobetin,ginkgetin,isoginkgetin,sciadopitysin showed a good linearity within the ranges of 0.02-13.20 mg·L-1(r=0.996 3),0.05-23.60 mg·L-1(r=0.995 5),0.09-18.60 mg·L-1(r=0.992 7),0.10-21.00 mg·L-1(r=0.998 8),0.06-16.00 mg·L-1(r=0.996 7),with average recoveries of 101.50%,98.78%,97.59%,97.24%,101.09%, and RSDs of 2.7%,2.7%,3.1%,2.8%,1.3%. The contents of amentoflavone,bilobetin,ginkgetin,isoginkgetin,sciadopitysin ranged between 121.30-434.74,268.39-847.14,251.80-1 297.10,195.87-691.10,477.48-3 003.90 μg·g-1. The total biflavones ranged between 1 474.45-5 635.40 μg·g-1. It shows a certain regularity that the low-vinegar leaves contain higher total flavonoids,and the total flavonoid content gradually decreases with the increase of tree age. Conclusion: The method was simple, and can be used for qualitative and quantitative analysis of biflavones.
ABSTRACT
This paper presents the chemical investigation of the leaves and stems of Ouratea castaneifolia (DC.) Engl.. There are no chemical or pharmacological studies with this species. Classic phytochemical investigation of the organic extracts together with high pressure liquid chromatography (HPLC) procedures lead to the identification of seventeen metabolites: seven triterpenes (friedelin, 3β-friedelinol, α-amyrin, β-amyrin, lupeol, germanicol and taraxerol), four steroids (sitosterol, stigmasterol and the glycosides sitosteryl 3-O-β-D-glucopyranoside and stigmasteryl 3-O-β-D-glucopyranoside), one isoflavone (5,7,4'-trimethoxyisoflavone), one flavone (5,4'-dihydroxy-7,3',5'-trimethoxyflavone) and four biflavones (amenthoflavone, 7,7"-O-dimethylamenthoflavone, heveaflavone and tetramethylamenthoflavone). The structures of the compounds were established by the analysis of ¹H, 13C NMR spectra including bidimensional techniques. The classes of the identified metabolites are in agreement with previous studies of the Ouratea genus.
O presente trabalho trata da investigação química das folhas e caule da espécie Ouratea castaneifolia (DC.) Engl., sobre a qual não há registros de estudos químicos ou farmacológicos anteriores. O estudo fitoquímico clássico dos extratos orgânicos do caule e das folhas de O. castaneifolia foi aliado à técnica da cromatografia líquida de alta eficiência (CLAE) e resultou na identificação de dezessete metabólitos: sete triperpenos (friedelina, 3β-friedelinol, α-amirina, β-amirina, lupeol, taraxerol e germanicol), quatro esteróides (sitosterol, estigmasterol e os glucosídeos sitosteril 3-O-β-D-glicopiranosídeo e estigmasteril 3-O-β-D-glicopiranosídeo), uma isoflavona (5,7,4´-trimetoxiisoflavona), uma flavona (5,4´-diidroxi-7,3´,5´-trimetoxiflavona), quatro biflavonas (amentoflavona, 7,7"-O-dimetil-amentoflavona, heveaflavona e tetrametilamentoflavona). A identificação das substâncias foi feita com base na análise de espectros de RMN de ¹H, 13C e técnicas bidimensionais. As classes dos metabólitos identificados estão de acordo com aquelas citadas em estudos químicos do gênero Ouratea.