Preparative separation of flavone dimers from Dysosma versipellis by counter‐current chromatography: Trifluoroacetic acid as a solvent system modifier

Abstract

The separation of natural products is grueling and time-consuming work with repeated isolations needed to obtain purified compounds. However, using counter-current chromatography, a unique liquid-liquid partition chromatography, constituents can usually be purified efficiently. During the separation of flavone dimers from Dysosma versipellis (Hance) by counter-current chromatography, the separation resolution and sample loading was impeded by the emulsification of the sample. By screening, trifluoroacetic acid was selected as the solvent modifier to eliminate the emulsification. Then, a quaternary solvent system of hexane/ethyl acetate/methanol/water (4:6:5:5 v/v/v/v) with trifluoroacetic acid at a low concentration of 0.5% v/v was used to purify the components from D. versipellis. Compared to that without trifluoroacetic acid, the separation resolution as well as the sample loading both increased greatly. In addition, flavone dimers in low concentrations could be enriched and purified at high sample loading. As a result, five podophyllotoxins and 11 flavonoids were purified and characterized by interpretation of spectroscopic data, in which two of eight flavone dimers were new and a known flavone dimer was first separated from this species.

Structurally diverse biflavonoids from Dysosma versipellis and their bioactivity

“…24 Only eleven biavonoids have been obtained from plants of the genus Dysosma. [13][14][15][16] Our phytochemical investigations on D. versipellis resulted in the isolation of ve pairs of new biavonoid enantiomers, (±)-dysosmabiavonoids A-E (1-5), two new biavonoids, dysosmabiavonoids F-G (6-7), along with four biosynthetically related precursors (8)(9)(10)(11). Racemates 1-2 represent the rst report of natural C-2-O-C-7 ′ ′ :C3-C6 ′′ biavonoids.…”

“…5 As a common folk medicine, it has a satisfactory effect on the treatment of parotitis, 4 cough, sore throat, scrofula, nameless swollen venom/carbuncles, snake bite, fall injury, rheumatoid arthritis, 5 epidemic encephalitis B, parasites, tumor, 6 lumbago, skelalgia, 7 ulcer, 8 weakness, condyloma accuminata, lymphadenopathy, 9 pyogenic infection, 10 hemiplegia, joint pain, 11 and syphilis 12 since the Han dynasty in China. Its previous phytochemical and pharmacological investigations revealed the presense of bioactive biflavonoids, 13–16 and their neuraminidase inhibitory 13 and cytotoxic properties. 14 In our search for bioactive natural products, five pairs of new biflavonoid enantiomers, (±)-dysosmabiflavonoids A–E ( 1–5 ), two new biflavonoids, dysosmabiflavonoids F–G ( 6–7 ), along with four biosynthetically related precursors ( 8–11 ) (Fig.…”

Bioassay‐guided separation and identification of the anticancer composition from Curcuma longa L. by the combination strategy of methanol gradient countercurrent chromatography and ultra‐high‐performance liquid chromatography coupled with high‐resolution mass spectrometry

“…The biphasic solvent was mixed thoroughly and the two phases were separated by a funnel. To prevent sample emulsification during the separation process, TFA (0.5%, v/v) was added into the lower phase [30]. The organic phase was used as the stationary phase.…”

“…The K-values for the main components of C. longa L. were determined by HPLC analysis according to a previous method [29,30]. In brief, the sample extract was dissolved with HepEMWat solvent systems with different solvent ratios.…”

Aryltetralin lignans from Hyptis brachiata inhibiting T lymphocyte proliferation

“…The cell surface was stained with two separate panels (panel 1: CD3-APC AlexaFluor750, CD4-AlexaFluor700, CD69-PC7; panel 2: CD3-APC Alexa Fluor750, CD8-AlexaFluor700, CD69-PC7 (all Abs from Beckman-Coulter)) for 30 min at room temperature in the dark. Cells were re-suspended in 100 µL Cytofix/Cytoperm solution for 15…”