Isolation and Identification of Two Phenolic Compounds from a Moderately Cytotoxic Fraction of Cousinia verbascifolia Bunge

Abstract

Background:Little information is available about chemical components of the Cousinia genus. A primary cytotoxicity screening on Cousinia verbascifolia showed moderate cytotoxic activity against OVCAR-3 ovarian and HT-29 colon cancer cells. Therefore, the aim of this study is a phytochemical investigation to identify the compounds responsible for this bioactivity.Materials and Methods:Extraction was done through percolation and fractionations by reverse phase column chromatography and normal column chromatography. Using standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay Fr.b8 with moderate cytotoxicity was selected for identification of major components. Fr.b8 was subjected to polyamide column chromatography. More purification was done using a new modified recycle high-performance liquid chromatography (HPLC) with flow splitter.Results:Two known compounds: Apigenin (flavone) and caffeic acid (phenolic acid) were obtained from phenolic bioactive fraction for the first time from this plant.Conclusions:Apigenin and caffeic acid with known antitumor and matrix metalloproteinase inhibitory effects seem to be the bioactive components responsible for moderate cytotoxicity of phenolic fraction. Recycle HPLC following with flow splitting is a new method useful for isolation of closely eluted compounds in HPLC chromatogram.

Flavone constituents of Phlomis bruguieri Desf. with cytotoxic activity against MCF-7 breast cancer cells

“…The 1 H-NMR spectrum displayed two meta coupled doublets at δ H 6.26 (1H, d, J = 1.6 Hz) and 6.45 (1H, d, J = 1.6 Hz) attributed to H-6 and H-8, a singlet proton at δ H 6.51 (1H, s, H-3) two ortho coupled proton signals at δ H 6.97 (1H, d, J = 8. 4 Hz) and 7.33 (1H, dd, J = 8.4, 2.0 Hz), corresponding to H-5′ and H-6′ as well as δ 7.41 (1H, d, J = 2.0 Hz) corresponding to H-2′ proton, indicated that compound 1 is 3′,4′, 5 7 tetrahydroxy flavone known as luteolin in agreement with literature data and co-TLC with authenticated sample( 18 19 ).…”

“…The 1 H-NMR spectrum displayed two meta doublets at δ 6.10 (1H, d, J = 2.0 Hz), and 6.36 (1H, d, J = 2.0 Hz) coupled to each other similar to those of H-8 and H-6 in flavones in addition to a singlet proton at 6.49 (H-3), and two ortho -coupled signals at δ 6.83 (2H, d, J = 8. 8 Hz) and 7.75 (2H, d, J = 8.8 Hz), describing to H-6′,2′ and H-5′, 3′ related to AA′BB′ spin system indicated that compound 3 is 4′, 5 7-trihydroxyflavone or apigenin( 19 ).…”

Bioactivity guided isolation of apigenin from Stachys lavandulifolia Vahl. in mice with anxiolytic effects

“…Its UV spectrum showed two absorptions maxima at 340.7 and 265.5 nm which is characteristic for flavones. (13). Phytochemical analysis of other fractions (Fr1-Fr3, and Fr5) was also performed in another research work which its data were published elsewhere (14).…”

Flavonoids: isolation, characterization, and health benefits

“…Myricetin and quercetin inhibited mammalian TrxRs with IC 50 values of 0.62 and 0.97 Mmol/L, respectively [92]. Apigenin has been reported to arrest HT29 colon cancer [50]. Oncamex showed a strong anti-tumor effect against breast cancer while hesperetin was active against lung and carcinoma cancer cells [93].…”