The cytotoxicity of phenolic antioxidants had attracted marked attention, posing serious challenges to food safety. This paper presented a screening method for two major phenolic antioxidants (butylated hydroxytoluene and tert -butylhydroquinone) added in edible oils. To specifically visualize the targeted compounds after developing with toluene/ethyl acetate/methanol 8:1:1 ( v / v / v ) to 70 mm solvent front, the plate was subjected to a standardized 1,1-diphenyl-2-picrylhydrazyl assay. In addition to synoptical eye inspection, accurate quantification was realized by modified densitometric measurements: fluorescence mode, excitation wavelength 530 nm (D 2 and W lamp) without optical filter, which offered satisfactory sensitivity (8.5–17.5 mg/kg) and acceptable linearity ( R 2 > 0.999 within 50–200 ng/zone). Moreover, the established method was validated with edible oil samples, against EU Directive 2006/52/EC. Apart from that, the unambiguous confirmation of positive results was conveniently achieved by TLC-MS interface-mediated mass spectrometry. Featuring the merits of screening conception, the proposed method not only reached the goal of accurate quantification and conclusive identification of multi-phenolic antioxidants, but also excellently balanced the simplicity, detectability, and throughput of the screening workup. Therefore, it might be an attractive alternative to conventional methods.
The chemical composition of the essential oil from roots and rhizomes of Ligularia hodgsonii was analyzed by gas chromatography (GC) and GC-mass spectrometry (MS). Forty-seven components were identified, representing 77.0% of the total oil. The main constituents were l-(+)-ascorbic acid 2,6-dihexadecanoate (15.7%), selina-6-en-4-ol (8.4%) and 9,10-dimethyl-1,2,3,4,5,6,7,8-octahydroanthracene (6.6%). The free radical scavenging activities of the essential oil, aqueous extract, ethanolic extract, and crude polysaccharides of L. hodgsonii, as well as some of their major components, were investigated using DPPH and ABTS assays. The essential oil displayed a lower capacity to quench free radicals than the extracts; the ethanolic and aqueous extracts showed considerably higher antioxidant potential that deserves further study.
Guilong Yan,Yuzhen Zhou,Yonghong Hu,Liqin Zhao,Wei Wang
Counter-current chromatography (CCC) target-guided by on-line HPLC with post-column DPPH assay was established for efficient screening and isolation of large amount of antioxidants from Eupatorium lindleyanum DC. On-line HPLC with post-column DPPH reaction was used to screen the antioxidants and optimize the biphasic solvent system of CCC, then the targeted peaks were purified using CCC. In the present study, three compounds, nepetin, cirsiliol and jaceosidin, were targeted and successively separated from n-butanol fraction of E. lindleyanum DC. by this strategy. All three compounds showed strong DPPH radical scavenging activity. These results confirmed that the strategy would be an efficient and effective method to isolate antioxidants from complex mixtures.
危险品化学品经营许可证（带存储）