A fast, efficient, and cost-effective method was developed for the analysis of aflatoxins in farm commodities with high-pigment content, such as chili powder, green bean, and black sesame. The proposed method involved matrix solid-phase dispersion (MSPD) and high-performance liquid chromatography (HPLC)-fluorescence detection (FLD) with postcolumn electrochemical derivatization in a Kobra cell. The MSPD procedure combined the extraction with neutral alumina and pigment cleanup with graphitic carbon black (GCB) in a single step. The recoveries of aflatoxins ranged from 88% to 95% with the relative standard deviations (RSD) less than 6% (n = 6). The limits of detection (LODs) were 0.25 ng/g aflatoxin B1, G1, and 0.10 ng/g aflatoxin B2, G2, respectively. The analytical results obtained by MSPD were compared to those of the immunoaffinity column (IAC) cleanup method. No significant differences were found between the two methods by t-test at the 95% confidence level.
Four new hybrid peptide-polyketide
cyclic tridepsipeptides, colletopeptides
A–D (1–4), were isolated and
characterized from the endophytic fungus Colletotrichum sp. S8 derived from the stems of Rubia podantha with the guidance of LC-UV-MS detection. Their structures were elucidated
by extensive spectroscopic analysis and X-ray crystallography. Compounds 1–4 are rare natural 12-membered cyclic
tridepsipeptides containing a 3,5,11-trihydroxy-2-methyl dodecanoic
acid unit in their structures. 1–4 inhibited lipopolysaccharide-induced nitric oxide production in
RAW264.7 macrophages with the IC50 values of 8.3, 38.7,
13.5, and 22.2 μM, respectively. 1 also inhibited
the production of inflammatory factors IL-6 and TNF-α, and decreased
the phosphorylation of NF-κB-associated proteins IκBα
and p65.
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