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Benzo (α) pyrene in soybean oil was determined by molecular imprinting column purification combined with high performance liquid chromatography (MIC-HPLC).The whole process was analyzed to evaluate the uncertainty of the analytical results.Meanwhile, the uncertainty components were quantified and synthesized by a metrological model of uncertainty.Furthermore, the extended uncertainty of the measurement results was calculated.The results showed that the main factors which affected the uncertainty were the calibration curve, recovery, sample weighting and working solution preparation.When the content of benzo (α) pyrene in soybean oil was 8.735 μg/kg, at 95% confidence interval, the expanded uncertainty was 0.794 μg/kg (k=2).The uncertainty of benzo (α) pyrene in edible oil determined by MIC-HPLC can be reduced by strictly control the processes of the curve fitting, recovery, sample weighting and working solution preparation.

Olibanum, a golden oleo-gum resin from species in the Boswellia genus (Burseraceae family), is a famous traditional herbal medicine widely used around the world. Previous phytochemical studies mainly focused on the non-polar fractions of olibanum. In this study, nine novel diterpenoids, boswellianols A–I (1–9), and three known compounds were isolated from the polar methanolic fraction of the oleo-gum resin of Boswellia carterii. Their structures were determined through comprehensive spectroscopic analysis as well as experimental and calculated electronic circular dichroism (ECD) data comparison. Compound 1 is a novel diterpenoid possessing an undescribed prenylmaaliane-type skeleton with a 6/6/3 tricyclic system. Compounds 2–4 were unusual prenylaromadendrane-type diterpenoids, and compounds 5–9 were new highly oxidized cembrane-type diterpenoids. Compounds 1 and 5 showed significant transforming growth factor β (TGF-β) inhibitory activity via inhibiting the TGF-β-induced phosphorylation of Smad3 and the expression of fibronectin and N-cadherin (the biomarker of the epithelial–mesenchymal transition) in a dose-dependent manner in LX-2 human hepatic stellate cells, indicating that compounds 1 and 5 should be potential anti-fibrosis agents. These findings give a new insight into the chemical constituents of the polar fraction of olibanum and their inhibitory activities on the TGF-β/Smad signaling pathway. [ABSTRACT FROM AUTHOR]

Alcoholism is a worldwide health problem, and diseases caused by alcoholism are killing people every year. Amomum kravanh is a traditional Chinese medicine used to relieve hangovers. However, whether its bioactive components improve alcohol metabolism is not clear. In this study, ten new (amomumols A-J, 1–10) and thirty-five known (11–45) compounds were isolated from the fruits of Amomum kravanh by an activity-guided separation. Ten novel compounds were identified as four sesquiterpenoids (1–4), three monoterpene derivatives (5–7), two neolignans (8, 9), and a novel norsesquiterpenoid (10) with a new C14 nor-bisabolane skeleton. Their structures were determined by the comprehensive analysis of high-resolution electrospray ionization mass spectrometry (HRESIMS), nuclear magnetic resonance (NMR), and electronic circular dichroism (ECD) calculation. The effects of all isolated compounds on the activity of alcohol dehydrogenase were evaluated in vitro, and it was found that eight compounds (11, 12, 15, 18, 26, and 36–38) exhibited significant activation effects on the alcohol dehydrogenase at 50 μM. [ABSTRACT FROM AUTHOR]

COVID-19 is still a global public health concern, and the SARS-CoV-2 mutations require more effective antiviral agents. In this study, the antiviral entry activity of thirty-one flavonoids was systematically evaluated by a SARS-CoV-2 pseudovirus model. Twenty-four flavonoids exhibited antiviral entry activity with IC50 values ranging from 10.27 to 172.63 µM and SI values ranging from 2.33 to 48.69. The structure–activity relationship of these flavonoids as SARS-CoV-2 entry inhibitors was comprehensively summarized. A subsequent biolayer interferometry assay indicated that flavonoids bind to viral spike RBD to block viral interaction with ACE2 receptor, and a molecular docking study also revealed that flavonols could bind to Pocket 3, the non-mutant regions of SARS-CoV-2 variants, suggesting that flavonols might be also active against virus variants. These natural flavonoids showed very low cytotoxic effects on human normal cell lines. Our findings suggested that natural flavonoids might be potential antiviral entry agents against SARS-CoV-2 via inactivating the viral spike. It is hoped that our study will provide some encouraging evidence for the use of natural flavonoids as disinfectants to prevent viral infections. [ABSTRACT FROM AUTHOR]

Primary bile acids (BAs), products of cholesterol metabolism and clearance, are synthesized in the liver and released into the intestine to facilitate the digestion and absorption of lipids. BAs are further converted by gut commensal bacteria into secondary colonic BAs and the metabolism disorder is closely linked to cholestatic liver diseases via regulating immune response. However, the effect and underlying mechanism of these host‐microorganism biliary metabolites on T lymphocyte remain unclear. In the current study, we synthesized a sulfated product of lithocholic acid (LCA), lithocholic acid 3‐sulfate (LCA‐3‐S), and investigated the binding affinity of the BAs metabolites on RORγt, the transcription factor of IL‐17A. Our results demonstrated that the sulfate of LCA, LCA‐3‐S, exhibited better effect than its oxidated metabolite, 3‐oxo‐LCA, binding to RORγt. The results further demonstrated that LCA‐3‐S selectively suppressed Th17 cell differentiation without influence on Th1, Th2, and Treg cells. Collectively, we synthesized the sulfated biliary metabolite LCA‐3‐S and demonstrated that LCA‐3‐S selectively inhibited Th17 cell differentiation by targeting RORγt, indicating that metabolite disorder of BAs resulting in the decrease of LCA‐3‐S probably contributes to the pathogenesis of cholestatic liver diseases. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The tribe Delphineae, comprising two genera, Aconitum L. and Delphinium L., is the richest source of bioactive diterpenoid alkaloids (DAs), while their highly similar chemical structures create a major challenge for dereplication from complex mixture. To solve the inefficient discovery process of natural DAs, a novel dereplication strategy based on pattern recognition of specific heteronuclear multiple bond correlation (HMBC) signals has been established in this study. This strategy utilized the diagnostic signals in the HMBC spectra of C19‐DAs, which could indicate the structural categories. The newly designed software MatchNat allowed in silico recognition of C19‐DA types. The developed dereplication system was demonstrated to be a practical strategy to dereplicate a variety of natural products from two Delphineae plants, including Aconitum vilmorinianum Kom. and Delphinium pachycentrum Hemsl. Known compounds could be rapidly recognized from the mixture, and novel DAs were found with the aid of MatchNat. Consequently, targeted isolation led to the explosive discovery of a series of novel DAs. This dereplication system has the potential to be adopted for dereplication of any other class of natural products and has shown promising application as a complementary tool in the nuclear magnetic resonance analysis of traditional Chinese medicines. [ABSTRACT FROM AUTHOR]

Atrachinenynes A–D (1–4), four novel diacetylenic derivatives, were isolated for the first time from the rhizomes of Atractylodes chinensis. Compound 1 features a new C26 skeleton with an unusual 8/6/6/5 tetracyclic ring system bearing a diacetylene sidechain. Compounds 2–4 are three novel diacetylenic terpenoids with an additional six-membered ring between terpenes and diacetylenes formed via a Diels–Alder reaction. The structures and the absolute configurations of 1–4 were elucidated by spectroscopic methods, electronic circular dichroism (ECD) calculations, and 13C quantum chemical calculations. Their plausible biogenetic pathways were also proposed. [ABSTRACT FROM AUTHOR]