Simple and sensitive determination of sulfites in Chinese herbal teas by ultrahigh-performance liquid chromatography tandem mass spectrometry.

Sulfites are used widely in food and beverage production to prevent browning or oxidation. However, the overingestion of sulfites is harmful to human health and may cause medical complications. Chinese herbal teas have been widely consumed for centuries. However, sulfite levels in Chinese herbal teas are rarely investigated and reported. Here, we present a simple, sensitive, and quantitative method to determine sulfites in Chinese herbal teas using ultrahigh-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) coupled with dispersive solid phase extraction. The method utilized a SeQuant ZIC-HILIC column for separation, and the optimal gradient eluents consisted of acetonitrile and aqueous solution with 0.1% acetic acid and 10 mM ammonium acetate. Porous chitosan/partially reduced graphene oxide/diatomite (CS/prGO/DM) composites were used as efficient dispersive solid phase extraction adsorbents for sample preparation. Several parameters were investigated during the extraction process, including sample-to-extraction solvent volume ratios, the extraction procedure and dosage of the adsorbent. Under the optimum conditions, the developed method gave a good determination coefficient (r2 > 0.99), low detection limits (0.51-12.1 µg kg-1) and high recoveries in the range of 83.8-102.7% at different spiked levels. The method has the great advantages of being time saving, good reproducibility and much lower detection limits when compared to titration methods. The method was further applied to analyze real herbal tea samples collected from the local market, demonstrating that our developed method is robust and useful for determining sulfites in practical application.

Profiling elements in Puerh tea from Yunnan province, China.

Puerh tea, as the most representative Chinese dark tea, has attracted global interest in recent years. Profiling the levels of metal elements in Puerh tea is very important since its presence is related to human health. In this study, 41 elements in 98 Puerh tea samples from Yunnan province, China including Puerh raw tea and Puerh ripe tea were evaluated by microwave digestion combined with inductively coupled plasma mass spectrometry . The content of toxic elements, essential elements and rare earth elements of Puerh tea from different regions was discussed in detail. The concentrations of Ba, Cr, As, Pb, Bi, Fe, Zn, V, Mn, Be, Ag and Tl showed significant differences (p < 0.05) by ANOVA analysis. Principal component analysis and linear discriminant analysis were used to describe the relationship of Puerh tea from different regions. This study provided a comprehensive database for Puerh tea quality control and intake risk assessment.

Anti-tumor effect of hot aqueous extracts from Sonchus oleraceus (L.) L. and Juniperus sabina L - Two traditional medicinal plants in China.

ETHNOPHARMACOLOGICAL RELEVANCE: Sonchus oleraceus (L.) L (SO) and Juniperus sabina L (JS) are traditional medicinal plants in China. And the aqueous extracts of them have been used to treat tumor, inflammatory diseases, infection and so on in Chinese folk culture. However, the underlying mechanisms of their anti-tumor activities have not been illustrated yet. OBJECTIVE: This study aims to evaluate the inhibitory effects of aqueous extracts from SO and JS on tumor cells. MATERIALS AND METHODS: The prepared aqueous extracts of SO and JS were used to treat HepG-2 and K562 tumor cells, while the human peripheral blood mononuclear cells (PBMCs) were set as normal control. The viabilities, cell cycle and apoptosis of tumor cells after extracts treatment were assessed, in addition the expression of apoptosis-related genes (FasL, caspase 3, 6, 7, 8, 9, and 10) were analyzed. Meanwhile, the adherence and migration of HepG-2 were tested, and the expression levels of MMPs and ICAM-1 were analyzed. On top of that, the pSTAT in the two cells were also analyzed and suggested the related signaling pathway that the extracts acted on with in these tumor cells. RESULTS: Results showed that aqueous extracts of SO and JS have inhibitory effects on HepG-2 and K562 cells by decreasing cell viability and inducing apoptosis via up-regulation of the expression of the apoptosis-related genes FasL, caspase 3 and caspase 9. The extracts had different IC50 on tumor cells and PBMCs, which could block the tumor cell cycle at the G(0)/G(1) stage and significantly inhibit the adherence of HepG-2 cells. The extracts inhibited migration of these cells by inhibiting the expression of ICAM-1, MMP-2 and MMP-9. Further study indicated that the inhibition of pSTAT1 and 3 might be responsible for the inhibitory effects of the extracts on tumor cells. DISCUSSION AND CONCLUSION: The results of this study indicated that SO and JS extracts had the anti-tumor effects, which may be developed as novel anti-tumor drugs and used in cancer therapy.