Epigallocatechin gallate (EGCG) nanoselenium application improves tea quality (Camellia sinensis L.) and soil quality index without losing microbial diversity: A pot experiment under field condition.

Applying selenium (Se) fertilizer is the only way to alleviate soil Se deficiency. Although effects of nanoselenium foliar application on plant growth and stress resistance have been extensively investigated, soil application of nanoselenium on soil microorganisms and their relationship with crop quality and soil health remains unclear. In this study, a steady-state homogeneous nanoparticle of epigallocatechin gallate Se (ESe) was synthesized, and a pot experiment was conducted applying ESe at five concentrations (0, 1, 10, 50, and 100 mg kg-1) to the tea planattion soil. The study revealed a significant increase in Se concentration in soil and tea with ESe application and identified 2.43-7.8 mg kg-1 as the safe and optimal range for soil application. Specifically, the moderate dose of ESe improved the tea quality [reduced tea polyphenols (TP), increased free amino acids (AA), and reduced TP/AA] and soil quality index (SQI). Besides, in marure tea leaves, antioxidant enzyme activities [promote catalase (CAT) superoxide dismutase (SOD), and peroxidase (POD)] increased, while level of oxidative stress [malondialdehyde (MDA), hydrogen peroxide (H2O2) and superoxide anion (O2-)] decreased with ESe application. The 16S rRNA of the soil bacteria showed that ESe application significantly changed the community structure of soil bacteria but did not alter the diversity of the bacteria and the abundance of dominant taxa (phylum and genus levels). Statistical analysis of the taxonomic and functional profiles (STAMP) detected 21 differential taxa (genus level), mainly low-abundance ones, under the ESe application. Linear regression and random forest (RF) modeling revealed that the low-abundance bacterial taxa were significantly correlated with SQI (R2 = 0.28, p < 0.01) and tea quality (R2 = 0.23-0.37, p < 0.01). Thus, the study's findings suggest that ESe application affects soil and tea quality by modulating the low-abundance taxa in soil. The study also highlights the crucial role of low-abundance bacterial taxa of the rhizosphere in regulating soil functions under the ESe application.

Uptake and translocation of organic pollutants in Camellia sinensis (L.): a review.

Camellia sinensis (L.) is a perennial evergreen woody plant with the potential for environmental pollution due to its unique growth environment and extended growth cycle. Pollution sources and pathways for tea plants encompass various factors, including atmospheric deposition, agricultural inputs of chemical fertilizers and pesticide, uptake from soil, and sewage irrigation. During the cultivation phase, Camellia sinensis (L.) can absorb organic pollutants through its roots and leaves. This review provides an overview of the uptake and translocation mechanisms involving the absorption of polycyclic aromatic hydrocarbons (PAHs), pesticides, anthraquinone (AQ), perchlorate, and other organic pollutants by tea plant roots. Additionally, we summarize how fresh tea leaves can be impacted by spraying pesticide and atmospheric sedimentation. In conclusion, this review highlights current research progress in understanding the pollution risks associated with Camellia sinensis (L.) and its products, emphasizing the need for further investigation and providing insights into potential future directions for research in this field.

Combined Hepatotoxicity and Toxicity Mechanism of Intermedine and Lycopsamine.

Pyrrolizidine alkaloids (PAs) are common constituents of plants and have serious hepatotoxicity. Intermedine (Im) and lycopsamine (La) are two monoesters of PAs that frequently coexist in the PA-containing plants (e.g., comfrey and tea). The present study aimed to explore the combined hepatotoxicity and toxicity mechanism of the Im and La mixture. In vitro, the combined cytotoxicity of the Im and La mixture on human hepatocytes (HepD) was examined by CCK-8, colony formation, wound healing, and Annexin V/PI staining assays. The combination of Im and La inhibited the ability of HepD cells to proliferate, colonize, and migrate and induced hepatocytes apoptosis in a dose-dependent manner. In addition to significantly causing a burst of intracellular reactive oxygen species (ROS), mitochondrial apoptosis, and endoplasmic reticulum (ER) stress, the Im and La mixture can also cause an increase in intracellular Ca2+, triggering the PERK/eIF2α/ATF4/CHOP apoptosis pathway. This study provided the first direct evidence that the combined PAs induced hepatotoxicity through ER-mediated apoptosis. These results supplemented the basic toxicity data for the combined PAs and provided a new perspective for the risk assessment of combined PA toxicity.

3D printed PCLA scaffold with nano-hydroxyapatite coating doped green tea EGCG promotes bone growth and inhibits multidrug-resistant bacteria colonization.

OBJECTIVES: 3D-printing scaffold with specifically customized and biomimetic structures gained significant recent attention in tissue engineering for the regeneration of damaged bone tissues. However, constructed scaffolds that simultaneously promote bone regeneration and in situ inhibit bacterial proliferation remains a great challenge. This study aimed to design a bone repair scaffold with in situ antibacterial functions. MATERIALS AND METHODS: Herein, a general strategy is developed by using epigallocatechin-3-gallate (EGCG), a major green tea polyphenol, firmly anchored in the nano-hydroxyapatite (HA) and coating the 3D printed polymerization of caprolactone and lactide (PCLA) scaffold. Then, we evaluated the stability, mechanical properties, water absorption, biocompatibility, and in vitro antibacterial and osteocyte inductive ability of the scaffolds. RESULTS: The coated scaffold exhibit excellent activity in simultaneously stimulating osteogenic differentiation and in situ resisting methicillin-resistant Staphylococcus aureus colonization in a bone repair environment without antibiotics. Meanwhile, the prepared 3D scaffold has certain mechanical properties (39.3 ± 3.2 MPa), and the applied coating provides the scaffold with remarkable cell adhesion and osteogenic conductivity. CONCLUSION: This study demonstrates that EGCG self-assembled HA coating on PCLA surface could effectively enhance the scaffold's water absorption, osteogenic induction, and antibacterial properties in situ. It provides a new strategy to construct superior performance 3D printed scaffold to promote bone tissue regeneration and combat postoperative infection in situ.

Dissipation pattern and conversion of pyrrolizidine alkaloids (PAs) and pyrrolizidine alkaloid N-oxides (PANOs) during tea manufacturing and brewing.

Pyrrolizidine alkaloids (PAs) and pyrrolizidine alkaloid N-oxides (PANOs) are toxic secondary metabolites in plants, and one kind of main exogenous pollutants of tea. Herein, the dissipation pattern and conversion behavior of PAs/PANOs were investigated during tea manufacturing and brewing using ultra high-performance liquid chromatography tandem mass spectrometry. Compared with PAs (processing factor (PF) = 0.73-1.15), PANOs had higher degradation rates (PF = 0.21-0.56) during tea manufacturing, and drying played the most important role in PANOs degradation. Moreover, PANOs were firstly discovered to be converted to corresponding PAs especially in the time-consuming (spreading of green tea manufacturing and withering of black tea manufacturing) and high-temperature tea processing (drying). Moreover, higher transfer rates of PANOs (≥75.84%) than that of PAs (≤56.53%) were observed during tea brewing. Due to higher toxicity of PAs than PANOs, these results are conducive to risk assessment and pollution control of PAs/PANOs in tea.