Five new flavan-4-ol glycosides jixueqiosides A-E (1-5) and two new flavan glycosides jixueqiosides F and G (6 and 7), along with twelve known flavan-4-ol glycosides (8-19), were isolated from the roots of Pronephrium penangianum. Comprehensive spectral analyses, X-ray single-crystal diffraction, and theoretical electronic circular dichroism (ECD) calculations established structures and absolute configurations. A single crystal structure of flavan-4-ol glycoside (14) was reported for the first time, while the characteristic ECD and NMR data for all isolated flavan-4-ol glycosides (1-5 , 8-19) were analyzed, establishing a set of empirical rules. Activity screening of these isolates showed that 8 and 9 could inhibit the proliferation of MDA-MB-231 and MCF-7 cells with IC₅₀ values of 7.93 ? 2.85 ?mol?L^-1 and 5.87 ? 1.58 ?mol?L^-1 (MDA-MB-231), and 2.21 ? 1.38 ?mol?L^-1 and 3.52 ? 1.55 ?mol?L^-1 (MCF-7), respectively. Western blotting and flow cytometry analyses demonstrated that 8 and 9 dose-dependently induced apoptosis in MDA-MB-231 cells by up-regulating BAX, activating caspase-3 and down-regulating BCL-2. Additionally, compound 8 affected autophagy-related proteins, increasing the ratio of LC3-II/LC3-I and Beclin-1 levels to inhibit MDA-MB-231 cell proliferation. Moreover, anti-inflammatory studies indicated that 2, 3, 7, 13, 14, and 18 moderately inhibited tumor necrosis factor-a (TNF-a), interleukin-6 (IL-6), and nitric oxide (NO) release.
Humans ; Plant Roots/chemistry* ; Glycosides/isolation & purification* ; Anti-Inflammatory Agents/isolation & purification* ; Flavonoids/isolation & purification* ; Cell Proliferation/drug effects* ; Antineoplastic Agents, Phytogenic/isolation & purification* ; Molecular Structure ; Apoptosis/drug effects* ; Cell Line, Tumor ; Tumor Necrosis Factor-alpha/immunology* ; Drugs, Chinese Herbal/pharmacology* ; Interleukin-6/immunology* ; Animals ; Mice

BACKGROUND/OBJECTIVES: Tibetan tea is a kind of dark tea, due to the inherent complexity of natural products, the chemical composition and beneficial effects of Tibetan tea are not fully understood. The objective of this study was to unravel the composition of Tibetan tea using knowledge-guided multilayer network (KGMN) techniques and explore its potential antioxidant and hypolipidemic mechanisms in mice.MATERIALS/METHODS: The C57BL/6J mice were continuously gavaged with Tibetan tea extract (T group), green tea extract (G group) and ddH 2 O (H group) for 15 days. The activity of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) in mice was detected.Transcriptome sequencing technology was used to investigate the molecular mechanisms underlying the antioxidant and lipid-lowering effects of Tibetan tea in mice. Furthermore, the expression levels of liver antioxidant and lipid metabolism related genes in various groups were detected by the real-time quantitative polymerase chain reaction (qPCR) method. RESULTS: The results showed that a total of 42 flavonoids are provisionally annotated in Tibetan tea using KGMN strategies. Tibetan tea significantly reduced body weight gain and increased T-AOC and SOD activities in mice compared with the H group. Based on the results of transcriptome and qPCR, it was confirmed that Tibetan tea could play a key role in antioxidant and lipid lowering by regulating oxidative stress and lipid metabolism related pathways such as insulin resistance, P53 signaling pathway, insulin signaling pathway, fatty acid elongation and fatty acid metabolism. CONCLUSIONS This study was the first to use computational tools to deeply explore the composition of Tibetan tea and revealed its potential antioxidant and hypolipidemic mechanisms, and it provides new insights into the composition and bioactivity of Tibetan tea.

COVID-19 has swept globally and Pakistan is no exception.To investigate the initial introductions and transmissions of the SARS-CoV-2 in Pakistan,we performed the largest genomic epidemiology study of COVID-19 in Pakistan and generated 150 complete SARS-CoV-2 genome sequences from samples collected from March 16 to June 1,2020.We identified a total of 347 mutated positions,31 of which were over-represented in Pakistan.Meanwhile,we found over 1000 intra-host single-nucleotide variants(iSNVs).Several of them occurred concurrently,indicating possible interactions among them or coevolution.Some of the high-frequency iSNVs in Pakistan were not observed in the global population,suggesting strong purifying selections.The genomic epidemiology revealed five distinctive spreading clusters.The largest cluster consisted of 74 viruses which were derived from different geographic locations of Pakistan and formed a deep hierarchical structure,indicating an extensive and persistent nation-wide transmission of the virus that was probably attributed to a signature mutation(G8371T in ORF 1ab)of this cluster.Further-more,28 putative international introductions were identified,several of which are consistent with the epidemiological investigations.In all,this study has inferred the possible pathways of introduc-tions and transmissions of SARS-CoV-2 in Pakistan,which could aid ongoing and future viral surveillance and COVID-19 control.