Mastitis, one of the most significant problems in women, is commonly caused by pathogens, especially Staphylococcus aureus (S.aureus). Schisandrin B (SCB), the main abundant derivatives from Schisandra chinensis, has been proven to have the ability to inhibiting inflammation and bacteria. However, few relevant researches systematically illustrate the role SCB in the treatment of mastitis. The aim of the present study is to demonstrate the mechanism that SCB functions in reducing pathological injury to the mammary gland in treating S.aureus-induced mastitis. H&E staining was used to identify pathological changes and injuries in mastitis. The levels of cytokines associated with inflammation were detected by ELISA. Key signals relevant to ferroptosis and Nrf2 signaling pathway were tested by western blot analysis and iron assay kit. Compared with the control group, inflammation-associated factors, such as IL-1β, TNF-α, MPO activity, increased significantly in S. aureus-treated mice. However, these changes were inhibited by SCB. Ferroptosis-associated factors Fe2+ and MDA increased significantly, and GSH, GPX4 and ferritin expression decreased markedly in S. aureus-treated mice. SCB treatment could attenuate S.aureus-induced ferroptosis. Furthermore, SCB increase SIRT1 and SLC7A11 expression and down-regulated p53 expression and NF-κB activation. In conclusion, SCB alleviates S.aureus-induced mastitis via up-regulating SIRT1/p53/SLC7A11 signaling pathway, attenuating the activation of inflammation-associated cytokines and ferroptosis in the mammary gland tissues.

Schisandra chinensis (S. chinensis) has a long history as a traditional Chinese medicine that is astringent, beneficial to vital energy, tonifies the kidney, tranquilizes the heart, etc. Significantly, Schisandrol A (SA) is extracted from S. chinensis and shows surprising and satisfactory biological activity, including anti-inflammatory, hepatoprotective, cardiovascular protection, and antitumor properties, among others. SA has a more pronounced protective effect on central damaged nerves among its numerous pharmacological effects, improving neurodegenerative diseases such as Alzheimer\'s and Parkinson\'s through the protection of damaged nerve cells and the enhancement of anti-oxidant capacity. Pharmacokinetic studies have shown that SA has a pharmacokinetic profile with a rapid absorption, wide distribution, maximal concentration in the liver, and primarily renal excretion. However, hepatic and intestinal first-pass metabolism can affect SA\'s bioavailability. In addition, the content of SA, as an index component of S. chinensis Pharmacopoeia, should not be less than 0.40%, and the content of SA in S. chinensis compound formula was determined with the help of high-performance liquid chromatography (HPLC), which is a stable and reliable method, and it can lay a foundation for the subsequent quality control. Therefore, this paper systematically reviews the preparation, pharmacological effects, pharmacokinetic properties, and content determination of SA with the goal of updating and deepening the understanding of SA, as well as providing a theoretical basis for the study of SA at a later stage.

Aligned with the increasing importance of bioorthogonal chemistry has been an increasing demand for more potent, affordable, multifunctional, and programmable bioorthogonal reagents. More advanced synthetic chemistry techniques, including transition-metal-catalyzed cross-coupling reactions, C-H activation, photoinduced chemistry, and continuous flow chemistry, have been employed in synthesizing novel bioorthogonal reagents for universal purposes. We discuss herein recent developments regarding the synthesis of popular bioorthogonal reagents, with a focus on s-tetrazines, 1,2,4-triazines, trans-cyclooctenes, cyclooctynes, hetero-cycloheptynes, and -trans-cycloheptenes. This review aims to summarize and discuss the most representative synthetic approaches of these reagents and their derivatives that are useful in bioorthogonal chemistry. The preparation of these molecules and their derivatives utilizes both classical approaches as well as the latest organic chemistry methodologies.

A pretargeted strategy that decouples targeting vectors from radionuclides has shown promise for nuclear imaging and/or therapy in vivo. However, the current pretargeted approach relies on the use of antibodies or nanoparticles as the targeting vectors, which may be compromised by poor tissue penetration and limited accumulation of targeting vectors in the tumor tissues. Herein, we present an orthogonal dual-pretargeted approach by combining stimuli-triggered in situ self-assembly strategy with fast inverse electron demand Diels-Alder (IEDDA) reaction and strong biotin-streptavidin (SA) interaction for near-infrared fluorescence (NIR FL) and magnetic resonance (MR) imaging of tumors. This approach uses a small-molecule probe (P-Cy-TCO&Bio) containing both biotin and trans-cyclooctene (TCO) as a tumor-targeting vector. P-Cy-TCO&Bio can efficiently penetrate subcutaneous HeLa tumors through biotin-assisted targeted delivery and undergo in situ self-assembly to form biotinylated TCO-bearing nanoparticles (Cy-TCO&Bio NPs) on tumor cell membranes. Cy-TCO&Bio NPs exhibited an \"off-on\" NIR FL and retained in the tumors, offering a high density of TCO and biotin groups for the concurrent capture of Gd-chelate-labeled tetrazine (Tz-Gd) and IR780-labeled SA (SA-780) via the orthogonal IEDDA reaction and SA-biotin interaction. Moreover, Cy-TCO&Bio NPs offered multiple-valent binding modes toward SA, which additionally regulated the cross-linking of Cy-Gd&Bio NPs into microparticles (Cy-Gd&Bio/SA MPs). This process could significantly (1) increase r1 relaxivity and (2) enhance the accumulation of Tz-Gd and SA-780 in the tumors, resulting in strong NIR FL, bright MR contrast, and an extended time window for the clear and precise imaging of HeLa tumors.

BACKGROUND: Shengmai Formula (SMF), a classic formula in treating Qi-Yin deficiency, is composed of Ginseng Radix et Rhizoma Rubra (GRR), Ophiopogon Radix (OR), and Schisandra chinensis Fructus (SC), and has been developed into various dosage forms including Shengmai Yin Oral Liquid (SMY), Shengmai Capsules (SMC), and Shengmai Injection (SMI). The pharmacological effects of compound Chinese medicine are attributed to the integration of multiple components. Yet the quality criteria of SMF are limited to monitoring schisandrol A or ginsenosides Rg1 and Re, but none for OR. Since the complexity of raw materials and preparations, establishing a economical and unified method for SMF is challenging. It is urgent to simultaneously quantify multiple components with different structures using a universal method for quality control of SMF. Charged aerosol detector (CAD) overcame the above shortcomings owing to its characteristics of high responsiveness, nondiscrimination, and low cost.
OBJECTIVE: We aimed to establish a versatile analysis strategy using HPLC-CAD for simultaneously quantifying the structurally diverse markers in quality control of SMF from raw materials to preparations.
METHODS: By optimizing the column, mobile phase, column temperature, flow rate, and CAD parameters, a HPLC-CAD method that integrated multi-component characterization, authenticity identification, transfer information of raw materials and quantitative determination of Shengmai preparations was established.
RESULTS: In total 50 components from SMF were characterized (28 in GRR, 13 in SC, and 9 in OR). The differences in raw materials between species of SC and Schisandrae sphenantherae Fructus (SS), processing methods of Ginseng Radix (GR) and GRR, and locations of OR from Sichuan (ORS) and Zhejiang (ORZ) were compared. Fourteen components in 19 batches of SMY, SMC and SMI from different manufacturers were quantified, including 11 ginsenosides and 3 lignans. The multivariate statistical analysis results further suggested that Rb1, Rg1 and Ro were the main differences among Shengmai preparations.
CONCLUSIONS: The established versatile analysis strategy based on HPLC-CAD was proven sensitive, simple, convenient, overcoming the discriminatory effect of UV detector, revealing the composition and transfer information of SMF and applicable for authentication of the ingredient herbs and improving the quality of Shengmai preparations.

We established myocardial injury models in vivo and in vitro to investigate the cardioprotective effect of gomisin D obtained from Schisandra chinensis. Gomisin D significantly inhibited isoproterenol-induced apoptosis and hypertrophy in H9C2 cells. Gomisin D decreased serum BNP, ANP, CK-MB, cTn-T levels and histopathological alterations, and inhibited myocardial hypertrophy in mice. In mechanisms research, gomisin D reversed ISO-induced accumulation of intracellular ROS and Ca2+. Gomisin D further improved mitochondrial energy metabolism disorders by regulating the TCA cycle. These results demonstrated that gomisin D had a significant effect on isoproterenol-induced myocardial injury by inhibiting oxidative stress, calcium overload and improving mitochondrial energy metabolism.

Achieving efficient and site-specific conjugation of therapeutic protein to polymer is crucial to augment their applicability in the realms of biomedicine by improving their stability and enzymatic activity. In this study, we exploited tetrazine bioorthogonal chemistry to achieve the site-specific conjugation of bottlebrush polymers to urate oxidase (UOX), a therapeutic protein for gout treatment. An azido-functionalized zwitterionic bottlebrush polymer (N3-ZBP) using a \"grafting-from\" strategy involving RAFT and ATRP methods was synthesized, and a trans-cyclooctene (TCO) moiety was introduced at the polymer end through the strain-promoted azide-alkyne click (SPAAC) reaction. The subsequent coupling between TCO-incorporated bottlebrush polymer and tetrazine-labeled UOX using a fast and safe bioorthogonal reaction, inverse electron demand Diels-Alder (IEDDA), led to the formation of UOX-ZBP conjugates with a 52% yield. Importantly, the enzymatic activity of UOX remained unaffected following polymer conjugation, suggesting a minimal change in the folded structure of UOX. Moreover, UOX-ZBP conjugates exhibited enhanced proteolytic resistance and reduced antibody binding, compared to UOX-wild type. Overall, the present findings reveal an efficient and straightforward route for synthesizing protein-bottlebrush polymer conjugates without compromising the enzymatic activity while substantially reducing proteolytic degradation and antibody binding.

BACKGROUND: Gomisin is a natural dibenzo cyclooctene lignan, which is mainly derived from the family Magnoliaceae. It has anti-inflammatory, antioxidant, anti-tumor, anti-aging, and hypoglycemic effects. Gomisins play important roles as medicines, nutraceuticals, food additives, and cosmetics.
OBJECTIVE: The objective of this study is to establish a micellar electrokinetic chromatography (MEKC) method for simultaneous separation and determination of seven biphenyl cyclooctene lignans (Gomisin D, E, G, H, J, N, and O) in Schisandra chinensis and its preparations.
METHODS: The method was optimized by studying the effects of the main parameters on the separation. The method has been validated and successfully applied to the determination of seven Gomisins in S. chinensis and its preparations.
RESULTS: In the separation system, the running buffer was composed of 20 mM Na2HPO4, 8.0 mM sodium dodecyl sulfate (SDS), 11% (v/v) methanol, and 6.0% (v/v) ethanol. A diode array detector was used with a detection wavelength of 230 nm, a separation voltage of 17 kV, and an operating temperature of 25°C. Under this condition, the seven analytes were separated at baseline within 20 min, and a good linear relationship was obtained with correlation coefficient ranging from 0.9919 to 0.9992. The limit of detection (LOD, S/N = 3) and the limit of quantification (LOQ, S/N = 10) ranged from 0.8 to 0.9 μg/mL and from 2.6 to 3.0 μg/mL, respectively. The recovery rate was between 99.1% and 102.5%.
CONCLUSIONS: The experimental results indicated that this method is suitable for the separation and determination of seven Schisandra biphenyl cyclooctene lignan compounds in real samples. At the same time, it provides an effective reference for the quality control of S. chinensis and its preparations.

BACKGROUND: As a traditional Chinese herbal medicine, Schisandra chinensis exhibits various effects such as liver protection, blood sugar regulation, blood lipid regulation, immune function regulation, antidepressant activity, etc. However, because of its intricate composition, diverse origins, and medicinal effects depending on complex compound groups, there are differences in the lignan composition of S. chinensis from different origins. Therefore, it is currently difficult to evaluate the quality of medicinal materials from plants of different origins using a single qualitative quality control index.
OBJECTIVE: This paper aims to investigate the potential relationship between the lignan components of S. chinensis from different origins and to establish stable assessment indices for determining the lignan content of S. chinensis from multiple perspectives.
METHODS: In this study, we collected S. chinensis samples of seven major origins in China, and randomly sampled 6-9 batches of each origin for a total of 60 batches. The lignan content was determined by HPLC, and its distribution law of the ratio of each lignan component of S. chinensis to Schisandrol A content was analyzed. Combining network pharmacology and differential analysis between samples, the stable and effective substances used as quality markers were determined.
RESULTS: There were some correlations among the lignan contents of S. chinensis, some correlations between schisandrin A and other lignans of S. chinensis could be determined. The ratio of each component to the indicator component schisandrol A was evenly distributed and reflected the lignan content of S. chinensis to some extent. Four substances (schisandrol A, schisandrol B, schisantherin A, and schisandrin C) were determined by network pharmacology combined with the analysis results of HCA, PCA and PLS-DA to further optimize the model. They displayed a strong connection with the core target, a large contribution rate to the principal components, and a stable content in each batch of samples, suggesting that these components may be the main active substances of S. chinensis lignans. Therefore, they could be used as main indicators evaluating the advantages and disadvantages of S. chinensis by examining the consistency of component proportions.
CONCLUSIONS: This method can intuitively evaluate the content of main lignans in S. chinensis. This quality assessment model is an exploration of the multi-component comprehensive evaluation system of S. chinensis, providing a new concept for the quality evaluation system of Chinese herbal medicines.

Non-Hodgkin lymphoma (NHL) is a heterogeneous group of malignant tumors occurring in B or T lymphocytes, and no small molecule-positive drugs to treat NHL have been marketed. Cluster of differentiation 20 (CD20) is an important molecule regulating signaling for the life and differentiation of B lymphocytes and possesses the characteristics of a drug target for treating NHL. 2-Methoxyestradiol induces apoptosis in lymphoma Raji cells and CD20 protein is highly expressed by Raji lymphoma cells. Therefore, in this study, a CD20-SNAP-tag/CMC model was developed to validate the interaction of 2-methoxyestradiol with CD20. 2-Methoxyestradiol was used as a small molecule control compound, and the system was validated for good applicability. The cell membrane chromatography model was combined with high-performance liquid chromatography ion trap time-of-flight mass spectroscopy (HPLC-IT-TOF-MS) in a two-dimensional system to successfully identify, analyze, and characterize the potential active compounds of Schisandra chinensis (Turcz.) Baill. extract and Lysionotus pauciflorus Maxim. extract, including Schisandrin A, Schizandrol A, Schizandrol B, Schisantherin B, and Nevadensin, which can act on CD20 receptors. The five potential active compounds were analyzed by non-linear chromatography. The thermodynamic and kinetic parameters of their interaction with CD20 were also analyzed, and the mode of interaction was simulated by molecular docking. Their inhibitory effects on lymphoma cell growth were assessed using a Cell Counting Kit-8 (CCK-8). Nevadensin and Schizandrin A were able to induce apoptosis in Raji cells within a certain concentration range. In conclusion, the present experiments provide some bases for improving NHL treatment and developing small molecule lead compounds targeting CD20 with low toxicity and high specificity.