Gold nanoclusters cure implant infections by targeting biofilm.

The biofilm-mediated implant infections pose a huge threat to human health. It is urgent to explore strategies to reverse this situation. Herein, we design 3-amino-1,2,4-triazole-5-thiol (ATT)-modified gold nanoclusters (AGNCs) to realize biofilm-targeting and near-infrared (NIR)-II light-responsive antibiofilm therapy. The AGNCs can interact with the bacterial extracellular DNA through the formation of hydrogen bonds between the amine groups on the ATT and the hydroxyl groups on the DNA. The AGNCs show photothermal properties even at a low power density (0.5 W/cm2) for a short-time (5 min) irradiation, making them highly effective in eradicating the biofilm with a dispersion rate up to 90 %. In vivo infected catheter implantation model demonstrates an exceptional high ability of the AGNCs to eradicate approximately 90 % of the bacteria encased within the biofilms. Moreover, the AGNCs show no detectable toxicity or systemic effects in mice. Our study suggests the great potential of the AGNCs for long-term prevention and elimination of the biofilm-mediated infections.

Acidic Environment-Responsive Metal Organic Framework-Mediated Dihydroartemisinin Delivery for Triggering Production of Reactive Oxygen Species in Drug-Resistant Lung Cancer.

Background: Dihydroartemisinin (DHA) has emerged as a promising candidate for anticancer therapy. However, the application of DHA in clinics has been hampered by several limitations including poor bioavailability, short circulation life, and low solubility, significantly restricting its therapeutic efficacy and leading to notable side effects during the treatment. Purpose: We present DHA-loaded zeolitic imidazolate framework-8 (D-ZIF) with controllable and targeted DHA release properties, leading to enhanced antitumor effects while reducing potential side effects. Methods: D-ZIF was prepared by one-pot synthesis method using methylimidazole (MIM), Zn(NO3)2•6H2O and DHA. We characterized the physical and chemical properties of D-ZIF by TEM, DLS, XRD, FT-IR, and TG. We measured the drug loading efficiency and the cumulative release of DHA in different pH conditions. We evaluated the cytotoxicity of D-ZIF on renal cell carcinoma (RCC786-O), glioma cells (U251), TAX-resistant human lung adenocarcinoma (A549-TAX) cells by CCK8 in vitro. We explored the possible antitumor mechanism of D-ZIF by Western blot. We evaluated the biocompatibility and hemolysis of D-ZIF and explored the in vivo antitumor efficiency in mice model by TUNEL testing and blood biomarker evaluations. Results: D-ZIF showed rhombic dodecahedral morphology with size of 129±7.2 nm and possessed a noticeable DHA encapsulation efficiency (72.9%). After 48 hours, D-ZIF released a cumulative 70.0% of the loaded DHA at pH 6.5, and only 42.1% at pH 7.4. The pH-triggered programmed release behavior of D-ZIF could enhance anticancer effect of DHA while minimizing side effects under normal physiological conditions. Compared with the free DHA group with 31.75% of A549-TAX cell apoptosis, the percentage of apoptotic cells was approximately 76.67% in the D-ZIF group. D-ZIF inhibited tumor growth by inducing tumor cell apoptosis through the mechanism of ROS production and regulation of Nrf2/HO-1 and P38 MAPK signaling pathways. D-ZIF showed potent effects in treating tumors with high safety in vivo. Conclusion: This pH-responsive release mechanism enhanced the targeting efficiency of DHA towards tumor cells, thereby increasing drug concentration in tumor sites with negligible side effects. Herein, D-ZIF holds great promise for curing cancers with minimal adverse effects.

Proinflammatory polarization of engineered heat-inducible macrophages reprogram the tumor immune microenvironment during cancer immunotherapy.

The success of macrophage-based adoptive cell therapy is largely constrained by poor polarization from alternatively activated (M2-like) to classically activated (M1-like) phenotype in the immunosuppressive tumor microenvironment (TME). Here, we show that the engineered macrophage (eMac) with a heat-inducible genetic switch can induce both self-polarization of adoptively transferred eMac and re-polarization of tumour-associated macrophages in response to mild temperature elevation in a mouse model. The locoregional production of proinflammatory cytokines by eMac in the TME dose not only induces the strong polarization of macrophages into a classically activated phenotype, but also ensures that the side effects typical for systemically administrate proinflammatory cytokines are avoided. We also present a wearable warming device which is adaptable for human patients and can be remotely controlled by a smartphone. In summary, our work represents a safe and efficient adoptive transfer immunotherapy method with potential for human translation.

Supramolecular Genome Editing: Targeted Delivery and Endogenous Activation of CRISPR/Cas9 by Dynamic Host-Guest Recognition.

We synthesize supramolecular poly(disulfide) (CPS) containing covalently attached cucurbit[7]uril (CB[7]), which is exploited not only as a carrier to deliver plasmid DNA encoding destabilized Cas9 (dsCas9), but also as a host to include trimethoprim (TMP) by CB[7] moieties through the supramolecular complexation to form TMP@CPS/dsCas9. Once the plasmid is transfected into tumor cells by CPS, the presence of polyamines can competitively trigger the decomplexation of TMP@CPS, thereby displacing and releasing TMP from CB[7] to stabilize dsCas9 that can target and edit the genomic locus of PLK1 to inhibit the growth of tumor cells. Following the systemic administration of TMP@CPS/dsCas9 decorated with hyaluronic acid (HA), tumor-specific editing of PLK1 is detected due to the elevated polyamines in tumor microenvironment, greatly minimizing off-target editing in healthy tissues and non-targeted organs. As the metabolism of polyamines is dysregulated in a wide range of disorders, this study offers a supramolecular approach to precisely control CRISPR/Cas9 functions under particular pathological contexts.

Molecular basis of SAP05-mediated ubiquitin-independent proteasomal degradation of transcription factors.

SAP05, a secreted effector by the obligate parasitic bacteria phytoplasma, bridges host SPL and GATA transcription factors (TFs) to the 26 S proteasome subunit RPN10 for ubiquitination-independent degradation. Here, we report the crystal structures of SAP05 in complex with SPL5, GATA18 and RPN10, which provide detailed insights into the protein-protein interactions involving SAP05. SAP05 employs two opposing lobes with an acidic path and a hydrophobic path to contact TFs and RPN10, respectively. Our crystal structures, in conjunction with mutagenesis and degradation assays, reveal that SAP05 targets plant GATAs but not animal GATAs dependent on their direct salt-bridged electrostatic interactions. Additionally, SAP05 hijacks plant RPN10 but not animal RPN10 due to structural steric hindrance and the key hydrophobic interactions. This study provides valuable molecular-level information into the modulation of host proteins to prevent insect-borne diseases.

A review of mitigation technologies and management strategies for greenhouse gas and air pollutant emissions in livestock production.

One of the key issues in manure management of livestock production is to reduce greenhouse gas (GHG) and air pollutant emissions, which lead to significant environmental footprint and human/animal health threats. This study provides a review of potentially efficacious technologies and management strategies that reduce GHG and air pollutant emissions during the three key stages of manure management in livestock production, i.e., animal housing, manure storage and treatment, and manure application. Several effective mitigation technologies and practices for each manure management stage are identified and analyzed in detail, including feeding formulation adjustment, frequent manure removal and air scrubber during animal housing stage; solid-liquid separation, manure covers for storage, acidification, anaerobic digestion and composting during manure storage and treatment stage; land application techniques at appropriate timing during manure application stage. The results indicated several promising approaches to reduce multiple gas emissions from the entire manure management. Removing manure 2-3 times per week or every day during animal housing stage is an effective and simple way to reduce GHG and air pollutant emissions. Acidification during manure storage and treatment stage can reduce ammonia and methane emissions by 33%-93% and 67%-87%, respectively and proper acid, such as lactic acid can also reduce nitrous oxide emission by about 90%. Shallow injection of manure for field application has the best performance in reducing ammonia emission by 62%-70% but increase nitrous oxide emission. The possible trade-off brings insight to the prioritization of targeted gas emissions for the researchers, stakeholders and policymakers, and also highlights the importance of assessing the mitigation technologies across the entire manure management chain. Implementing a combination of the management strategies needs comprehensive considerations about mitigation efficiency, technical feasibility, local regulations, climate condition, scalability and cost-effectiveness.

Boosting the output performance of triboelectric nanogenerators via surface engineering and structure designing.

Triboelectric nanogenerators (TENGs) have been utilized in a wide range of applications, including smart wearable devices, self-powered sensors, energy harvesting, and high-voltage power sources. The surface morphology and structure of TENGs play a critical role in their output performance. In this review, we analyze the working mechanism of TENGs with the aim to improve their output performance and systematically summarize the morphological engineering and structural design strategies for TENGs. Additionally, we present the emerging applications of TENGs with specific structures and surfaces. Finally, we discuss the potential future development and industrial application of TENGs. By deeply exploring the surface and structural design strategy of high-performance TENGs, it is conducive to further promote the application of TENGs in actual production. We hope that this review provides insights and guidance for the morphological and structural design of TENGs in the future.

Metabolism of Two Mogroside Isomers, Mogroside III and Mogroside IIIE, in Normal and Drug-Metabolizing Enzyme-Induced Rats.

Mogrosides III (1) and IIIE (2) are two important bioactive cucurbitane-type triterpenoid triglycosides in the edible fruits of Siraitia grosvenorii (Swingle), which are isomers and have only a minor difference in their structures. To clarify the effects of structural difference and drug-metabolizing-enzyme induction on their metabolism in vivo, their metabolites in normal rats and drug-metabolizing-enzyme-induced rats were tentatively identified and semiquantified by using the HPLC-DAD-ESI-IT-TOF-MSn technique. Totally, 76, 78, 96, and 121 metabolites of mogrosides were identified in the NIII (normal rats orally administered with mogroside III), NIIIE (normal rats orally administered with mogroside IIIE), EIII (drug-metabolizing-enzyme-induced rats orally administered with mogroside III), and EIIIE (drug-metabolizing-enzyme-induced rats orally administered with mogroside IIIE) groups, respectively. The metabolite differences among these groups indicated that their minor structural differences are responsible for the significant differences in their metabolites, and the induction of drug-metabolizing enzymes significantly increased the number of their metabolites. These findings would improve our understanding of the in vivo processes of mogrosides III and IIIE as well as their interactions with other food bioactive components or drugs.

Recent advances in nanoantibiotics against multidrug-resistant bacteria.

Multidrug-resistant (MDR) bacteria-caused infections have been a major threat to human health. The abuse of conventional antibiotics accelerates the generation of MDR bacteria and makes the situation worse. The emergence of nanomaterials holds great promise for solving this tricky problem due to their multiple antibacterial mechanisms, tunable antibacterial spectra, and low probabilities of inducing drug resistance. In this review, we summarize the mechanism of the generation of drug resistance, and introduce the recently developed nanomaterials for dealing with MDR bacteria via various antibacterial mechanisms. Considering that biosafety and mass production are the major bottlenecks hurdling the commercialization of nanoantibiotics, we introduce the related development in these two aspects. We discuss urgent challenges in this field and future perspectives to promote the development and translation of nanoantibiotics as alternatives against MDR pathogens to traditional antibiotics-based approaches.

The Triterpenoids from Munronia pinnata and Their Anti-Proliferative Effects.

Six new tirucallane-type triterpenoids, named munropenes A-F (1-6), were extracted from the whole plants of Munronia pinnata using a water extraction method. Their chemical structures were determined based on detailed spectroscopic data. The relative configurations of the acyclic structures at C-17 of munropenes A-F (1-6) were established using carbon-proton spin-coupling constants (2,3JC,H) and inter-proton spin-coupling constants (3JH,H). Furthermore, the absolute configurations of munropenes A-F (1-6) were determined through high-performance liquid chromatography (HPLC), single-crystal X-ray diffraction, and electronic circular dichroism (ECD) analyses. The antiproliferative effects of munropenes A-F were evaluated in five tumor cell lines: HCT116, A549, HepG2, MCF7, and MDAMB. Munropenes A, B, D, and F (1, 2, 4, and 6) inhibited proliferation in the HCT116 cell line with IC50 values of 40.90, 19.13, 17.66, and 32.62 µM, respectively.

Iridoid-glycoside isolation and purification from Premna fulva leaves.

Premna fulva Craib, rich in iridoid glycosides, is widely used to treat periarthritis, osteoproliferation, pain, and other diseases. However, no studies have reported effective purification methods for obtaining iridoid glycosides as active materials. This paper describes an efficient strategy for separating iridoid glycosides from Premna fulva leaves using high-speed counter-current chromatography and preparative high-performance liquid chromatography. A two-phase solvent system, ethyl acetate/n-butanol/water (7.5:2.5:10, v/v), was selected for high-speed counter-current chromatography separation. The proposed method effectively separated and purified four iridoid glycosides and four lignans, including three new iridoid glycosides (4-6) and five known compounds (1-3, 7, 8), from Premna fulva leaves, indicating that high-speed counter-current chromatography combined with prep-HPLC can efficiently isolate catalpol derivatives from the genus Premna. Additionally, the in vitro anti-inflammatory activities of all isolated compounds were analyzed using lipopolysaccharide-stimulated RAW 264.7 cells, and the results indicated that six compounds (1 and 3-7) exhibited potential anti-inflammatory activities.

Identification and Isolation of α-Glucosidase Inhibitors from Siraitia grosvenorii Roots Using Bio-Affinity Ultrafiltration and Comprehensive Chromatography.

The discovery of bioactive compounds from medicinal plants has played a crucial role in drug discovery. In this study, a simple and efficient method utilizing affinity-based ultrafiltration (UF) coupled with high-performance liquid chromatography (HPLC) was developed for the rapid screening and targeted separation of α-glucosidase inhibitors from Siraitia grosvenorii roots. First, an active fraction of S. grosvenorii roots (SGR2) was prepared, and 17 potential α-glucosidase inhibitors were identified based on UF-HPLC analysis. Second, guided by UF-HPLC, a combination of MCI gel CHP-20P column chromatography, high-speed counter-current countercurrent chromatography, and preparative HPLC were conducted to isolate the compounds producing active peaks. Sixteen compounds were successfully isolated from SGR2, including two lignans and fourteen cucurbitane-type triterpenoids. The structures of the novel compounds (4, 6, 7, 8, 9, and 11) were elucidated using spectroscopic methods, including one- and two-dimensional nuclear magnetic resonance spectroscopy and high-resolution electrospray ionization mass spectrometry. Finally, the α-glucosidase inhibitory activities of the isolated compounds were verified via enzyme inhibition assays and molecular docking analysis, all of which were found to exhibit certain inhibitory activity. Compound 14 exhibited the strongest inhibitory activity, with an IC50 value of 430.13 ± 13.33 µM, which was superior to that of acarbose (1332.50 ± 58.53 µM). The relationships between the structures of the compounds and their inhibitory activities were also investigated. Molecular docking showed that the highly active inhibitors interacted with α-glucosidase through hydrogen bonds and hydrophobic interactions. Our results demonstrate the beneficial effects of S. grosvenorii roots and their constituents on α-glucosidase inhibition.

Acylated iridoid glucoside and xanthones from Canscora lucidissima: Their structures and ferroptosis inhibitory activity.

Phytochemical study on the whole plants of a Gentianaceous medicinal plant, Canscora lucidissima, gave one new acylated iridoid glucoside, canscorin A (1), and two new xanthone glycosides (2 and 3) together with 17 known compounds including five xanthones, eight xanthone glycosides, two benzophenone glucosides, caffeic acid, and loganic acid. Canscorin A (1) was assigned as a loganic acid derivative having a hydroxyterephthalic acid moiety by spectroscopic analysis together with chemical evidence, while 2 and 3 were elucidated to be a rutinosylxanthone and a glucosylxanthone, respectively. The absolute configurations of the sugar moieties of 2 and 3 were determined by HPLC analysis. The isolated compounds were evaluated for their inhibitory activities against erastin-induced ferroptosis on human hepatoma Hep3B cells and LPS-stimulated IL-1ß production from murine microglial cells.

Highly Deformable High-Strength SiO2 Aerogel Designed with an Alternating Structure of Hard Cores and Flexible Chains for Thermal Insulation.

Thermally insulating aerogels can now be prepared from ceramics, polymers, carbon, and metals and composites between them. However, it is still a great challenge to make aerogels with high strength and excellent deformability. We propose a design concept of hard cores and flexible chains that alternately construct the aerogel skeleton structure. The approach gives the designed SiO2 aerogel excellent compressive (fracture strain 83.32%), tensile. and shear deformabilities, corresponding to maximum strengths of 22.15, 1.18, and 1.45 MPa, respectively. Also, the SiO2 aerogel can stably perform 100 load-unload cycles at a 70% large compression strain, demonstrating an excellent resilient compressibility. In addition, the low density of 0.226 g/cm3, the high porosity of 88.7%, and the average pore size of 45.36 nm effectively inhibit heat conduction and heat convection, giving the SiO2 aerogel outstanding thermal insulation properties [0.02845 W/(m·K) at 25 °C and 0.04895 W/(m·K) at 300 °C], and the large number of hydrophobic groups itself also gives it excellent hydrophobicity and hydrophobic stability (hydrophobic angle of 158.4° and saturated mass moisture absorption rate of about 0.327%). The successful practice of this concept has provided different insights into the preparation of high-strength aerogels with high deformability.

Recognition of an Ala-rich C-degron by the E3 ligase Pirh2.

The ribosome-associated quality-control (RQC) pathway degrades aberrant nascent polypeptides arising from ribosome stalling during translation. In mammals, the E3 ligase Pirh2 mediates the degradation of aberrant nascent polypeptides by targeting the C-terminal polyalanine degrons (polyAla/C-degrons). Here, we present the crystal structure of Pirh2 bound to the polyAla/C-degron, which shows that the N-terminal domain and the RING domain of Pirh2 form a narrow groove encapsulating the alanine residues of the polyAla/C-degron. Affinity measurements in vitro and global protein stability assays in cells further demonstrate that Pirh2 recognizes a C-terminal A/S-X-A-A motif for substrate degradation. Taken together, our study provides the molecular basis underlying polyAla/C-degron recognition by Pirh2 and expands the substrate recognition spectrum of Pirh2.

CLL stereotyped B-cell receptor immunoglobulin sequences are recurrent in the B-cell repertoire of healthy individuals: Apparent lack of central and early peripheral tolerance censoring.

Introduction: The leukemic cells of patients with chronic lymphocytic leukemia (CLL) are often unique, expressing remarkably similar IGHV-IGHD-IGHJ gene rearrangements, "stereotyped BCRs". The B-cell receptors (BCRs) on CLL cells are also distinctive in often deriving from autoreactive B lymphocytes, leading to the assumption of a defect in immune tolerance. Results: Using bulk and single-cell immunoglobulin heavy and light chain variable domain sequencing, we enumerated CLL stereotype-like IGHV-IGHD-IGHJ sequences (CLL-SLS) in B cells from cord blood (CB) and adult peripheral blood (PBMC) and bone marrow (BM of healthy donors. CLL-SLS were found at similar frequencies among CB, BM, and PBMC, suggesting that age does not influence CLL-SLS levels. Moreover, the frequencies of CLL-SLS did not differ among B lymphocytes in the BM at early stages of development, and only re-circulating marginal zone B cells contained significantly higher CLL-SLS frequencies than other mature B-cell subpopulations. Although we identified CLL-SLS corresponding to most of the CLL major stereotyped subsets, CLL-SLS frequencies did not correlate with those found in patients. Interestingly, in CB samples, half of the CLL-SLS identified were attributed to two IGHV-mutated subsets. We also found satellite CLL-SLS among the same normal samples, and they were also enriched in naïve B cells but unexpectedly, these were ~10-fold higher than standard CLL-SLS. In general, IGHV-mutated CLL-SLS subsets were enriched among antigen-experienced B-cell subpopulations, and IGHV-unmutated CLL-SLS were found mostly in antigen-inexperienced B cells. Nevertheless, CLL-SLS with an IGHV-mutation status matching that of CLL clones varied among the normal B-cell subpopulations, suggesting that specific CLL-SLS could originate from distinct subpopulations of normal B cells. Lastly, using single-cell DNA sequencing, we identified paired IGH and IGL rearrangements in normal B lymphocytes resembling those of stereotyped BCRs in CLL, although some differed from those in patients based on IG isotype or somatic mutation. Discussion: CLL-SLS are present in normal B-lymphocyte populations at all stages of development. Thus, despite their autoreactive profile they are not deleted by central tolerance mechanisms, possibly because the level of autoreactivity is not registered as dangerous by deletion mechanisms or because editing of L-chain variable genes occurred which our experimental approach could not identify.

Lindenane-Type Sesquiterpene Dimers Mitigate Lipopolysaccharide-Induced Inflammation by Inhibiting Toll-Like Receptor Signaling.

Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns and trigger an inflammatory response via the myeloid differential factor 88 (MyD88)-dependent and toll-interleukin-1 receptor domain-containing adapter-inducing interferon-ß (TRIF)-dependent pathways. Lindenane type sesquiterpene dimers (LSDs) are characteristic metabolites of plants belonging to the genus Sarcandra (Chloranthaceae). The aim of this study was to evaluate the potential anti-inflammatory effects of the LSDs shizukaol D (1) and sarcandrolide E (2) on lipopolysaccharides (LPS)-stimulated RAW264.7 macrophages in vitro, and explore the underlying mechanisms. Both LSDs neutralized the LPS-induced morphological changes and production of nitric oxide (NO), as determined by CCK-8 assay and Griess assay, respectively. Furthermore, shizukaol D (1) and sarcandrolide E (2) downregulated interferon ß (IFNß), tumor necrosis factor α (TNFα) and interleukin-1ß (IL-1ß) mRNA levels as measured by reverse transcription polymerase chain reaction (RT-PCR), and inhibited the phosphorylation of nuclear factor kappa B p65 (p65), nuclear factor kappa-Bα (IκBα), Jun N-terminal kinase (JNK), extracellular regulated kinase (ERK), mitogen-activated protein kinase p38 (p38), MyD88, IL-1RI-associated protein kinase 1 (IRAK1), and transforming growth factor-ß-activated kinase 1 (TAK1) proteins in the Western blotting assay. In conclusion, LSDs can alleviate the inflammatory response by inhibiting the TLR/MyD88 signalling pathway.

Acceptance and attitude towards the traditional chinese medicine among asymptomatic COVID-19 patients in Shanghai Fangcang hospital.

OBJECTIVE: The Coronavirus Disease 2019 (COVID-19) has brought severe damage to global health and socioeconomics. In China, traditional Chinese medicine (TCM) is the most important complementary and alternative medicine (CAM) and it has shown a beneficial role in the prevention and treatment of COVID-19. However, it is unknown whether patients are willing to accept TCM treatment. The objective of our study is to investigate the acceptance, attitude, and independent predictors of TCM among asymptomatic COVID-19 patients admitted to Shanghai fangcang hospital during the outbreak of the COVID-19 pandemic in Shanghai in 2022. METHODS: A cross-sectional study was conducted on asymptomatic COVID-19 patients in the largest fangcang hospital in Shanghai, China, from April 22, 2022, to May 25, 2022. Based on the literature review of previous similar studies, a self-report questionnaire was developed to assess the patients' attitude and acceptance of TCM, and a multivariate logistic regression analysis was conducted to determine the independent predictors of TCM acceptance. RESULTS: A total of 1,121 patients completed the survey, of whom 91.35% were willing to accept CAM treatment whereas 8.65% of participants showed no willingness. Multivariate logistic regression analysis revealed that the patients who have received two doses of COVID-19 vaccine (OR = 2.069, 95%CI: 1.029-4.162, P = 0.041 vs. not received), understood the culture of TCM (OR = 2.293, 95%CI: 1.029-4.162, P = 0.014 vs. not understood), thought the TCM treatment is safe (OR = 2.856, 95%CI: 1.334-6.112, P = 0.007 vs. not thought), thought the TCM treatment is effective (OR = 2.724, 95%CI: 1.249-5.940, P = 0.012 vs. not thought), and those who informed their attending physician if using TCM for treatment (OR = 3.455, 95%CI:1.867-6.392, P < 0.001 vs. not informed) were more likely to accept TCM treatment. However, patients who thought TCM might delay your treatment (OR = 0.256, 95%CI: 0.142-0.462, P < 0.001 not thought) was an independent predictor for unwillingness to accept TCM treatment. CONCLUSION: This study preliminarily investigated the acceptance, attitude, and predictors of intention to receive TCM among asymptomatic COVID-19 patients. It is recommended to increase the publicity of TCM, clarify the impact of TCM and communicate with attending doctors that meet the healthcare needs of asymptomatic COVID-19 patients.

GUESS - A simple approach to accelerate optimization countercurrent separation.

The generally useful estimate of solvent systems (GUESS) method, which is based on thin layer chromatography, is a simple and practical method for selecting solvent systems for countercurrent chromatography (CCC). However, it is rarely used for complex samples derived from natural products. In this study, GUESS was used for CCC solvent system selection and polarity-adjusted CCC separations of several fractions, which were obtained from a silica gel column containing complex compositions with a broad polarity from Salvia bowleyana Dunn. The GUESS method was performed on five fractions based on solvent systems in the n-hexane-ethyl acetate-methanol-water (HEMWat) family. Based on the GUESS results, the optimal solvent systems were selected for CCC separation. Twelve diterpenoids were obtained from the five silica gel column fractions of S. bowleyana Dunn using elution-extrusion countercurrent chromatography (EECCC). These demonstrate that GUESS guidance and the polarity adjustment of the solvent system accelerate the optimization of CCC separation conditions and simplify the process of accommodating a broad polarity of components in complicated mixture fractions. We therefore confirmed the feasibility and advantage of the GUESS method for complex natural chemical component separations.

The generally useful estimate of solvent systems method facilitates off-line two-dimensional countercurrent chromatography for isolating compositions from Siraitia grosvenorii roots.

Solvent system selection is a crucial and the most time-consuming step for successful countercurrent chromatography separation. A thin-layer chromatography-based generally useful estimate of solvent systems method has been developed to simplify the solvent system selection. We herein utilized the method to select a solvent system for off-line two-dimensional countercurrent chromatography to separate chemical compositions from a complex fraction of the Siraitia grosvenorii root extract. The first-dimensional countercurrent separation using chloroform/methanol/water (10:5.5:4.5, v/v/v) yielded four compounds with high purity and three mixture fractions (Fr I, III, and VII). The second-dimensional countercurrent separation conducted on Fr I, III, and VII using the hexane/ethyl acetate/methanol/water (4:6:6:4, 3:7:3:7, v/v/v) and chloroform/methanol/water (10:9:6, v/v/v) solvent systems, respectively, produced another four compounds. Four triterpenoids and four lignans were finally isolated, including two novel compounds. Hence, the generally useful estimate of solvent systems method is a feasible and efficient approach for selecting an applicable solvent system for separating complex samples. In addition, the off-line two-dimensional countercurrent chromatography method can improve both the peak resolution and the capacity of countercurrent chromatography.