Screening Bioactive Compounds of Siraitia grosvenorii by Immobilized β2-Adrenergic Receptor Chromatography and Druggability Evaluation

Prediction of the binding interactions between rosmarinic acid and cysteinyl leukotriene receptor type 1 by molecular docking and immobilized receptor chromatography

Drug-protein interaction analysis is still at the center of research efforts to illustrate binding mechanisms and provide valuable information for selecting drug candidates with ideal properties in the early drug discovery stage. We present the prediction of the binding of rosmarinic acid (RA) to cysteinyl leukotriene receptor type1 (CysLTR1) by molecular docking. According to our findings, CysLTR1 is a potential anti-inflammatory target of RA. Under this assumption, we prepared the immobilized CysLTR1 column via a one-step method and characterized the immobilized CysLTR1 by fluorescent and chromatographic analyses. Furthermore, we used the immobilized CysLTR1 column to evaluate the binding interactions between RA and the immobilized receptor. Molecular docking showed that Tyr 249, Phe 174, Thr 280, Pro 177, and Thr 100 are the main sites for RA to interact with CysLTR1. The main forces that drive the findings are hydrogen bonds and hydrophobic interactions. Characterization results show that CysLTR1 is successfully immobilized with high specificity and stability. Almost no non-specific binding is observed on the immobilized CysLTR1 gels. The association constant and the binding sites are calculated to be 7.268 × 105 L mol-1 and 1.237 × 10-8 mol L-1 by injection amount-dependent method. These results, taken together, confirm the potential target of RA on the anti-inflammatory effect. We believe that it can provide valuable reference information on the in-depth exploration of drug-protein interaction mechanisms, and lead compound screening by this method.

A comprehensive review of Siraitia grosvenorii (Swingle) C. Jeffrey: chemical composition, pharmacology, toxicology, status of resources development, and applications

Siraitia grosvenorii (Swingle) C. Jeffrey (S. grosvenorii), a perennial indigenous liana from the Cucurbitaceae family, has historically played a significant role in southern China's traditional remedies for various ailments. Its dual classification by the Chinese Ministry of Health for both medicinal and food utility underscores its has the potential of versatile applications. Recent research has shed light on the chemical composition, pharmacological effects, and toxicity of S. grosvenorii. Its active ingredients include triterpenoids, flavonoids, amino acids, volatile oils, polysaccharides, minerals, vitamins, and other microconstituents. Apart from being a natural sweetener, S. grosvenorii has been found to have numerous pharmacological effects, including alleviating cough and phlegm, preventing dental caries, exerting anti-inflammatory and anti-allergic effects, anti-aging and anti-oxidative, hypoglycemic, lipid-lowering, anti-depression, anti-fatigue, anti-schizophrenic, anti-Parkinson, anti-fibrotic, and anti-tumor activities. Despite its versatile potential, there is still a lack of systematic research on S. grosvenorii to date. This paper aims to address this gap by providing an overview of the main active components, pharmacological efficacy, toxicity, current status of development and application, development dilemmas, and strategies for intensive exploitation and utilization of S. grosvenorii. This paper aims to serve as a guide for researchers and practitioners committed to exploiting the biological resources of S. grosvenorii and further exploring its interdisciplinary potential.

Advances in receptor chromatography for drug discovery and drug-receptor interaction studies

Receptor chromatography involves high-throughput separation and accurate drug screening based on specific drug-receptor recognition and affinity, which has been widely used to screen active compounds in complex samples. This review summarizes the immobilization methods for receptors from three aspects: random covalent immobilization methods, site-specific covalent immobilization methods and dual-target receptor chromatography. Meanwhile, it focuses on its applications from three angles: screening active compounds in natural products, in natural-product-derived DNA-encoded compound libraries and drug-receptor interactions. This review provides new insights for the design and application of receptor chromatography, high-throughput and accurate drug screening, drug-receptor interactions and more. Teaser: This review summarizes the immobilization methods of receptors and the application of receptor chromatography, which will provide new insights for the design and application of receptor chromatography, rapid drug screening, drug-receptor interactions and more.

Screening potential ligands of endothelin receptor A from Choerospondias axillaris and evaluation of their drug-like properties by affinity chromatographic methods

Tibetan medicine is traditionally prescribed as crude extracts or mixtures owing to the theoretical basis with cross fertilization from other medical systems like Ayurveda and traditional Chinese medicine. This is challenged to elucidate the action mechanism and material foundation of Tibetan medicine due to lacking a method to confirm the bioactive compounds determining the therapy. This work created a new strategy for screening and evaluating the bioactive compounds against cardiovascular ailments from Choerospondias axillaris. It involved the immobilization of endothelin receptor A (ET_AR) by a one-step covalent assay, the screening and identification of the bioactive compounds by ET_AR column combined with tandem mass spectrometry, and the evaluation of their drug-like properties by calculating the efficiency indexes using the data collected by frontal analysis and adsorption energy distribution. The immobilized ET_AR remained good stability in three weeks in terms of specificity and repeatability. Catechin, pinocembrin, and hyperoside were identified as potential ET_AR ligands from Choerospondias axillaris with two types of binding sites on the immobilized receptor. Their association constants on the high and low affinity binding sites were (2.53 ± 0.11) × 10⁵ and (9.94 ± 0.02) × 10³ M^-1 for catechin, (1.01 ± 0.12) × 10⁶ and (7.40 ± 0.03) × 10⁴ for hyperoside, and (2.05 ± 0.04) × 10⁵ and (2.47 ± 0.09)× 10⁴ M^-1 for pinocembrin, respectively. Owing to the highest association constant, hyperoside presented a surface efficiency index of 7.95, and binding efficiency index of 20.7, and the ligand-lipophilicity efficiency of 1.38. These indicated that the three compounds were the main ingredients for the therapy of Choerospondias axillaris, and had potential to become lead compounds for anti-cardiovascular drugs based on drug-ET_AR interaction. The immobilized receptor-based strategy is possible to become an alternative for screening and assessing bioactive compounds from Tibetan medicine.

The Protective Effects of Mogroside V Against Neuronal Damages by Attenuating Mitochondrial Dysfunction via Upregulating Sirtuin3

Mitochondrial dysfunction and oxidative stress are thought to play a dominant role in the pathogenesis of Parkinson's disease (PD). Mogroside V (MV), extracted from Siraitia grosvenorii, exhibits antioxidant-like activities. The aim of this study was to investigate the function of MV in neuroprotection in PD and to reveal its mechanism of action. To that end, we firstly set up mice models of PD with unilateral striatum injection of 0.25 mg/kg rotenone (Rot) and co-treated with 2.5 mg/kg, 5 mg/kg, and 10 mg/kg MV by gavage. Results showed that Rot-induced motor impairments and dopaminergic neuronal damage were reversed by treatment of 10 mg/kg MV. Then, we established cellular models of PD using Rot-treated SH-SY5Y cells, which were divided into six groups, including control, Rot, and co-enzyme Q10 (CQ10), as well as MV groups, MV25, MV50, and MV100 treated with 25 μM, 50 μM, and 100 μM MV doses, respectively. Results demonstrated that MV effectively attenuates Rot neurotoxicity through a ROS-related intrinsic mitochondrial pathway. MV reduced overproduction of reactive oxygen species (ROS), recovered the mitochondrial membrane potential (MMP), and increased the oxygen consumption rate and adenosine triphosphate (ATP) production in a dose-dependent manner. Hence, treatment with MV led to a reduction in the number of apoptotic cells, as reflected by Annexin-V/propidium iodide co-staining using flow cytometry and TdT-mediated dUTP Nick-End Labeling (TUNEL) assay. In addition, the Sirtuin3 (SIRT3) protein level and activity were decreased upon exposure to Rot both in substantia nigra (SN) of mice and SH-SY5Y cells. SIRT3 impairment hyperacetylated a key mitochondrial antioxidant enzyme, superoxide dismutase 2 (SOD2). MV alleviates SIRT3 and SOD2 molecular changes. However, after successfully inhibiting SIRT3 by its specific inhibitor 3-1H-1, 2, 3-triazol-4-yl pyridine (3TYP), MV was not able to reduce ROS levels, reverse abnormal MMP, or decrease apoptotic cells. Motor impairments and dopaminergic neuronal injury in the SN were alleviated with the oral administration of MV in Rot-treated PD mice, indicating a relationship between protection against defective motility and preservation of dopaminergic neurons. Therefore, we conclude that MV can alleviate Rot-induced neurotoxicity in a PD model, and that SIRT3 may be an important regulator in the protection of MV.

Identification of selective ligands targeting two GPCRs by receptor-affinity chromatography coupled with high-throughput sequencing techniques

The rapid growth of demands for drug discovery has necessitated the ongoing pursuit of new methods for specific ligands screening and identification. This work combined receptor-affinity chromatography (RAC) with high-throughput sequencing techniques to rapidly screen and identify the specific ligands. By this method, immobilized angiotensin II type I receptor (AT₁R) and endothelin receptor A (ET_AR) based on RAC were utilized for lead screening from a DNA-encoded library. The specific ligands of AT₁R (ligand A₁, A₂) and ET_AR (ligand B₁, B₂) were synthesized after decoding by high-throughput sequencing techniques. The dissociation rate constants (k_d) of ligand A₁, A₂ to AT₁R and B₁, B₂ to ET_AR were 9.65 × 10^-4, 31.1 × 10^-4 and 0.66, 1.22 s^-1 by peak profiling assay. The association constant (K_A) to the receptors of four ligands was 5.4 × 10⁶, 3.3 × 10⁶ and 1.6 × 10⁶, 2.2 × 10⁵ by injection amount dependent method. The kinetic and thermodynamic parameters of the four specific ligands are similar to those of the positive drugs. This indicates that they are promising to drug candidates. The druggability of the four ligands through pharmacokinetic investigation by HPLC-MS/MS presented desired pharmacokinetic behavior including the fast absorption, the relatively slow elimination. These results, taking together, indicated that the RAC combined with high-throughput sequencing techniques can screen and identify the specific ligands according to various proteins, thus creating a general strategy for rapid discovery of promising drug candidates.

Rapid screening of bioactive compound in Sanzi Yangqin Decoction and investigating of binding mechanism by immobilized β2-adrenogic receptor chromatography coupled with molecular docking

Screening bioactive compounds from traditional Chinese medicines plays pivotal role in preventing and curing diseases. Sanzi Yangqin Decoction (SYD) is a commonly used prescription for the treatment of cough, asthma and some other respiratory diseases for hundreds of years in practice. This reminds us that there may exist some bioactive compounds strongly binding with the recognized receptors mediating these diseases like β₂-adrenegic receptor (β₂-AR). Therefore, this work intends to screen bioactive compounds from SYD and revealed the binding mechanism by immobilized β₂-AR chromatography and molecular docking. Taking advantages of a 3-high based enzymatic trans-methylation reaction (high speed, high specificity and high activity), the immobilization of β₂-AR was successfully achieved. Representative chromatographic peaks of SYD on the immobilized β₂-AR column was collected and recognized as rosmarinic acid and sinapine thiocyanate. Tension changes of the trachea ring showed that the two compounds were in a concentration-dependent manner when exerting their effects and the concentration ranges were 10^-9-10^-4 mol/L and 10^-12-10^-7 mol/L, respectively. Molecular docking revealed Ser203, Ser204, Ser207, Tyr316 and Asn312 were the main residues for the two compounds to bind with β₂-AR. We concluded that the proposed method is becoming an alternative in rapid recognizing bioactive compounds from complex matrix.

Development and evaluation of poly adenosine 5'-diphosphate-ribose polymerase 1 immobilization-based receptor chromatography

Yanghe decoction is a traditional Chinese medicine prescription and has been used for breast cancer treatment for many years. However, the effective ingredients in the decoction have not been identified. The expression of poly(ADP-ribose) polymerase-1 is highly related to breast cancer. Using poly(ADP-ribose) polymerase-1 as a probe, we expressed the haloalkane dehalogenase-tagged protein in BL21(DE3) E. coli, immobilized it on hexachlorocaproic acid-modified macroporous silica gel, and established a poly(ADP-ribose) polymerase-1 chromatographic model. The feasibility of the model was verified by testing the retention behaviors of five drugs on the protein column. We applied the model in screening the bioactive components in yanghe decoction. Rutin, liquiritin, and a compound ([M-H]^- 681.7) were identified to be the potential bioactive ingredients. We studied the binding property between rutin and poly(ADP-ribose) polymerase-1 by injection amount dependent method, competitive studies, and molecular docking. We found that rutin can bind to the protein through the typical inhibitor binding site of the protein. Therefore, the chromatographic model is a useful tool to screen bioactive compounds from traditional Chinese medicine. The method is fast, reliable, and applicable to other functional proteins that can screen the potential lead compounds for the treatment of the related diseases.

Adsorption mechanism of triterpenoid saponins in reversed-phase liquid chromatography and hydrophilic interaction liquid chromatography: Mogroside V as test substance

In this paper, adsorption mechanism of triterpenoid saponins in reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC) was proposed based on the study of the retention behavior of mogroside V as test substance. The change of peak shape of mogroside V and its influencing factors was first investigated. As the increase of sample loading, a tailing peak of mogroside V was observed in MeOHH₂O of both two modes. It was the fronting peak in ACNH₂O of HILIC while there was a transition from fronting peak to tailing peak in ACNH₂O of RPLC that was largely affected by column temperature and ACN concentration. The adsorption isotherm of mogroside V in ACNH₂O of RPLC was fitted by Moreau model, where a monolayer adsorption with large inter-molecular interaction was formed on the C18 surface. While in ACNH₂O of HILIC, the adsorption of mogroside V was in accordance with BET model, showing multilayer adsorption behavior. In MeOHH₂O of both HILIC and RPLC, there was always monolayer adsorption, which was fitted by Langmuir model. At last, by choosing the suitable chromatographic mode, controlling the key factors such as the solvent concentration and column temperature, and predicting the broadening trend of peak, three methods were screened out, namely, C18 column with 22% ACN (30 °C), Click XIon column with 90% MeOH or 70% ACN, to get mogroside V of purity greater than 98% from Siraitia grosvenorii extract. Among them, the RPLC method of 22% ACN that showed the highest loading sample per hour (1.92%) and the lowest solvent consumption emerged as the best approach.