Interactions between thrombin and natural products of Millettia nitita var. hirsutissima using capillary zone electrophoresis

Utilizing Integrated UHPLC-Q-Exactive Orbitrap-MS, Multivariate Analysis, and Bioactive Evaluation to Distinguish between Wild and Cultivated Niudali (Millettia speciosa Champ.)

Millettia speciosa Champ. (MSCP) enjoys widespread recognition for its culinary and medicinal attributes. Despite the extensive history of MSCP cultivation, the disparities in quality and bioactivity between wild and cultivated varieties have remained unexplored. In this study, 20 wild and cultivated MSCP samples were collected from different regions in China. We embarked on a comprehensive investigation of the chemical constituents found in both wild and cultivated MSCP utilizing UHPLC-Q-Exactive Orbitrap-MS technology and multivariate analysis such as principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). In total, 62 chemical components were unequivocally identified or tentatively characterized. Via the multivariate statistical analysis, we successfully pinpointed nine compounds with the potential to serve as chemical markers, enabling the differentiation between wild and cultivated MSCP varieties. Moreover, both genotypes exhibited substantial antioxidant and anti-fatigue properties. The bioactivities of wild MSCP were marginally higher when compared to their cultivated counterparts. This study illuminates the impressive antioxidant and anti-fatigue potential present in both wild and cultivated MSCP genotypes, further augmenting the allure of this species and opening new avenues for the economic valorization of MSCP. Hence, this study provides a valuable method for the identification and quality control of MSCP and a method in chemistry and pharmacology to assess an alternative possibility for cultivated MSCP.

A review on genus Millettia: Traditional uses, phytochemicals and pharmacological activities

The genus Millettia belongs to Fabaceae includes 200 species which are distributed in tropical and subtropical regions of the world. Plants belong to this genus are used as folkloric medicine, for the treatment of different ailments like in wound healing, boil, sores, skin diseases, snake bite, muscle aches, pains, rheumatic arthritis, and gynaecological diseases. The aim of the review is to provide updated, comprehensive and categorized information on the aspects of ethnobotanical, phytochemical, pharmacological uses and toxicity of genus Millettia in order to identify their therapeutic potential and generate space for future research opportunities. The present study comprises of isolated flavonoids, phenolic compounds, phytosterols, saponins, alkaloids, polysaccharides, terpenoids and resins and pharmacological activities of various Millettia species. The relevant data were searched by using the keyword "Millettia" in different scientific databases like, "Google Scholar"; "NISCAIR repository"; "Pub Med"; "Science Direct"; "Scopus" and the taxonomy is validated by "The Plant List". This review discusses the existing information of the traditional evaluation as well as phytochemical and pharmacological evaluation of the extract and active constituents of the genus "Millettia". This review confirms that several Millettia species have emerged as a high-quality medicine in a traditional system for arthritis, wound healing, inflammation, skin diseases. Numerous conventional uses of Millettia species have been validated by modern pharmacology research. Intensive investigations of the genus Millettia relating to phytochemistry and pharmacology, especially their mechanism of action, safety, and efficacy could be the future research interests by the researcher in the area of phytomedicine.

3'-O-Methylorobol Inhibits the Voltage-Gated Sodium Channel Nav1.7 with Anti-Itch Efficacy in A Histamine-Dependent Itch Mouse Model

An itch is a clinical complication that affects millions of patients. However, few treatment options are available. The voltage-gated sodium channel Nav1.7 is predominantly expressed in peripheral sensory neurons and is responsible for the rising phase of action potentials, thereby mediating nociceptive conduction. A gain-of-function mutation of Nav1.7 results in the hyperexcitability of sensory neurons and causes the inherited paroxysmal itch. Conversely, a monoclonal antibody that selectively inhibits Nav1.7 is able to effectively suppress the histamine-dependent itch in mice. Therefore, Nav1.7 inhibitors may possess the potential to relieve the itch. In the present study, using whole-cell voltage-clamp recordings, we demonstrated that 3’-O-methylorobol inhibited Na⁺ currents in Nav1.7-CHO cells and tetrodotoxin-sensitive Na⁺ currents in mouse dorsal root ganglion (DRG) neurons with IC₅₀ (half-maximal inhibitory concentration) values of 3.46 and 6.60 μM, respectively. 3’-O-methylorobol also suppressed the tetrodotoxin-resistant Na⁺ currents in DRG neurons, though with reduced potency (~43% inhibition at 30 µM). 3’-O-methylorobol (10 µM) affected the Nav1.7 by shifting the half-maximal voltage (V_1/2) of activation to a depolarizing direction by ~6.76 mV, and it shifted the V_1/2 of inactivation to a hyperpolarizing direction by ~16.79 mV. An analysis of 3’-O-methylorobol activity toward an array of itch targets revealed that 3’-O-methylorobol was without effect on histamine H₁ receptor, TRPV1, TRPV3, TRPV4, TRPC4 and TRPM8. The intrathecal administration of 3’-O-methylorobol significantly attenuated compound 48/80-induced histamine-dependent spontaneous scratching bouts and the expression level of c-fos in the nuclei of spinal dorsal horn neurons with a comparable efficacy to that of cyproheptadine. Our data illustrated the therapeutic potential for 3’-O-methylorobol for histamine-dependent itching, and the small molecule inhibition of Nav1.7 may represent a useful strategy to develop novel therapeutics for itching.

Combining Chemical Profiling and Network Analysis to Investigate the Pharmacology of Complex Prescriptions in Traditional Chinese Medicine

We present a paradigm, combining chemical profiling, absorbed components detection in plasma and network analysis, for investigating the pharmacology of combination drugs and complex formulae. On the one hand, the composition of the formula is investigated comprehensively via mass spectrometry analysis, followed by pharmacological studies of the fractions as well as the plasma concentration testing for the ingredients. On the other hand, both the candidate target proteins and the effective ingredients of the formula are predicted via analyzing the corresponding networks. The most probable active compounds can then be identified by combining the experimental results with the network analysis. In order to illustrate the performance of the paradigm, we apply it to the Danggui-Jianzhong formula (DJF) from traditional Chinese medicine (TCM) and predict 4 probably active ingredients, 3 of which are verified experimentally to display anti-platelet activity, i.e., (Z)-Ligustilide, Licochalcone A and Pentagalloylglucose. Moreover, the 3-compound formulae composed of these 3 chemicals show better anti-platelet activity than DJF. In addition, the paradigm predicts the association between these 3 compounds and COX-1, and our experimental validation further shows that such association comes from the inhibitory effects of the compounds on the activity of COX-1.

Screening of thrombin inhibitors from phenolic acids using enzyme-immobilized magnetic beads through direct covalent binding by ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry

Thrombin was immobilized on dynabeads^®M-270 epoxy by direct covalent binding method for the first time. The enzyme coated magnetic beads were combined with ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry technique to establish a simple, rapid and reliable approach for screening thrombin inhibitors from Danshen preparation. The conjugation of thrombin to the magnetic beads was characterized using scanning electron microscope, transmission electron microscope and infrared spectroscopy, and the enzyme activity was determined by the analysis of enzyme-bead ratio and peak areas of target compounds. Several factors including amount of magnetic beads, type of elution solvent, incubation temperature and time were optimized. Additionally, two thrombin-bound compounds (protocatechuic aldehyde and salvianolic acid C) in Danshen injection were validated by conventional inhibitory assay and the IC₅₀ values were 286.11 and 66.09μg/mL, respectively. Our findings suggested that the proposed method was efficient in screening active compounds from medicinal plants.

Research on drug-receptor interactions and prediction of drug activity via oriented immobilized receptor capillary electrophoresis

Oriented covalent immobilized β2 -adrenergic receptor (β2 -AR) CE (OIRCE) was developed to determine the interactions between a set of natural extracts of Radix Paeoniae Rubra (NERPR) and β2 -AR, and to predict the activity of NERPR. The inner capillary surface is chemically bonded with stable β2 -AR coating via microwave-assisted technical synthesis. The modified capillaries were characterized via infrared spectroscopy and fluorescence microscopy. Furthermore, the bonding amounts of β2 -AR were first obtained via fluorescence spectroscopy method. In determining the amount of bonded β2 -AR, the regression equation A  =  576 707C + 35.449 and the correlation coefficient 0.9995 were obtained. This result revealed an excellent linear relationship in the range of 2 × 10(-4)  mg/mL to 1 × 10(-3)  mg/mL. The normalized capacity factor (KRCE ) was obtained using OIRCE in evaluating drug-receptor interactions. Related theories and equations were used to calculate KRCE values from apparent migration times of a solute and EOF. The order of KRCE and the binding constant (Kb ) values between drugs and β2 -AR was well consistent. The results confirmed that the OIRCE and KRCE values can be effectually used to investigate drug-receptor interactions, and OIRCE has the potential to predict drug activity and to select leading compounds from natural chemicals.

Flavonoids from Millettia nitida var. hirsutissima with their anticoagulative activities and inhibitory effects on NO production

Two new compounds, (2R)-7,3'-dihydroxy-6,4'-methoxyflavan (1) and (3R)-7,4'-dihydroxy-2'-methoxyisoflavan (2), along with 12 known flavonoids (3-14), were isolated from the vine stems of Millettia nitida var. hirsutissima. The structures of the isolated compounds were elucidated based on spectroscopic analyses and comparison of literature data. All of the isolates were evaluated for their effects on in-vitro anticoagulative assay and on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated RAW264.7 macrophages. As a result, all compounds showed weak antiplatelet aggregation activities and compounds 4, 5, 7, 8 and 9 demonstrated antithrombin activity with a good dose-effect relationship from 5 to 100 μg mL⁻¹ in rabbit plasma. Compounds 8, 9, 10 and 14 exhibited inhibitory effects on LPS-induced NO production in RAW264.7 macrophages with IC₅₀ values of 4.79 ± 0.20, 8.23 ± 0.35, 5.23 ± 0.11 and 6.30 ± 0.30 μg mL⁻¹, respectively.