Simultaneous determination of gentiopicroside and its two active metabolites in rat plasma by LC–MS/MS and its application in pharmacokinetic studies

Regulatory mechanisms of Gentiopicroside on human diseases: a brief review

Gentiopicroside (GPS), a single compound isolated from Gentiana lutea L. and the crucial representative of secoiridoid constituent, has been permitted for centuries in traditional Chinese medicine. GPS and its metabolites have been increasingly used in the search for clinical management with therapeutic properties and fewer side effects. The objective of this review was to provide a comprehensive overview of the involvement of molecular pathways in the therapeutic effects of GPS on human diseases and chronic conditions. This study presents a meticulously conducted comprehensive search of the PubMed and Google Scholar databases (from 1983 to 2023), aimed at identifying articles relating to regulatory mechanisms of GPS on human diseases and the pharmacokinetics of GPS. The inclusion criteria were meticulously and precisely defined to encompass original research papers that explicitly focused on elucidating the regulatory mechanisms of GPS in various human diseases through in vitro and animal studies. Notably, these studies were mandated to integrate specific genetic markers or pathways as essential components of their research inquiries. The evaluated pharmacokinetic parameters included maximum plasma concentration (Cmax), time to reach maximum plasma concentration (Tmax), area under the curve (AUC), clearance, and plasma half-life (t1/2). Subsequently, through a rigorous screening process of titles and abstracts, studies conducted in vitro or on animals, as well as those reporting pharmacokinetic data related to drugs other than GPS or language barriers, were systematically excluded. Drawing from the data and studies pertaining to this review, we conducted a thorough and informative analysis of the pharmacological characteristics and biological functions of GPS. These encompassed a wide range of effects, including hepatoprotective, anti-inflammatory, antifibrotic, antioxidant, analgesic, antitumor, and immunomodulatory properties. The analysis provided a comprehensive and insightful understanding of GPS's pharmacological profile and its diverse activities. Enhancing theoretical and experimental methodologies could prove advantageous in expanding the clinical applications of GPS. This could involve optimizing the bioavailability and pharmacokinetics of GPS, uncovering additional biomarkers and potential biotransformation pathways, and investigating its combined effects with standard-of-care medications.

Metabolic Transformation of Gentiopicrin, a Liver Protective Active Ingredient, Based on Intestinal Bacteria

Gentiopicrin, the main component of the famous Chinese patent medicine Long Dan Xie Gan Wan, has the characteristics of fast absorption in vivo and low bioavailability. Intestinal bacteria play an important role in the absorption and pharmacokinetics of oral drugs. In this study, the metabolic transformation of gentiopicrin by intestinal bacteria was examined. High-performance liquid chromatography coupled with ion trap time-of-flight mass spectrometry (LC/MSn-IT-TOF) and nuclear magnetic resonance (NMR) were used, and six metabolites were identified, including reduction products (G-M1, G-M2, G-M4, and G-M6), a hydrolytic product (G-M3), and a dehydration product (G-M5) of gentiopicrin aglycone after hydrolysis, reduction, and dehydration reactions were performed by the intestinal flora. This is the first time that chiral metabolites of gentiopicrin (G-M1 and G-M2) were found in this study. In addition, the precursors of glucuronic acid conjugates previously reported in vivo may have come from the intestinal bacterial metabolites G-M1, G-M2, and G-M3. In addition, the metabolic transformation of gentiopicrin in liver microsomes was studied in vitro, and it was found that gentiopicrin did not undergo metabolic transformation under the action of liver microsomes. It is suggested that gentiopicroside may be metabolized in the intestine. This study provides both new insight regarding the investigation of effective substances and an exploration of the pharmacodynamic and toxicological properties of gentiopicrin.

Safety of a feed additive consisting of a tincture derived from the roots of Gentiana lutea L. (gentian tincture) for all animal species (FEFANA asbl)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety of a tincture derived from Gentiana lutea L. (gentian tincture). It is intended to be used as a sensory additive for all animal species. The product is a water/ethanol solution, with a dry matter content of approximately 4.3% and it contains on average 0.0836% polyphenols (of which 0.0463% are flavonoids and 0.0027% xanthones) and 0.0022% gentiopicroside. The additive is intended for use in complete feed or drinking water up to a maximum level of 50 mg tincture/kg for all animal species, except horses, for which the proposed use is 200 mg/kg in complete feed. In a previous assessment, due to the genotoxic potential identified in vitro for xanthones (gentisin and isogentisin) and gentiopicroside the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) could not conclude on the safety of the additive for long-living animals and on risks of genotoxicity and carcinogenicity for dermal exposure of unprotected users. The additive did not raise safety concern for short-living animals, consumers and the environment. The applicant has provided information in the form of literature to address the previously identified genotoxic activity of xanthones and gentiopicroside and the risk for the user. Considering that the literature identified provided no new evidence, the FEEDAP Panel reiterated that it is not in a position to conclude on the safety of the additive for long-living and reproductive animals. No conclusions could be drawn on the potential of the additive to be a dermal/eye irritant or a skin sensitiser. When handling the tincture, exposure of unprotected users to xanthones (gentisin and isogentisin) and gentiopicroside cannot be excluded. Therefore, to reduce the risk, the exposure of the users should be minimised.

Preparation, Characterization, and In Vivo Evaluation of Gentiopicroside-Phospholipid Complex (GTP-PC) and Its Self-Nanoemulsion Drug Delivery System (GTP-PC-SNEDDS)

The objective of the present study was to develop a gentiopicroside-phospholipid complex (GTP-PC) and its self-nanoemulsion drug delivery system (GTP-PC-SNEDDS) to increase the oral bioavailability of gentiopicroside (GTP). The factors affecting the formation of GTP-PC were studied with the complexation efficiency and dissociation rate. The properties of the complex were investigated by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), dissolution, etc. Then, GTP-PC was loaded into SNEDDS by investigating the effects of weight ratios of GTP-PC to blank SNEDDS, preparation technology, dilution media, and dilution multi, based on the screening results of oils, surfactants, and cosurfactants. In rats, GTP, GTP-PC, and GTP-PC-SNEDDS were orally administered at different times, and GTP concentrations were determined using RP-HPLC. The optimal GTP-PC was prepared with tetrahydrofuran as the reaction solvent, GTP:phospholipid = 1:2, and stirring for 4 h. The optimal prescription for GTP-PC-SNEDDS was as follows: Maisin 35-1:Miglycol = 30%, Labrasol:Cremophor EL = 1:4 = 40%, Transcutol P = 30%; Maisin 35-1:Miglycol = 12, and the ratio of GTP-PC to blank was 1:10-then the mixture was stirred at 37 °C for 1 d and then placed for 2 d to form stable GTP-PC-SNEDDS. After oral administration of GTP, GTP-PC and GTP-PC-SNEDDS, and mean plasma GTP concentration-time curves were all in accordance with the single-compartment model. The C_max, AUC_0-∞, and Fr of the three formulations were significantly higher than that of GTP, demonstrating that GTP was metabolized rapidly, and its higher bioavailability could be achieved by the formation of GTP-PC and GTP-PC-SNEDDS. Among the three formations, the bioavailability of GTP-PC-SNEDDS was highest, with approximately 2.6-fold and 1.3-fold of Fr value, compared with GTP-PC (suspension) and GTP-PC (oil solution), respectively. Compared with GTP, GTP-PC and GTP-PC-SNEDDS enhanced the bioavailability of GTP significantly. In the future, this study could serve as a reference for clinical trials using GTP-PC and GTP-PC-SNEDDS.

Identification of Protosappanoside D from Caesalpinia decapetala and Evaluation of Its Pharmacokinetic, Metabolism and Pharmacological Activity

Protosappanoside D (PTD) is a new component isolated from the extract of Caesalpinia decapetala for the first time. Its structure was identified as protosappanin B-3-O-β-D-glucoside by ¹H-NMR, ¹³C-NMR, 2D-NMR and MS techniques. To date, the pharmacological activities, metabolism or pharmacokinetics of PTD has not been reported. Therefore, this research to study the anti-inflammatory activity of PTD was investigated via the LPS-induced RAW264.7 cells model. At the same time, we also used the UHPLC/Q Exactive Plus MS and UPLC-MS/MS methods to study the metabolites and pharmacokinetics of PTD, to calculate its bioavailability for the first time. The results showed that PTD could downregulate secretion of the pro-inflammatory cytokines. In the metabolic study, four metabolites were identified, and the primary degradative pathways in vivo involved the desaturation, oxidation, methylation, alkylation, dehydration, degradation and desugarization. In the pharmacokinetic study, PTD and its main metabolite protosappanin B (PTB) were measured after oral and intravenous administration. After oral administration of PTD, its T_max was 0.49 h, t_1/2z and MRT_(0–t) were 3.47 ± 0.78 h and 3.06 ± 0.63 h, respectively. It shows that PTD was quickly absorbed into plasma and it may be eliminated quickly in the body, and its bioavailability is about 0.65%.

Simultaneous Determination of Three Coumarins in Rat Plasma by HPLC-MS/MS for Pharmacokinetic Studies Following Oral Administration of Chimonanthi Radix Extract

Chimonanthi Radix (CR) is widely used in the treatment of influenza in China. Extensive studies revealed that the major bioactive constituents of CR were coumarins. However, pharmacokinetic study of coumarins in CR has not been fully studied. The purpose of this study was to establish a convenient and effective high-performance liquid chromatography-tandem mass spectrometry method that was used to simultaneously determine scopoletin, scopolin and isofraxidin in rat plasma after oral administration of CR extract using xanthotoxin as the internal standard. The chromatographic separation was carried out on a COSMOCORE C18 column (100 × 2 mm, 2.6 μm), using gradient elution with the mobile phase consisting of 0.1% formic acid (A) and acetonitrile (B). Three coumarins and IS were quantified by positive ion electrospray ionization in multiple reaction monitoring mode. The method was fully validated in terms of specificity, accuracy, precision (intra- and inter-day), matrix effect, recovery as well as the stability of the analytes under various conditions. The results could provide further research foundation for anti-influenza mechanism of three coumarins in CR.

A Validated HPLC-MS/MS Method for Simultaneous Determination of Militarine and Its Three Metabolites in Rat Plasma: Application to a Pharmacokinetic Study

A rapid, reliable, and sensitive HPLC-electrospray ionization-tandem mass spectrometry (HPLC-MS/MS) method was established and validated for simultaneous determination of militarine and its three metabolites (gastrodin, α-isobutylmalic acid, and gymnoside I) in rat plasma. Plasma was acidified with formic acid, and protein was precipitated with methanol. MS/MS with ESI and multiple reaction monitoring at m/z 725.3→457.3, 457.1→127, 304.3→107.2, 189→129, and 417.1→267.1 was used for determination of militarine, gastrodin, α-isobutylmalic acid, gymnoside I, and puerarin (internal standard), respectively. Chromatographic separation was conducted using an ACE UltraCore SuperC18 (2.1 × 100 mm, 2.5 μm) column with gradient mobile phase (0.1% formic acid in water and acetonitrile). The lower limits of quantitation for militarine, gastrodin, α-isobutylmalic acid, and gymnoside I were 1.02, 2.96, 1.64, and 0.3 ng/mL, respectively. The relative standard deviations of intra- and interday measurements were less than 15%, and the method accuracy ranged from 87.4% to 112.5%. The extraction recovery was 83.52%-105.34%, and no matrix effect was observed. The three metabolites (gastrodin, α-isobutylmalic acid, and gymnoside I) were synchronously detected at 0.83 h, suggesting that militarine was rapidly transformed to gastrodin, α-isobutylmalic acid, and gymnoside I. Moreover, the area under the curve (AUC) and C_max of militarine were significantly lower than those of gastrodin and α-isobutylmalic acid, showing that militarine was largely metabolized to gastrodin and α-isobutylmalic acid in vivo. The studies on pharmacokinetics of militarine and its three metabolites were of great use for facilitating the clinical application of militarine and were also highly meaningful for the potential development of militarine.

Identification of metabolites of liquiritin in rats by UHPLC-Q-TOF-MS/MS: metabolic profiling and pathway comparisonin vitroandin vivo

Liquiritin (LQ), the main bioactive constituent of licorice, is a common flavoring and sweetening agent in food products and has a wide range of pharmacological properties, including antidepressant-like, neuroprotective, anti-cancer and anti-inflammatory properties. This study investigated the metabolic pathways of LQ in vitro (rat liver microsomes) and in vivo (rat model) using ultra high-performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). Moreover, supplementary tools such as key product ions (KPIs) were employed to search for and identify compounds. As a result, 56 in vivo metabolites and 15 in vitro metabolites were structurally characterized. Oxidation, reduction, hydrolysis, methylation, acetylation, and sulfate and glucuronide conjugation were determined to be the major metabolic pathways of LQ, and there were differences in LQ metabolism in vitro and in vivo. In addition, the in vitro and in vivo metabolic pathways were compared in this study.

Liquiritin (LQ), the main bioactive constituent of licorice, is a common flavoring and sweetening agent in food products and has a wide range of pharmacological properties, including antidepressant-like, neuroprotective and anti-cancer properties.