Pharmacokinetic study of isocorynoxeine metabolites mediated by cytochrome P450 enzymes in rat and human liver microsomes

Advanced researches of traditional uses, phytochemistry, pharmacology, and toxicology of medical Uncariae Ramulus Cum Uncis

ETHNOPHARMACOLOGICAL RELEVANCE

Medical Uncariae Ramulus Cum Uncis consists of Uncaria rhynchophylla (Miq.) Miq. ex Havil, Uncaria macrophylla Wall, Uncaria sinensis (Oliv.) Havil, Uncaria hirsuta Havil, and Uncaria sessilifructus Roxb, which belongs to the species widely used in the genus Uncaria. These species resource widely distributed in China and abroad, and the hook-bearing stem is the primary constituent enrichment site. There are many different forms and architectures of chemicals, depending on the extraction site. Traditional remedies employing URCU had been used widely in antiquity and were first compiled in renowned ancient masterpiece 'Mingyi Bielu ()' written by Hongjing Tao. In modern pharmacological studies, both the total extracts and the phytoconstituents isolated from URCU have been shown to have neuroprotective, antioxidant, anti-inflammatory, anticancer, antibacterial, and autophagy-enhancer properties.

AIM OF THE STUDY

This review concentrates on the traditional uses, phytochemistry, pharmacology, toxicology, and nanomaterials studies of URCU, with a perspective to assist with further research and advance.

MATERIAL AND METHODS

The Chinese and English literature studies of this review are based on these database searches including Science Direct, CNKI, Wiley online library, Spring Link, Web of Science, PubMed, Medalink, Google scholar, Elsevier, ACS Publications, iPlant, Missouri Botanical Garden, Plant of the World Online. The pertinent data on URCU was gathered.

RESULTS

Based on the examination of the genus Uncaria, 107 newly marked chemical compositions have been identified from URCU from 2015 to present, including alkaloids, terpenoids, flavonoids, steroids, and others. Pharmacological studies have demonstrated that URCU has a variety of benefits in diseases such as neurodegenerative diseases, cancer, cardiovascular diseases, diabetes, and migraine, due to its neuroprotective, anti-inflammatory, antioxidant, anti-tumor, anti-bacterial and anti-viral properties. According to metabolic and toxicological studies, the dosage, frequency, and interactions of the drugs that occur in vivo are of great significance for determining whether the organic bodies can perform efficacy or produce toxicity. The research on URCU-mediated nanomaterials is expanding and increasing in order to address the inadequacies of conventional Chinese medicine. The alkaloids in URCU have the capability to self-assemble with other classes of components in addition to being biologically active.

CONCLUSION

URCU plants are widely distributed, abundant in chemical constituents, and widely used in both traditional and modern medicine for a variety of pharmacological effects. The utilization of herbal medicines can be raised by assessing the pharmacological distinctions among several species within the same genus and may accelerate the modernization of traditional Chinese medicine. Controlling the concentration of drug administration, monitoring metabolic markers, and inventing novel nanotechnologies are effective strategies for synergistic influence and detoxification to alleviate the main obstacles that toxicity, low bioavailability, and poor permeability. This review can assist further research and advances.

Discovery of a cytochrome P450 enzyme catalyzing the formation of spirooxindole alkaloid scaffold

Spirooxindole alkaloids feature a unique scaffold of an oxindole ring sharing an atom with a heterocyclic moiety. These compounds display an extensive range of biological activities such as anticancer, antibiotics, and anti-hypertension. Despite their structural and functional significance, the establishment and rationale of the spirooxindole scaffold biosynthesis are yet to be elucidated. Herein, we report the discovery and characterization of a cytochrome P450 enzyme from kratom (Mitragyna speciosa) responsible for the formation of the spirooxindole alkaloids 3-epi-corynoxeine (3R, 7R) and isocorynoxeine (3S, 7S) from the corynanthe-type (3R)-secoyohimbane precursors. Expression of the newly discovered enzyme in Saccharomyces cerevisiae yeast allows for the efficient in vivo and in vitro production of spirooxindoles. This discovery highlights the versatility of plant cytochrome P450 enzymes in building unusual alkaloid scaffolds and opens a gateway to access the prestigious spirooxindole pharmacophore and its derivatives.

Diversity-Oriented Synthesis of Spiropyrrolo[1,2-a]isoquinoline Derivatives via Diastereoselective and Regiodivergent Three-Component 1,3-Dipolar Cycloaddition Reactions: In Vitro and in Vivo Evaluation of the Antidiabetic Activity of Rhodanine Analogues

An efficient diastereoselective route is developed to get access to novel spiropyrrolo[1,2-a]isoquinoline-oxindole skeletons by a one-pot three-component [3 + 2] cycloaddition reaction of (Z)-5-arylidene-1,3-thiazolidine-2,4-diones, isatin derivatives, and 1,2,3,4-tetrahydroisoquinoline (THIQ). Interestingly, the regioselectivity of the reaction is both temperature- and solvent-dependent, allowing the synthesis of two regioisomeric endo-dispiropyrrolo[2,1-a]isoquinolineoxindoles in excellent yield. Unprecedentedly, each isomeric dispiropyrrolo[2,1-a]isoquinolineoxindole endured retro-1,3-dipolar cycloaddition/recycloaddition reactions under thermal or catalytic conditions to regenerate the corresponding regioisomeric counterpart. In addition, DFT calculations were performed at the M062X/6-31++g(d,p) level of theory to unravel the origin of the reversal of regioselectivity and endo-stereoselectivity of the title 1,3-dipolar cycloaddition reactions. Upon treatment of Isatin, THIQ with (Z)-4-arylidene-5-thioxo-thiazolidin-2-ones as dipolarophiles, unusual rhodanine analogues were formed, along with smaller amounts of a dispirooxindole-piperazine. The structure and the relative configuration of these N-heterocycles were unambiguously assigned by spectroscopic techniques and confirmed by four single-crystal structures. In vitro and in vivo studies reveal that the novel rhodanine derivatives exert antidiabetic activity. The binding affinity with the active site of the enzyme α-amylase was studied by molecular docking. Furthermore, the bioavailability assessed through virtual ADME parameters (Absorption, Distribution, Metabolism, Elimination pharmacokinetics) and the excellent fit with the Lipinski and Veber rules predict good drug-likeness properties for a bromo-substituted 2-sulfanylidene-1,3-thiazolidin-4-one.

Properties, Pharmacology, and Pharmacokinetics of Active Indole and Oxindole Alkaloids in Uncaria Hook

Uncaria Hook (UH) is a dry stem with hook of Ucaria plant and is contained in Traditional Japanese and Chinese medicine such as yokukansan, yokukansankachimpihange, chotosan, Gouteng-Baitouweng, and Tianma-Gouteng Yin. UH contains active indole and oxindole alkaloids and has the therapeutic effects on ailments of the cardiovascular and central nervous systems. The recent advances of analytical technology led to reports of detailed pharmacokinetics of UH alkaloids. These observations of pharmacokinetics are extremely important for understanding the treatment’s pharmacological activity, efficacy, and safety. This review describes properties, pharmacology, and the recently accumulated pharmacokinetic findings of UH alkaloids, and discusses challenges and future prospects. UH contains major indole and oxindole alkaloids such as corynoxeine, isocorynoxeine, rhynchophylline, isorhynchophylline, hirsuteine, hirsutine, and geissoschizine methyl ether (GM). These alkaloids exert neuroprotective effects against Alzheimer’s disease, Parkinson’s disease, and depression, and the mechanisms of these effects include anti-oxidant, anti-inflammatory, and neuromodulatory activities. Among the UH alkaloids, GM exhibits comparatively potent pharmacological activity (e.g., agonist activity at 5-HT_1A receptors). UH alkaloids are absorbed into the blood circulation and rapidly eliminated when orally administered. UH alkaloids are predominantly metabolized by Cytochrome P450 (CYP) and converted into various metabolites, including oxidized and demethylated forms. Regarding GM metabolism by CYPs, a gender-dependent difference is observed in rats but not in humans. Several alkaloids are detected in the brain after passing through the blood–brain barrier in rats upon orally administered. GM is uniformly distributed in the brain and binds to various channels and receptors such as the 5-HT receptor. By reviewing the pharmacokinetics of UH alkaloids, challenges were found, such as differences in pharmacokinetics between pure drug and crude drug products administration, food-influenced absorption, metabolite excretion profile, and intestinal tissue metabolism of UH alkaloids. This review will provide readers with a better understanding of the pharmacokinetics of UH alkaloids and their future challenges, and will be helpful for further research on UH alkaloids and crude drug products containing UH.

Evaluation of the effects of notoginseng total saponins (NS), safflower total flavonoids (SF), and the combination of NS and SF (CNS) on the activities of cytochrome P450 enzymes using a cocktail method in rats

Notoginseng total saponins (NS), safflower total flavonoids (SF), and the combination of NS and SF, namely CNS, are used for the treatment of cardiovascular diseases in clinic. This study developed a cocktail assay involving seven cytochrome P450 (CYP) enzymes to elucidate the effect of NS, SF, and CNS on CYP enzymes and to explore the synergistic effect of CNS in terms of CYP enzymes. Ultra-performance liquid chromatography-MS and reverse-transcription polymerase chain reaction were applied to detect the activities and mRNA expression levels of CYP enzymes. SF exhibited inhibitory effects on CYP1A2, 2B1, 2E1, and 2C11 and induction effects on CYP2C19 and 2D4. NS exhibited induction effects on CYP1A2, 2B1, 2E1, 2C11, 2C19, and 2D4. CNS exhibited induction effects on CYP1A2, 2B1, 2E1, 2C19, and 2D4 and inhibitory effects on CYP3A1 in vivo. Moreover, mRNA expression results were consistent with pharmacokinetic results. Potential herb-drug interactions should be studied closely when SF, NS, or CNS with clinical drugs are metabolized by CYP1A2, 2B1, 2E1, 2C11, 2C19, 2D4, and 3A1. CNS could change the inhibition or induction effects of CYP compared to the NS group, which might be one of the causes for the synergistic effects of the combination of NS and SF.

Pharmacokinetics of isocorynoxeine in rat plasma after intraperitoneal administration by UPLC–MS/MS

Isocorynoxeine is one of the main alkaloids in Chinese medicinal herbs, and has pharmacological activities such as antihypertensive, sedative, anticonvulsant, and neuronal protection. It is an effective component of Uncaria for the treatment of hypertension. In this study, we used a fast and sensitive ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) to detect isocorynoxeine in rat plasma and investigated its pharmacokinetics in rats. Six rats were given isocorynoxeine (15 mg/kg) by intraperitoneal (i.p.) administration. Blood (100 μL) was withdrawn from the caudal vein at 5 and 30 min and 1, 2, 4, 6, 8, 12, and 24 h after administration. Chromatographic separation was achieved using a UPLC BEH C18 column using a mobile phase of acetonitrile–0.1% formic acid with gradient elution. Electrospray ionization (ESI) tandem mass spectrometry in the multiple reaction monitoring (MRM) mode with positive ionization was applied. Intra-day and inter-day precisions (relative standard deviation, %RSD) of isocorynoxeine in rat plasma were lower than 12%. The method was successfully applied in the pharmacokinetics of isocorynoxeine in rats after intraperitoneal administration. The t1/2 of isocorynoxeine is 4.9 ± 2.1 h, which indicates quick elimination.

Simultaneous determination of eight bioactive compounds by LC-MS/MS and its application to the pharmacokinetics, liver first-pass effect, liver and brain distribution of orally administrated Gouteng-Baitouweng (GB) in rats

Only focusing on the circulating levels is insufficient for the comprehensive understanding of the physiological disposition of herbal medicine in vivo. Therefore, we conducted the comprehensive investigation on the in vivo dynamic process of orally administrated Gouteng-Baitouweng (GB), a classical herb pair with anti-Parkinson potentials. Serving as the technical base, a sensitive and selective liquid chromatography-tandem mass spectrometry method was established and validated in the plasma, liver and brain, for simultaneous determination of five alkaloids (rhynchophylline, isorhynchophylline, corynoxeine, isocorynoxeine and geissoschizine methyl ether) and three saponins (anemoside B4, anemoside A3 and 23-hydroxybetulinic acid). Following liquid-liquid extraction, favorable chromatographic behaviors of eight analytes were obtained on Waters Xbrigde C18 column within 13 min. This method elicited good linearity for the analytes at the concentration range of 0.3-1000 or 1.8-6000 ng/mL with favorable precision, accuracy and stability. Following oral administration of GB (25 g/kg) in rats, this method was applied to the quantitative analysis in the portal vein plasma, liver, systemic plasma, and brain. Consequently, anemoside B4 was of the highest exposure, followed by 23-hydroxybetulinic acid, anemoside A3, rhynchophylline and isocorynoxeine in vivo. Notably, three saponins were all observed with certain exposure in the brain, along with rhynchophylline at low levels. Besides, five alkaloids and 23-hydroxybetulinic acid underwent serious liver first-pass effect. Hence, the pharmacokinetics, liver first-pass effect, liver and brain distribution of ingredients in GB were clarified, which laid a solid foundation for interpreting its efficacy and safety.