Analysis of dihydroindole-type alkaloids in Strychnos nux-vomica unprocessed and processed seeds by high-performance liquid chromatography coupled with diode array detection and mass spectrometry

Semen Strychni Pulveratum and vomicine alleviate neuroinflammation in amyotrophic lateral sclerosis through cGAS-STING-TBK1 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Amyotrophic lateral sclerosis (ALS) is a fetal neuromuscular disorder characterized by the gradual deterioration of motor neurons. Semen Strychni pulveratum (SSP), a processed version of Semen Strychni (SS) powder, is widely used to treat ALS in China. Vomicine is one of the most primary components of SS. However, their pharmacological effects and mechanisms for ALS remain elusive.

AIM OF THE STUDY

This study aimed to evaluate the neuroprotective and anti-neuroinflammatory effects of SSP and vomicine, as well as to explore their protective roles in ALS and the underlying mechanisms.

MATERIALS AND METHODS

In vivo, 8-week-old hSOD1-WT mice and hSOD1-G93A mice were orally administered different concentrations of SSP (SSP-L = 5.46 mg/ml, SSP-M = 10.92 mg/ml or SSP-H = 16.38 mg/ml) once every other day for 8 weeks. A series of experiments, including body weight measurement, footprint tests, Hematoxylin & Eosin staining, and Nissl staining, were performed to evaluate the preventive effect of SSP. Immunofluorescence staining, western blotting, and RT-qPCR were subsequently performed to evaluate activation of the cGAS-STING-TBK1 pathway in the spinal cord. In vitro, hSOD1G93A NSC-34 cells were treated with vomicine to further explore the pharmacological mechanism of vomicine in the treatment of ALS via the cGAS-STING-TBK1 pathway.

RESULTS

SSP improved motor function, body weight loss, gastrocnemius muscle atrophy, and motor neuron loss in the spine and cortex of hSOD1-G93A mice. Furthermore, the cGAS-STING-TBK1 pathway was activated in the spinal cord of hSOD1-G93A mice, with activation predominantly observed in neurons and microglia. However, the levels of cGAS, STING, and pTBK1 proteins and cGAS, IRF3, IL-6, and IL-1β mRNA were reversed following intervention with SSP. Vomicine not only downregulated the levels of cGAS, TBK1, IL-6 and IFN-β mRNA, but also the levels of cGAS and STING protein in hSOD1G93A NSC-34 cells.

CONCLUSION

This study demonstrated that SSP and vomicine exert neuroprotective and anti-neuroinflammatory effects in the treatment of ALS. SSP and vomicine may reduce neuroinflammation by regulating the cGAS-STING-TBK1 pathway, and could thereby play a role in ALS treatment.

Detoxification and underlying mechanisms towards toxic alkaloids by Traditional Chinese Medicine processing: A comprehensive review

BACKGROUND

Alkaloids have attracted enduring interest worldwide due to their remarkable therapeutic effects, including analgesic, anti-inflammatory, and anti-tumor properties, thus offering a rich source for lead compound design and new drug discovery. However, some of these alkaloids possess intrinsic toxicity. Processing (Paozhi) is a pre-treatment step before the application of herbal medicines in traditional Chinese medicine (TCM) clinics, which has been employed for centuries to mitigate the toxicity of alkaloid-rich TCMs.

PURPOSE

To explore the toxicity phenotypes, chemical basis, mode of action, detoxification processing methods, and underlying mechanisms, we can gain crucial insights into the safe and rational use of these toxic alkaloid-rich herbs. Such insights have the great potential to offer new strategies for drug discovery and development, ultimately improving the quality of life for millions of people.

METHODS

Literatures published or early accessed until December 31, 2023, were retrieved from databases including PubMed, Web of Science, and CNKI. The following keywords, such as "toxicity", "alkaloid", "detoxification", "processing", "traditional Chinese medicine", "medicinal plant", and "plant", were used in combination or separately for screening.

RESULTS

Toxicity of alkaloids in TCM includes hepatotoxicity, nephrotoxicity, neurotoxicity, cardiotoxicity, and other forms of toxicity, primarily induced by pyrrolizidines, quinolizidines, isoquinolines, indoles, pyridines, terpenoids, and amines. Factors such as whether the toxic-alkaloid enriched part is limited or heat-sensitive, and whether toxic alkaloids are also therapeutic components, are critical for choosing appropriate detoxification processing methods. Mechanisms of alkaloid detoxification includes physical removal, chemical decomposition or transformation, as well as biological modifications.

CONCLUSION

Through this exploration, we review toxic alkaloids and the mechanisms underlying their toxicity, discuss methods to reduce toxicity, and unravel the intricate mechanisms behind detoxification. These offers insights into the quality control of herbs containing toxic alkaloids, safe and rational use of alkaloid-rich TCMs in clinics, new strategies for drug discovery and development, and ultimately helping improve the quality of life for millions of people.

A nitrogenous heterocyclic ring-bonded stationary phase for separating alkaloids in supercritical fluid chromatography

A novel silica stationary phase was designed and prepared through thiol-epoxy click chemistry for supercritical fluid chromatography (SFC). The developed stationary phase was characterized by elemental analysis, Fourier transform infrared spectrometry and solid-state 13C/CP MAS NMR spectroscopy. In order to evaluate the chromatographic performance and retention mechanisms of the prepared column, a variety of alkaloids were used, including indoles, isoquinolines, pyrrolidines, piperidines, quinolizidines and organic amines. The stationary phase showed more symmetrical peak shapes and better performance for these compounds compared to the conventional SFC stationary phases. The investigations on the effects of pressure and temperature on retention provided information that the selectivity of the compounds can be improved by changing the density of the supercritical fluids. Moreover, it shows improved separation efficiency of three natural products with alkaloids as the main components at high sample loading. In conclusion, the developed stationary phase could offer flexible selectivity toward alkaloids and complex samples.

Systematic pharmacology-based strategy to explore the mechanism of Semen Strychni for treatment of papillary thyroid carcinoma

The aim of the study was to investigated the mechanism of Strychnos nux-vomica L. (Semen Strychni, SS) against papillary carcinoma thyroid (PTC) by combined of network pharmacology and experimental verification. By searching the TCMSP, SEA and SwissTarget Prediction database, the main active ingredients and related targets were obtained. Utilizing Venny 2.1.0 String database and Cytoscape 3.7.2 to screened the intersection target and constructed protein-protein interaction (PPI) network diagram. Using R 4.0.4 software carried out the enrichment analysis of GO and KEGG. HPLC was carried out using LC-20A modular HPLC system to identify the bioactive compound brucine present in SS. Molecular docking was performed using Discovery 2019 software. The inhibition rate was detected by CCK8 method. Western blot was used to detect the expression levels of brucine anti-PTC related pathway proteins. 14 active components were screened out, of which 4 main components showed tight relationship with PTC. SS may play the anti-PTC role by acting on two main pathways (TNF signaling pathway and MAPK signaling pathway) and mediating various biological functions. HPLC analysis revealed that brucine was a suitable marker for standardization of the SS. 4 active components exhibit strong binding energy with core protein. Brucine could significantly reduce the activity of BCPAP cells compared with isobrucine, stigmasterol, (+)-catechin. Brucine may reduce the protein expression levels of IL-6, VEGFA, JUN, TP53, 1L1B, PTGS2, BCL2, CASP3, CASP8, and CASP9 while increase the protein expression levels of BAD, cleaved-CASP3, cleaved-CASP8, and cleaved-CASP9 in BCPAP cells, respectively. The active components of SS against PTC mainly include isobrucine, stigmasterol, (+)-catechin, brucine. Among them, brucine exhibits the strongest anti-PTC activity in BCPAP cells, which may reduce the PTC-related protein expression levels. Therefore, SS may exhibits the anti-PTC activities through multiple targets and pathways.

Processing methods and the underlying detoxification mechanisms for toxic medicinal materials used by ethnic minorities in China: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Various toxic medicinal materials have been used by different ethnic minorities in China for thousands of years because of their extraordinary pharmacological activities. However, the improper use and complex toxicity-efficacy relationship could cause poisoning and even death. Therefore, the study of toxicity-attenuating methods and mechanisms is necessary.

AIM OF THE STUDY

This review aims to summarize commonly used toxic ethnomedicines and their processing methods as well as the underlying mechanisms to potentially reduce toxicity and even enhance or preserve efficacy. Prospective for possible future investigations is also discussed.

MATERIALS AND METHODS

Processing methods and mechanisms are investigated mainly through literature review.

RESULTS

Processing methods with heating (boiling, stir frying, and steaming, etc.) and without heating (soaking) are usually used by Chinese ethnic minorities to attenuate the toxicity of ethnomedicines. Wheat bran, vinegar, wine, and herbal decoction are commonly used processing excipients. The mechanisms of detoxification by processing can be briefly summarized into three major categories: (1) direct elimination of impurities or reduction of toxic constituents' contents of ethnomedicines by cutting, washing, soaking or frosting; (2) chemical structure transformation of toxic constituents, such as alkaloids, glycosides, toxic proteins, animal toxicants, and mineral components, during heating and/or soaking; and (3) biological synergism or antagonism effects between the chemical constituents of processing excipients and ethnomedicines in vivo, to reduce toxicity and protect target organs.

CONCLUSION

Toxic ethnomedicines have long been used in China, and detoxification by processing is the prerequisite for their safe clinical application. However, understanding on the special processing methods and detoxification mechanisms of ethnomedicines in China remains insufficient. Investigations on quality control of toxic ethnomedicines, as well as evaluation of processing methods and studies of the corresponding mechanisms should be further strengthened for safe and effective clinical application.

HPLC-MS/MS analysis of primary alkaloids in rat plasma after oral administration of "Nux vomica - Glycyrrhiza glabra decoction": A pharmacokinetic study

ETHNOPHARMACOLOGICAL RELEVANCE

Decoction is the most common form of administering traditional Chinese medicine (TCM). During the preparation of decoction, the high temperature and complex chemical environment result in the formation of complex and multiple phases. The differences in drug components in different phases induce gastrointestinal absorption and physiological response. Nux vomica (Strychnos nux-vomica L) is a typical toxic TCM used in China, with remarkable pharmacological activity. In order to reduce its toxicity, nux vomica (NV) is often decocted with Glycyrrhiza glabra (GG) in clinic, and the detoxification mechanism has always been the focus of research interest. Most studies investigated the compatibility of NV-GG, but the in vivo behavior of individual constituents based on phase state has yet to be elucidated.

AIM OF THE STUDY

To investigate the pharmacokinetic behavior of typical toxic components in different phase states of "NV-GG decoction" in rat plasma.

MATERIALS AND METHODS

The sediment, suspension, colloid and true solution of "NV-GG decoction" was obtained via physical methods. The main components in different phase states were analyzed via reliable UFLC-Q-TOF-MS high-resolution mass spectrometry. A rapid and accurate HPLC-qqq-MS/MS method was established and validated for accurate determination of brucine and strychnine levels in plasma, followed by pharmacokinetic evaluation of different phase states of "NV-GG decoction" in rats. Kinetex F5 100A (50 mm × 3.0 mm, 2.6 μm) column was used for chromatographic separation. Aqueous solution containing acetonitrile and 0.1% formic acid was used as the mobile phase, followed by gradient elution at 0.4 mL/min. Mass spectra were detected by electrospray ionization (ESI) multiple reaction monitoring (MRM) in positive ion mode.

RESULTS

Fifteen different alkaloids were detected in different phase states of "NV-GG decoction". Strychnine and brucine, which are toxic components with high content, were selected for quantitative analysis. The established UPLC-qqq-MS/MS method is accurate and reliable with a good linearity (R² > 0.99) in the respective concentration range, satisfying the quantitative requirements. The pharmacokinetic parameters of different phase states of rats differed significantly after gavage. The deposition phase was the most prominent. The index components showed higher C_max, AUC₀ and T_max, while the T_1/2, MRT, V/F and CL/F were the smallest, with a relatively slow plasma clearance rate in rats. The true solution group showed the lowest T_max and the fastest absorption.

CONCLUSION

This method has been successfully utilized to study the pharmacokinetics of different phase states of "NV-GG decoction". Among the four phases, the deposition phase contributed to a large proportion of the in vivo kinetic behavior similar to that of sustained-release preparations, with slow absorption of toxic components and prolonged peak time. The pharmacokinetic parameters and plasma concentration-time curves of each phase can be used to study toxicity reduction of NV-GG and increase its biocompatibility.

In silico screening of therapeutic potentials from Strychnos nux-vomica against the dimeric main protease (Mpro) structure of SARS-CoV-2

The novel coronavirus also referred to as SARS-CoV-2 causes COVID-19 and became global epidemic since its initial outbreak in Wuhan, China, in December 2019. Research efforts are still been endeavoured towards discovering/designing of potential drugs and vaccines against this virus. In the present studies, we have contributed to the development of a drug based on natural products to combat the newly emerged and life-threatening disease. The main protease (M^Pro) of SARS-CoV-2 is a homodimer and a key component involved in viral replication, and is considered as a prime target for anti-SARS-CoV-2 drug development. Literature survey revealed that the phytochemicals present in Strychnos nux-vomica possess several therapeutic activities. Initially, in the light of drug likeness laws, the ligand library of phytoconstituents was subjected to drug likeness analysis. The resulting compounds were taken to binding site-specific consensus-based molecular docking studies and the results were compared with the positive control drug, lopinavir, which is a main protease inhibitor. The top compounds were tested for ADME-Tox properties and antiviral activity. Further molecular dynamics simulations and MM-PBSA-based binding affinity estimation were carried out for top two lead compounds' complexes along with the apo form of main protease and positive control drug lopinavir complex, and the results were comparatively analysed. The results revealed that the two analogues of same scaffold, namely demethoxyguiaflavine and strychnoflavine, have potential against M^pro and can be validated through clinical studies.Communicated by Ramaswamy H. Sarma.

Processing methods and mechanisms for alkaloid-rich Chinese herbal medicines: A review

The processing of Chinese herbal medicine is a form of pharmaceutical technology developed over thousands of years, in order to increase efficiency and decrease toxicity of herbs in traditional Chinese medicine (TCM). Herbal processing is essential for safe and effective application of TCM in clinical practice, as it alters the active chemical components and therefore the functions of herbal medicines. Alkaloid-rich herbal medicines in TCM are commonly processed by cleansing, cutting, processing by dry stir-frying, stir-frying with liquid adjuvants, and processing by water decoction. In addition, commonly used adjuvants for processing alkaloid-rich herbal medicines are river sand, wine, vinegar, brine, honey and herbal juice. For alkaloid-rich herbal medicines, the main chemical reactions that occur during processing include hydrolysis, oxidation, replacement, decomposition and condensation. This paper aimed to summarize the processing methods and mechanisms for alkaloid-rich Chinese herbal medicines, and provide much-needed theoretical support and scientific evidence for understanding those mechanisms and effects. Information on processing methods for alkaloid-rich herbal medicines was collected from classic books of herbal medicine, PhD and MSc dissertations, online scientific databases including PubMed, SciFinder, Scopus, Web of Science, Baidu Scholar and Google Scholar. This paper should help to advance our knowledge of the processing mechanisms and aid in the development of processing methods for alkaloid-rich Chinese herbal medicines.