Exploring allocryptopine as a neuroprotective agent against oxidative stress-induced neural apoptosis via Akt/GSK-3β/tau pathway modulation

Alzheimer's disease (AD) is characterized by neuronal loss due to hyperphosphorylated proteins induced by oxidative stress. AD remains a formidable challenge in the medical field, as current treatments focusing on single biomarkers have yielded limited success. Hence, there's a burgeoning interest in investigating novel compounds that can target mechanisms, offering alternative therapeutic approaches. The aim of this study is to investigate the effects of allocryptopine, an isoquinoline alkaloid, on mechanisms related to AD in order to develop alternative treatment strategies. In this study, the in vitro AD cell model was obtained by inducing nerve growth factor (NGF)-differentiated PC12 (dPC12) cells to oxidative stress with H2O2, and also the effect mechanism of different allocryptopine concentrations on the in vitro AD cell model was studied. The treatments' antioxidative effects at the ROS level and their regulation of the cell cycle were assessed through flow cytometry, while their anti-apoptotic effects were evaluated using both flow cytometry and qRT-PCR. Additionally, the phosphorylation levels of Akt, GSK-3β, and tau proteins were analyzed via western blot, and the interactions between Akt, GSK-3β, CDK5 proteins, and allocryptopine were demonstrated through molecular docking. Our study's conclusive results revealed that allocryptopine effectively suppressed intracellular ROS levels, while simultaneously enhancing the Akt/GSK-3β signaling pathway by increasing p-Akt and p-GSK-3β proteins. This mechanism played a critical role in inhibiting neural cell apoptosis and preventing tau hyperphosphorylation. Moreover, allocryptopine demonstrated its ability to regulate the G1/S cell cycle progression, leading to cell cycle arrest in the G1 phase, and facilitating cellular repair mechanisms, potentially contributing to the suppression of neural apoptosis. The in silico results of allocryptopine were shown to docking with the cyclin-dependent kinase 5 (CDK 5) playing a role in tau phosphorylation Akt and GSK-3β from target proteins. Therefore, the in silico study results supported the in vitro results. The results showed that allocryptopine can protect dPC12 cells from oxidative stress-induced apoptosis and hyperphosphorylation of the tau protein by regulating the Akt/GSK-3β signaling pathway. Based on these findings, it can be suggested that allocryptopine, with its ability to target biomarkers and its significant effects on AD-associated mechanisms, holds promise as a potential candidate for drug development in the treatment of AD. Further research and clinical trials are recommended in the future.

Genus Berberis: A Comprehensive and Updated Review on Ethnobotanical Uses, Phytochemistry and Pharmacological Activities

Genus Berberis is an excellent choice for research due to its history in traditional medicine, diverse pharmacological properties, and it has potential for drug discovery. This review presents information on the ethnobotany, pharmacological activities, and many phytochemicals identified from Berberis species. It examines the existing literature on the genus Berberis, drawn from online databases, including PubMed, Web of Science, Science Direct, Elsevier, and Google Scholar, etc encompassing the data from 1960 to 2023. This review focuses on the structural details of reported phytochemicals of Berberis species and pharmacological actions. Different extraction techniques were evaluated for extracts preparation. According to literature review, phytochemical analysis exhibited the presence of alkaloids, flavonoids, and phenolic compounds. A major bioactive alkaloid, berberine exhibits its main role in treatment of many gastric, infectious, and chronic disorders. This literature indicates that Berberis genus exhibits a variety of biological activities, i.e anti-inflammatory, cytotoxic, hepatoprotective, antimicrobial, antidiabetic and antioxidant activities and utilization of these effects in the treatment and management of various diseases, like diabetes, microbial infections, inflammation, liver disorders, and cancer. However, conventional medicines, validation of traditional uses, and in-depth phytochemical analysis are areas of research in genus Berberis.

Allocryptopine Attenuates Inflammatory Responses in Microglial Cells Via TLR4-Dependent NF-κB and p38 MAPK Pathways

Studies in the existing literature propose that allocryptopine possesses both antioxidant and anti-inflammatory properties, showcasing its neuroprotective effects by potentially mitigating oxidative stress and inflammation. This study aims to investigate the antioxidant and anti-inflammatory effects of allocryptopine on various targets and potential mechanisms that have not been previously explored in the literature. Initially, we used MTT and LDH methods to evaluate the effects of allocryptopine on cell viability in BV-2 cells exposed to LPS-induced damage. Subsequently, we evaluated the impact of allocryptopine on pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), other inflammatory mediators (Cox-2 and iNOS), and p38 MAPK genes and proteins through qRT-PCR and Western blot analyses. Also, we evaluated the impact of allocryptopine on NF-κB proteins (TLR4, MyD88, IκBα, p-p50, and p-p65) through ELISA assay. Molecular docking analyses were performed to investigate the potential binding of allocryptopine to target proteins (TLR4, MyD88, IκBα, p50, p65, MKK3, MKK4, MKK6, p38, AP-1 (c-Jun and ATF2), IL-1β, IL-6, TNF-α, Cox-2, and iNOS) associated with the TLR4, NF-κB, and p38 MAPK pathways. Our results indicate that allocryptopine exerts a comprehensive influence on pro-inflammatory cytokines and other inflammatory mediators by inhibiting TLR4 signaling and modulating the NF-κB and p38 MAPK pathways. The outcomes of our study suggest that the antioxidant and anti-inflammatory efficacy of allocryptopine is intricately linked to the modulation of key molecular pathways associated with oxidative stress and inflammation. These findings highlight the potential of allocryptopine as a therapeutic agent for addressing neurodegenerative diseases by safeguarding neuronal health.

Protopine-Type Alkaloids Alleviate Lipopolysaccharide-Induced Intestinal Inflammation and Modulate the Gut Microbiota in Mice

In this study, we assessed the therapeutic effects of Macleaya cordata (Willd). R. Br.-derived protopine-type alkaloids (MPTAs) in a mouse model of lipopolysaccharide (LPS)-induced intestinal inflammation. The experimental design involved the allocation of mice into distinct groups, including a control group, a model group treated with 6 mg/kg LPS, a berberine group treated with 50 mg/kg berberine hydrochloride and low-, medium- and high-dose MPTA groups treated with 6, 12 and 24 mg/kg MPTAs, respectively. Histological analysis of the ileum, jejunum and duodenum was performed using Hematoxylin and Eosin (H&E) staining. Moreover, the quantification of intestinal goblet cells (GCs) was performed based on PAS staining. The serum levels of IL-1β, IL-6, IL-8 and TNF-α were quantified using an enzyme-linked immunosorbent assay (ELISA), while the mRNA levels of TLR4, NF-κB p65, NLRP3, IL-6 and IL-1β were assessed using quantitative PCR (qPCR). The protein levels of TLR4, Md-2, MyD88, NF-κB p65 and NLRP3 were determined using Western blotting. Furthermore, the 16S rDNA sequences of bacterial taxa were amplified and analysed to determine alterations in the gut microbiota of the mice following MPTA treatment. Different doses of MPTAs were found to elicit distinct therapeutic effects, leading to enhanced intestinal morphology and an increased abundance of intestinal GCs. A significant decrease was noted in the levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-8 and TNF-α). Additionally, the protein levels of TLR4, MyD88, NLRP3 and p-p65/p65 were markedly reduced by MPTA treatment. Furthermore, 16S rDNA sequencing analysis revealed that the administration of 24 mg/kg MPTAs facilitated the restoration of microbial composition.

Effects of Dietary Macleaya cordata Extract Containing Isoquinoline Alkaloids Supplementation as an Alternative to Antibiotics in the Diets on Growth Performance and Liver Health of Broiler Chickens

This study aimed to investigate the effects of dietary supplementation with Macleaya cordata extract (MCE) containing protopine and allotypotopine on the growth performance and liver health in broiler chickens. A total of 486 1-day-old male AA broiler chickens were randomly assigned to the following three groups: (1) control (CON) group, broiler chickens fed a basal diet; (2) AGP group (positive control), broiler chickens fed a basal diet supplemented with 50 mg/kg aureomycin; (3) MCE group, broiler chickens fed a basal diet supplemented with 0.6 mg/kg MCE including 0.4 mg/kg protopine and 0.2 mg/kg allotypotopine. The results showed that the MCE group had significantly higher final body weight and average daily gain from d 0 to 42 than the other groups (p < 0.05), and groups MCE and AGP both had significantly lower feed-to-gain ratio from d 0 to 42 than the CON group (p < 0.05). Serum total protein, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, glucose, immunoglobulin A, immunoglobulin M, and complements (C3, C4) concentrations in the MCE group were significantly higher than in the CON group (p < 0.05). Dietary MCE or aureomycin supplementation significantly reduced the hepatic contents of 8-hydroxy-2'-deoxyguanosine, malondialdehyde, interleukin (IL)-1β, IL-6, NLRs family pyrin domain containing 3 (NLRP3), and caspase-1 in the liver (p < 0.05). Moreover, MCE or aureomycin supplementation significantly inhibited mRNA expressions of Toll-like receptor 4, myeloid differentiation factor 88, nuclear factor-κB, and NLRP3, as well as the expression ratio of Bax to Bcl-2 mRNA (p < 0.05). Therefore, our study suggested that dietary supplementation with 0.6 mg/kg MCE containing protopine and allocryptopine improved growth performance and benefited liver health in broiler chickens possibly through inhibiting caspase-1-induced pyroptosis by inactivating TLR4/MyD88/NF-κB/NLRP3 signaling pathway, and provided support for the application of MCE containing protopine and allocryptopine as an alternative to antibiotics in the feed industry.

Effects of Dietary Bopu Powder Supplementation on Serum Antioxidant Capacity, Egg Quality, and Intestinal Microbiota of Laying Hens

The purpose of this study was to investigate the effects of dietary Bopu powder supplementation on the serum antioxidant capacity, serum biochemical indices, egg quality, and intestinal microbiota. Six hundred and forty-eight 33-week-old Lohmann Brown commercial laying hens were randomly allocated into six groups and fed a basal diet supplemented with 0, 25, 50, 100, 200, and 400 mg/kg Bopu powder for 8 weeks, denoted BP0, BP25, BP50, BP100, BP200, and BP400, respectively. The results showed that dietary Bopu powder supplementation reduced serum cholesterol concentrations (linear, p < 0.01) while increasing serum globulin and albumin concentrations (linear, p < 0.05). Furthermore, the BP50 and BP100 groups had greater serum catalase and glutathione peroxidase activity (p < 0.05). The egg Haugh Units were considerably higher in BP25 and BP50 (p < 0.05), and eggshell thickness was higher in BP25, BP200, and BP400 (p < 0.05) when compared to BP0. Dietary treatment with Bopu powder at doses ranging from 25–100 mg/kg improved glutathione peroxidase and catalase activities while decreasing malondialdehyde concentrations in the yolk (p < 0.05). The addition of Bopu powder increased the diversity of microbiota and the relative abundance of Bacteroidota in the gut. For instance, dietary Bopu powder supplementation of 25–50 mg/kg significantly raised the relative abundance of Enterococcus, Bacteroides, and Fusobacterium in the foregut. Supplementing the diet with 50–100 mg/kg of Bopu powder improved the relative abundance of Lactobacillus in the hindgut. In conclusion, dietary Bopu powder supplementation enhanced the abundance of beneficial bacteria in the foregut of laying hens and improved egg quality and antioxidant capacity. Furthermore, in the laying hen diet, the optimal dosage of Bopu powder additive was 25–50 mg/kg.

Phytochemistry and pharmacology of alkaloids from Glaucium spp

Glaucium Mill. comprising 28 species with 78 synonyms, 3 subspecies, and 3 varieties worldwide belongs to the Papaveraceae family. The plants are well known for their different types of alkaloids. In the present study, we attempted to review the chemistry and pharmacology of the alkaloids from the genus Glaucium. For this purpose, the relevant data were collected from different scientific databases including, "Google Scholar", "ISI Web of Knowledge", "PubMed", "Scopus", and available books and e-books. Our results showed that aporphine alkaloids are dominated in the species; however, other types of alkaloids including protopines, benzophenanthridines, benzylisoquinolines, protoberberines, and morphinanes have also been reported from the genus. The pharmacological studies have shown that the alkaloids from Glaucium species have several biological activities of which anti-cancer and anti-cholinesterase effects have been highly reported. Besides, the data indicated that most of the species have been investigated neither phytochemically nor pharmacologically. Glaucium flavum, known as yellow horn poppy, is the most studied species. According to the reports, the plants from this genus have anti-cancer and anti-cholinesterase potentials and can be used as a source for aporphine alkaloids.

Neuroprotective effects of allocryptopine-rich alkaloid extracts against oxidative stress-induced neuronal damage

BACKGROUND

Oxidative stress is a significant feature in the pathomechanism of neurodegenerative diseases. Thus, the search for an effective and safe novel antioxidant agent with neuroprotective properties has increased the interest in medicinal plant products as a bioactive phytochemical source. However, little is known about the potential effects of the medically important Glaucium corniculatum as a natural antioxidant.

OBJECTIVE

In the present study, it was aimed to investigate the anti-oxidative, anti-apoptotic, and cell cycle regulatory mechanisms underlying the neuroprotective effects of alkaloid extracts (chloroform, methanol, and water) from G. corniculatum, which was profiled for major alkaloid/alkaloids, against H₂O₂-induced neuronal damage in differentiated PC12 cells.

MATERIALS AND METHODS

The profiles of the alkaloid extracts were analyzed by GC-MS. The effects of the alkaloid extracts on intracellular ROS production, level of apoptotic cells, and cell cycle dysregulation were analyzed by flow cytometry; the effects on mRNA expression of apoptosis-related genes were also analyzed by qRT-PCR.

RESULTS

The same alkaloid components, allocryptopine, tetrahydropalmatine, and tetrahydroberberine N-oxide were obtained in all three solvents, but the ratios of the components differed according to the solvents. Allocryptopine was determined to be the major alkaloid ingredient in the alkaloid extracts, with the highest amount of allocryptopine (497 μg/mg) being found in the chloroform alkaloid extract (CAE) (*p < 0.05). The best results were obtained from CAE, which has the highest amount of allocryptopine among alkaloid extracts in all studies. CAE suppressed intracellular ROS production (5.7-fold), percentage of apoptotic cells (3.0-fold), and cells in the sub G1 phase (6.8-fold); additionally, it increased cells in the G1 phase (1.5-fold) (**p < 0.01). CAE remarkably reduced the expressions of Bax, Caspase-9/-3 mRNA (2.4-3.5-fold) while increasing the expression of Bcl-2 mRNA (3.0-fold) (*p < 0.05).

CONCLUSIONS

Our results demonstrated that alkaloid extracts from G. corniculatum, which contain allocryptopine, tetrahydropalmatine, and tetrahydroberberine N-oxide suppressed oxidative stress-induced neuronal apoptosis, possibly by suppressing the mitochondrial apoptotic pathway and regulating the cell cycle. These results are the first report that related alkaloids have played a neuroprotective role by regulating multiple mechanisms. Thus, our study indicated that these alkaloids especially allocryptopine could offer an efficient and novel strategy to explore novel drugs for neuroprotection and cognitive improvement.

Biotransformation and tissue distribution of protopine and allocryptopine and effects of Plume Poppy Total Alkaloid on liver drug-metabolizing enzymes

In this study, the biotransformation in the plasma, urine and feces of rats following oral administration of protopine (PRO) and allocryptopine (ALL)were explored using HPLC-QqTOF MS. An HPLC-MS/MS method for the determination of tissues was developed and applied to the tissue distribution study in rats following intragastric administration of Plume Poppy Total Alkaloid for 3 weeks. A total of ten PRO metabolites and ten ALL metabolites were characterized in rats in vivo. Among these metabolites, six PRO metabolites and five ALL metabolites were reported for the first time. The predicated metabolic pathways including ring cleavage, demethylation following ring cleavage, and glucuronidation were proposed. The low-concentration residue of PRO and ALL in various tissues was detected at 24 h and 48 h after dosing, which indicated that both compounds could be widely distributed in tissues and exist as low levels of residue. The activities of erythromycin N-demethylase, aminopyrine N-demethylase and NAD (P)H quinone oxidoreductase in female rats can be induced post-dose, but these activities were inhibited in male rats. The proposed biotransformation and residues of PRO and ALL and their effects on enzymes may provide a basis for clarifying the metabolism and interpreting pharmacokinetics.

Cholinesterase and Prolyl Oligopeptidase Inhibitory Activities of Alkaloids from Argemone platyceras (Papaveraceae)

Alzheimer's disease is an age-related, neurodegenerative disorder, characterized by cognitive impairment and restrictions in activities of daily living. This disease is the most common form of dementia with complex multifactorial pathological mechanisms. Many therapeutic approaches have been proposed. Among them, inhibition of acetylcholinesterase, butyrylcholinesterase, and prolyl oligopeptidase can be beneficial targets in the treatment of Alzheimer's disease. Roots, along with aerial parts of Argemone platyceras, were extracted with ethanol and fractionated on an alumina column using light petrol, chloroform and ethanol. Subsequently, repeated preparative thin-layer chromatography led to the isolation of (+)-laudanosine, protopine, (-)-argemonine, allocryptopine, (-)-platycerine, (-)-munitagine, and (-)-norargemonine belonging to pavine, protopine and benzyltetrahydroisoquinoline structural types. Chemical structures of the isolated alkaloids were elucidated by optical rotation, spectroscopic and spectrometric analysis (NMR, MS), and comparison with literature data. (+)-Laudanosine was isolated from A. platyceras for the first time. Isolated compounds were tested for human blood acetylcholinesterase, human plasma butyrylcholinesterase and recombinant prolyl oligopeptidase inhibitory activity. The alkaloids inhibited the enzymes in a dose-dependent manner. The most active compound (-)-munitagine, a pavine alkaloid, inhibited both acetylcholinesterase and prolyl oligopeptidase with IC50 values of 62.3 ± 5.8 µM and 277.0 ± 31.3 µM, respectively.

Anti-inflammatory, Anti-bacterial and Anti-acetylcholinesterase Activities of two Isoquinoline Alkaloids–Scoulerine and Cheilanthifoline

Corydalis plants containing isoquinoline alkaloids are reported to possess promising pharmacological properties for the treatment of important diseases including cancer, inflammation, Alzheimer's disease and microbial infections. As part of a wider program investigating Bhutanese medicinal plants, we have previously identified eight isoquinoline alkaloids from C. dubia. Out of these, we report here on two of the major alkaloids, scoulerine (1) and cheilanthifoline (2) and their inhibitory activities against acetylcholinesterase (anti-AChE), tumor necrosis factor alpha (anti TNF-α) and a bacterial strain, Helicobacter pylori. Both alkaloids showed weak anti TNF-α and antibacterial activities. However, the anti-AChE activity of scoulerine (1) was promising as it significantly inhibited AChE with a minimum inhibitory requirement (MIR) value of 0.0015 nmol, which was two-fold better than the reference drug, galanthamine (MIR value of 0.003 nmol). As there are limited anti-Alzheimer's chemotherapeutics, scoulerine (1) is worthy of further exploration, including lead optimization, structure-activity-relationship studies, analog development, pharmacodynamics and in vivo animal studies

Identification of allocryptopine and protopine metabolites in rat liver S9 by high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry

RATIONALE

Allocryptopine (AL) and protopine (PR) have been extensively studied because of their anti-parasitic, anti-arrhythmic, anti-thrombotic, anti-inflammatory and anti-bacterial activity. However, limited information on the pharmacokinetics and metabolism of AL and PR has been reported. Therefore, the purpose of the present study was to investigate the in vitro metabolism of AL and PR in rat liver S9 using a rapid and accurate high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (HPLC/QqTOFMS) method.

METHODS

The incubation mixture was processed with 15% trichloroacetic acid (TCA). Multiple scans of AL and PR metabolites and accurate mass measurements were automatically performed simultaneously through data-dependent acquisition in only a 30-min analysis. The structural elucidations of these metabolites were performed by comparing their changes in accurate molecular masses and product ions with those of the precursor ion or metabolite.

RESULTS

Eight and five metabolites of AL and PR were identified in rat liver S9, respectively. Among these metabolites, seven and two metabolites of AL and PR were identified in the first time, respectively. The demethylenation of the 2,3-methylenedioxy, the demethylation of the 9,10-vicinal methoxyl group and the 2,3-methylenedioxy group were the main metabolic pathways of AL and PR in liver S9, respectively. In addition, the cleavage of the methylenedioxy group of the drugs and subsequent methylation or O-demethylation were also the common metabolic pathways of drugs in liver S9. In addition, the hydroxylation reaction was also the metabolic pathway of AL.

CONCLUSIONS

This was the first investigation of in vitro metabolism of AL and PR in rat liver S9. The detailed structural elucidations of AL and PR metabolites were performed using a rapid and accurate HPLC/QqTOFMS method. The metabolic pathways of AL and PR in rat were tentatively proposed based on these characterized metabolites and early reports. Copyright © 2016 John Wiley & Sons, Ltd.

Modulatory Effects of Eschscholzia californica Alkaloids on Recombinant GABAA Receptors

The California poppy (Eschscholzia californica Cham.) contains a variety of natural compounds including several alkaloids found exclusively in this plant. Because of the sedative, anxiolytic, and analgesic effects, this herb is currently sold in pharmacies in many countries. However, our understanding of these biological effects at the molecular level is still lacking. Alkaloids detected in E. californica could be hypothesized to act at GABAA receptors, which are widely expressed in the brain mainly at the inhibitory interneurons. Electrophysiological studies on a recombinant α 1 β 2 γ 2 GABAA receptor showed no effect of N-methyllaurotetanine at concentrations lower than 30 μM. However, (S)-reticuline behaved as positive allosteric modulator at the α 3, α 5, and α 6 isoforms of GABAA receptors. The depressant properties of aerial parts of E. californica are assigned to chloride-current modulation by (S)-reticuline at the α 3 β 2 γ 2 and α 5 β 2 γ 2 GABAA receptors. Interestingly, α 1, α 3, and α 5 were not significantly affected by (R)-reticuline, 1,2-tetrahydroreticuline, codeine, and morphine-suspected (S)-reticuline metabolites in the rodent brain.

Nitrogen-Containing Constituents of Black Cohosh: Chemistry, Structure Elucidation, and Biological Activities

The roots/rhizomes of black cohosh (Actaea racemosa L. syn. Cimicifuga racemosa [L]. Nutt., Ranunculaceae) have been used traditionally by Native Americans to treat colds, rheumatism, and a variety of conditions related to women's health. In recent years black cohosh preparations have become popular dietary supplements among women seeking alternative treatments for menopausal complaints. The popularity of the plant has led to extensive phytochemical and biological investigations, including several clinical trials. Most of the phytochemical and biological research has focused on two abundant classes of compounds: the triterpene glycosides and phenolic acids. A third group of phytoconstituents that has received far less attention consists of the alkaloids and related compounds that contain nitrogen. This chapter summarizes the current state of knowledge of the chemistry and biological activities associated with this group of constituents and provides some perspective on their significance for future research on this interesting plant.

Facile synthesis of tetrahydroprotoberberine and protoberberine alkaloids from protopines and study on their antibacterial activities

A series of isoquinoline alkaloids including tetrahydroprotoberberines, N-methyl tetrahydroprotoberberines and protoberberines were facile synthesised with protopines as the starting material. All compounds were evaluated for their antibacterial activities against four pathogenic bacteria Escherichia coli, Staphyloccocus aureus, Staphylococcus gallinarum and Salmonella choleraesuis. Experimental results indicated that protoberberines were the most active compounds to the target bacteria among the tested alkaloids. It was suggested that planar molecule with high aromatisation level (e.g. coptisine 5 and berberine 6) or a positive charge of the molecules (e.g. N-methyl tetrahydroprotoberberines 11 and 12) had a positive influence on the antibacterial effects.

A new protoberberine alkaloid from Meconopsis simplicifolia (D. Don) Walpers with potent antimalarial activity against a multidrug resistant Plasmodium falciparum strain

ETHNOPHARMACOLOGICAL RELEVANCE

The aerial components of Meconopsis simplicifolia (D. Don) Walpers are indicated in Bhutanese traditional medicine for treating malaria, coughs and colds, and the infections of the liver, lung and blood. This study is to validate the ethnopharmacological uses of this plant and also identify potent antimalarial drug leads through bioassays of its crude extracts and phytochemical constituents.

MATERIALS AND METHODS

Meconopsis simplicifolia (D. Don) Walpers was collected from Bhutan and its crude MeOH extract was subjected to acid-base fractionation. Through repeated extractions, separations and spectroscopic analysis, the alkaloids obtained were identified and tested for their antimalarial and cytotoxicity activities.

RESULTS

Phytochemical studies resulted in the isolation of one new protoberberine type alkaloid which we named as simplicifolianine and five known alkaloids: protopine, norsanguinarine, dihydrosanguinarine, 6-methoxydihydrosanguinarine and oxysanguinarine. Among the five of the alkaloids tested, simplicifolianine showed the most potent antiplasmodial activities against the Plasmodium falciparum strains, TM4/8.2 (chloroquine-antifolate sensitive strain) and K1CB1 (multidrug resistant strain) with IC50 values of 0.78 μg/mL and 1.29 μg/mL, respectively. The compounds tested did not show any significant cytotoxicity activities against human oral carcinoma KB cells and normal Vero cells of African kidney epithelial cells.

CONCLUSIONS

This study validated the traditional uses of the plant for the treatment of malaria and identified a new alkaloid, simplicifolianine as a potential antimalarial drug lead.

Phytochemical and Biological Activity Studies of the Bhutanese Medicinal Plant Corydalis crispa

The chemical constituents and biological activities of Corydalis crispa (Fumariaceae) were investigated for the first time. The phytochemical study resulted in the isolation of nine known isoquinoline alkaloids: protopine (1), 13-oxoprotopine (2), 13-oxocryptopine (3), stylopine (4), coreximine (5), rheagenine (6), ochrobirine (7), sibiricine (8) and bicuculline (9), with complete NMR data for 2 and 3 provided here for the first time. Crude extracts exhibited significant anti-inflammatory (p<0.01) activity against TNF- α production in LPS activated THP-1 cells. The acetylcholinesterase inhibitory activity of compounds 2, 4 and 7 and the antiplasmodial activity of compound 5 against P. falciparum strains TM4/8.2 and K1CB1 (multidrug resistant strain) are reported here for the first time. Stylopine (4) did not show antimalarial activity against the K1CB1 strain in contrast to a previous report. This study generated a scientific basis for the use of this plant in Bhutanese traditional medicine, either individually or in combination with other medicinal ingredients to treat a broad range of disorders. This study also identified compound 5 as potential new antimalarial lead compound.