Synthesis and Characterization of Graphene Oxide/Polyethylene Glycol/Folic Acid/Brucine Nanocomposites and Their Anticancer Activity on HepG2 Cells

Background

Liver cancer is the sixth most prevalent form of cancer and the second major cause of cancer-associated mortalities worldwide. Cancer nanotechnology has the ability to fundamentally alter cancer treatment, diagnosis, and detection.

Objective

In this study, we explained the development of graphene oxide/polyethylene glycol/folic acid/brucine nanocomposites (GO/PEG/Bru-FA NCs) and evaluated their antimicrobial and anticancer effect on the liver cancer HepG2 cells.

Methodology

The GO/PEG/Bru-FA NCs were prepared using the co-precipitation technique and characterized using various techniques. The cytotoxicity of the GO/PEG/Bru-FA NCs was tested against both liver cancer HepG2 and non-malignant Vero cells using an MTT assay. The antimicrobial activity of the GO/PEG/Bru-FA NCs was tested against several pathogens using the well diffusion technique. The effects of GO/PEG/Bru-FA NCs on endogenous ROS accumulation, apoptosis, and MMP levels were examined using corresponding fluorescent staining assays, respectively. The apoptotic protein expressions, such as Bax, Bcl-2, and caspases, were studied using the corresponding kits.

Results

The findings of various characterization assays revealed the development of GO/PEG/Bru-FA NCs with face-centered spherical morphology and an agglomerated appearance with an average size of 197.40 nm. The GO/PEG/Bru-FA NCs treatment remarkably inhibited the growth of the tested pathogens. The findings of the MTT assay evidenced that the GO/PEG/Bru-FA NCs effectively reduced the HepG2 cell growth while not showing toxicity to the Vero cells. The findings of the fluorescent assay proved that the GO/PEG/Bru-FA NCs increased ROS generation, reduced MMP levels, and promoted apoptosis in the HepG2 cells. The levels of Bax, caspase-9, and -3 were increased, and Bcl-2 was reduced in the GO/PEG/Bru-FA NCs-treated HepG2 cells.

Conclusion

The results of this work demonstrate that GO/PEG/Bru-FA NCs suppress viability and induce apoptosis in HepG2 cells, indicating their potential as an anticancer candidate.

Brucine Inhibits Proliferation of Pancreatic Ductal Adenocarcinoma through PI3K/AKT Pathway-induced Mitochondrial Apoptosis

INTRODUCTION

The purpose of this research was to settle the role of brucine in pancreatic ductal adenocarcinoma (PDAC) and the mechanisms involved.

METHODS

The findings of this study suggest that brucine exerts inhibitory effects on cell growth, clonogenicity, and invasive potential of Panc02 and Mia Paca-2 cells. These effects may be linked to an increase in apoptotic-prone cell population.

RESULTS

Gene sequencing data suggests that these effects are mediated through the induction of apoptosis. Experimental evidence further supports the notion that brucine reduces mitochondrial membrane potential and upregulates Bax expression while downregulating Bcl-2 expression. These effects are believed to be a result of brucine-mediated suppression of PI3K/Akt activity, which serves as a regulatory factor of mTOR, Bax, and Bcl-2. Suppression of PI3K activity enhances the tumor-suppressing effects of brucine.

CONCLUSION

Overall, these findings suggest that brucine has therapeutic potential as a remedy option for PDAC.

Brucine suppresses proliferation and promotes apoptosis of human cholangiacarcinoma cells via the inhibition of COX2 expression

Aims The aim of this study was to investigate the anti-tumor efficacy of brucine on intrahepatic cholangiocarcinoma (ICC). Methods ICC QBC939 cells were treated with brucine, cell viability, cell cycle and apoptosis were analyzed using CCK-8 and flow cytometry. The expression of COX-2 and apoptosis related proteins Casp3, Bax and Bcl-2 were detected by Western blot analysis. QBC939 cells were subcutaneously transplanted into nude mice and the mice were injected with brucine intraperitoneally. The expression of Ki67, COX-2 and apoptosis related proteins were detected by immunohistochemical staining and Western blot analysis. Results Brucine significantly inhibited the proliferation and cell cycle progression while promoted the apoptosis of QBC939 cells. The expression of the apoptotic proteins Casp3 and Bax was upregulated, while the expression of Bcl-2 and COX-2 was downregulated in QBC939 cells with brucine treatment. Moreover, the overexpression of COX-2 could antagonize the effects of brucine on QBC939 cells. In vivo, brucine inhibited subcutaneous tumor formation in nude mice, and the expression of Ki67, COX-2 and Bcl-2 decreased while the expression of Casp3 and Bax increased in tumor tissues from nude mice with brucine treatment. Conclusions Brucine can significantly inhibit the progression of cholangiocarcinoma in vitro and in vivo, and the mechanism may be related to the inhibition of COX-2 expression.

A Combination of In Silico ADMET Prediction, In Vivo Toxicity Evaluation, and Potential Mechanism Exploration of Brucine and Brucine N-oxide-A Comparative Study

Brucine (BRU) and brucine N-oxide (BNO) are prominent, bioactive, and toxic alkaloids in crude and processed Semen Strychni. Studies have demonstrated that BRU and BNO possess comprehensive pharmacological activities, such as anti-inflammatory and analgesic. In this context, a comparative study of BRU and BNO was performed by combination analysis of in silico ADMET prediction, in vivo toxicity evaluation, and potential action mechanism exploration. ADMET prediction showed that BRU and BNO might induce liver injury, and BRU may have a stronger hepatoxic effect. The prediction was experimentally verified using the zebrafish model. The BRU-induced hepatotoxicity of zebrafish larvae had a dose-response relationship. The mechanism of BRU-induced hepatotoxicity might relate to phosphorylation, kinase activity, and signal transduction. By comparison, signal transduction and gap junctions might involve BNO-induced hepatotoxicity. Our results provided a better understanding of BRU- and BNO-induced hepatotoxicity. We also built a foundation to elucidate the material base of the hepatotoxicity of traditional Chinese medicine Semen Strychni.

Effect of a combination of Atractylodes macrocephala extract with strychnine on the TLR4/NF-κB/NLRP3 pathway in MH7A cells

Rheumatoid arthritis (RA) is now widely recognized as a chronic systemic inflammatory autoimmune disease characterized by swelling, pain and stiffness, which are often disabling. Although the number of drugs available for the treatment of RA has increased in recent years, they are generally expensive, leave patients prone to relapse and can result in severe effects when discontinued. Thus, there is a need for an inexpensive drug with fewer side effects that can be adhered to relieve pain and slow down the progression of the disease. Strychnine, a traditional Chinese medicine, was often used in ancient times to treat swollen and painful joints; however, because of its somewhat toxic nature, it is often combined with Atractylodes macrocephala to reduce its toxicity for safer therapeutic action. The present study performed high-performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) analysis to confirm whether the use of strychnine with Atractylodes macrocephala had the effect of reducing strychnine content. MH7A cells were induced using IL-1β to study the effect of strychnine with Atractylodes macrocephala on the Toll-like receptor 4 (TLR4)/NF-κB/NLR family pyrin domain-containing 3 (NLRP3) pathway in order to verify its role in the treatment of RA. The results indicated that the combined application of HPLC-MS/MS strychnine and Atractylodes macrocephala had a reducing effect on the strychnine content. From the subsequent experimental results, it can be inferred that Strychnine combined with Atractylodes macrocephala extract could promote the apoptosis of synovial cells, and could inhibit the expression levels of TLR4, NF-κB and NLRP3 in the cells as well as reducing the MH7A-positive cells. The expression levels of TLR4, IκB kinase β, NF-κB and NLRP3 were significantly reduced after treatment with each administration group, resulting in a decrease in the phosphorylation levels of TLR4 and NF-κB, indicating that the combination potently inhibited their phosphorylation. The combination of strychnine and atractylenolide II was also revealed to be the main active ingredient in the treatment of RA.

ATF3 contributes to brucine-triggered glioma cell ferroptosis via promotion of hydrogen peroxide and iron

Ferroptotic cell death is characterized by iron-dependent lipid peroxidation that is initiated by ferrous iron and H2O2 via Fenton reaction, in which the role of activating transcription factor 3 (ATF3) remains elusive. Brucine is a weak alkaline indole alkaloid extracted from the seeds of Strychnos nux-vomica, which has shown potent antitumor activity against various tumors, including glioma. In this study, we showed that brucine inhibited glioma cell growth in vitro and in vivo, which was paralleled by nuclear translocation of ATF3, lipid peroxidation, and increases of iron and H2O2. Furthermore, brucine-induced lipid peroxidation was inhibited or exacerbated when intracellular iron was chelated by deferoxamine (500 μM) or improved by ferric ammonium citrate (500 μM). Suppression of lipid peroxidation with lipophilic antioxidants ferrostatin-1 (50 μM) or liproxstatin-1 (30 μM) rescued brucine-induced glioma cell death. Moreover, knockdown of ATF3 prevented brucine-induced accumulation of iron and H2O2 and glioma cell death. We revealed that brucine induced ATF3 upregulation and translocation into nuclei via activation of ER stress. ATF3 promoted brucine-induced H2O2 accumulation via upregulating NOX4 and SOD1 to generate H2O2 on one hand, and downregulating catalase and xCT to prevent H2O2 degradation on the other hand. H2O2 then contributed to brucine-triggered iron increase and transferrin receptor upregulation, as well as lipid peroxidation. This was further verified by treating glioma cells with exogenous H2O2 alone. Moreover, H2O2 reversely exacerbated brucine-induced ER stress. Taken together, ATF3 contributes to brucine-induced glioma cell ferroptosis via increasing H2O2 and iron.

Brucine promotes apoptosis in cervical cancer cells (ME-180) via suppression of inflammation and cell proliferation by regulating PI3K/AKT/mTOR signaling pathway

Brucine are the main constituents of Strychnos nux-vomica. Earlier reports have determined brucine shows anti-inflammatory, analgesic and excellent anti-tumor drug. Even though its anticervical cancer cells remains not clearly evaluated. So that, we hypothesized the anti-cervical cancer activity of brucine against the cervical (ME-180) cells. Brucine inhibited the inflammation, cell proliferation and promoted rate of apoptotic cell death ad reduced the mitochondrial potential, which is evidenced by respective (AO/EB, Rh-123, and PI) staining. Furthermore ELISA and real time PCR reaction determined that brucine were down regulated inflammatory (TNF-α, NF-kB, IL-6 & COX-2) cell proliferation (Cyclin D1) and apoptotic marker Bax, caspase-3, PI3K (phosphoinosital 3 kinase), AKT, mTOR (mammalian target of rapamycin) and over expression Bcl-2, associated death promoter. These findings were confirmed and finally suggested that brucine inhibited inflammation, cell proliferation and promoted the apoptosis through the down-regulation of PI3K/AKT/mTOR pathway. Taken together, these data were exhibited brucine as a good therapeutic agents for the prevention of anticancer cervical cancer drugs.

Quality by Design for Development, Optimization and Characterization of Brucine Ethosomal Gel for Skin Cancer Delivery

Natural products have been extensively used for treating a wide variety of disorders. In recent times, Brucine (BRU) as one of the natural medications extracted from seeds of nux vomica, was investigated for its anticancer activity. As far as we know, this is the first study on BRU anticancer activity against skin cancer. Thus, the rational of this work was implemented to develop, optimize and characterize the anticancer activity of BRU loaded ethosomal gel. Basically, thin film hydration method was used to formulate BRU ethosomal preparations, by means of Central composite design (CCD), which were operated to construct (3²) factorial design. Two independent variables were designated (phospholipid percentage and ethanol percentage) with three responses (vesicular size, encapsulation efficiency and flux). Based on the desirability function, one formula was selected and incorporated into HPMC gel base to develop BRU loaded ethosomal gel. The fabricated gel was assessed for all physical characterization. In-vitro release investigation, ex-vivo permeation and MTT calorimetric assay were performed. BRU loaded ethosomal gel exhibited acceptable values for the characterization parameters which stand proper for topical application. In-vitro release investigation was efficiently prolonged for 6 h. The flux from BRU loaded ethosome was enhanced screening optimum SSTF value. Finally, in-vitro cytotoxicity study proved that BRU loaded ethosomal gel significantly improved the anticancer activity of the drug against A375 human melanoma cell lines. Substantially, the investigation proposed a strong motivation for further study of the lately developed BRU loaded ethosomal gel as a prospective therapeutic strategy for melanoma treatment.

Mechanism of action of strychni semen for treating Rheumatoid arthritis and methods for attenuating the toxicity

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease, which destructs joints and causes significant pain, impairing a patient's quality of life. Strychni semen showed promising results in treating RA. However, there are increasing safety concerns in using Strychni Semen due to its severe toxicity.

AIM AND OBJECTIVE

The purpose of this review is to provide insight into using Strychni Semen as an alternative medicine to treat RA, as well as to offer a method for the safe application of Strychni Semen through processing and compatibility studies.

METHODS

Publications were retrieved and surveyed from CNKI and PubMed relevant to Strychni Semen for a literature review.

RESULTS

This article summarized the mechanism of function of strychni semen in treating RA with its anti-inflammatory, analgesic, and immunomodulatory effect. Commonly used methods to attenuate the toxicity of strychni semen were also discussed in this article.

CONCLUSION

Strychni semen has a good therapeutic effect on RA, mainly by the modulation of immunity with anti-inflammatory and analgesic effects. Also, the reported toxicity of strychni semen can be effectively reduced by processing and reasonable compatibility. Hence, as an alternative medicine for RA treatment, strychni semen has a broad prospect.

Chronotoxicity of Semen Strychni is associated with circadian metabolism and transport in mice

OBJECTIVES

We aimed to determine the circadian responses of mice to Semen Strychni and to investigate the role of pharmacokinetics in generating chronotoxicity.

METHODS

Total extract of Semen Strychni was administered by oral gavage to wild-type (WT) and Bmal1-/- (a circadian clock-deficient model) mice at different circadian time points for toxicity (including survival) and pharmacokinetic characterization. Nephrotoxicity and neurotoxicity were evaluated by measuring plasma creatinine and creatine kinase BB (CK-BB), respectively. Drug metabolism and transport assays were performed using liver/intestine microsomes and everted gut sacs, respectively.

KEY FINDINGS

Semen Strychni nephrotoxicity and neurotoxicity as well as animal survival displayed significant circadian rhythms (the highest level of toxicity was observed at ZT18 and the lowest level at ZT2 to ZT6). According to pharmacokinetic experiments, herb dosing at ZT18 generated higher plasma concentrations (and systemic exposure) of strychnine and brucine (two toxic constituents) compared with ZT6 dosing. This was accompanied by reduced formation of both dihydroxystrychnine and strychnine glucuronide (two strychnine metabolites) at ZT18. Bmal1 ablation sensitized mice to Semen Strychni-induced toxicity (with increased levels of plasma creatinine and CK-BB) and abolished the time dependency of toxicity. Metabolism of Semen Strychni (strychnine and brucine) in the liver and intestine microsomes of WT mice was more extensive at ZT6 than at ZT18. These time differences in hepatic and intestinal metabolism were lost in Bmal1-/- mice. Additionally, the intestinal efflux transport of Semen Strychni (strychnine and brucine) was more extensive at ZT6 than ZT18 in WT mice. However, the time-varying transport difference was abolished in Bmal1-/- mice.

CONCLUSIONS

Circadian responses of mice to Semen Strychni are associated with time-varying efflux transport and metabolism regulated by the circadian clock (Bmal1). Our findings may have implications for optimizing phytotherapy with Semen Strychni via timed delivery.

Brucine inhibits proliferation of glioblastoma cells by targeting the G-quadruplexes in the c-Myb promoter

The proto-oncogene c-Myb plays an important role in cell proliferation, and its upregulation affects the development of glioblastomas. G-quadruplexes are secondary DNA or RNA structures that usually form in the promoter region of oncogenes, including c-Myb, and regulate the expression of these genes. The traditional Chinese medicine, brucine, is a ligand of the G-quadruplexes located in the promoter region of c-Myb. The present study investigated the therapeutic effects and mechanism of action of brucine in U87, LN18, and LN229 cells in vitro and in vivo. Our results showed that brucine suppressed the growth of these cells in vitro by arresting the cell cycle and reducing c-Myb expression. Dual-luciferase reporter assays showed that brucine inhibited c-Myb expression by targeting the guanine-rich sequence that forms G-quadruplexes in the c-Myb promoter. Moreover, U87 tumors were suppressed by brucine in a tumor xenograft nude mouse model. Therefore, brucine is potentially effective for treating glioblastomas.

Brucine inhibits TNF-α-induced HFLS-RA cell proliferation by activating the JNK signaling pathway

Rheumatoid arthritis (RA) is a diffuse connective tissue disease. Brucine selectively inhibits cell immunity, immune hypersensitivity and induces apoptosis. The current study aimed to investigate effects of brucine on human fibroblast-like synoviocytes (HFLS) of RA and to clarify associated molecular mechanisms. HFLS-RA were treated with tumor necrosis factor (TNF)-α prior to treatment with brucine at carrying concentrations. Cell Counting Kit-8 assays were performed to evaluate HFLS-RA proliferation. Western blot assays were employed to examine c-Jun N-terminal kinase (JNK) expression and phosphorylation in TNF-α-induced HFLS-RA. An association between brucine treatment and JNK phosphorylation was assessed by employing a linear regression analysis. The results suggested that low doses of brucine (0.125 and 0.25 mg/ml) significantly reversed proliferation effects induced by TNF-α, however, final cell viabilities were increased compared with the untreated control (P>0.05 and P<0.05, respectively). High brucine doses (≥0.5 mg/ml) significantly reversed TNF-α-induced proliferation and further inhibited viability compared with the untreated control (P<0.05). Regarding JNK expression, there were no significant differences among the brucine treatment, and between the Control and the TNF-α groups (P>0.05). Brucine treatment significantly decreased JNK phosphorylation compared with the TNF-α group (P<0.05). JNK specific inhibitor, SP600125, significantly inhibited brucine-induced cell viability enhancement compared with the brucine-treated groups without inhibitor (P<0.05). A linear regression analysis suggested that brucine was associated with JNK phosphorylation in TNF-α-treated HFLS-RA. In conclusion, brucine significantly inhibited TNF-α-induced HFLS-RA proliferation by activating the JNK signaling pathway. Therefore, brucine may have potential clinical applications in the treatment of RA.

Biochemical studies evaluating the chemopreventive potential of brucine in chemically induced mammary carcinogenesis of rats

The present study was aimed to investigate the dose dependent chemopreventive activity of brucine against 7, 12-dimethylbenz (a) anthracene induced mammary gland tumorigenesis in rats. The mammary tumor was induced by a single dose of DMBA (25 mg/rat) injected subcutaneously near the mammary gland. We observed reduced body weight and increase in tumor incidence, the total number of tumors, and tumor volume in DMBA alone injected rats and also observed decreased antioxidant status (SOD, CAT, GPX, and GSH) and increased lipid peroxidation (TBARS and LOOH) in plasma and mammary tissues. Increased levels of CYP450, Cyt-b5 and decreased levels of phase II (GST and GR) biotransformation enzymes were noticed in the liver and mammary tissues. Further, increased levels of lipid profile (TC, TG, PL, and FFA) and lipoprotein (LDL and VLDL) were noticed. Whereas, decrease in the levels of HDL in plasma and decreased levels of PL and FFA in mammary tissues were observed. Oral administration of brucine in different doses (2, 4 and 8 mg/kg bw) inhibited the tumor incidence and restored the levels of biochemical markers near to normal in dose responsive manner. Biochemical findings are supported by histopathological studies. The results suggest that brucine at a dose of 8 mg/kg bw shows more significant chemopreventive activity in DMBA-induced mammary carcinogenesis.

[In vitro transdermal permeation and penetration properties for transfersomes of brucine]

To prepare the liposomes and transfersomes of brucine, characterize their pharmaceutical properties, and compare their in vitro transdermal permeation properties. The liposomes and transfersomes of brucine were prepared by ammonium sulfate gradient method to investigate their pharmaceutical properties such as the particle size, encapsulation efficiency and deformation. The transdermal permeation properties in vitro of liposome and transfersomes from different prescriptions were compared by using modified Franz-diffustion cells with rat skin as the transdermal barrier. The results showed that the particle size of liposomes and transfersomes for brucine ranged from 100 nm to 150 nm, with even distribution for particle size. As compared with the soybean phosphatidylcholine (SPC) transfersomes, the encapsulation efficiency of complex phospholipid transfersomes was significantly improved. The deformation index of complex phospholipid transfersomes in brucine was 2.09 times and 1.76 times as much as SPC liposomes and SPC transfersomes respectively. The steady state flux of complex phospholipid transfersomes was 3.43 times and 1.41 times as much as SPC liposomes and SPC transfersomes. The steady state flux of the physical mixture of brucine and blank complex phospholipid transfersomes was 2.20 times as much as brucine solution. The concentration of complex phospholipid had effect on transdermal permeation of blank transfersomes. In conclusion, as compared with liposomes, the permeation behavior of transfersomes was significantly improved; complex phospholipid technology can improve the membrane phase behavior of transfersomes, and further improve the deformation index and transdermal flux of transfersomes; in addition, blank transfersomes have promoting effect on transdermal absorption of brucine.

Antitumor effects of brucine immuno-nanoparticles on hepatocellular carcinoma in vivo

In vitro and in vivo studies have demonstrated that brucine is able to inhibit the proliferation of liver cancer cells and growth of animal tumors, and may be a promising anticancer drug. However, high toxicity, poor water solubility, short half-life, narrow therapeutic window, and similar therapeutic and toxic doses limit its clinical application in the treatment of malignant tumors. In our previous study, brucine immuno-nanoparticles were successfully prepared and added to the culture medium of liver cancer SMMC-7721 cells, and the results indicated that the brucine immuno-nanoparticles were able to target the cell membrane of liver cancer SMMC-7721 cells and significantly inhibit the proliferation, adhesion, invasion and metastasis of SMMC-7721 cells. The aim of the present study was to investigate the antitumor effect of brucine immuno-nanoparticles in vivo by establishing an in situ transplanted liver cancer in nude mice. The results indicated that in vivo application of the brucine immuno-nanoparticles resulted in temporary liver and kidney damage, and significantly reduced the α-fetoprotein (AFP) secretion of tumor cells (Bru-NP-MAb vs. the other groups; P<0.05). The brucine concentration of tumor tissues in the brucine immuno-nanoparticles group was significantly increased compared with that of the brucine nanoparticles group (Bru-NP-MAb vs. Bru-NP group or brucine group; P<0.05). The brucine immuno-nanoparticles were able to inhibit tumor growth and cluster of differentiation 34 expression and angiogenesis of tumor tissues, and induce the apoptosis of tumor cells (Bru-NP-MAb vs. Bru-NP group or brucine group; P<0.05). In conclusion, as a novel type of targeted drug, brucine nanoparticles combined with anti-AFP monoclonal antibodies was more effective compared with brucine nanoparticles or brucine alone in inhibiting tumor growth via the enhancement of apoptosis, and the suppression of proliferation and angiogenesis in vivo. Therefore, the brucine immuno-nanoparticle is a promising targeted drug for the treatment of hepatocellular carcinoma.

Toxicokinetics of strychnine and brucine after the oral administration of Biqi capsule to rats by RRLC-MS/MS

Biqi capsule is a well-known traditional Chinese medicine formula that has been widely applied for the clinical treatment of such diseases as rheumatoid arthritis, scapulohumeral periarthritis and cervical spondylopathy. However, there is concern regarding the toxicity of Biqi capsule owing to its active ingredients, strychnine and brucine. To investigate the toxicokinetics of strychnine and brucine after oral administration of Biqi capsule to rats, a sensitive and simple rapid-resolution liquid chromatography/tandem mass spectrometry method was developed to determine the levels of strychnine and brucine in rat plasma. Chromatographic separation was performed on a Capcell Pak C₁₈ MG II (3.0 μm, 2.0 × 35 mm) column by gradient elution with acetonitrile and 0.2% formic acid as the mobile phase. The method was validated over the range of 0.25-250 ng/mL for strychnine and 0.025-25 ng/mL for brucine. The intra- and inter-day accuracies of strychnine and brucine in rat plasma were 100.3-106.6 and 90.75-106.1% respectively, and the precisions were within 14.2%. The established method was successfully applied to the toxicokinetic study of strychnine and brucine after single and multiple oral administration of Biqi capsule to male and female rats at 0.4, 0.8 and 1.6 g/kg doses. The results showed different toxicokinetic characteristics in the different groups.

In vitro and in vivo evaluation of novel NGR-modified liposomes containing brucine

In this study, a novel NGR (Asn-Gly-Arg) peptide-modified liposomal brucine was prepared by using spray-drying method. The surface morphology of the liposomes, encapsulation efficiency and particle size were investigated. The data showed that the addition of NGR did not produce any significant influence on brucine liposomes in terms of particle size or zeta potential. In addition, after 3 months of storage, no dramatic change such as visible aggregation, drug content changes or precipitation in the appearance of NGR-brucine liposomes occurred. The in vitro release results indicated that the release of brucine from NGR liposomes was similar to that of liposomes, demonstrating that the NGR modification did not affect brucine release. The in vitro drug-release kinetic model of NGR-brucine liposomes fitted well with the Weibull's equation. In vivo, NGR-brucine liposomes could significantly extend the bioavailability of brucine; however, there was no significant difference observed in the pharmacokinetic parameters between liposomes and NGR liposomes after intravenous administration. Antitumor activity results showed that NGR-modified liposomes exhibited less toxicity and much higher efficacy in HepG2-bearing mice compared with non-modified liposomes. The enhanced antitumor activity might have occurred because brucine was specifically recognized by NGR receptor on the surface of tumor cells, which enhanced the intracellular uptake of drugs.

Brucine suppresses breast cancer metastasis via inhibiting epithelial mesenchymal transition and matrix metalloproteinases expressions

OBJECTIVE

To examine the effect of brucine on the migration, invasion, adhesion and expressions of epithelial-to-mesenchymal transition (EMT) markers and matrix metalloproteinases (MMPs) in the highly metastatic breast cancer cell lines MDA-MB-231 and Hs578-T.

METHODS

MDA-MB-231 and Hs578-T cells were divided to 4 groups: the control group (0.1% DMSO), and 25, 50 and 100 μmol/L brucine groups. The cell viability was determined using a CellTiter-Glo® luminescent cell viability. The scratch wound healing assay and tanswell migration assay were used to determine the migration ability of these cells treated by different concentrations of brucine. The proliferation rate, invasive potential and adhesive ability were respectively performed by colony formation assay, transwell invasion assay and adhension assay. The protein and mRNA expressions of EMT biomarkers, MMP-2 and MMP-9 were investigated by real-time reverse transcription polymerase chain reaction and Western blot.

RESULTS

Compared with the control group, brucine had little effect on cell viability or proliferation (P>0.05), but led to a dose-dependent decrease on migration, invasion, adhension of MDA-MB-231 and Hs578-T cells (P<0.01). Furthermore, brucine increased the protein and mRNA levels of EMT markers such as E-cadherin and β-catenin in MDA-MB-231 and Hs578-T cells, and decreased the protein and mRNA levels of mesenychmal markers such as vimentin and fibronectin, as well as the expressions of MMP-2 and MMP-9 (all P<0.01).

CONCLUSION

Brucine inhibited triple negative breast cancer cells metastasis potentially through EMT reversion and MMP-2 and MMP-9 inhibition.

Why do Hydrates (Solvates) Form in Small Neutral Organic Molecules? Exploring the Crystal Form Landscapes of the Alkaloids Brucine and Strychnine

Computational methods were used to generate and explore the crystal structure landscapes of the two alkaloids strychnine and brucine. The computed structures were analyzed and rationalized by correlating the modelling results to a rich pool of available experimental data. Despite their structural similarity, the two compounds show marked differences in the formation of solid forms. For strychnine only one anhydrous form is reported in the literature and two new solvates from 1,4-dioxane were detected in the course of this work. In contrast, 22 solid forms are so far known to exist for brucine, comprising two anhydrates, four hydrates (HyA - HyC and a 5.25-hydrate), twelve solvates (alcohols and acetone) and four heterosolvates (mixed solvates with water and alcohols). For strychnine it is hard to produce any solid form other than the stable anhydrate while the formation of specific solid state forms of brucine is governed by a complex interplay between temperature and relative humidity/water activity and it is rather a challenging to avoid hydrate formation. Differences in crystal packing and the high tendency for brucine to form hydrates are not intuitive from the molecular structure alone, as both molecules have hydrogen bond acceptor groups but lack hydrogen bond donor groups. Only the evaluation of the crystal energy landscapes, in particular the close-packed crystal structures and high-energy open frameworks containing voids of molecular (water) dimensions, allowed us to unravel the diverse solid state behavior of the two alkaloids at a molecular level. In this study we demonstrate that expanding the analysis of anhydrate crystal energy landscapes to higher energy structures and calculating the solvent-accessible volume can be used to estimate non-stoichiometric or channel hydrate (solvate) formation, without explicitly computing the hydrate/solvate crystal energy landscapes.

Anticancer effects of brucine and gemcitabine combination in MCF-7 human breast cancer cells

This study was designed to investigate the combination effects of brucine and gemcitabine, each with anticancer properties, in MCF-7 human breast cancer cells in culture. With regard to cell viability, effects of both the drugs and their combinations were inversely proportional to dose and time. For various proportional drug combinations studied, combination effects were analysed using CompuSyn software. The analyses revealed synergistic and/or additive effects regarding cell viability, anchorage-independent growth and cell migration. Combination analyses exhibited diversified impacts of the type of combination treatment, namely pretreatment with either drug followed by exposure to the other, or treatment with both drugs at the same time. Compared with untreated cells, combination treatment of asynchronised MCF-7 cells resulted in 17.2 × decrease in G2 phase, increasing G1 (2.1 × ) and S (1.5 × ) phase cells in cell cycle analysis. Brucine, either individually or in combination, but not gemcitabine, inhibited NF-kB subunit (p65) expression in MCF-7 cells.

Effect of Shodhana (processing) on Kupeelu (Strychnos nux-vomica Linn.) with special reference to strychnine and brucine content

Kupeelu (Strychnos nux-vomica Linn.) commonly known as nux vomica is a poisonous plant used extensively in various ayurvedic formulations, with great therapeutic significance. Ayurveda recommended the administration of Kupeelu only after purification in different media like cow's urine (Go mutra), cow's milk (Go dugdha), cow's ghee (Go ghrita), Kanji (sour gruel), and so on. Apart from the classical methods some other methods are also adopted by the traditional practitioners using castor oil (Eranda taila), ginger juice (Ardraka swarasa), in the purification of Kupeelu seeds. In the present study an attempt has been made to purify the seeds by performing two different methods (one classical and another traditional) using Kanji and Ardrakaswarasa as Shodhana media. This study reveals that both the methods studied reduce the strychnine and brucine contents in comparison to the raw seeds as determined by high performance thin layer chromatography (HPTLC). After purification in Kanji and Ardraka swarasa, the strychnine content was reduced by 39.25% and 67.82%, respectively, and the brucine content in the purified seeds was also found to have decreased by 17.60% and 40.06%, in comparison to the raw seeds.

Improved pharmacokinetics and reduced toxicity of brucine after encapsulation into stealth liposomes: role of phosphatidylcholine

OBJECTIVE

Brucine was encapsulated into stealth liposomes using the ammonium sulfate gradient method to improve therapeutic index.

MATERIALS AND METHODS

Four brucine stealth liposomal formulations were prepared, which were made from different phosphatidylcholines (PCs) with different phase transition temperatures (T(m)). The PCs used were soy phosphatidylcholine (SPC), dipalmitoyl phosphatidylcholine (DPPC), hydrogenated soy phosphatidylcholine (HSPC), and distearoyl phosphatidylcholine (DSPC). The stabilities, pharmacokinetics, and toxicities of these liposomal formulations were evaluated and compared.

RESULTS

Size, zeta potential, and entrapment efficiency of brucine-loaded stealth liposomes (BSL) were not influenced by PC composition. In vitro release studies revealed that drug release rate increased with decreased T(m) of PCs, especially with the presence of rat plasma. After intravenous administration, the area under the curve (AUC) values of BSL-SPC, BSL-DPPC, BSL-HSPC, and BSL-DSPC in plasma were 7.71, 9.24, 53.83, and 56.83-fold as large as that of free brucine, respectively. The LD(50) values of brucine solution, BSL-SPC, BSL-DPPC, BSL-HSPC, and BSL-DSPC following intravenous injection were 13.17, 37.30, 37.69, 51.18, and 52.86 mg/kg, respectively. It was found in calcein retention experiments that the order of calcein retention in rat plasma was SPC < DPPC << HSPC < DSPC stealth liposomes.

CONCLUSION

PC composition could exert significant influence on the stabilities, pharmacokinetics, and toxicities of brucine-loaded stealth liposomes. DSPC or HSPC with T(m) above 50°C should be used to prepare the stealth liposomal formulation for the intravenous delivery of brucine. However, it was found in the present paper that the pharmacokinetics and toxicity of BSL were not influenced by the PC composition when the T(m) of the PC was in the range of -20°C to 41°C.

Simultaneous HPTLC determination of strychnine and brucine in strychnos nux-vomica seed

OBJECTIVE

A simple, sensitive, and specific thin layer chromatography (TLC) densitometry method has been developed for the simultaneous quantification of strychnine and brucine in the seeds of Strychnos nux-vomica.

MATERIALS AND METHODS

The method involved simultaneous estimation of strychnine and brucine after resolving it by high performance TLC (HPTLC) on silica gel plate with chloroform-methanol-formic acid (8.5:1.5:0.4 v/v/v) as the mobile phase.

RESULTS

The method was validated as per the ICH guidelines for precision (interday, intraday, intersystem), robustness, accuracy, limit of detection, and limit of quantitation. The relationship between the concentration of standard solutions and the peak response was linear within the concentration range of 50-1000 ng/spot for strychnine and 100-1000 ng/spot for brucine. The method precision was found to be 0.58-2.47 (% relative standard deviation [RSD]) and 0.36-2.22 (% RSD) for strychnine and brucine, respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.75% for strychnine and 100.52% for brucine, respectively.

CONCLUSIONS

The HPTLC method for the simultaneous quantification of strychnine and brucine was found to be simple, precise, specific, sensitive, and accurate and can be used for routine analysis and quality control of raw material of S. nux-vomica and several unani and ayurvedic formulations containing this as an ingredient.

Effect of purificatory measures through cow's urine and milk on strychnine and brucine content of Kupeelu (Strychnos nuxvomica Linn.) seeds

Strychnos nux vomica Linn.(Loganaceae) commonly known as Nux vomica (Kupeelu), is a poisonous plant and its seeds are used widely in Ayurvedic system of medicine since time immemorial. Ayurveda advocates that nux vomica seeds are to be administered in therapeutics only after going through certain purificatory measures (Shodhana). There are more than six media: cow's urine (Go mutra), cow's milk (Go dugdha), cow's ghee (Go ghrita), Kanji (thin gruel), castor oil (Eranda taila) and fresh ginger juice (Ardraka swarasa) etc., which have been reported in different classical texts of Ayurveda for proper processing of nux vomica seeds. In this study, an attempt has been made to purify the seeds by using three different methods as described in ancient treatise by using cow's urine and cow's milk as media alone and together. This study revealed that all the methods studied reduced the toxicity of strychnine and brucine contents in comparison to the raw seeds as determined by HPTLC. Out of these three methods maximum reduction in strychnine and brucine contents was found when the seeds were purified by keeping them in cow's urine for seven days followed by boiling in cow's milk for three hrs.

The effects of brucine and alcuronium on the inhibition of [3H]acetylcholine release from rat striatum by muscarinic receptor agonists

1. Radioligand binding experiments indicate that the affinity of muscarinic receptors for their agonists may be enhanced by allosteric modulators. We have now investigated if brucine can enhance the inhibitory effects of muscarinic receptor agonists on the electrically evoked release of [3H]acetylcholine ([3H]ACh) from superfused slices of rat striatum. 2. The evoked release of [3H]ACh was inhibited by all agonists tested (i.e., furmethide, oxotremorine-M, bethanechol and oxotremorine). 3. Brucine enhanced the inhibitory effects of furmethide, oxotremorine-M and bethanechol on the evoked [3H]ACh release without altering the inhibitory effect of oxotremorine. 4. Alcuronium was applied for comparison and found to diminish the inhibitory effect of furmethide on the evoked [3H]ACh release. 5. The results demonstrate that it is possible both to enhance and diminish the functional effects of muscarinic receptor agonists by allosteric modulators. 6. The direction of the observed effects of brucine and alcuronium on [3H]ACh release fully agrees with the effects of these modulators on the affinities of human M4 receptors for furmethide, oxotremorine-M, bethanechol and oxotremorine, as described by Jakubik et al. (1997). This supports the view that the presynaptic muscarinic receptors responsible for the autoinhibition of ACh release in rat striatum belong to the M4 muscarinic receptor subtype.