Chemical constituents from Brucea javanica

The mechanism of UNC-51-like kinase 1 and the applications of small molecule modulators in cancer treatment

Autophagy is a process of self-renewal in cells, which not only provides the necessary nutrients for cells, but also clears necrotic organelles. Autophagy disorders are closely related to diseases such as cancer. UNC-51-like kinase 1 (ULK1) is a serine/threonine protein kinase that plays a crucial role in receiving input from energy and nutrient sensors, activating autophagy to maintain cellular homeostasis under stressful conditions. In recent years, targeting ULK1 has become a highly promising strategy for cancer treatment. This review introduces the regulatory mechanism of ULK1 in autophagy through the AMPK/mTOR/ULK1 pathway and reviews the research progress of ULK1 activators and inhibitors and their applications in cancer treatment. In addition, we analyze the binding modes between ULK1 and modulators through virtual molecular docking, which will provide a reliable basis and theoretical guidance for the design and development of new therapeutic drugs targeting ULK1.

A review of Brucea javanica: metabolites, pharmacology and clinical application

This review examines advances in the metabolites, pharmacological research, and therapeutic applications of the medicinal fruit of Brucea javanica (L.) Merr. Brucea javanica (BJ) is derived from the fruit of the Brucea javanica (L.) Merr. There are nearly 200 metabolites present in BJ, and due to the diversity of its metabolites, BJ has a wide range of pharmacological effects. The traditional pharmacological effects of BJ include anti-dysentery, anti-malaria, etc. The research investigating the contemporary pharmacological impacts of BJ mainly focuses on its anti-tumor properties. In the article, the strong monomeric metabolites among these pharmacological effects were preliminarily screened. Regarding the pharmacological mechanism of action, current research has initially explored BJ's pharmacological agent and molecular signaling pathways. However, a comprehensive system has yet to be established. BJ preparations have been utilized in clinical settings and have demonstrated effectiveness. Nevertheless, clinical research is primarily limited to observational studies, and there is a need for higher-quality research evidence to support its clinical application. There are still many difficulties and obstacles in studying BJ. However, it is indisputable that BJ is a botanical drugs with significant potential for application, and it is expected to have broader global usage.

Bruceine D and Narclasine inhibit the proliferation of breast cancer cells and the prediction of potential drug targets

BACKGROUND

Breast cancer is one of the most common female malignancies. This study explored the underlying mechanism through which the two plant compounds (Brucaine D and Narclasine) inhibited the proliferation of breast cancer cells.

OBJECTIVE

The purpose of this study was to explore the effect of Brucaine D and Narclasine on breast cancer development and their potential drug targets.

METHODS

GSE85871 dataset containing 212 samples and the hallmark gene set "h.all.v2023.1.Hs.symbols.gmt" were downloaded from the Gene Expression Omnibus (GEO) database and the Molecular Signatures Database (MSigDB) database, respectively. Principal component analysis (PCA) was applied to classify clusters showing similar gene expression pattern. Single sample gene set enrichment analysis (ssGSEA) was used to calculate the hallmark score for different drug treatment groups. The expressions of genes related to angiogenesis, glycolysis and cell cycle were detected. Protein-protein interaction (PPI) network analysis was performed to study the interaction of the hub genes. Then, HERB database was employed to identify potential target genes for Narclasine and Bruceine D. Finally, in vitro experiments were conducted to validate partial drug-target pair.

RESULTS

PCA analysis showed that the significant changes in gene expression patterns took place in 6 drugs treatment groups (Narciclasine, Bruceine D, Japonicone A, 1beta-hydroxyalatolactone, Britanin, and four mixture drugs) in comparison to the remaining drug treatment groups. The ssGSEA pathway enrichment analysis demonstrated that Narciclasine and Bruceine treatments had similar enriched pathways, for instance, suppressed pathways related to angiogenesis, Glycolysis, and cell cycle, etc.. Further gene expression analysis confirmed that Narciclasine and Bruceine had a strong ability to inhibit these cell cycle genes, and that MYC, CHEK2, MELK, CDK4 and EZH2 were closely interacted with each other in the PPI analysis. Drug target prediction revealed that Androgen Receptor (AR) and Estrogen Receptor 1 (ESR1) were the targets for Bruceine D, and Cytochrome P450 3A4 enzyme (CYP3A4) was the target for Narciclasine. Cell experiments also confirmed the connections between Narciclasine and CYP3A4.

CONCLUSION

The present study uncovered that Narciclasine and Bruceine D could inhibit the growth of breast cancer and also predicted the potential targets for these two drugs, providing a new therapeutic direction for breast cancer patients.

Post-Cyclization Skeletal Rearrangements in Plant Triterpenoid Biosynthesis by a Pair of Branchpoint Isomerases

Triterpenoids possess potent biological activities, but their polycyclic skeletons are challenging to synthesize. The skeletal diversity of triterpenoids in plants is generated by oxidosqualene cyclases based on epoxide-triggered cationic rearrangement cascades. Normally, triterpenoid skeletons then remain unaltered during subsequent tailoring steps. In contrast, the highly modified triterpenoids found in Sapindales plants imply the existence of post-cyclization skeletal rearrangement enzymes that have not yet been found. We report here a biosynthetic pathway in Sapindales plants for the modification of already cyclized tirucallane triterpenoids, controlling the pathway bifurcation between different plant triterpenoid classes. Using a combination of bioinformatics, heterologous expression in plants and chemical analyses, we identified a cytochrome P450 monooxygenase and two isomerases which harness the epoxidation-rearrangement biosynthetic logic of triterpene cyclizations for modifying the tirucallane scaffold. The two isomerases share the same epoxide substrate made by the cytochrome P450 monooxygenase CYP88A154, but generate two different rearrangement products, one containing a cyclopropane ring. Our findings reveal a process for skeletal rearrangements of triterpenoids in nature that expands their scaffold diversity after the initial cyclization. In addition, the enzymes described here are crucial for the biotechnological production of limonoid, quassinoid, apoprotolimonoid, and glabretane triterpenoids.

Brujavanoids A-U, structurally diverse apotirucallane-type triterpenoids from Brucea javanica and their anti-inflammatory effects

Extensive phytochemical investigation on the methanol extract of the inflorescences, twigs, and leaves of Brucea javanica led to the isolation and identification of 27 triterpenoids, including 21 previously undescribed ones, named brujavanoids A-U (1-21). Their structures were determined based on comprehensive spectroscopic analysis and single-crystal X-ray diffraction. Of these compounds, brujavanoid A (1) represents the first apotirucallane-type triterpenoid with a novel 19(10 → 9)abeo motif, and brujavanoids B and C (2-3) are the first apotirucallane-type triterpenoids with a rarely occurring 14-hydorxy-15,16-epoxy fragment. All the isolates were evaluated for their anti-inflammatory effect in an LPS-activated RAW264.7 cells model. Furthermore, the most active one, brujavanoid E (5), can suppress the transcriptional expression of typical pro-inflammatory mediators and inhibit the nuclear translocation of NF-κB p65 in the LPS- activated RAW264.7 cells.

Major Constituents From Brucea javanica and Their Pharmacological Actions

Brucea javanica (Ya-dan-zi in Chinese) is a well-known Chinese herbal medicine, which is traditionally used in Chinese medicine for the treatment of intestinal inflammation, diarrhea, malaria, and cancer. The formulation of the oil (Brucea javanica oil) has been widely used to treat various types of cancer. It has also been found that B. javanica is rich in chemical constituents, including quassinoids, triterpenes, alkaloids and flavonoids. Pharmacological studies have revealed that chemical compounds derived from B. javanica exhibit multiple bioactivities, such as anti-cancer, anti-bacterial, anti-diabetic, and others. This review provides a comprehensive summary on the pharmacological properties of the main chemical constituents presented in B. javanica and their underlying molecular mechanisms. Moreover, the review will also provide scientific references for further research and development of B. javanica and its chemical constituents into novel pharmaceutical products for disease management.

Bruceae Fructus Oil Inhibits Triple-Negative Breast Cancer by Restraining Autophagy: Dependence on the Gut Microbiota-Mediated Amino Acid Regulation

Triple-negative breast cancer (TNBC) has been acknowledged as an aggressive disease with worst prognosis, which requires endeavor to develop novel therapeutic agents. Bruceae fructus oil (BO), a vegetable oil derived from the fruit of Brucea javanica (L.) Merr., is an approved marketable drug for the treatment of cancer in China for several decades. Despite that the anti–breast cancer activity of several quassinoids derived from B. javanica has been found, it was the first time that the potential of BO against TNBC was revealed. Although BO had no cytotoxicity on TNBC cell lines in vitro, the oral administration of BO exhibited a gut microbiota–dependent tumor suppression without toxicity on the non-targeted organs in vivo. By metagenomics and untargeted metabolomics, it was found that BO not only altered the composition and amino acid metabolism function of gut microbiota but also regulated the host’s amino acid profile, which was in accordance with the metabolism alternation in gut microbiota. Moreover, the activity of mTOR in tumor was promoted by BO treatment as indicated by the phosphorylation of 4E-binding protein 1 (4E-BP1) and ribosomal protein S6, and hyper-autophagy was consequently restrained. By contrast, the failure of tumor suppression by BO under pseudo germ-free (PGF) condition came with indistinctive changes in autophagy and mTOR activity, implying the critical role of the gut microbiota in BO’s anticancer activity. The present study highlighted a promising application of BO against breast cancer with novel efficacy and safety.

Quassinoids from Brucea javanica and attenuates lipopolysaccharide-induced acute lung injury by inhibiting PI3K/Akt/NF-κB pathways

Four new quassinoids (1-4) and twenty known analogues (5-24) were isolated from the seeds of Brucea javanica. All the compounds belong to tetracyclic quassinoids. The structures of the new compounds were elucidated by comprehensive spectroscopic analysis, including HRESIMS and 1D, 2D NMR. In in vitro bioassays, (5-9, 17-19 and 23) showed inhibitory activities for nitric oxide (NO) release in LPS-activated MH-S macrophages and IC₅₀ values of 0.11-45.56 μM. Among them, bruceoside B significantly decreased LPS-induced NO, secretion of inflammatory factor cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β). Western Blot was used to verify the expression of p-IκB-α, IκB-α, p-NF-κB, NF-κB, Bax, Bcl-2, Caspase-3, p-PI3K, PI3K, p-Akt, and Akt proteins in PI3K/Akt/NF-κB signal pathway. Bruceoside B inhibited the activity of Akt and its downstream pathways and reduced the activation of apoptotic. In vivo, it was found that bruceoside B had obvious therapeutic effect on LPS-induced acute lung injury (ALI) in mice, and the effect of tissue section was obvious. The regulatory signal pathway of bruceoside B on inflammation was consistent with the anti-inflammatory pathway in vitro. Therefore, the results implied that bruceoside B has a certain therapeutic effect on inflammation and has a certainly effect on acute lung injury.

A brief overview of antitumoral actions of bruceine D

Cancer remains the second leading cause of mortality globally. In combating cancer, conventional chemotherapy and/or radiotherapy are administered as first-line therapy. However, these are usually accompanied with adverse side effects that decrease the quality of patient’s lives. As such, natural bioactive compounds have gained an attraction in the scientific and medical community as evidence of their anticancer properties and attenuation of side effects mounted. In particular, quassinoids have been found to exhibit a plethora of inhibitory activities such as anti-proliferative effects on tumor development and metastasis. Recently, bruceine D, a quassinoid isolated from the shrub Brucea javanica (L.) Merr. (Simaroubaceae), has come under immense investigation on its antineoplastic properties in various human cancers including pancreas, breast, lung, blood, bone, and liver. In this review, we have highlighted the antineoplastic effects of bruceine D and its mode of actions in different tumor models.

Ethanol Extract of Brucea javanica Seed Inhibit Triple-Negative Breast Cancer by Restraining Autophagy via PI3K/Akt/mTOR Pathway

Triple-negative breast cancer (TNBC) is an aggressive disease with worst prognosis than other subtypes of breast cancer. Owing to the lack of hormone receptors and HER2 expression on TNBC cells, patients do not have targeted therapy options available with other breast cancer subtypes. Extensive efforts have been made to identify novel therapeutics against TNBC. Interestingly, recent studies had shown that plant-derived natural products could modulate the autophagy and induce the breast cancer cells death. Seed of Brucea javanica has been used as an important traditional Chinese medicine against cancers. In the present study, the anti-breast cancer potential of ethanol crude extracts from B. javanica seed (BJE) was explored. Data demonstrated that BJE could inhibit the TNBC cell line MDA-MB-231 proliferation and induced apoptosis. In the cells exposed to BJE, protein expressions of UNC-51-like kinase-1 (ULK1) and Beclin-1 and the ratio of light chain 3 II/I (LC3 II/I) were reduced, while the expression of p62 was increased, indicating an inhibition on autophagy. Moreover, BJE promoted the phosphorylation of mammalian target of rapamycin (mTOR), phosphatidylinositol 3-kinase (PI3K), and Akt in MDA-MB-231. BJE also suppressed the MDA-MB-231 tumor growth in vivo. Coincide with the results in vitro, autophagy in the tumor tissue was weakened as indicated by decreased ratio of LC 3 II/I and Beclin-1 accompanied by enhanced phosphorylation of mTOR, which confirmed that autophagy restraint via the PI3K/Akt/mTOR signaling pathway contributes to the suppression by BJE. Notably, no noticeable toxicity in non-targeted organs was found, including small intestine, liver, and kidney. Taken together, this study revealed anti-breast cancer activity of BJE based on autophagy restraint, highlighting its clinical importance as a novel natural agent against TNBC.

Quassinoids in Brucea javanica are potent stimulators of lipolysis in adipocytes

Obesity is associated with a number of metabolic disorders. Lipolysis is the initial step in the metabolism of lipids stored in adipocytes and is therefore considered a therapeutic target for obesity. Quassinoids are unique terpenes found in plants of the Simaroubaceae family, which were recently reported to have lipolytic activity and to suppress weight gain. Brucea javanica is a plant employed in traditional medicines in Asia, which is known to contain various quassinoids. Here, we investigated the lipolytic activity of B. javanica extracts, and identified six quassinoids: brucein A, brucein B, brucein C, 3'-hydroxybrucein A, brusatol, and bruceantinol, which represent the bioactive principals. The quassinoids contained in B. javanica demonstrated lipolytic activity at nanomolar concentrations, which were an order of magnitude lower than those of the previously reported quassinoids, suggesting that they may be useful for the treatment of obesity.

Bruceine D Isolated from Brucea Javanica (L.) Merr. as a Systemic Feeding Deterrent for Three Major Lepidopteran Pests

Systemicity is a desirable property for insecticides. Many phytochemicals show good systemic properties and thus are natural sources of novel systemic insecticidal ingredients. Bruceine D, a quassinoid, was identified in Brucea javanica (L.) Merr. and displayed outstanding systemic properties and excellent antifeedant activity against the diamondback moth (DBM, Plutella xylostella L.), beet armyworm ( Spodoptera exigua Hübner), and cotton leafworm ( Spodoptera litura Fabricius). Its antifeedant effect on third instar larvae of DBM was approximately 6.2-fold stronger than that of azadirachtin. When bruceine D was applied to roots at a concentration of 100 μg/mL for 24 and 48 h, its concentration in flowering Chinese cabbage ( Brassica campestris L. ssp. chinensis var. utiliz Tsen et Lee) leaves was 38.69 μg/g (fresh weight, FW) and 108.45 μg/g (FW), respectively. These concentrations could achieve 93.80% and 96.83% antifeedant effects, which were significantly greater than those of azadirachtin. Similar to azadirachtin, bruceine D also posed a potent growth inhibition effect on insect larvae. After feeding with 20 μg/g bruceine D, no pupae were observed. The results demonstrated that bruceine D is an effective botanical insect antifeedant with outstanding systemic properties, causing potent pest growth inhibitory activity.

Quassinoids from seeds of Brucea Javanica and their anticomplement activities

An investigation on seeds of Brucea javanica led to the acquisition of a new quassinoid, 20-hydroxyyadanzigan (1), along with five known quassinoids (2-6). The structure of the new compound was elucidated on the basis of extensive spectral analysis. All of the compounds were assayed for their anticomplement activities through classical and alternative pathways. Compounds 1-6 exhibited potent anticomplement activity with CH₅₀ and AP₅₀ values of 0.032-0.075 mg/mL and 0.061-0.118 mg/mL, respectively. Moreover, the structure-activity relationships of these compounds are discussed.[Formula: see text].

Triterpenoids

Covering: 2013. Previous review: Nat. Prod. Rep., 2015, 29, 1028-1065This review covers the isolation and structure determination of triterpenoids reported during 2013 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 350 references are cited.

Antimalarial and cytotoxic quassinoids from the roots of Brucea javanica

Two new quassinoids, brujavanol A (1) and brujavanol B (2), along with five known quassinoids (3-7), were isolated from the roots of Brucea javanica. Their structures were elucidated by spectroscopic methods. The antimalarial and cytotoxic activities of the isolated compounds were also assessed. Compounds 1 and 2 exhibited significant in vitro cytotoxicity against human oral cavity cancer (KB) cells with IC₅₀ values of 1.30 and 2.36 μg/ml, respectively, whereas compound 3 showed excellent antiplasmodial activity against the Plasmodium falciparum strains, K1 (IC₅₀ = 0.58 μg/ml).

Cytotoxic Tirucallane and Apotirucallane Triterpenoids from the Stems of Picrasma quassioides

Phytochemical investigation on the stems of Picrasma quassioides led to the isolation of a novel compound, picraquassin A (1), with an unprecedented 21,24-cycloapotirucallane skeleton, and four new apotirucallane-type triterpenoids (2-5), together with 15 new tirucallane-type triterpenoids (6-20) and 10 known tirucallane-type triterpenoids (21-30). To our knowledge, this is the first report demonstrating the presence of apotirucallane-type triterpenoids in the genus Picrasma. The structures of the new compounds were determined based on spectroscopic data interpretation. Cytotoxicities of the isolated compounds were evaluated using three human cancer cell lines, MKN-28, A-549, and MCF-7. Compound 2 exhibited the most potent activity against MKN-28 cells with an IC50 value of 2.5 μM. Flow cytometry and Western blot analysis revealed that 2 induces the apoptosis of MKN-28 cells via activating caspase-3/-9, while increasing Bax and Bad and decreasing Bcl-2 expression levels.

Determination of a potential antitumor quassinoid in rat plasma by UPLC-MS/MS and its application in a pharmacokinetic study

A sensitive UPLC-MS/MS method was developed and validated for the determination of brusatol in rat plasma. Chromatographic separation was carried out on a C18 column using methanol and 10mM ammonium acetate containing 0.1% (v/v) formic acid (55:45, v/v). The lower limit of quantification (LLOQ) was 1.0 ng/mL for brusatol in plasma. The intra- and inter-day precision for the analyte ranged from 3.2% to 9.2% and 1.3% to 7.8%, and the accuracy was between 97.3% and 108.5%. The method was successfully applied in a pharmacokinetic study of brusatol following intravenous injection (0.5, 1.0, and 2.0mg/kg) of brusatol.

Apoptosis induction of dehydrobruceine B on two kinds of human lung cancer cell lines through mitochondrial-dependent pathway

BACKGROUND

Brucea javanica is an effective traditional medicine listed in Chinese Pharmacopoeia. In China, the seed oil of B. javanica has long been used as commercially available drug for the treatment of tumor in clinic. Dehydrobruceine B (DHB) is a quassinoid isolated from B. javanica.

PURPOSE

The aim of the present study is to investigate the apoptotic effects induced by DHB in human lung cancer A549 and NCI-H292 cells. The involvement of a mitochondria-mediated intrinsic pathway in the pro-apoptotic action of DHB was also investigated.

MATERIAL AND METHODS

Cell viability was determined by MTT assay. Cell cycle and apoptosis were assessed by flow cytometry analysis. Mitochondrial membrane potential (MMP) was examined through JC-1 staining. The protein translocation in cells was examined by immunostaining. The expression levels of proteins which are closely related to mitochondria-mediated apoptosis pathway were measured by immunoblot analysis.

RESULTS

Treatment with DHB decreased cell viability, induced apoptosis and blocked cell cycle at S phase. DHB-induced apoptosis was found to be mediated through mitochondrial intrinsic pathway, evidenced by the loss of MMP, the release of cytochrome c into cytosol, and the cleavage of caspase-9, caspase-3 and poly (ADP-ribose) polymerase (PARP).

CONCLUSION

DHB triggers apoptosis in A549 and NCI-H292 cells via mitochondrial pathway, making it a promising candidate as a therapeutic agent for lung carcinoma.

Suppression of human hepatocellular cancer cell proliferation by Brucea javanica oil-loaded liposomes via induction of apoptosis

INTRODUCTION

Hepatocellular carcinoma (HCC) is a type of malignancy with high incidence and poor prognosis. Brucea javanica is extracted from Simaroubaceae plants. It is found to have low toxicity but high anti-cancer efficiency. The aim of this study is to determine the effects of Brucea javanica oil-loaded liposomes (BJOL) on human hepatocellular cancer cell line HepG2. The related molecular mechanisms were determined.

MATERIAL AND METHODS

Morphologic changes of HepG2 cells were observed by transmission electron microscope after treatment with BJOL in vitro. Cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay after cell treatment with different doses of BJOL. Flow cytometry was performed. Nude mice were divided into 4 groups randomly and treated with different doses of BJOL. The apoptosis hepatocellular carcinoma was detected by TUNEL.

RESULTS

Proliferation of HepG2 was inhibited significantly by BJOL in a dose-dependent manner (2.5 mg/l or 5 mg/l). Compared with the animal models treated with the negative control, the animal models in the BJOL group had higher weight and lower metastasis rates (p < 0.01). The rate of apoptosis in hepatocellular carcinoma tissue of the BJOL groups was increased when compared with the control group (p < 0.05).

CONCLUSIONS

Brucea javanica oil-loaded liposomes inhibits proliferation of HepG2. The effect appears to be dose-dependent, possibly by inducing apoptosis of cancer cells.

Bioactive limonoid and triterpenoid constituents of Turraea pubescens

Eleven new limonoids, turrapubins A-K (1-11), and three new triterpenoids (12-14), along with 14 known compounds, were isolated from the twigs of Turraea pubescens. The structures of 1-14 were elucidated on the basis of NMR and MS analysis. Compounds 12, 16, 18, and 19 exhibited inhibitory activities against lipopolysaccharide-induced nitric oxide production in RAW264.7 cells. In addition, compounds 2, 11, 18, and 26 exhibited inhibitory activities against brine shrimp larvae (Artemia salina) at 100 ppm with the corrected mortality ranging from 81.7% to 100%.