Quassinoids from Twigs of Harrisonia perforata (Blanco) Merr and Their Anti-Parkinson's Disease Effect.

Six new C-20 and one new C-19 quassinoids, named perforalactones F-L (1-7), were isolated from twigs of Harrisonia perforata. Spectroscopic and X-ray crystallographic experiments were conducted to identify their structures. Through oxidative degradation of perforalactone B to perforaqussin A, the biogenetic process from C-25 quassinoid to C-20 via Baeyer-Villiger oxidation was proposed. Furthermore, the study evaluated the anti-Parkinson's disease potential of these C-20 quassinoids for the first time on 6-OHDA-induced PC12 cells and a Drosophila Parkinson's disease model of PINK1B9. Perforalactones G and I (2 and 4) showed a 10-15% increase in cell viability of the model cells at 50 µM, while compounds 2 and 4 (100 µM) significantly improved the climbing ability of PINK1B9 flies and increased the dopamine level in the brains and ATP content in the thoraces of the flies.

Quassinoid analogs exert potent antitumor activity via reversible protein biosynthesis inhibition in human colorectal cancer.

Cellular protein synthesis is accelerated in human colorectal cancer (CRC), and high expression of protein synthesis regulators in CRC patients is associated with poor prognosis. Thus, inhibition of protein synthesis may be an effective therapeutic strategy for CRC. We previously demonstrated that the quassinoid bruceantinol (BOL) had antitumor activity against CRC. Herein, potent tumor growth suppression (>80%) and STAT3 inhibition was observed in two different mouse models following BOL administration. Loss of body and spleen weight was observed but was eliminated upon nanoparticle encapsulation while maintaining strong antitumor activity. STAT3 siRNA knockdown exhibited modest suppression of cell proliferation. Surprisingly, STAT3 inhibition using a PROTAC degrader (SD-36) had little effect on cancer cell proliferation suggesting the possibility of additional mechanism(s) of action for quassinoids. BOL-resistant (BR) cell lines, HCT116BR and HCA7BR, were equally sensitive to standard CRC therapeutic agents and known STAT3 inhibitors but resistant to homoharringtonine (HHT), a known protein synthesis inhibitor. The ability of quassinoids to inhibit protein synthesis was dependent on the structure of the C15 sidechain. Of note, BOL did not inhibit protein synthesis in normal human colon epithelial cells whereas HHT and napabucasin remained effective in these normal cells. Novel quassinoids were designed, synthesized, and evaluated in pre-clinical CRC models. Treatment with the most potent analog, 5c, resulted in significant inhibition of cell proliferation and protein synthesis at nanomolar concentrations. These quassinoid analogs may represent a novel class of protein synthesis inhibitors for the treatment of human CRC.

Chemical constituents from the twigs and leaves of Picrasma quassioides.

Two new compounds, including a norsesquiterpenoid, annuionone H (1), and a quassinoid, picraqualide G (2), along with eleven known compounds (3-13), were isolated from the twigs and leaves of Picrasma quassioides. Comprehensive spectroscopic analyses and NMR calculation with DP4+ analysis were used to identify their structures. Moreover, of all these compounds, compound 4 showed a week inhibition rate in the anti-inflammatory screening results against mouse macrophage J774A.1 cell.

Antiviral Activity of Ailanthone from Ailanthus altissima on the Rice Stripe Virus.

Rice stripe disease caused by the rice stripe virus (RSV), which infects many Poaceae species in nature, is one of the most devastating plant viruses in rice that causes enormous losses in production. Ailanthone is one of the typical C20 quassinoids synthesized by the secondary metabolism of Ailanthus altissima, which has been proven to be a biologically active natural product with promising prospects and great potential for use as a lead structure for pesticide development. Based on the achievement of the systemic infection and replication of RSV in Nicotiana benthamiana plants and rice protoplasts, the antiviral properties of Ailanthone were investigated by determining its effects on viral-coding RNA gene expression using reverse transcription polymerase chain reaction, and Western blot analysis. Ailanthone exhibited a dose-dependent inhibitory effect on RSV NSvc3 expression in the assay in both virus-infected tobacco plants and rice protoplasts. Further efforts revealed a potent inhibitory effect of Ailanthone on the expression of seven RSV protein-encoding genes, among which NS3, NSvc3, NS4, and NSvc4 are the most affected genes. These facts promoted an extended and greater depth of understanding of the antiviral nature of Ailanthone against plant viruses, in addition to the limited knowledge of its anti-tobacco mosaic virus properties. Moreover, the leaf disc method introduced and developed in the study for the detection of the antiviral activity of Ailanthone facilitates an available and convenient screening method for anti-RSV natural products or synthetic chemicals.

Quassinoids from Eurycoma longifolia and their bone formation evaluation in zebrafish, C3H10 cells and silico.

Phytochemicals with bone formation potential in traditional medicines captured more and more attentions due to their advantages to bone loss and fewer side effects. As a famous aphrodisiac phytomedicine, Eurycoma longifolia (EL) has acquired general recognition in improving male sexual health, and thus been considered as traditional medicine for the treatment of androgen-deficient osteoporosis. Although the aqueous extract of EL had been proved to be beneficial to bone loss, the active constituents and the mechanisms underlying the effects are still obscure. The current study performed a chemical investigation on the roots of EL, which resulted in the isolation and identification of ten quassinoids (EL-1-EL-10), and then conducted their osteogenic activity evaluations in vivo zebrafish model with or without dexamethasone (Dex) and in vitro C3H10 cell model. The result displayed that most tested concentrations of EL-1-EL-5 could significantly increase the mineralization areas and integrated optical densities (IODs) of skull in both zebrafish model. The majority tested concentrations of EL-1-EL-5 could also improve the mRNA expression of early osteogenic associated genes ALPL, Runx2a, Sp7 in zebrafish model without Dex, but only a few could accelerate the mRNA expression of late osteogenic associated genes OCN. These results suggested the ability of EL-1-EL-5 to increase bone formation mainly by accelerating osteogenic differentiation at the early stage. The structure-based virtual screening based on the pharmacophores in ePharmaLib, as well as the molecular docking study, implied that the effects of the quassinoids (EL-1-EL-5) on the enhancement of bone formation might be related with improving the content and the activity of androgen through binding with CYP19A, SHBG and AKR1C2, and activating bone metabolism-related ANDR target genes and signal pathways by combining with ANDR directly. Although the assumptions are in silico model-based and further in vitro and in vivo validations are still necessary, we provided a new perspective to explore the potential of EL to be used as an alternative treatment for not only androgen-deficient osteoporosis, but also estrogen-deficient bone loss, by combining with SHBG.

A New C22-Quassinoid with Anti-Pancreatic Adenocarcinoma Activity from Seeds of Brucea javanica.

An undescribed C22-quassinoid named sergeolide A (1) and fifteen known quassinoids (2-16) were obtained from the seeds of Brucea javanica (Simaroubaceae). All chemical structures were established based on spectroscopic data and X-ray diffraction analysis. Sergeolide A (1) is the first example of a naturally occurring C22-quassinoid bearing a butenolide group fused the A ring of the bruceolide skeleton from Brucea genus. And this is the first report of the NMR data for desmethyl-bruceines B (2) and C (3) and the crystal structure for bruceolide (11). In addition, all isolates were evaluated for their anti-pancreatic adenocarcinoma activity by measuring the growth inhibitory of the MIA PaCa-2 cell lines. Consequently, compounds 1, 7-10, and 12-16 exhibited potent anti-pancreatic cancer activity in vitro (IC50 =0.054∼0.357 µM).

The Anthelmintic Quassinoids Ailanthone and Bruceine a Induce Infertility in the Model Organism Caenorhabditis elegans by an Apoptosis-like Mechanism Induced in Gonadal and Spermathecal Tissues.

In continuation of the search for new anthelmintic natural products, the study at hand investigated the nematicidal effects of the two naturally occurring quassinoids ailanthone and bruceine A against the reproductive system of the model nematode Caenorhabditis elegans to pinpoint their anthelmintic mode of action by the application of various microscopic techniques. Differential Interference Contrast (DIC) and the epifluorescence microscopy experiments used in the presented study indicated the genotoxic effects of the tested quassinoids (c ailanthone = 50 µM, c bruceine A = 100 µM) against the nuclei of the investigated gonadal and spermathecal tissues, leaving other morphological key features such as enterocytes or body wall muscle cells unimpaired. In order to gain nanoscopic insight into the morphology of the gonads as well as the considerably smaller spermathecae of C. elegans, an innovative protocol of polyethylene glycol embedding, ultra-sectioning, acridine orange staining, tissue identification by epifluorescence, and subsequent AFM-based ultrastructural data acquisition was applied. This sequence allowed the facile and fast assessment of the impact of quassinoid treatment not only on the gonadal but also on the considerably smaller spermathecal tissues of C. elegans. These first-time ultrastructural investigations on C. elegans gonads and spermathecae by AFM led to the identification of specific quassinoid-induced alterations to the nuclei of the reproductive tissues (e.g., highly condensed chromatin, impaired nuclear membrane morphology, as well as altered nucleolus morphology), altogether implying an apoptosis-like effect of ailanthone and bruceine A on the reproductive tissues of C. elegans.

Two Novel Quassinoid Glycosides with Antiviral Activity from the Samara of Ailanthus altissima.

Phytochemistry investigations on Ailanthus altissima (Mill.) Swingle, a Simaroubaceae plant that is recognized as a traditional herbal medicine, have afforded various natural products, among which C20 quassinoid is the most attractive for their significant and diverse pharmacological and biological activities. Our continuous study has led to the isolation of two novel quassinoid glycosides, named chuglycosides J and K, together with fourteen known lignans from the samara of A. altissima. The new structures were elucidated based on comprehensive spectra data analysis. All of the compounds were evaluated for their anti-tobacco mosaic virus activity, among which chuglycosides J and K exhibited inhibitory effects against the virus multiplication with half maximal inhibitory concentration (IC50) values of 56.21 ± 1.86 and 137.74 ± 3.57 µM, respectively.

Medicinal Activities and Nanomedicine Delivery Strategies for Brucea javanica Oil and Its Molecular Components.

Brucea javanica oil (BJO) is widely used in traditional Chinese medicine to treat various types of cancer and inflammatory diseases. There is significant interest in understanding the medicinal activities of BJO and its molecular components, especially quassinoids, and in exploring how they can be incorporated into nanomedicine delivery strategies for improved application prospects. Herein, we cover the latest progress in developing different classes of drug delivery vehicles, including nanoemulsions, liposomes, nanostructured lipid carriers, and spongosomes, to encapsulate BJO and purified quassinoids. An introduction to the composition and medicinal activities of BJO and its molecular components, including quassinoids and fatty acids, is first provided. Application examples involving each type of drug delivery vehicle are then critically presented. Future opportunities for nanomedicine delivery strategies in the field are also discussed and considered within the context of translational medicine needs and drug development processes.

[Qualitative and quantitative analysis of quassinoid diterpenoids from Eurycoma longifolia by UPLC-Q-TOF-MS combined with UPLC-QQQ-MS/MS].

In this work, a sensitive and efficient method was established and validated for qualitative and quantitative analysis of major quassinoid diterpenoids constituents from the extract of Eurycoma longifolia by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) and ultra-performance liquid chromatography coupled with a triple quadrupole mass spectrometry(UPLC-QQQ-MS/MS). The UPLC-Q-TOF-MS analysis was performed on an Agilent Eclipse Plus C_(18) RRHD(2.1 mm×100 mm,1.8 µm) column with acetonitrile and 0.1% formic acid water as mobile phase by gradient elution. The UPLC-QQQ-MS/MS analysis was performed on an Agilent Eclipse Plus C_(18) RRHD(2.1 mm×50 mm, 1.8 µm)column with acetonitrile and 0.1% formic acid water as mobile phase by gradient elution. The data was collected by electrospray ionization in positive mode. According to the contrast of the reference standards and the accurate masses of molecules, a total of 32 quassinoid diterpenoids in E. longifolia extract were identified by UPLC-Q-TOF-MS. For quantitative the linear range of 4 detected quassinoid diterpenoids were good(r≥0.999 6), and the overall recoveries ranged from 90.35% to 106.4%, with the RSD ranging from 1.8% to 3.6%. The method was accurate, reliable and efficient, and could comprehensively reflect the chemical constituents and content of E. longifolia, and could provide a reference for further elucidating its pharmacological basis and quality control.

Extract and the quassinoid ailanthone from Ailanthus altissima inhibit nematode reproduction by damaging germ cells and rachis in the model organism Caenorhabditis elegans.

Bark and leaves of Ailanthus altissima (Mill.) Swingle are widely used in European folk medicine to treat intestinal worm infections. The study aimed to rationalize a potential anthelmintic effect of A. altissima extract against the model organism Caenorhabditis elegans. A methanol-water (7:3, v/v) extract of the primary stem bark was tested on L4 larvae of C. elegans for induction of mortality and influence on reproduction. Bioactivity-guided fractionation was performed by chromatography on MCI-gel, preparative HPLC on RP18 stationary phase and fast-centrifugal-partition-chromatography. Structural elucidation of isolated quassinoids was performed by NMR and HR-ESI-MS. The sterilizing effect on C. elegans was investigated by light microscopy and atomic force microscopy of ultra-sections. Different GFP-tagged reporter strains were used to identify involved signaling pathways. A. altissima extract (1 mg/mL) irreversibly inhibited the reproduction of C. elegans L4 larvae. This effect was dependent on the larval stage since L3 larvae and adults were less affected. Bioactivity-guided fractionation revealed the quassinoid ailanthone 1 as the major active compound (IC50 2.47 µM). The extract caused severe damages to germ cells and rachis, which led to none or only poorly developed oocytes. These damages led to activation of the transcription factor DAF-16, which plays a major role in the nematode's response to stress. A regulation via the respective DAF-2/insulin-like signaling pathway was not observed. The current findings support the traditional use of A. altissma in phytotherapy to treat helminth infections and provide a base for standardization of the herbal material.

Anticancer properties and mechanism of action of the quassinoid ailanthone.

Ailanthone (AIT) is a quassinoid natural product isolated from the worldwide-distributed plant Ailanthus altissima. The drug displays multiple pharmacological properties, in particular significant antitumor effects against a variety of cancer cell lines in vitro. Potent in vivo activities have been evidenced in mice bearing hepatocellular carcinoma, nonsmall cell lung cancer and castration-resistant prostate cancer. This review focusses on the mechanism of action of AIT, notably to highlight the capacity of the drug to activate DNA damage responses, to inhibit the Hsp90 co-chaperone p23 and to modulate the expression of several microRNA. The interconnexion between these effects is discussed. The unique capacity of AIT to downregulate oncogenic miR-21 and to upregulate the tumor suppressor miRNAs miR-126, miR-148a, miR-195, and miR-449a is presented. AIT exploits several microRNAs to exert its anticancer effects in distinct tumor types. AIT is one of the rare antitumor natural products that binds to and strongly inhibits cochaperone p23, opening interesting perspectives to treat cancers. However, the toxicity profile of the molecule may limit its development as an anticancer drug, unless it can be properly formulated to prevent AIT-induced gastro-intestinal damages in particular. The antitumor properties of AIT and analogs are underlined, with the aim to encourage further pharmacological studies with this underexplored natural product and related quassinoids. HIGHLIGHTS: Ailanthone (AIT) is an anticancer quassinoid isolated from Ailanthus altissima It inhibits proliferation and induces cell death of many cancer cell types The drug activates DNA damage response and targets p23 cochaperone Up or downregulation of several microRNA by AIT contributes to the anticancer activity Analogs or specific formulations must be developed to prevent the toxicity of AIT.

Ailanthone inhibition data on seed germination and seedling growth of Lepidium sativum L. and Raphanus sativus L.

Ailanthone is a quassinoid from Ailanthus altissima (Mill.) Swingle with allelopathic properties that deserves interest for its potential use as a natural herbicide. Data about seed germination and root and hypocotyl length of two model species (Lepidium sativus L.'Inglese' and Raphanus sativus L.'Tondo Rosso BIO') treated with different concentrations of ailanthone are reported. Data derive from experiments performed in a growth chamber on filter paper, non-sterile urban soil, and a cultivation substrate for horticulture. Part of their elaboration and interpretation can be found in the research article titled "Ailanthone from Ailanthus altissima (Mill.) Swingle as potential natural herbicide" (Demasi et al., 2019).

Relationship between Structural Characteristics and Plant Sources along with Pharmacology Research of Quassinoids.

Quassinoids, one kind of triterpenoids with multiple bioactivities such as anti-cancer, anti-malarial, anti-oxidative, anti-microbial, anti-diabetic, anti-viral, and anti-inflammatory effects, have drawn much attention in recent years. Between 2004 and 2018, the structural characteristics and plant sources of 190 quassinoids were reported. Herein, the structure-activity relationships (SARs) of quassinoids along with the anti-cancer mechanisms of four representative quassinoids, eurycomanone, bruceine D, dehydrobruceine B, and brusatol are discussed. This review might be useful for further research and development of quassinoids.

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.

Pharmacokinetic study on bruceoside A revealed the potential role of quassinoid glycosides for the anticancer properties of Fructus Bruceae.

Bruceoside A, an abundant quassinoid glycoside in Fructus Bruceae, was chosen for the pharmacokinetic study. It is the first case report on the pharmacokinetic study of quassinoid glycosides so far. A sensitive, accurate, and repeatable UHPLC-MS/MS method was developed for the determination of bruceoside A and its major metabolite. The results showed bruceoside A could be transformed into the potent anticancer component brusatol in vivo, rather than its direct deglycosylated metabolite bruceosin. And the intestinal bacteria were proposed to take a potential role during such transformation. Based on the present study, it could be concluded that the quassinoid glycosides possessing weak activities in vitro could do contribution to the anticancer properties of Fructus Bruceae in vivo via transforming into more active metabolites.

Antitumor activity of the Ailanthus altissima bark phytochemical ailanthone against breast cancer MCF-7 cells.

Ailanthone is isolated from the bark of Ailanthus altissima (Mill.) Swingle (Simaroubaceae). The mechanism that underlies the activity of ailanthone on MCF-7 cells was investigated by MTT assay. Breast cancer MCF-7 cells were treated with 0.5, 1.0, 2.0, 4.0 and 8.0 µg/ml ailanthone for 24, 48 and 72 h. The inhibition of proliferation induced by treatment with ailanthone was assessed by MTT assay. Apoptosis and cell cycle distribution in MCF-7 cells with the same doses of ailanthone for 48 h were determined by flow cytometry. Expression of apoptosis-associated genes and proteins were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis, respectively. The results revealed that ailanthone inhibited MCF-7 cell proliferation. Flow cytometry assay demonstrated that ailanthone induced apoptosis and G0/G1 cell cycle arrest in MCF-7 cells. Western blotting and RT-PCR assays demonstrated that upregulation of pro-apoptotic caspase-3 and Bcl-associated X, and downregulation of anti-apoptotic apoptosis regulator B-cell lymphoma-2 in MCF-7 cells may be associated with the induction of apoptosis and inhibition of proliferation. To the best of our knowledge, the present study is the first to investigate the antitumor activity of ailanthone from A. altissima on MCF-7 cells and to attempt to elucidate the underlying mechanism. The present study revealed the presence of ailanthone-mediated antitumor effects, indicating that ailanthone may be a novel phytomedicine with potential use in breast cancer therapy.

Production of eurycomanone from cell suspension culture of Eurycoma longifolia.

CONTEXT: Eurycomanone is found in the Eurycoma longifolia Jack (Simaroubaceae) tree, exhibits significant antimalarial activity, improves spermatogenesis, suppresses expression of lung cancer cell tumour markers and regulates signalling pathways involved in proliferation, cell death and inflammation. OBJECTIVES: Establishment of cell suspension culture of E. longifolia to determine the eurycomanone accumulation during cultures. MATERIALS AND METHODS: Callus of E. longifolia was cultured in MS medium supplemented with 0.8% agar, 30/L sucrose, 1.25 mg/L NAA and 1 mg/L KIN for biomass production. Cell suspension culture was established by transferring friable calli to the same medium without agar. Eurycomanone content during cell culture was determined by HPLC with a C18 column, flow rate of 0.8 mL/min, run time of 17.5 min, detector wavelength of 254 nm. The stationary phase was silica gel and the mobile phase was acetonitric:H2O. Roots of 5 year-old trees were used as the control. RESULTS: The cells from 3 g of inoculum increased in biomass with a maximum value of 16 g fresh weight (0.7 g dry weight) at 14th day of culture. The cell growth then decreased from day 14 to day 20. Eurycomanone was produced during culture from the beginning to 20th day, its highest content (1.7 mg/g dry weight) also obtained at 14th day (the control is 2.1 mg/g dry weight). DISCUSSION AND CONCLUSIONS: Cell suspension culture of E. longifolia is a suitable procedure to produce eurycomanone. The yield of eurycomanone biosynthesis in 14 days-old cells are relatively high, approximately 0.8 times the control.

HPLC-MS/MS method for bioavailability study of bruceines D & E in rat plasma.

Bruceines D and E are quassinoids from seeds of Brucea javanica (L.) Merr. exhibiting hypoglycemia effect. The crude drug is used as a traditional medicine by diabetes patients. The aim of this study is to understand the bioavailability and pharmacokinetics of both the bruceines D & E. A rapid and sensitive HPLC-MS/MS method was developed and validated for the quantification of both quassinoids, bruceines D & E in rat plasma. Both the bruceines D & E were separated with the Zorbax SBC-18 column with gradient elution and mobile phase system of acetonitrile and deionized water with 0.1% formic acid at a flow rate of 0.5mL/min. Analytes were detected in multiple reaction monitoring (MRM) mode with electrospray positive ionization. The quassinoids, namely bruceines D & E were detected with transitions of m/z 411.2→393.2 and m/z 395.2→377.2, respectively. Another quassinoid, eurycomanone was used as the internal standard with transition of m/z 409.2→391.2. The method was validated and conformed to the regulatory requirements. The validated method was applied to pharmacokinetic and bioavailability studies in rats. The pharmacokinetic study indicated both bruceine D and E were rapidly absorbed into the circulation system and reached its peak concentration at 0.54±0.34h and 0.66±0.30h, respectively. Bruceine E was eliminated slower than Bruceine D with t1/2 value almost increased two-fold compared to Bruceine D. In conclusion, a rapid, selective and sensitive HPLC-MS/MS method was developed for the simultaneous determination of both the bruceines D and E in rat plasma. Both bruceines D and E displayed poor oral bioavailability.

Quassinoids from the Root of Eurycoma longifolia and Their Antiproliferative Activity on Human Cancer Cell Lines.

BACKGROUND: The roots of Eurycoma longifolia Jack have traditionally been used as an aphrodisiac tonic besides the other remedies for boils, fever, bleeding gums, and wound ulcer. Recently, the antiproliferative activity of E. longifolia has been reported and remained attractive to natural chemists. OBJECTIVE: The objective of this study was to study on antiproliferative compounds from the root of E. longifolia. MATERIALS AND METHODS: Column chromatography was used to separate individual compounds, spectroscopic data including nuclear magnetic resonances and mass spectrometry were analyzed to determine the chemical structure of the isolates and for biological testing, antiproliferative activity of compounds was tested on seven human cancer cell lines (KATO III, HCT-15, Colo205, HepG2, PC-3, Jurkat, HL-60) by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. RESULTS: Nine quassinoids including a new C19 longilactone-type quassinoid glycoside were characterized from the roots of the title plant. Among them, the major quassinoid eurycomanone exhibited selectively potential antiproliferative activities on the leukemia cell lines (HL-60 and Jurkat) and had very low toxic effects on normal skin fibroblast cell line (NB1RGB). CONCLUSION: The current study reveals one new quassinoid glycoside and the potential active component (eurycomanone) from E. longifolia for the leukemia treatment. SUMMARY: Nine quassinoids (1-9) including one new quassinoid glycoside (9) and eight known ones were isolated from the roots of Eurycoma longifoliaThe structure of the new quassinoid 9 was determined by extensive chemical and spectroscopic analysesThe major quassinoid, eurycomanone (3), exhibited selectively potential antiproliferative activities on both Jurkat and HL-60 leukemia cells and had very low toxic effects on normal skin fibroblast cell line (NB1RGB). Abbreviations used: COSY: Correlation spectroscopy; HMBC: Heteronuclear multiple-bond correlation; HMQC: Heteronuclear multiple quantum correlation; NMR: Nuclear magnetic resonance; NOESY: Nuclear Overhauser enhancement spectroscopy; TLC: Thin layer chromatography.