Quassinoid Compound Research Articles

Bruceantinol targeting STAT3 exerts promising antitumor effects in in vitro and in vivo osteosarcoma models.

Bruceantinol (BOL) is a quassinoid compound found in the fruits of Brucea javanica. Previous research has highlighted the manifold physiological and pharmacological activities of BOL. Notably, BOL has demonstrated antitumor cytotoxic and antibacterial effects, lending support to its potential as a promising therapeutic agent for various diseases. Despite being recognized as a potent antitumor inhibitor in multiple cancer types, its efficacy against osteosarcoma (OS) has not been elucidated. In this work, we investigated the antitumor properties of BOL against OS. Our findings showed that BOL significantly decreased the proliferation and migration of OS cells, induced apoptosis, and caused cell death without affecting the cell cycle. We further confirmed that BOL potently suppressed tumor growth in vivo. Mechanismly, we discovered that BOL directly bound to STAT3, and prevent the activation of STAT3 signaling at low nanomolar concentrations. Overall, our study demonstrated that BOL potently inhibited the growth and metastasis of OS, and efficiently suppressed STAT3 signaling pathway. These results suggest that BOL could be a promising therapeutic candidate for OS.

Brusatol's anticancer activity and its molecular mechanism: a research update.

Brusatol (BT) is a quassinoid compound extracted from Brucea javanica that is a traditional Chinese herbal medicine. Brusatol possesses biological and medical activity, including antitumor, antileukemia, anti-inflammatory, antitrypanosomal, antimalarial, and antitobacco mosaic virus activity. To summarize and discuss the antitumor effects of BT and its mechanisms of actions, we compiled this review by combining the extensive relevant literature and our previous studies. We searched and retrieved the papers that reported the pharmacological effects of BT and the mechanism of BT antitumor activity from PubMed until July 2023. Numerous studies have shown that BT is a unique nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor that acts on various signaling pathways and has good antitumor properties. Brusatol shows great potential in cancer therapy by inhibiting cell proliferation, blocking the cell cycle, promoting tumor cell differentiation, accelerating tumor cell apoptosis, inducing autophagy, suppressing angiogenesis, inhibiting tumor invasion and metastasis, and reversing multidrug resistance. This review summarizes recent updates on the antitumor activity and molecular mechanisms of BT and provides references for future development and clinical translation of BT and its derivatives as antitumor drugs.

Comparison of Three Aphrodisiac Plants (Eurycoma longifolia, Polyalthia bullata and Stema tuberosa) Synonymous with Tongkat Ali

The indigenous people of Malaysia pioneered the use of Tongkat Ali for its aphrodisiac purposes. They gave at least three plants the common name of Tongkat Ali, including E. longifolia, P. bullata and S. tuberosa. Since E. longifolia is the most widely used root of the three, it has undergone extensive research compared to P. bullata and S. tuberosa. Proteins found in E. longifolia have been proven to be the aphrodisiac bioactive constituent. Parameters such as pH level, moisture content, heavy metal content and microbial load were compared between all three roots after aqueous extraction under reflux, followed by quantitative protein assay, SDS PAGE and HPLC. The pH and moisture content of the extracts were within the acceptable ranges of 5% to 6% and 3% to 7% (w/w), respectively; additionally, no heavy metals were found. Microbes, which were initially detected, were undetectable once a decontamination step was introduced during the treatment. The protein yield for E. longifolia, P. bullata and S. tuberosa were 0.014%, 0.008% and 0.006% (w/w), respectively, and the SDS PAGE provided a single band within the range of 10 to 20 kDa molecular weight. The HPLC of Eurycomanone, a common quassinoid compound, was found in E. longifolia but not in the other two Tongkat Ali. In conclusion, the three plants investigated possess several physicochemical differences but share the same protein, likely contributing to their aphrodisiac activity.&nbsp

Bruceine A protects against diabetic kidney disease via inhibiting galectin-1

Bruceine A is a natural quassinoid compound extracted from the fruit of the Traditional Chinese Medicine Brucea javanica (L.) Merr. that has various types of various biological activities. However, whether the compound has a protective effect on diabetic kidney disease remains unknown. Galectin-1 is actively involved in a variety of chronic inflammation-relevant human diseases including diabetic kidney disease. Here, we identified Bruceine A as a kidney protective molecule against a model of diabetic kidney disease in db/db mice with potent anti-inflammatory activity both invitro and invivo. Mechanistically, by selectively binding to the conserved carbohydrate-recognition domain of galectin-1 and disrupting the interaction between galectin-1 and the receptor for activated protein C kinase 1, Bruceine A was found to inhibit galectin-1-mediated inflammatory signal transduction under high glucose stress in rat mesangial HBZY-1 cells. Thus, our findings reveal Bruceine A as an unidentified galectin-1 inhibitor affording significant protection against diabetic kidney disease and may provide novel pharmacological therapeutics for the disease.

The botanical eurycomanone is a potent growth regulator of the diamondback moth

Eurycomanone is a quassinoid compound that is derived from Eurycoma longifolia, and it is often used as an indicator to evaluate the active ingredients of Eurycoma longifolia. However, Eurycomanone has rarely been reported to have biological activity toward pests. In this study, we evaluated the antifeedant activity of eurycomanone against the diamondback moth(Plutella xylostella), with a non-selective AFC50(the concentration that corresponds to 50% antifeedant action) value and selective AFC50 of 17.5 mg/L and 14.2 mg/L, respectively, which were 2.1-fold (36.9 mg/L) and 2-fold (28.5 mg/L) lower than that of azadirachtin, respectively. In addition, eurycomanone was used to treat the roots of Brassica chinensis L. at a concentration of 100 µg/g for 72 h. The antifeedant index was found to reach 93% by tracking the leaves. After feeding with 20 µg/g eurycomanone, no pupae or eclosion were observed. To explore this mechanism, we used scanning electron microscopy to discover that eurycomanone could prevent the development of taste receptors on the maxillary palp of diamondback moth larvae. Additional electrophysiological measurements showed that eurycomanone exhibited excitatory action to the central taste neurons of diamondback moth and significantly inhibited the GABAA receptor current. Eurycomanone exhibited significant activity as an antifeedant, inhibited growth and excelled at systemic absorption.

Can Javanicins be Potential Inhibitors of SARS-Cov-2 C-3 like Protease? An Evaluation through Molecular Docking Studies

Objectives: Corona virus SARS-CoV-2, otherwise known as COVID-19 has created a pandemic from which any respite seems far away. Since its outbreak in late December in 2019, till as of June 9, 2020 the virus has infected 7,237,929 people throughout practically every country of the world and caused deaths of 409,630 persons. Thus far, despite the best efforts of scientists, any vaccine or drug against COVID-19 is yet to be discovered. The objective of the present study was to evaluate through molecular docking studies a number of quassinoid compounds (javanicins) present in the plant Picrasma javanica regarding their ability to bind to the main protease of COVID-19 [C3-like protease or 3CLpro, (PDB ID: 6LU7)]. Methods: Molecular docking (blind) were done with the help of AutodockVina. Results: We observed that of the twelve javanicins studied, nine showed moderate to strong binding affinities to the main protease of COVID-19. Furthermore, the binding in each case was to the active site of the protease. We observed that the javacinins bound to the region, which the protease inhibitor N3 has been shown to bind. Conclusion: It is therefore very likely that the javanicins are inhibitors of the coronavirus main protease. Since the protease plays an essential part in viral replication, javanicins merit further study for their potential use as therapeutic agents.

Simalikalactone D, a Potential Anticancer Compound from Simarouba tulae, an Endemic Plant of Puerto Rico.

Species of the genus Simarouba have been studied because of their antimalarial and antileukemic activities. A group of oxygenated terpenes called quassinoids have been isolated from species of the Simarouba genus, and are responsible for its therapeutic properties. We hypothesized that Simarouba tulae, an endemic plant from Puerto Rico, is a natural source rich in quassinoid compounds with anticancer activity. The leaves were processed and extracted with solvents of different polarities. The extracts were screened for their antiproliferative activity, and it was shown that the chloroform extract was the most active extract. This extract was purified using different chromatographic techniques to afford the quassinoid simalikalactone D (SKD). This compound was further characterized using NMR and X-ray diffraction analysis. A reassessment of original structural assignments for SKD is proposed. SKD showed high cytotoxicity activity, with an IC50 of 55, 58, and 65 nM in A2780CP20 (ovarian), MDA-MB-435 (breast), and MDA-MB-231 (breast) cell lines, respectively. Exposure to SKD led to 15% inhibition of the migration of MDA-MB-231 cells.

The protein synthesis inhibitor brusatol normalizes high‐fat diet‐induced glucose intolerance in male C57BL/6 mice: role of translation factor eIF5A hypusination

The naturally occurring quassinoid compound brusatol improves the survival of insulin-producing cells when exposed to the proinflammatory cytokines IL-1β and IFN-γ in vitro. The aim of the present study was to investigate whether brusatol also promotes beneficial effects in mice fed a high-fat diet (HFD), and if so, to study the mechanisms by which brusatol acts. In vivo, we observed that the impaired glucose tolerance of HFD-fed male C57BL/6 mice was counteracted by a 2 wk treatment with brusatol. Brusatol treatment improved both β-cell function and peripheral insulin sensitivity of HFD-fed mice. In vitro, brusatol inhibited β-cell total protein and proinsulin biosynthesis, with an ED50 of ∼40 nM. In line with this, brusatol blocked cytokine-induced iNOS protein expression via inhibition of iNOS mRNA translation. Brusatol may have affected protein synthesis, at least in part, via inhibition of eukaryotic initiation factor 5A (eIF5A) hypusination, as eIF5A spermidine association and hypusination in RIN-5AH cells was reduced in a dose- and time-dependent manner. The eIF5A hypusination inhibitor GC7 promoted a similar effect. Both brusatol and GC7 protected rat RIN-5AH cells against cytokine-induced cell death. Brusatol reduced eIF5A hypusination and cytokine-induced cell death in EndoC-βH1 cells as well. Finally, hypusinated eIF5A was reduced in vivo by brusatol in islet endocrine and endothelial islet cells of mice fed an HFD. The results of the present study suggest that brusatol improves glucose intolerance in mice fed an HFD, possibly by inhibiting protein biosynthesis and eIF5A hypusination.-Turpaev, K., Krizhanovskii, C., Wang, X., Sargsyan, E., Bergsten, P., Welsh, N. The protein synthesis inhibitor brusatol normalizes high-fat diet-induced glucose intolerance in male C57BL/6 mice: role of translation factor eIF5A hypusination.

A Rapid and Sensitive UPLC-MS/MS Method for Quantification of Bruceantinol in Rat Plasma and Its Application to a Pharmacokinetic Study.

Bruceantinol (BOL), a quassinoid compound isolated from the fruits of Brucea javanica, has been reported to have cytotoxic and antibacterial effects. In this study, a rapid, sensitive, and specific ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed for the quantitative determination of BOL in rat plasma. The samples were treated by simple liquid-liquid extraction with ethyl acetate and separated on an UPLC BEH C18 column (2.1 mm × 50 mm) using a 3-min gradient elution scheme, which consists of water (0.1% v/v, formic acid) and methanol (0.1%, v/v, formic acid) to achieve the separation of BOL and sinomenine (IS) with high selectivity. The electrospray ionization source was used in positive ion mode; the multiple reaction monitoring quantified the target fragment ions m/z 629.6 → 569.5 for BOL and m/z 330.5 → 207.3 for IS. This work was evaluated with regards to the specificity, extraction recovery, matrix effect, linearity, accuracy, precision, stability, and dilution integrity. This approach was used to examine the pharmacokinetics of BOL in rats after oral (0.3 mg/kg) and intravenous (0.15 mg/kg) administration. BOL presented fast excretion and very low oral bioavailability.

Dehydrobruceine C, A New Quassinoid from the Seeds of Brucea javanica

Background: The seeds of Brucea javanica are known to be an abundant source of quassinoids, which have a structurally diverse and wide spectrum of biological effects, such as potential antiinflammatory, antitumor, antimalarial, antiamebic, and cytotoxic activities. However, only several dehydro-quassinoids were isolated and identified in this plant. Methods: The EtOAc extract of the seeds of B. javanica was submitted to silica gel CC, ODS, Sephadex LH-20, and RP-HPLC to get four compounds. Their chemical structures were elucidated by spectroscopic methods including UV, IR, 1D-NMR, 2D-NMR, and HR-MS. The inhibitory effects of 1-4 on nitric oxide (NO) production in lipopolysaccharide-activated macrophages were also evaluated. Results: A new dehydro-quassinoid namely, dehydrobruceine C (1), along with bruceine B (2), bruceine C (3), and bruceantinol (4) were separated from the EtOAc extract of the seeds of B. javanica. Compounds 1-4 displayed different intensity inhibitory effects on NO production, and their IC50 values were 33.11, 26.83, 9.08 and 8.25 μM, respectively, compared to indomethacin. Conclusion: B. javanica has been proven to contain structurally diverse and biologically active quassinoids. This is the first report on the isolation and chemical structure identification of dehydrobruceine C (1), this new quassinoid compound exhibited moderate anti-inflammatory activities in vitro. Keywords: Brucea javanica, dehydrobruceine C, nitric-oxide production, quassinoid, simaroubaceae.

CYTOTOXIC COMPOUND FROM ETHYL ACETATE FRACTION OF Brucea javanica (L.) Merr FRUIT AGAINST HeLa CELL LINE

<p>The pure compound relatively (85 mg) was isolated from 4.5 kg <em>Brucea javanica</em> (L.) Merr. fruits sample. It was obtained from ethyl acetate fraction as a red-brownish amorphous solid of melting point 202-206 <sup>o</sup>C. Phytochemical screening of isolate showed positive result of terpenoid group. Based on analysis by UV, IR,<sup>1</sup>H-NMR and <sup>13</sup>C-NMR spectroscopy and by comparison with known related compounds, indicated that isolate is quassinoid compound named Picras 3- en- 21- oat acid, 15-(acetyloxy)-13,20- epoxy-3-(ß-D- glucopyranosyloxy)-11, 12- dihydroxy -2, 16- dioxo -, methyl ester. Cytotoxic test using MTT assay method showed that compound have IC<sub>50</sub> 9,7 µg/mL.</p>

CYTOTOXIC COMPOUND FROM ETHYL ACETATE FRACTION OF Brucea javanica (L.) Merr FRUIT AGAINST HeLa CELL LINE

<p>The pure compound relatively (85 mg) was isolated from 4.5 kg <em>Brucea javanica</em> (L.) Merr. fruits sample. It was obtained from ethyl acetate fraction as a red-brownish amorphous solid of melting point 202-206 <sup>o</sup>C. Phytochemical screening of isolate showed positive result of terpenoid group. Based on analysis by UV, IR,<sup>1</sup>H-NMR and <sup>13</sup>C-NMR spectroscopy and by comparison with known related compounds, indicated that isolate is quassinoid compound named Picras 3- en- 21- oat acid, 15-(acetyloxy)-13,20- epoxy-3-(ß-D- glucopyranosyloxy)-11, 12- dihydroxy -2, 16- dioxo -, methyl ester. Cytotoxic test using MTT assay method showed that compound have IC<sub>50</sub> 9,7 µg/mL.</p>

New findings on Simalikalactone D, an antimalarial compound from Quassia amara L. (Simaroubaceae)

Quassia amara L. (Simaroubaceae) is a species widely used as tonic and is claimed to be an efficient antimalarial all over the Northern part of the Amazon basin. Quassinoid compound Simalikalactone D (SkD) has been shown to be one of the molecules responsible for the antiplasmodial activity of a watery preparation made out of juvenile fresh leaves of this plant. Because of its strong antimalarial activity, we decided to have a further insight of SkD pharmacological properties, alone or in association with classical antimalarials. At concentrations of up to 200μM, we showed herein that SkD did not exert any apoptotic or necrotic activities in vitro on lymphoblastic cells. However, an antiproliferative effect was evident at concentrations higher than 45nM. SkD was inefficient at inhibiting heme biomineralization and the new permeability pathways induced by the parasite in the host erythrocyte membrane. With respect to Plasmodium falciparum erythrocytic stages, SkD was almost inactive on earlier and later parasite stages, but potently active at the 30th h of parasite cycle when DNA replicates in mature trophozoites. In vitro combination studies with conventional antimalarial drugs showed that SkD synergizes with atovaquone (ATO). The activity of ATO on the Plasmodium mitochondrial membrane potential was enhanced by SkD, which on its own had a poor effect on this cellular parameter.

Spectroscopic Analysis and Cytotoxic Activity of Quas-Sinoid Isolated from the Seeds of Brucea Javanica on Hela Cell

The quessinoids from Bruce Javanica exhibit bioloical activitas as antimalarial, antitumor, antiviral and antiamoebic activities. These quaasinoids aving a promising antitumor activity. This research was aimed to isolated quassinoid (bruceine A, MW 522 g/mol) compound from B. Javanica and to investigate the cytotoxicity of bruceine A under invitro conditions in Hela cells.The cytotoxicity assays using MTTT asay. The bruceine showed a good cytotoxic activity in Hela cells at 24 hours with doxorubicine as a positive control. Stuctural recored on Tesia av600, (400 MHz) 1HNMR in pyridine (Ds), some in Gyro (300 MHz) 1HNMR i acetone-(d6), DMSO-(06) and CdCI3 13CNMR, 75 MHz, mass spectra on biospectometry LC-MS. Analytical HPLCretention time, ta was 4.617 minutes (Met/H2O) 60;40. Its Molecular formula was determined to be (C26 H34 O11) by the (M+H)+ ion peak at m/z 523 and m/z 1045 confirmed by high Resolution mass spectra Orbitrap (HRESIMS), From the results demonstrated that could be bruceine A compound refers to our spectral data. Its has activity in IC50 value 191,5 µM on Hella under invitro conditions

4,5,7,8,17-Penta-hydr-oxy-14,18-dimethyl-6-methyl-ene-3,10-dioxapenta-cyclo-[9.8.0.0.0.0]nona-dec-14-ene-9,16-dione methanol solvate dihydrate.

The title quassinoid compound, C20H24O9·CH3OH·2H2O, is a natural eurycomanone isolated from the roots of Eurycoma longifolia. The mol­ecules contain a fused five-ring system, with one tetra­hydro­furan ring adopting an envelope conformation, one tetra­hydro­pyran-2-one ring in a screw boat conformation, one cyclo­hexenone ring in a half-chair conformation and two cyclo­hexane rings in chair conformations. Intra­molecular C—H⋯O inter­actions generate S(5) ring motifs and an O—H⋯O inter­action generates an S(7) ring motif. In the crystal, mol­ecules are linked via inter­molecular O—H⋯O inter­actions along the b axis and further stacked along a axis. The absolute configuration of the title compound was inferred from previously solved structures of its analogues.

Evaluation of Efficacy of Bruceine A, a Natural Quassinoid Compound Extracted from a Medicinal Plant, Bruced javanica, for Canine Babesiosis

Bruceine A, a natural quassinoid compound extracted from the dried fruits of Brucea javanica (L.) Merr., was evaluated for its antibabesial activity in vitro and in vivo. Bruceine A inhibited the in vitro growth of Babesia gibsoni in canine erythrocytes at lower concentration compared with the standard antibabesial drug diminazene aceturate and killed the parasites within 24 hr at a concentration of 25 nM. Oral administration of bruceine A at a dosage of 6.4 mg/kg/day for 5 days resulted in no clinical findings in a dog with normal ranges of hematological and biochemical values in the blood. Three dogs were infected with B. gibsoni and two of them were treated with bruceine A at a dosage of 6.4 mg/kg/day for 6 days from day 5 post-infection. An untreated dog developed typical acute babesiosis symptoms including severe anemia, high fever, and complete loss of appetite and movement. However, the two bruceine A-treated dogs maintained their healthy conditions throughout the experimental period of 4 weeks although complete elimination of parasites from the peripheral blood was not achieved and decreases in the packed cell volume and the erythrocyte and platelet counts were observed. Since natural quassinoid compounds have been used as traditional medicines for the treatment of various ailments including cancer and malaria, the present results suggest that bruceine A or other related compounds are potential candidates for the treatment of canine babesiosis.

In vitro antitrypanosomal activities of quassinoid compounds from the fruits of a medicinal plant, Brucea javanica

The medicinal plant Brucea javanica (L.) Merr. (Simaroubaceae) is widely distributed throughout Asia where its bitter fruits have been used in traditional medicine for various ailments. Fifteen C-20 quassinoids were isolated from the fruits of B. javanica and examined for their in vitro antitrypanosomal activities against trypomastigotes of Trypanosoma evansi. Bruceine A, bruceantinol, bruceine C, brusatol, and bruceine B showed strong antitrypanosomal activities with IC 50 values in the range of 2.9–17.8 nM, which compared well with the standard trypanocidal drugs diminazene aceturate (IC 50 = 8.8 nM) and suramin (IC 50 = 43.2 nM). However, dehydrobruceine A, dehydrobruceine B, and dehydrobrusatol were about 2100, 900, and 1200 times less active, respectively, than bruceine A, bruceine B, and brusatol. The relationship of the structure and antitrypanosomal activity of these quassinoid compounds suggested that the presence of a diosphenol moiety in ring A and the nature of the C-15 side chain are important for their activities against T. evansi. This is the first report on the antitrypanosomal activity of isolated quassinoids.

Identification of an allelopathic compound from Ailanthus altissima (Simaroubaceae) and characterization of its herbicidal activity

Aqueous extracts of Ailanthus altissima bark and foliage were previously shown to be toxic to other plants. Using bioassay‐directed fractionation, I isolated the phytotoxic compound from A. altissima root bark and identified it to be ailanthone, a quassinoid compound having molecular mass of 376. Ailanthone was highly phytotoxic, with concentrations of 0.7 ml/L causing 50% inhibition of radicle elongation in a standardized bioassay with garden cress (Lepidium sativum) seeds. Ailanthone exhibited potent pre‐ and postemergence herbicidal activity in greenhouse trials. Postcmergence activity was especially striking; even the lowest application rate (0.5 kg/ha) caused complete mortality of five of the seven plant species tested within 5 d of treatment. In contrast, the highest application rate (8 kg/ha) did not cause any detectable injury to A. altissima seedlings, indicating the presence of a protective mechanism in the producer species to prevent autotoxicity. Ailanthone was rapidly detoxified in field soil as a result of microbial activity. Applications of ailanthone equivalent to 0.5 and 4.0 kg/ha completely lost their phytotoxicity within ≤5 d when incubated in the presence of nonsterile soil. When incubated with sterile soil under identical conditions, however, ailanthone remained highly phytotoxic throughout the 21‐d duration of the investigation. The high level of postemergence herbicidal activity in conjunction with its rapid biodegradation in soil suggest ailanthone may have potential for development as a natural‐product herbicide.

Structure-activity relationships for binding and inactivation of rabbit reticulocyte ribosomes by quassinoid antineoplastic agents.

A series of quassinoid compounds was investigated to determine the structure‐activity relationships for the binding and inactivation steps associated with the inhibition of protein synthesis by these compounds in a rabbit reticulocyte system. The binding of these compounds to rabbit reticulocyte run‐off ribosomes was measured in a competition‐binding assay using [14C]trichodermin as the competing ligand. Previous studies have shown that trichodermin and quassionoids compete for a single binding site on yeast ribosomes. Our experiments confirmed this behavior with rabbit reticulocyte ribosomes and ind9icated that binding equlibrium could be reached in 2.5 min at 30°C. The comparative binding data indicated the following: (a) The nature of the side‐chain at position 15 has very little effect on the association of these compounds with rabbit reticulocyte ribosomes. There is one exception to this general rule, however. saturation of the double bond in brusaatol (compound II) to give dihydrobrusatol (compound IV) increases the d form 1.6μM to 8.7 μM. (b) Easy access to the A ring is required for optimal binding. The addition of any bulky hydrophobic group to the A ring increased the Kd significantly. However, the double bond in the A ring does not appear to be required for binding since the Kd values for dihydrobrusatol (compound IV) and tetrahydrobrusatol (compound VI) to the corresponding lactol (compound X) has only a minor effect on Kd. In order to determine whether inactivation of rabbit reticulocyte ribosomes had any structural requirements which differed from those required for simple binding, we also compared the concentrations of these compounds required to give 50% inhibition of protein synthesis (ID50) in rabbit reticulocye lysates. Previous studies had indicated that binding of quassinoids to the peptidyl transferase center and inhibition of peptide bond formation was probably the only mode of action of these compounds. Our experiments indicated that the ID50 values for several of thse compounds were the same in whole reticulocytes and reticulocyte lysates, suggesting that transport and/or metabolism of these compounds was probably not limiting for their inhibitory effects. The inhibition studies indicated that (a) The nature of the side‐chain at position 15 had no detectable effect on the inhibition: (b) the double bonds in the A ring and lactone ring are probably involved in the inactivation of rabbit reticulocyte ribosomes.

Quantitative high-performance liquid chromatographic analysis of the bitter quassinoid compounds from Simaruba glauca seeds

Quantitative high-performance liquid chromatographic analysis of the bitter quassinoid compounds from Simaruba glauca seeds