Antifeedant and Insecticidal Activity of Quassinoids against Diamondback Moth (Plutella xylostella)

The antifeedant and insecticidal activities of sixteen quassinoids against 3rd instar larvae of the diamondback moth (Plutella xylostella) were compared with those of known insect antifeedant chlordimeform (1), and the structure-activity relationship was discussed. The insecticidal activity of quassin (2) was higher than that of 1, although its antifeedant activity was nearly the same as that of the reference compound.     

Structural requirements of quassinoids for the inhibition of cell transformation

The effects of eleven quassinoids on Rous sarcoma virus induced cell transformation and on growth of normal cells were examined. At concentrations of 0.15-1 μg/ml they inhibited foci formation (76–99 %) without toxic effects on normal cells. The most active compounds also affected virus production by transformed cells. In intact normal and transformed cells, protein and DNA synthesis was equally affected after 3 hours of exposure to quassinoids of both cell types. RNA synthesis was not inhibited. This study has shown that the structural requirement of a C-15 ester in the quassinoids for antileukemic activity $\text{in vitro}$ and $\text{in vivo}$ is not essential for their antitransforming activity.     

Chemical Constituents of the Branches and Leaves of Picrasma chinensis P.Y. Chen and Tyrosinase Inhibiting Activity

One new alkaloid, picrasine A, two new quassinoids, picralactones A−B, together with eleven known compounds were isolated from Picrasma chinensis P.Y. Chen. The structures of these compounds were determined using 1D and 2D NMR, HR-ESI-MS, and IR spectroscopic data, and by comparison with published data. Some compounds were tested for tyrosinase inhibiting activity, however, none of them exhibited strong inhibitory effects.     

Quassinoids from the leaves of the Madagascan Simaroubaceae Samadera madagascariensis

An investigation of the leaves of the Madagascan Simaroubaceae Samadera madagascariensis has yielded three C18 quassinoids, 5beta,6-dihydrosamaderine A, 2-chlorosamaderine A, and samaderolactone A, and a C19 quassinoid, 3,4beta-dihydrosamaderine C, together with the known quassinoids samaderine A, samaderine B, and cedronin. The compounds isolated displayed little or no anti-tumour activity.     

Canthin-6-one,undulatone and two quassinoids from Hannoa klaineana roots

Canthin-6-one, scopoletin, undulatone and two new quassinoids, 15-desacetylundulatone and 6α-tigloyloxyglaucarubol were isolated from Hannoa klaineana roots; quassinoids were obtained in high yields from this plant material.     

Quassinoids from Eurycoma longifolia as plant growth inhibitors.

Seven quassinoids including a new 12-epi-11-dehydroklaineanone were isolated from the leaves of Eurycoma longifolia (Simaroubaceae) as plant growth inhibitors or related compounds. The strongest activity was found in 14,15beta-dihydroxyklaineanone.     

Quassinoids Exhibit Greater Selectivity Against Plasmodium Falciparum Than Against Entamoeba Histolytica, Giardia Intestinalis Or Toxoplasma Gondii In Vitro

ABSTRACT. The in vitro activities of a series of quassinoids against Plasmodium falciparum, Entamoeba histolytica, Giardia intestinalis and Toxoplasma gondii have been compared with their in vitro cytotoxic effects against KB cells (human epidermoid carcinoma of the nasopharynx). All of the compounds tested were more toxic to KB cells than to G. intestinalis , but four (ailanthinone, bruceine D, brusatol and glaucarubinone) were slightly less toxic to KB cells than to E. histolytica. Glaucarubinone was similarly more toxic to intracellular T. gondii than to KB cells but ailanthinone was more selective (36 times more toxic to T. gondii than to KB cells). All of the compounds were more toxic to P. falciparum than to KB cells; the most selective quassinoids—glaucarubinone, bruceine D, ailanthinone and brusatoi—were found to have toxicity/activity ratios of 285, 76, 48 and 32 respectively. These results suggest that quassinoids have a selective action on P. falciparum. Further studies to elucidate the basis for this are in progress.     

Quassinoids from the twigs and thorns of Castela polyandra

The structures of six new C20 quassinoids and one new C19 quassinoid, all isolated from the twigs and thorns of Castela polyandra, were established by a combination of spectroscopic and single-crystal X-ray analysis. Five known quassinoids and one known sterol were also identified.     

Cytotoxic quassinoids from Ailanthus altissima

Two new quassinoids, altissinol A (1) and B (7), together with 12 known quassinoids, were isolated from the 95% ethanol extract of the barks of Ailanthus altissima. The structures of the new compounds (1 and 7) were determined on the basis of the spectroscopic methods including UV, IR, HR-ESI-MS, 1D and 2D NMR. The cytotoxic potential of all isolates were evaluated in vitro against three human hepatoma cell lines. Quassinoids 1–7 displayed potent cytotoxic activities against human hepatoma Hep3B and HepG2 cell lines. Interestingly, compounds 2, 3, and 5 exhibited cytotoxic activity against multidrug resistance HepG2/ADM cell line with IC₅₀ value 4.3-fold more sensitive to Doxorubicin (DOX).     

Quassinoids from Eurycoma harmandiana.

Three quassinoids, iandonosides A and B and iandonone, were isolated from the root of Eurycoma harmandiana, along with five known quassinoids, casteloside B, 13 beta, 21-dihydroeurycomanone, chaparrinone, glaucarubolone and ailanquassin B as well as the coumarin, scopoletin. The structural elucidations were based on analyses of spectroscopic data.     

LC-MS/MS-based metabolites of Eurycoma longifolia (Tongkat Ali) in Malaysia (Perak and Pahang)

A number of three LC-MS/MS hybrid systems (QTof, TripleTof and QTrap) has been used to profile small metabolites (m/z 100-1000) and to detect the targeted metabolites such as quassinoids, alkaloids, triterpene and biphenylneolignans from the aqueous extracts of Eurycoma longifolia. The metabolite profiles of small molecules showed four significant clusters in the principle component analysis for the aqueous extracts of E. longifolia, which had been collected from different geographical terrains (Perak and Pahang) and processed at different extraction temperatures (35°C and 100°C). A small peptide of leucine (m/z 679) and a new hydroxyl methyl β-carboline propionic acid have been identified to differentiate E. longifolia extracts that prepared at 35°C and 100°C, respectively. From the targeted metabolites identification, it was found that 3,4?-dihydroeurycomanone (quassinoids) and eurylene (squalene-type triterpene) could only be detected in the Pahang extract, whereas canthin-6-one-3N-oxide could only be detected in the Perak extract. Overall, quassinoids were present in the highest concentration, particularly eurycomanone and its derivatives compared to the other groups of metabolites. However, the concentration of canthin-6-one and β-carboline alkaloids was significantly increased when the roots of the plant samples were extracted at 100°C.     

Quassinoids from Ailanthus excelsa

Three quassinoids, 1, 2 and 3, 4-dihydro excelsin 3 were isolated from the stem bark of Ailanthus excelsa, along with five known quassinoids excelsin, glaucarubine, ailanthinone, glaucarubinone and glaucarubolone. The glaucarubolone has been isolated for the first time from this plant. The structural elucidation is based on the analysis of spectroscopic data.     

Quassinoids from Eurycoma longifolia

Three quassinoids, eurycolactone D (1), eurycolactone E (2) and eurycolactone F (3) were isolated from the roots of Eurycoma longifolia Jack. The structures of 1-3 were elucidated by spectroscopic methods, and that of 3 was further confirmed by X-ray crystallography. The known quassinoids, laurycolactone B (4) and eurycomalactone (5) were also identified.     

Chemometric analysis applied to a chemophenetics approach in Simaroubaceae family: The relevance of alkaloids and quassinoids

Simaroubaceae family belongs to the order Sapindales, which in turn is part of Eurosides II (APG IV). It consists of 23 genera: Ailanthus; Amaroria; Brucea; Castela; Eurycoma; Gymnostemon; Hannoa; Holacantha; Homalolepsis; Iridosma; Laumoniera; Leitneria; Nothospondias; Odyendeya; Perriera; Picrasma; Picrolemma; Pierreodendron; Quassia; Samadera; Simaba; Simarouba; Soulamea. Over the years, the classification of Simaroubaceae has changed and there is still a lot to evolve in this direction since there are still not many studies on some of its genera. In this sense, the present work discusses the chemistry of Simaroubaceae through the micromolecular chemical data, evolutionary indexes and chemometric analysis in order to assess affinities between its genera. The chemistry of this family is diverse and includes quassinoids, alkaloids, triterpenes, flavonoids, simple phenolics, coumarins, lignans and quinones. In addition to presenting specificity, quassinoids and alkaloids are prevalent among the substances already identified in the family and can be considered the chemical markers of it. Quassionoids are degraded triterpenes and can be classified as c25, c22, c20, c 19 and c18; c20 being the most common type in the family. The alkaloids already isolated in Simaroubaceae are predominantly beta-carboline and canthinone, both originating from the amino acid tryptophan. The evolutionary indexes calculated for the chemical markers showed great variation between the genera of Simaroubaceae and showed no correlation among them. The chemometric analysis positioned Simaroubaceae close to Rutaceae within the order Sapindales and, among the genera, alkaloids and quassinoids were very important for their distribution in Simaroubaceae considering the evolutionary proximity, corroborating their selection as chemical markers.     

Eurycomanone and eurycomanol,quassinoids from the roots of Eurycoma longifolia

From the roots of Eurycoma longifolia, used as an Indonesian folk medicine, two highly oxygenated quassinoids, named eurycomanone and eurycomanol were isolated. The structures of both new bitter principles were elucidated by NMR, MS, UV and IR.     

Molecular Diversity from Arid‐Land Plants: Valorization of Terpenes and Biotransformation Products

Asteraceae plants from arid lands are a source of biomass, resin and latex rich in terpenoids with diverse biological effects. Thirty‐six previously isolated terpenes, comprising sesquiterpenes, diterpenes, triterpenes and quassinoids, isolated from arid‐land plants and a series of metabolites from the biotransformation of some lead compounds were evaluated against insect pests (Spodoptera littoralis, Leptinotarsa decemlineata, Myzus persicae and Rhopalosiphum padi), cells (insect, hamster, murine and human tumoral cells) and parasites (Trypanosoma cruzi and Leishmania infantum). Among the insecticidal sesquiterpenes, maalian‐1α,8α‐diol ( 12 ) and γ‐eudesmol ( 17 ) were antifeedant against L. decemlineata, M. persicae and cytotoxic to Sf9 insect cells, and (?)‐maali‐3‐en‐8α‐ol ( 10 ), (+)‐maaliane‐5α,8α,9α‐triol ( 11 ), chrysothame ( 31 ) and holacanthone ( 35 ) were antifeedant against S. littoralis. The parasite L. infantum was slightly more sensitive than T. cruzi to the test compounds (39 % vs. 33 % of active compounds) with compound 17 and the biotransformed diterpene 27 being antiparasitic to L. infantum, with no cytotoxic effects on mammalian cells. Moreover, sesquiterpenes 3 and 17 , and grindelane diterpenes 22 , 23 and 26 showed selective activity against chemoresistant human colon, cervical and melanoma cancer cells. Thus, considering our results, the best candidates for future studies are compounds 17 and 3 , due to their activity on insect pests, parasites ( 17 ) and tumoral cells ( 3 , 17 , 22 , 23 and 26 ).     

Five new quassinoids and cytotoxic constituents from the roots of Eurycoma longifolia

Eurycoma longifolia has been widely used for various traditional medicinal purposes in South-East Asia. In this study, five new quassinoids, eurylactone E (1), eurylactone F (2), eurylactone G (3), eurycomalide D (4), and eurycomalide E (5), along with ten known quassinoids (6–15) were isolated from the roots of E. longifolia. Their structures were determined by extensive spectroscopic methods, including 1D and 2D NMR, and MS spectra data. Among the isolated compounds, 13β-methyl,21-dihydroeurycomanone (6) has been reported as a synthetic derivative. However, it was isolated from the natural product for the first time in this study. The cytotoxic activities of fifteen compounds were evaluated against human lung cancer cell line, A549 and human cervical cancer cell line, HeLa.     

Javanicinosides D-H, quassinoid glucosides from Picrasma javanica

From Picrasma javanica, five new quassinoid glucosides, javanicinosides D-H, together with known quassinoids, neoquassin and picrasin A and triterpenoids, hispidol A and lanosta-7,24-dien-3-one were isolated. The structures have been determined by spectral analysis and chemical evidence.     

Exciton coupling between enones: Quassinoids revisited

The electronic circular dichroism (ECD) spectra of two previously reported quassinoids containing a pair of enone chromophores are revisited to gain insight into the consistency and applicability of the exciton chirality method. Our study is based on time‐dependent Density Functional Theory calculations, transition and orbital analysis, and numerical exciton coupling calculations. In quassin ( 1 ) the enone/enone exciton coupling is quasi‐degenerate, yielding strong rotational strengths that account for the observed ECD spectrum in the enone π‐π* region. In perforalactone C ( 2 ) the nondegenerate coupling produces weak rotational strengths, and the ECD spectrum is dominated by other mechanisms of optical activity. We remark the necessity of a careful application of the nondegenerate exciton coupling method in similar cases.     

Determination of quassin in picogram quantities by an enzyme-linked immunosorbent assay

A double-antibody, enzyme-linked immunosorbent assay has been developed for the detection of quassin, neoquassin and 18-hydroxyquassin, the bitter natural products of Quassia amara and related species. Antiserum was raised in rabbits using 18-hydroxyquassin-bovine serum albumin as immunogen. The assay described is able to detect these closely related seco-triterpenes at concentrations as low as 5 pg per 0.1 ml sample, and the antiserum shows little cross-reactivity with other quassinoids. The distribution of quassin within small plants of Q. amara, Q. indica and Picrasma quassioides is described.