Inhibitory effects of triptogelin A-1 on 12-O-tetradecanoylphorbol-13- acetate-induced skin tumor promotion

Phenolic profile and antioxidant activity of Euonymus japonicus Thunb

The aim of this study was to characterise the phenolic profile and evaluate the antioxidant activity of aqueous and methanol leaf extracts from Euonymus japonicus Thunb., a species of flowering plant in the Celastraceae family. Liquid chromatography (HPLC) with diode array and electrospray-tandem mass spectrometry (DAD-ESI-MSⁿ) detection was used to characterise and quantify phenolic compounds. Thirty-two compounds were detected; among them, flavonoids (mainly quercetin and kaempferol glycosides) were the most abundant compounds in both extracts. The results obtained for DPPH and ABTS assays in the extracts were in agreement with the highest content of phenolics in the methanol extract.

Podocarpane trinorditerpenes from Celastrus angulatus and their biological activities

Five new podocarpane trinorditerpenes (1-5) and a dimeric trinorditerpene with an unprecedented skeleton bearing a 1,4-benzodioxane moiety (6) along with seven known compounds (7-13) were isolated from the stems of Celastrus angulatus (Celastraceae). These compounds' structures were elucidated by comprehensive spectroscopic analysis. In addition, the absolute configuration of 1 was determined by single crystal X-ray diffraction analysis. Compounds 3, 4, 7, and 12 exhibited moderate inhibitory activity against LPS-induced NF-κB activation in murine macrophage RAW264.7 cells at IC₅₀ values of 25.08, 18.64, 15.33 and 3.89 μM, respectively. However, compound 6 exhibited potent cytotoxicity against the A549 and MDA-MB-231 human tumour cell lines with IC₅₀ values of 4.47 μM and 5.86 μM, respectively. Compound 9 exhibited potent cytotoxicity against the HCT116 and BEL7404 human tumour cell lines with IC₅₀ values of 6.77 μM and 9.45 μM, respectively.

Untargeted analysis of sesquiterpene pyridine alkaloids from the dried roots of Tripterygium wilfordii using high-performance liquid chromatography/electrospray ionization tandem mass spectrometry

RATIONALE

Sesquiterpene pyridine alkaloids are a large group of highly oxygenated sesquiterpenoids that have attracted attention in the fields of medicine because of their significant biological activities.

METHODS

Reference compounds including 14 sesquiterpene pyridine alkaloids and one dihydroagarofuran ester were analyzed by collision-induced dissociation tandem mass spectrometry (CID-MS/MS). A high-performance liquid chromatography/electrospray ionization (HPLC/ESI)-MS/MS method at two collision energies was adopted to investigate the botanical extracts of Tripterygium wilfordii.

RESULTS

For 15 reference compounds, in the high mass range, the product ions were formed by the loss of side chains or H2 O. In the low mass range, the high-abundance product ions at m/z 206, 204, or 194 were the characteristic ions of the pyridine moiety. The characteristic product ion at m/z 310 was formed through an ion-neutral complex intermediate. Fifty-four sesquiterpenoid derivatives, including 50 sesquiterpene pyridine alkaloids, were identified or tentatively characterized in botanical extracts of T. wilfordii based on their elemental constituents, characteristic fragmentation patterns, and the major product ion profiles of the reference compounds ascertained with HPLC/ESI-MS/MS at two collision energies. It seems that isocratic energy was appropriate for the untargeted analysis of compounds with molecular weights exceeding 800 Da, whereas a linear gradient energy vs molecular weight was suitable for those compounds with molecular weights below 800 Da.

CONCLUSIONS

The HPLC/ESI-MS/MS method, combining characteristic fragmentation patterns and the profiles of the product ions generated at different collision energies, is an effective technique for characterizing untargeted compounds.

Wightianines A-E, dihydro-β-agarofuran sesquiterpenes from Parnassia wightiana, and their antifungal and insecticidal activities

Five new sesquiterpene polyol esters with a dihydro-β-agarofuran skeleton, designated as wightianines A-E (1-5), besides two known compounds, were isolated from the methanolic extract of the whole plant of the traditional herbal medicine Parnassia wightiana Wall. The structures of the isolated compounds were elucidated on the basis of spectroscopic analyses, including two-dimensional nuclear magnetic resonance techniques (correlation spectroscopy, heteronuclear multiple-quantum coherence, nuclear Overhauser effect spectrometry, and heteronuclear multiple-bond correlation) and electronic circular dichroism studies. The antifungal and insecticidal activities of five compounds were evaluated against several plant pathogenic fungi and armyworm larvae (Mythimna separata Walker). Among the test metabolites, compounds 2 and 7 both exhibited potent antifungal activity against the phytopathogenic fungus Cytospora sp. with minimum inhibitory concentration values of 0.78 μg/mL, which are equal to the two positive controls, hymexazol and carbendazim. However, no insecticidal activity of the test compounds was observed in the present study. Compounds 2 and 7 could be promising leads for developing new fungicides against agriculturally important fungus Cytospora sp.

A new dihydroagarofuranoid sesquiterpene from the roots of Tripterygium hypoglaucum

A new sesquiterpene ester (1) has been isolated from the root bark of Tripterygium hypoglaucum. The structure was determined as 1α-acetoxy-6β,9β-dibenzoyloxy-4β-hydroxy-dihydroagarofuran by the extensive analysis of NMR data, and the absolute configurations were established as 1R, 4R, 6S, and 9R by application of the CD excitation chirality method. Compound 1 exhibited weak cytotoxicity against HeLa cells, with an IC₅₀ value of 30.2 μM.

Semisynthesis and antifeedant activity of new derivatives of a dihydro-β-agarofuran from Parnassia wightiana

Five new derivatives (2-6) were semi-synthesized using compound 1, a dihydro-β-agarofuran sesquiterpene with C-2 ketone obtained from Parnassia wightiana, as the starting material by acylation, oxidation, reduction, esterification, and amination, respectively. Structures of 2-6 were confirmed by 1D- and 2D-NMR and HR-ESI-MS spectra. In addition, antifeedant activities of these compounds (1-6) were tested against the 3rd-instar larvae of Mythimna separata. Antifeedant effects of compounds 2 and 4 were greater than the parent compound 1 whereas other compounds exhibited low to no feeding deterrent effects against third instar M. separata larvae in lab bioassays. Therefore, our results suggest that acylated and reduced derivatives at C-8 and C-2, respectively, of 1 may improve the antifeeding effect. This preliminary information will be useful in designing new insect control agents against M. separata and other important pests.

Isolation, biological evaluation and 3D-QSAR studies of insecticidal/narcotic sesquiterpene polyol esters

For the first time, a set of (43) natural sesquiterpene polyol esters isolated from the root bark of Celastrus angulatus Maxim and Euonymus japonicus Thunb were subjected to 3D-QSAR comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) studies, with the aim of proposing novel sesquiterpene-based compounds with optimal narcotic or insecticidal activities. The established 3D-QSAR models exhibit reasonable statistical quality and prediction capabilities, with internal cross-validated Q (2) values of ∼ 0.5 and external predicted R (2) values of >0.9, respectively. The relative contributions of the steric/electrostatic fields of the 3D-QSAR models show that the electronic effect governs the narcotic activities of the molecules, but the hybrid effect of the electrostatic and hydrophobic interactions is more influential in the insecticidal activities of the compounds. These findings may have valuable implications for the development of novel natural insecticides.

Three New Insecticidal Sesquiterpene Polyol Esters from Celastrus angulatus

Three new insecticidal sesquiterpene polyol esters with dihydro-β-agarofuran skeletons, Kupiteng esters A (1), B (2) and C (3), were isolated from the methanol extracts of the root bark of Celastrus angulatus and their structures elucidated by analyses of MS and NMR spectral data. The insecticidal activities of these compounds against the 4th instar larvae of Mythimna separata were evaluated. The KD50 values of compounds 1-3, were 260.2, 445.5 and 1260.0 μg-g−1, respectively.

The dihydro-β-agarofuran sesquiterpenoids

Dihydro-Beta-agarofuran sesquiterpenoids are a structurally diverse class of natural products based on tricyclic 5,11-epoxy-5Beta,10alpha-eudesman-4-(14)-ene skeleton. Between January 1990 and June 2006, 462 new dihydro-Beta-agarofuran sesquiterpenoids of 74 structural types have been isolated from about 64 species of Celastraceae, 3 species of Hippocrateaceae and one species of Lamiaceae. The present review covers the chemical and biological activity research of dihydro-Beta-agarofuran sesquiterpenoids in the past 16 years. The chemical research includes structural classification into sesquiterpene polyesters and macrolide sesquiterpene pyridine alkaloids, synthesis of dihydro-Beta-agarofuran as well as extraction, isolation and purification methods. The biological activity research includes activities such as multidrug resistance (MDR) reversal activity, HIV inhibition, cytotoxicity, antitumor activity, antifeedant activity and insecticidal activity with some insights to their modes of actions.

Inhibitory Effects ofScutellaria BarbataD. Don. andEuonymus Alatus Sieb. on Aromatase Activity of Human Leiomyomal Cells

It is now well documented that a large proportion of breast tumors express their own aromatase. This intratumoral aromatase produces estrogen in situ and therefore may contribute significantly to the amount of estrogen to which the cell is exposed. Thus it is not only important that aromatase inhibitors potently inhibit the peripheral production of estrogen and eliminate the external supply of estrogen to the tumor cell, but that they in addition potently inhibit intratumoral aromatase and prevent the tumor cell from making its own estrogen within the cell. To study the inhibition of intracellular aromatase, we have examined the aromatase-inhibiting potency of the Scutellaria barbata D. Don. (SB) and Euonymus alatus Sieb. (EA) in myometrial and leiomyomal cells which contain aromatase. We have also used human placental tissues. Although SB and EA are approximately equipotent in a cell-free aromatase system (human placental microsomes), EA is consistently 10-30 times more potent than SB in inhibiting intracellular aromatase in myometrial and leiomyomal cells. To provide insights into the effect of SB and EA on aromatase activity in leiomyomal cells, we examined the cell lines, which is induced to differentiate toward the more transformed cell phenotype by 12-tetradecanoylphorbal-13-acetate (TPA) as a protein kinase C activator and transforming growth factor-beta1 (TGF-beta1). Enzyme activity was inhibited in a time-and dose-dependent fashion by SB and EA and by either 1-50 nM TPA or 0.01-0.5 ng/ml TGF-beta1, with maximal responses after 2-3 h exposure.

Anti-tumor promoting effects of sesquiterpenes from Maytenus cuzcoina (Celastraceae)

Ten sesquiterpenoids (1-10), with a dihydro-beta-agarofuran skeleton, were isolated from Maytenus cuzcoina (Celastraceae). Their structures were elucidated on the basis of spectral analysis, including homo- and heteronuclear correlations NMR experiments (COSY, ROESY, HMQC and HMBC), and chemical correlations. The compounds have been tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), as a test for potential cancer chemopreventive agents. Compounds 1-3, 6 and 7 showed strong inhibitory effects on EBV-EA induction (100% inhibition at 1000 mol ratio/TPA). Their structure-activity relationship is discussed.

Terpenoids from Tripterigyum hypoglaucum

Six terpenoids have been isolated from the root bark of Tripterygium hypoglaucum, along with 14 known compounds. The structures of the terpenoids were elucidated as 3,11,14-oxo-abieta-8,12-diene, 3beta-hydroxy-12,14-dimethoxyabieta-8,11,13-triene, 3beta-hydroxy-11alpha-ethoxyurs-12-ene, 3beta-hydroxy-11alpha-methoxyurs-12-ene, 3beta-hydroxy-11alpha-methoxyolean-12-ene-28-oic acid, and 1beta-benzoyl-8alpha-cinnamoyl-4alpha,5alpha- dihydroxydihydroagarofuran.

Detection of tumor promoters by early antigen expression of EB virus in Raji cells using a fluorescence microplate-reader

As an in vitro assay for possible tumor promoters, we designed a quantitative immunofluorometric method to detect Epstein-Barr virus early antigen (EBV-EA) expression in Raji cells. In this method, anti-EBV-EA monoclonal antibody, a fluorogenic substrate and a fluorescence microtiterplate-reader were employed. 12-O-Tetradecanoylphorbol-13-acetate (TPA) was shown to be a potent inducer. EBV-EA induction by TPA was related to the activation of protein kinase C and phospholipase A2. The chemicals that reacted positively were okadaic acid, diethylstilbestrol, progesterone, sodium phenobarbital, aldrin and dieldrin. Lithocholic acid, testosterone and DDT were equivocal in the present experiments. Eight other chemicals tested did not react.

Toxic effects of Erycibe obtusifolia, a Chinese medicinal herb, in mice

Extract of stem of Erycibe obtusifolia (EO) at doses of 10, 20 and 30 mg/kg was experimentally tested through oral and intraperitoneal administration. Toxic effects of EO were assessed through functional changes of the liver and kidneys. Mice died immediately following the i.p. injection at the dose of 10 mg/kg. However, no death occurred after the oral administration at the dose of 10, 20 or 30 mg/kg under close observations for at least 2 weeks. Changes of several functional parameters in both the liver and kidney appeared simultaneously after the oral administration. Although the higher dose increased the levels of serum glutamate-oxalate-transaminase (sGOT), serum glutamate-pyruvate-transaminase (sGPT), and blood urea nitrogen (BUN), and decreased the levels of hematocrit at 6 h after the treatment, no distinct dose-dependent relationship existed between the administered doses and the changes in functional parameters observed.