Cytotoxic Limonoids from the Twigs and Leaves of Toona ciliata.

Eight new limonoids, toononoids A-H (1-8), eight new B-seco-29-norlimonoids, toonanoronoids A-H (9-16), and seven known analogues were obtained from the EtOAc extract of the twigs and leaves of Toona ciliata. Compounds 2, 4, 8, and 16 are rare lactam-bearing limonoids. Compounds 1, 14, and 15 possess an unusual γ-methoxybutenolide moiety at C-17, while compounds 9, 10, and 15 have a rare 3ß-hydroxy group. Their 2D structure and relative configurations were identified using spectroscopic data. The absolute configurations of 1, 9, 14, and 15 were established via X-ray diffraction crystallography or comparison of experimental and calculated ECD data. The cytotoxicity of the compounds was assessed toward five human tumor cell lines, and their anti-inflammatory activity was assessed based on NO production using LPS-stimulated RAW264.7 macrophages. Compounds 11 and 12 exerted inhibition toward two tumor cell lines (MCF-7, SW-480) with IC50 values between 2.1 and 3.7 µM, while 18-22 inhibited the proliferation of HL-60, MCF-7, and SW-480 cells (IC50 0.6-4.0 µM). Only compound 4 exhibited weak anti-inflammatory activity with an IC50 value of 28.3 µM.

Cytotoxicity of Triterpenoid Alkaloids from Buxus microphylla against Human Tumor Cell Lines.

Three new triterpenoid alkaloids, namely buxmicrophyllines P-R (1-3), were isolated from the twigs and leaves of Buxus microphylla. Their structures were elucidated on the basis of NMR and MS spectroscopic analyses. Structurally, compounds 1-3 belong to the 9,10-cycloartane type alkaloids. In addition, compound 3 exhibited moderate cytotoxic activities in vitro against HL-60, SMMC-7221, A-549, MCF-7, and SW480 cell lines (with IC50 values ranging from 4.51 to 15.58 µM).

The antigluconeogenic activity of cucurbitacins from Momordica charantia.

Five new cucurbitacins, kuguacins II-VI (1-5), along with five known analogues (6-10), were obtained from the fruit of Momordica charantia. Structures of the new compounds were elucidated as 5ß,19-epoxycucurbit-23-en-7-on-3ß,25-diol (1), 5ß,19-epoxycucurbit-7,23-dion-3ß,25-diol (2), 5ß,19-epoxycucurbit-6-en-19,23-dion-3ß,25-diol (3), 5ß,19-epoxy-23,24,25,26,27-pentanorcucurbit-6-en-7,19-dion-3ß,22-diol (4), and cucurbit-5-en-7,23-dion-3ß,19,25-triol (5) by extensive spectroscopic and single-crystal X-ray diffraction analyses. Some cucurbitane compounds from this species were screened for their potential antidiabetic properties in terms of antigluconeogenic activity. As a result, compounds 1, 10, 11, and 12 (at 25-100 µM) showed concentration-dependent inhibition on glucose production from liver cells. In addition, compounds 11 and 12 (at 100 µM) showed around 20-30 % inhibition on PEPCK activity.

Identification and antifeedant activities of limonoids from Azadirachta indica.

Four new limonoids, azadiraindins A-D (1-4, resp.), together with seven known analogs, were isolated from the MeOH extract of Azadirachta indica. The structures of 1-4 were elucidated by NMR and MS spectroscopic analyses, and the relative configuration of 1 was determined by single-crystal X-ray crystallography. The compounds isolated in comparatively large amount were evaluated for their antifeedant activities against Plutella xylostella; the antifeedant rate of 10 was 90.6% and the corrected mortality of 8 was 79.2%.

Three new limonoids from Azadirachta indica.

Three new limonoids, azadiraindins E-G (1-3, respectively), together with six known analogs, were isolated from the fresh fruit coats of Azadirachta indica. The structures of these compounds were elucidated by spectroscopic methods (IR, MS, HR-ESI-MS, 1D NMR, and 2D NMR).

[Influence of C-Fe Lines Interference Correction on Laser-Induced Breakdown Spectroscopy Measurement of Unburned Carbon in Fly Ash].

In coal-fired plants, Unburned carbon (UC) in fly ash is the major determinant of combustion efficiency in coal-fired boiler. The balance between unburned carbon and NO(x) emissions stresses the need for rapid and accurate methods for the measurement of unburned carbon. Laser-induced breakdown spectroscopy (LIBS) is employed to measure the unburned carbon content in fly ash. In this case, it is found that the C line interference with Fe line at about 248 nm. The interference leads to C could not be quantified independently from Fe. A correction approach for extracting C integrated intensity from the overlapping peak is proposed. The Fe 248.33 nm, Fe 254.60 nm and Fe 272.36 nm lines are used to correct the Fe 247.98 nm line which interference with C 247.86 nm, respectively. Then, the corrected C integrated intensity is compared with the uncorrected C integrated intensity for constructing calibration curves of unburned carbon, and also for the precision and accuracy of repeat measurements. The analysis results show that the regression coefficients of the calibration curves and the precision and accuracy of repeat measurements are improved by correcting C-Fe interference, especially for the fly ash samples with low level unburned carbon content. However, the choice of the Fe line need to avoid a over-correction for C line. Obviously, Fe 254.60 nm is the best

Studies on the constituents of Cimicifuga foetida collected in Guizhou Province and their cytotoxic activities.

Two new triterpenoids and a chromone glycoside, namely, 24-epi-cimigenol-3-one (1), foetinoside (2), cimifugin-4'-O-[6″-feruloyl]-ß-D-glucopyranoside (3), together with 18 known compounds, were isolated from the rhizomes of Cimicifuga foetida L. collected in Guizhou Province, China. All of the compounds were identified by spectroscopic methods, as well as chemical methods. In the in vitro cytotoxicity evaluation of these compounds against 5 human cancer cell lines, cimigenol (8) exerted the most potent cytotoxic activity against SMMC-7721 (7.87 µM) and A-549 (12.16 µM), while cimiacerin B (9) also showed obvious cytotoxicity against the A-549 cell line, with an IC(50) value of 16.77 µM.

Cytotoxic steroids from Sarcococca saligna.

Two new C21-steroidal esters, sarsaligates A(1) and B(2), and two new steroidal alkaloids, sarsaligenines A(3) and B(4), together with four known compounds (sarcovagine, sarcorucinine, dimethylamino-3 ß-pregnane-20-one, and ß-sitosterol 5- 8, respectively), were isolated from the leaves and stems of Sarcococca saligna. The structures of compounds 1-4 were elucidated by NMR and MS spectroscopic analysis. Of the compounds tested, 5 and 6 were the most cytotoxic against the cell lines K562, SK-BR-3, and PANC-1, with IC50 values in the range of 2.25-5.00 µM, while 3 and 4 selectively inhibited HL-60 cells with IC50 values of 2.87 and 3.61 µM, respectively. Compounds 3-6 therefore deserve further evaluation of their cytotoxic potentials.

Three steroids with unique structural feature of 5ß-Spirostan-1ß,3ß,17α-trihydroxyl from Reineckia carnea.

A new spirostanol sapogenin and two spirostanol saponins, tentatively named reineckiagenin A (1), reineckiagenoside A (2), and reineckiagenoside B (3), were isolated from the whole plant of Reineckia carnea. By detailed analysis of their 1D and 2D NMR spectra, chemical methods, and by comparison with spectra data of known compounds, the structures of the new steroids were determined to be 25(S)-5ß-spirostan-1ß,3ß,17α-triol (1), 25(S)-5ß-spirostan-1ß,3ß,17α-triol 1-O-ß-D-xylopyranoside (2), 25(S)-5ß-spirostan-1ß,3ß,17α-triol 1-O-α-L-rhamnopyranosyl-(1→2)-ß-D-xylopyranoside (3). Compounds 1, 2, and 3 are the first naturally occurring steroids with unique structural feature of 5ß-spirostan-1ß,3ß,17α-trihydroxyl.

Cytotoxic chemical constituents from the roots of Cimicifuga foetida. [corrected].

Seven new 9,19-cycloartane triterpene glycosides, 25-O-acetylcimigenol-3-O-[2'-O-(E)-2-butenoyl]-beta-d-xylopyranoside (1), 25-O-acetylcimigenol-3-O-[4'-O-(E)-2-butenoyl]-beta-d-xylopyranoside (2), 25-O-acetylcimigenol-3-O-[3'-O-acetyl]-beta-d-xylopyranoside (3), 25-O-acetylcimigenol-3-O-[4'-O-acetyl]-beta-d-xylopyranoside (4), 25-O-acetyl-12beta-acetoxycimigenol-3-O-beta-d-xylopyranoside (5), 3'-O-acetylactein (6), and 3'-O-acetyl-23-epi-26-deoxyactein (7), together with eight known compounds (8-15), were isolated from the roots of Cimicifuga fetida. Their structures were established by spectroscopic and chemical methods. Most of these compounds showed more selective and higher cytotoxicity against the human HepG2 cell line than against the MCF7, HT29, and MKN28 cell lines. Compounds 2, 3, and 7 exhibited significant cytotoxicity against HepG2 cells, with IC(50) values of 1.29, 0.71, and 1.41 microM, respectively.

Five new triterpene bisglycosides with acyclic side chains from the rhizomes of Cimicifuga foetida L.

Five new triterpene bisglycosides, foetidinosides A (1), B (2), C (3), D (4) and E (5), including three of the cycloartane type, one of its derivative, and one of the lanostane type were isolated from the rhizomes of Cimicifuga foetida. Their structures were elucidated on the basis of spectroscopic data and chemical evidence. They were the first bisglycosides with acyclic side chains which were different from the typical triterpenes with side chains epoxidized with ring D in Cimicifuga species.

Triterpenoid alkaloids from Buxus microphylla.

Two new triterpenoid alkaloids, buxmicrophyllines J and K (1 and 2, resp.), together with four analogues, 3-6, were isolated from the leaves and stems of Buxus microphylla. The structures of the new compounds were elucidated by NMR and MS spectroscopic analyses. The partial assignments of the NMR spectra of 3 were also revised. Compounds 1 and 3-6 were evaluated for their growth inhibitory activity against human cell lines HL-60, SMMC-7721, A-549, SK-BR-3, and PANC-1. Compound 6 showed significant cytotoxicity against HL-60, SK-BR-3, and PANC-1 cell lines, with IC(50) values of 6.46, 19.61, and 28.57 microM, respectively.

Cucurbitane-Type Triterpene Glycosides from Momordica charantia and Their α-Glucosidase Inhibitory Activities.

Ten cucurbitane-type triterpene glycosides, including five new compounds named charantosides H (1), J (2), K (3), momorcharacoside A (4), goyaglycoside-L (5), and five known compounds (6-10), were isolated from the EtOAc extract of Momordica charantia fruits. The chemical structures of these compounds were identified by 1D and 2D NMR and HRESIMS spectroscopic analyses. Configurations of new compounds were determined by ROESY correlations and comparison of their 13C NMR data with literature reported values. All compounds were evaluated for their inhibition against α-glucosidase, in which compounds 2, 5, 7, 8, 9 showed moderate inhibitory activities with IC50 values ranging from 28.40 to 63.26 µM comparing with the positive control (acarbose, IC50 87.65 ± 6.51 µM).

Virtual Screening and Optimization of Novel mTOR Inhibitors for Radiosensitization of Hepatocellular Carcinoma.

BACKGROUND: Radiotherapy has an ameliorative effect on a wide variety of tumors, but hepatocellular carcinoma (HCC) is insensitive to this treatment. Overactivated mammalian target of rapamycin (mTOR) plays an important part in the resistance of HCC to radiotherapy; thus, mTOR inhibitors have potential as novel radiosensitizers to enhance the efficacy of radiotherapy for HCC. METHODS: A lead compound was found based on pharmacophore modeling and molecular docking, and optimized according to the differences between the ATP-binding pockets of mTOR and PI3K. The radiosensitizing effect of the optimized compound (2a) was confirmed by colony formation assays and DNA double-strand break assays in vitro. The discovery and preclinical characteristics of this compound are described. RESULTS: The key amino acid residues in mTOR were identified, and a precise virtual screening model was constructed. Compound 2a, with a 4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine scaffold, exhibited promising potency against mTOR (mTOR IC50=7.1 nmol/L (nM)) with 126-fold selectivity over PI3Kα. Moreover, 2a significantly enhanced the sensitivity of HCC to radiotherapy in vitro in a dose-dependent manner. CONCLUSION: A new class of selective mTOR inhibitors was developed and their radiosensitization effects were confirmed. This study also provides a basis for developing mTOR-specific inhibitors for use as radiosensitizers for HCC radiotherapy.

Kuguacins F-S, cucurbitane triterpenoids from Momordica charantia.

Chemical investigation of the vines and leaves of Momordica charantia resulted in isolation of fourteen cucurbitane triterpenoids, kuguacins F-S (1-14), including two pentanorcucurbitacins (6 and 7), one octanorcucurbitacin (8), and two trinorcucurbitacins (11 and 12), along with six known analogues. Their structures were elucidated on the basis of extensive spectroscopic and single-crystal X-ray diffraction analyses. Compounds 1-14 exhibited weak anti-HIV-1 activities in vitro.

Cytotoxic triterpenoid alkaloids from Buxus microphylla.

Five new triterpenoid alkaloids, buxmicrophyllines E-I (1-5), and six known ones (6-11) were isolated from the leaves and stems of Buxus microphylla. The structures of compounds 1-5 were elucidated by NMR and MS spectroscopic analysis, and the relative stereochemistry of 5 was determined by single-crystal X-ray crystallography. Compounds 3 and 9 were cytotoxic against HepG2 cells, with IC(50) values of 0.89 and 0.78 microM, and compounds 2, 3, 7, 8, and 9 were cytotoxic against K562 cells, with IC(50) values of 2.95, 4.44, 1.70, 5.61, and 0.37 microM, respectively.

New cucurbitane triterpenoids and steroidal glycoside from Momordica charantia.

Three new cucurbitane triterpenoids 1-3 and one new steroidal glycoside 4, were isolated together with ten known compounds from Momordica charantia. The structures of new compounds were determined to be 19(R)-n-butanoxy-5 beta,19-epoxycucurbita-6,23-diene-3beta,25-diol 3-O-beta-glucopyranoside (1), 23-O-beta-allopyranosylecucurbita-5,24-dien-7 alpha,3beta,22(R),23(S)-tetraol 3-O-beta-allopyranoside. (2), 23(R),24(S),25-trihydroxycucurbit-5-ene 3-O-{[beta-glucopyranosyl(1-->6)]-O-beta-glucopyranosyl}-25-O-beta-glucopyranoside (3), and 24(R)-stigmastan-3beta,5 alpha,6 beta-triol-25-ene 3-O-beta-glucopyranoside (4), respectively. Their structures were elucidated by the combination of mass spectrometry (MS), one and two-dimensional NMR experiments and chemical reactions.

Cucurbitane-type triterpenoids from the stems and leaves of Momordica charantia.

Six new cucurbitane-type triterpenoids, karavilagenin F (1), karavilosides XII and XIII (2, 3), momordicines VI, VII, and VIII (4, 5 and 6), along with four known ones, 5ß,19-epoxy-25-methoxycucurbita-6,23-diene-3ß,19-diol (7), 5ß,19-epoxycucurbita-6, 23-diene-3ß,19,25-triol (8), kuguacin R (9), and (19R,23E)-5ß,19-epoxy-19-methoxycucurbita-6,23,25-trien-3ß-ol (10), were isolated from the stems and leaves of Momordica charantia L. Their chemical structures were elucidated by extensive 1D NMR and 2D NMR (HSQC, HMBC, COSY, and ROESY), MS experiments, and CD spectrum. Compound 6 showed weak cytotoxicity against five human cancer cells lines with IC50 values of 14.3-20.5µmol/L.

Chukfuransins A-D, four new phragmalin limonoids with ß-furan ring involved in skeleton reconstruction from Chukrasia tabularis.

Four new phragmalin limonoids (chukfuransins A-D) were isolated from the twigs and leaves of Chukrasia tabularis. Chukfuransins A (1) and B (2) feature a unique C-15/C-20 linkage proposed to be built by a biogenetic pathway involving Michael addition. Chukfuransins C (3) and D (4) feature the C-15/C-21 linkage. Their structures and absolute configurations were established by NMR techniques and X-ray crystallographic analysis.

Limonoids from the leaves of Swietenia macrophylla.

One new limonoid of the phragmalin type (1) named Swietenine J with nine known compounds methyl-6-ß-hydroxy angolensate (2), 1-O-acetylkhayanolide A(3), Khayanolide E (4), Khayalactone (5), Khayanone (6), 1-O-Acetylkhayanolide B (7), 1-O-Deacetylkhayanolide E (8), Khayanolide A (9), Khayanolide B (10) were isolated from Swietenia macrophylla. The structure of 1 was elucidated on the basis of 1D and 2D- NMR spectroscopic analysis.