Synchronous high-performance liquid chromatography with a photodiode array detector and mass spectrometry for the determination of citrinin, monascin, ankaflavin, and the lactone and acid forms of monacolin K in red mold rice

The Monascus fermentation product red mold rice (RMR) has been found to contain the cholesterol-lowering agent monacolin K (MK) in both its lactone (MKL) and acid (MKA) forms and the mycotoxin citrinin (CT). The yellow pigments in RMR, namely, monascin (MS) and ankaflavin (AK), have been reported to exhibit antimetastatic and antiangiogenic activities. Currently, MK and these yellow pigments are usually detected in RMR by different analytical methods that are inconvenient, expensive, and time-consuming. The goal of this study was to establish a rapid, synchronous analytical method for determination of the MKA, MKL, MS, AK, and CT levels in RMR. MKA, MKL, MS, AK, and CT were extracted by the same extraction method, then separated by RP-HPLC with a C18 column. The effluent from the column was passed through a photodiode array detector and then introduced directly into a fluorescence detector. The results showed that high recovery rates of MKA, MKL, MS, AK, and CT are possible if RMR powder is extracted with 75% ethanol (10 mL) at 80 degrees C for 30 min. With regard to the optimal conditions of the HPLC, the peaks of MKA, MKL, MS, AK, and CT can be clearly separated from any noise peaks by isocratic elution with a mobile phase comprising 0.05% trifluoroacetic acid in acetonitrile-water (62.5 + 37.5, v/v).     

New indications of potential rat intestinal α-glucosidase inhibition by Syzygium zeylanicum (L.) and its hypoglycemic effect in mice

Research on Chemical Intermediates - Natural α-glucosidase inhibitors (aGIs) have been considered effective agents for type 2 diabetes management. In this study, Syzygium zeylanicum (L.)...     

Cytotoxic phenylpropanoids and a new triterpene, turformosinic acid, from Turpinia formosana Nakai

One new phenylpropanoid, turformosin A (1), and one new triterpene, turformosinic acid (2), together with 16 known compounds, were isolated from the stems of Turpinia formosana Nakai. All structures were elucidated on the basis of spectroscopic analysis, including 1D- and 2D-NMR techniques and MS analysis. Selected isolated compounds were evaluated for in vitro cytotoxicity against four human cancer cell lines and antioxidant scavenging effects on DPPH. (-)-(7'S,8'S)-threo-carolignan X (3) exhibited cytotoxicity against Hep2, WiDr, Daoy, and MCF-7 cell lines with ED(50) values of 3.60, 4.45, 6.07, and 13.7 μg/mL, respectively. Turformosin A (1), (-)-(7'S,8'S)- threo-carolignan X (3), methoxyhydroquinone-4-β-D-glucopyranoside (5), and methoxy-hydroquinone-1-β-D-glucopyranoside (6), exhibited similar anti-oxidative activity. Hep2 cells treated with 10 μg/mL of 3 showed elevation of sub-G1 population (from 20% at 8 h to 60% at 48 h), and activation of caspase-9/caspase-3/PARP cascade. Compound 3 induced intrinsic apoptotic pathway in Hep2 cells with dose and time dependence (10 μg/mL for 8 h).     

Two novel sesquiterpene lactones,cytotoxic vernolide-A and -B,from Vernonia cinerea

Bioassay-directed fractionation of an ethanolic extract of stems of Vernonia cinerea has resulted in the isolation of two novel sesquiterpene lactones, vernolide-A and -B. Their structures were elucidated on the basis of spectroscopic analysis. Biological evaluation showed that vernolide-A demonstrated potent cytotoxicity against human KB, DLD-1, NCI-661, and Hela tumor cell lines (ED(50)=0.02, 0.05, 0.53, 0.04 microg/ml for KB, DLD-1, NCI-661, and Hela, respectively); vernolide-B had marginal cytoxicity (ED(50)=3.78, 5.88, 6.42 microg/ml for KB, NCI-661, and Hela, respectively).     

Antioxidant and anti-nitric oxide components from Quercus glauca

From the ethanolic extract of Quercus glauca, two new lignans, (+)-5'-methoxyisolariciresinol-9'-O-α-L-rhamnopyranoside (1) and (7R,8S)-dihydrodehydrodiconiferyl alcohol 4-β-D-xyloside (2), along with fourteen known compounds including four lignanoids (3-6), five triterpenoids (7-11), two flavonoids (12, 13), two aromatics (14, 15), and one steroid (16) were isolated. The structures of the new compounds were elucidated on the basis of spectroscopic analysis. Moreover, compounds 9 and 14 strongly inhibited nitric oxide (NO) production with IC50 values of 8.25 and 14.04?μM, respectively, and compounds 1, 4-6, 14, and 15 showed moderate antioxidant activities.     

Cytotoxic constituents from Podocarpus fasciculus

A new diterpene, 16-hydroxy communic acid (1), along with thirty one known compounds including five norditerpenes (2-6), twenty two flavonoids containing four biflavonoids (7-10), nine monoflavonoids (11-19) and nine flavanoid glycosides (20-28), as well as four phenolic constituents (29-32) were isolated from the 95% ethanolic extract of Podocarpus fasciculus. The structure of 1 was elucidated using spectral methods. Of these isolates, nagilactone C (2) showed the most significant inhibitory effects against DLD cells (human colon carcinoma) (ED(50)=2.57 microg/ml) and compounds 7, 8, 10, 11, and 12 had moderate cytotoxic activity against human KB (human oral epithelium carcinoma), Hela (human cervical carcinoma), Hepa (human hepatoma), DLD (colon carcinoma), and A-549 (human lung carcinoma) tumor cell lines. Preliminary structure-activity relationship studies of the isolated diterpenoids and biflavonoids are discussed.     

Novel taxane diterpenes from Taxus sumatrana with the first C-21 taxane ester

Phytochemical investigation of the taxane diterpenes content of an acetone extract of the leaves and twigs of Taxus sumatrana (Taxaceae) has resulted in the isolation of five new taxane diterpenes esters, tasumatrols H-L (1-5) together with 13 known taxanes (11-23). Compound 5 is the first 21-carbon taxane ester to be isolated from a natural source. The structures of these taxanes as well as their derivatives were established on the basis of spectral analyses, especially MS as well as 1-and 2D NMR. Compounds 2 and 4 showed significant activity against human liver carcinoma (Hepa59T/VGH), human large cell carcinoma of the lungs (NCI), human cervical epitheloid carcinoma (Hela), human colon adenocarcinoma (DLD-1) and human medulloblastoma (Med) cell lines.     

Briarenolides A-C, briarane diterpenoids from the gorgonian coral Briareum sp.

Chemical investigation on the gorgonian coral Briareum sp. has led to the isolation of six oxygenated briaran diterpenes 1-6, including three new compounds briarenolides A-C (1-3). The structures of 1-3 were determined on the basis of extensive spectroscopic analysis and by comparison of their spectral data with those of related metabolites. Among these metabolites, 1 and 2 are rarely found 9-ketobriaranes. Also, 1 is the first briarane derivative possessing a 20-hydroxy group.     

Induction of apoptosis in human breast adenocarcinoma cells MCF-7 by monapurpyridine A, a new azaphilone derivative from Monascus purpureus NTU 568

A new azaphilonidal derivative, monapurpyridine A (MPA), has recently been isolated from the fermented products of Monascus purpureus NTU 568. The structure of MPA was elucidated by nuclear magnetic resonance (1H-NMR, 13C-NMR, COSY, HMQC, and HMBC) and other spectroscopic analyses. Biological evaluation revealed that MPA could induce cell death in human breast adenocarcinoma cells MCF-7, and it has no significant toxicity to normal mammary epithelial cells M10. The MTT assay and flow cytometric analysis were employed to investigate cell viability and cell cycle influenced by MPA. Moreover, we used Western blot and caspase activity assay to demonstrate the activation of caspase-3, -8 and -9 resulted from MPA. All evidence supported that MPA was suitable for developing into a chemotherapeutic or chemopreventive agent against breast cancer.     

The anti-HBsAg (human type B hepatitis, surface antigen) and anti-HBeAg (human type B hepatitis, e antigen) C18 dibenzocyclooctadiene lignans from Kadsura matsudai and Schizandra arisanensis

The C(18) dibenzocyclooctadiene lignans including three novel schizanrin F (1), G (2), H (3), along with the known kadsurarin (4), were isolated from Kadsura matsudai. A new C(19) homolignan named schiarisanrin E (5), together with the known C(18) lignans, gomisin B (6), G (7) and (+)-gomisin K(3) (8) were obtained from Schizandra arisanensis. Gomisin B, G and (+)-gomisin K(3) showed moderate to strong activity for antihepatitis in anti-HBsAg (human type B hepatitis, surface antigen) and/or anti-HBeAg (human type B hepatitis, e antigen) tests. The structural elucidations of new compounds 1-3 and 5 were based on two-dimensional (2D) NMR techniques including COSY, HMQC, HMBC, NOESY and CD spectra. Preliminary structure-activity relationship studies for these isolated lignans are also discussed.