Stilbenoids and Flavonoids from Cajanus cajan (L.) Millsp. and Their α-Glucosidase Inhibitory Activities.

Two new stilbenoids, cajanstilbenoid C (1) and cajanstilbenoid D (2), together with eight other known stilbenoids (3-10) and seventeen known flavonoids (11-27), were isolated from the petroleum ether and ethyl acetate portions of the 95% ethanol extract of leaves of Cajanus cajan (L.) Millsp. The planar structures of the new compounds were elucidated by NMR and high-resolution mass spectrometry, and their absolute configurations were determined by comparison of their experimental and calculated electronic circular dichroism (ECD) values. All the compounds were assayed for their inhibitory activities against yeast α-glucosidase. The results demonstrated that compounds 3, 8-9, 11, 13, 19-21, and 24-26 had strong inhibitory activities against α-glucosidase, with compound 11 (IC50 = 0.87 ± 0.05 µM) exhibiting the strongest activity. The structure-activity relationships were preliminarily summarized. Moreover, enzyme kinetics showed that compound 8 was a noncompetitive inhibitor, compounds 11, 24-26 were anticompetitive, and compounds 9 and 13 were mixed-competitive.

Two new cytotoxic stilbenoid dimers isolated from Cajanus cajan.

Two new stilbenoid dimers, cajanstilbenoids A (1) and B (2), were isolated from the leaves of Cajanus cajan. Planar structures of these compounds were verified by NMR (1D and 2D) and high-resolution electrospray ionization mass spectroscopy (HR-ESI-MS). Absolute configurations were assigned by comparing experimental and calculated electronic CD values. The cytotoxicity of 1 and 2 against human hepatoma (HepG2), human breast adenocarcinoma (MCF-7), and human lung cancer (A549) cells were evaluated in vitro. Compound 1 showed strong cytotoxicity against all the tested cell lines (IC50 values: 2.14-2.56 µM), whereas compound 2 showed strong toxicity only against HepG2 (IC50 value: 5.99 µM) and A549 cells (IC50 value: 6.18 µM).

Two new sesquiterpene lactones from the fruits of Illicium jiadifengpi.

Two new seco-prezizaane-type sesquiterpenes, 3,4-dehydroneomajucin (1) and 1,2,3,4-tetradehydroneomajucin (2), were isolated from the fruits of Illicium jiadifengpi. The structure of these compounds was determined using 1D and 2D NMR and ESI-MS. The isolates were evaluated for their anti-hepatitis B virus activities on the Hep G2.2.15 cell line. The inhibitory rates of compounds 1 and 2 on the HBeAg and HBsAg expression were 30.08 ± 3.09% and 11.43 ± 1.92% at a concentrations of 68.00 µM and 7.88 ± 1.21% and 16.96 ± 4.24% at a concentration of 68.50 µM, respectively.

[Chemical Constituents from Periploca forrestii].

Objective: To study the chemical constituents from Periploca forrestii. Methods: The constituents were separated by column chromatography and their structures were elucidated by spectroscopic methods. Results: Seven compounds were isolated from Periploca forrestii and identified as wogonin( 1),negletein( 2),vanilline( 3),isovanilline( 4),periplocoside L( 5),ß-sitosterol( 6) and ß-daucosterol( 7). Conclusion: Compounds 1 and 2 are obtained from this genus for the first time,and compounds 3 ~ 5 are isolated from this plant for the first time.

A Halogen-Containing Stilbene Derivative from the Leaves of Cajanus cajan that Induces Osteogenic Differentiation of Human Mesenchymal Stem Cells.

A new natural halogen-containing stilbene derivative was isolated from the leaves of Cajanus cajan (L.) Millsp. and identified as 3-O-(3-chloro-2-hydroxyl-propanyl)-longistylin A by comprehensive spectroscopic and chemical analysis, and named cajanstilbene H (1). It is the first halogen-containing stilbene derivative found from plants. In human mesenchymal stem cells (hMSC) from bone marrow, 1 did not promote cell proliferation, but distinctly enhanced osteogenic differentiation of hMSC in time- and dose-dependent manners. In six human cancer cell lines, 1 showed a moderate inhibitory effect on cell proliferation, with IC50 values of 21.42-25.85 µmol·L(-1).

Synthesis and cytotoxicity of longistylin C derivatives.

The present study was designed to identify potent anti-tumor compounds from a series of new longistylin C derivatives. Ten longistylin C derivatives were synthesized and their structures were confirmed by (1)H NMR, MS, and elemental analyses. Their cytotoxicity in vitro against three human cancer cell lines (A549, HepG2, and MCF-7) were evaluated by the MTT assay. Among these compounds, DT-6 and DT-9 displayed much better cytotoxicity against A549, HepG2, and MCF-7 cells, DT-1 exhibited selective cytotoxicity against HepG2, and the structure-activity relationships were investigated. In conclusion, Compounds DT-6 and DT-9 may serve as potential lead compounds for the discovery of new anti-cancer drugs.

A new inositol triester from Taraxacum mongolicum.

One new inositol triester, 4,5,6-tri-O-p-hydroxyphenylacetyl-chiro-inositol (1), was isolated from the ethanolic extract of Taraxacum mongolicum, along with two known compounds, 11ß,13-dihydrotaraxinic acid (2) and taraxinic acid ß-d-glucopyranosyl ester (3). The isolates were tested for their anti-hepatitis B virus (HBV) activities; 11ß,13-dihydrotaraxinic acid (2) exhibited an IC50 value of 0.91 mM inhibiting the secretion of the HBV surface antigen and an IC50 value of 0.34 mM inhibiting the secretion of the HBV e antigen using HBV transfected Hep G2.2.15 cell line.

A new flavanocoumarin from the root of Flemingia philippinensis.

One new flavanocoumarin, flemicoumarin A (1) was isolated from the EtOAc-soluble partition of the root of Flemingia philippinensis, along with three known compounds, namely 4,2'-epoxy-4',5-dihydroxy-7,5'-dimethoxy-3-phenylcoumarin (2), kaempferol 6-C-glucoside (3) and dracocephaloside (4). The structure of compound 1 was elucidated on the basis of its 1D, 2D NMR, CD and MS data. The structures of the known compounds were identified by comparison of their spectroscopic data with those reported in the literature. Compounds 1-4 exhibited inactivity against MCF-7, A549 and Hep-G2 human cancer cell lines in vitro by MTT colorimetric assay.