Anti-hepatitis B virus lignans from the root of Streblus asper.

Four new lignans, strebluslignanol F (1), (7'R,8'S,7″R,8″S)-erythro-strebluslignanol G (2), isomagnaldehyde (3) and isostrebluslignanaldehyde (4), along with 12 known lignans (5-16) were isolated from the ethyl acetate-soluble part of MeOH extract of the root of Streblus asper. Their structures were elucidated through various spectroscopic methods, including 1D NMR ((1)H NMR, (13)C NMR), 2D NMR (HMQC, HMBC and NOESY) and HRMS. The stereochemistry at the chiral centers was determined using CD spectra, as well as analyses of coupling constants and optical rotation data. The isolated lignans were evaluated for their anti-HBV activities in vitro using the HBV transfected HepG2.2.15 cell line. The most active lignans, (7'R,8'S,7″R,8″S)-erythro-strebluslignanol G, magnolol, isomagnolol and isolariciresinol, exhibited significant anti-HBV activities with IC50 values of 1.58, 2.03, 10.34 and 3.67 µM, respectively, for HBsAg with no cytotoxicity, and of 3.24, 3.76, 8.83 and 14.67 µM, respectively, for HBeAg with no cytotoxicity. (7'R,8'S,7″R,8″S)-erythro-Strebluslignanol G and magnolol showed significant anti-HBV activities to inhibit the replication of HBV DNA with the IC50 values of 9.02 and 8.67 µM, respectively.

Anti-hepatitis B virus constituents from the stem bark of Streblus asper.

Seven compounds, (7'S,8'S)-trans-streblusol A, (7'R,8'S)-erythro-streblusol B, (7'S,8'S)-threo-streblusol B, 8'R-streblusol C, streblusquinone, (8R,8'R)-streblusol D, and streblusol E, along with 15 known compounds (8-22) were isolated from the n-butanol-soluble part of the MeOH extract of stem bark of Streblus asper. Their structures were elucidated through application of extensive spectroscopic methods, including ESI-MS and 2D NMR spectroscopy (HMQC and HMBC). The stereochemistry at the chiral centers was determined using CD spectra, as well as analyses of coupling constants and optical rotation data. The isolated lignans and allylbenzene derivatives were evaluated for their anti-HBV activities in vitro using the HBV transfected Hep G2.2.15 cell line. The most active compounds, magnolol and 9-ß-xylopyranosyl-isolariciresinol, exhibited significant anti-HBV activities with IC(50) values of 2.03 and 6.58µM for secretion of HBsAg, with no cytotoxicity, and of 3.76 and 24.86µM for secretion of HBeAg, with no cytotoxicity.

Water-soluble constituents of the heartwood of Streblus asper.

A new lignan, (7'R,8'R)-threo-strebluslignanol-2-O-beta-D-glucopyranoside, along with 8 known compounds (2-9) were isolated from the water-soluble part of the MeOH extract of the heartwood of Streblus asper. Their structures were elucidated through various spectroscopic methods, including 1D NMR (1H NMR, 13C NMR), 2D NMR (HMQC, HMBC, and NOESY), and HRMS. The stereochemistry at the chiral centers was determined using the CD spectrum, as well as analyses of coupling constants and optical rotation data. In the preliminary bioassay, the isolated compounds did not show anti-HBV activities in vitro using the HBV transfected HepG2.2.15 cell line.

Anti-HBV activities of Streblus asper and constituents of its roots.

The extracts from leaves, heartwood, barks and roots of the Streblus asper were investigated for anti-HBV activities, separately. The results suggested that the MeOH extracts of the heartwood, barks, and roots exhibited good anti-HBV activities. Further investigations displayed that ethyl acetate and n-butanol soluble parts of their MeOH extracts showed more significant anti-HBV activities. Moreover, a new lignan, together with 11 known compounds, was isolated from n-butanol-soluble part of MeOH extract of the roots of S. asper. The structures were elucidated by spectroscopic methods, including 1D NMR ((1)H NMR, (13)C NMR), 2D NMR (HMQC, HMBC) and HR-EI-MS experiments. Compounds 1-3 were evaluated for their anti-HBV activities. Honokiol showed significant anti-HBV activity with IC(50) values of 3.14µM and 4.74µM for HBsAg and HBeAg with no cytotoxicity respectively, while lamivudine (3TC, positive control) exhibited weak anti-HBV activity with IC(50) values of 11.81µM and 25.80µM for HBsAg and HBeAg respectively.

Hypoglycemic effects and constituents of the barks of Cyclocarya paliurus and their inhibiting activities to glucosidase and glycogen phosphorylase.

The various fractions of the barks of Cyclocarya paliurus were systematically tested for hypoglycemic effects in alloxan-induced diabetic rats. The results showed that the chloroform fraction of the 75% EtOH extract of the barks of this plant exhibited significant blood sugar reducing activity, most of which were significantly higher than that of positive-drug metformin hydrochloride. A new compound, together with nine known compounds, was isolated from the most active fraction. The structure elucidation was based on spectroscopic methods, including two-dimensional NMR experiments (¹H-¹H COSY, HMQC, and HMBC). All of the isolates were evaluated for their α-glycosidase and glycogen phosphorylase inhibitory activities.