Xuan-Qin Chen

Lycojapodine A, a Novel Alkaloid from Lycopodium japonicum

Lycojapodine A, a novel C(16)N-type Lycopodium alkaloid with an unprecedented 6/6/6/7 tetracyclic ring system, was isolated from the club moss Lycopodium japonicum. The structure and relative stereochemistry were elucidated on the basis of spectroscopic data and were further confirmed by X-ray analysis. A possible biosynthetic pathway for 1 was proposed. Its inhibitory activity on acetylcholinestrease and anti-HIV-1 activity were also evaluated.

Polycyclic polyprenylated acylphloroglucinols and chromone O-glucosides from Hypericum henryi subsp. uraloides.

Two new C(30)‐epimeric polycyclic polyprenylated acylphloroglucinols (PPAPs), named uralodins B and C (1 and 2, resp.), were isolated from the aerial parts of Hypericum henryi subsp. uraloides together with two new chromone glucosides, urachromones A and B (3 and 4, resp.), as well as 16 known compounds. Their structures were established by extensive NMR techniques and MS analysis. The epimers 1 and 2 always behaved like a single compound when examined by TLC, and were separated by HPLC. Their configuration was distinguished by comparative analysis of the NMR data with known analogues together with the ROESY experiment. All the isolated PPAPs were evaluated for their cytotoxic activities against HepG2, SGC7901, HL‐60, and K562 cell lines. Compound 1 showed modest cytotoxic activities against SGC7901 and HL‐60 cell lines, and 2 showed modest cytotoxic activities against HepG2, SGC7901, HL‐60, and K562 cell lines.

Hupehenols A-E, Selective 11 beta-Hydroxysteroid Dehydrogenase Type 1 (11 beta-HSD1) Inhibitors from Viburnum hupehense

Five selective 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) competitive inhibitors, hupehenols A-E (1-5), were isolated from Viburnum hupehense. The structure elucidation indicated that compounds 1-5 are new 20,21,22,23,24,25,26,27-octanordammarane triterpenoids. Their structures were established on the basis of NMR spectroscopic and mass spectrometric analysis. Hupehenols A-E (1-5) showed inhibition against human 11β-HSD1, with hupehenols B (2) and E (5) having IC50 values of 15.3 and 34.0 nM, respectively. Moreover, hupehenols C (3) and D (4) are highly selective inhibitors of human 11β-HSD1 when compared to murine 11β-HSD1.

Vibsane-type diterpenes from leaves and twigs of Viburnum odoratissimum

Seven new vibsane-type diterpenes, vibsanols C-H (1-6) and vibsanin X (7), together with seven analogues, were isolated from the leaves and twigs of Viburnum odoratissimum. The structures of the new compounds were elucidated by extensive spectroscopic methods. All the new compounds were detected for their cytotoxicity. Compound 1 showed significant cytotoxicity against all the tested cell lines (HL-60, SMMC-7721, A-594, MCF-7, and SW-480), with IC50 values of 3.35, 4.41, 5.18, 11.30, and 3.70 μM, respectively. Compounds 4 and 5 also displayed significant cytotoxicity against hepatocellular carcinoma SMMC-7721 cell line, with IC50 values of 3.69 and 3.52 μM, respectively.

Norditerpenoids from Salvia castanea Diels f. pubescens

Three new norditerpenoids, castanol A-C (1-3), along with eighteen known diterpenoids, were isolated from Salvia castanea Diels f. pubescens. Their structures were elucidated by extensive spectroscopic analysis. All compounds were evaluated for their cytotoxic activities against five human cancer cell lines. The known compounds neo-tanshinlactone (12) and methyltanshinoate (17) exhibited significant cytotoxic activities against some cells.

Antioxidant and Antimicrobial Phenolic Compounds from Setaria viridis

A chemical study of the 80% aqueous acetone extract of aerial parts of Setaria viridis led to the isolation of three new naphthol rhamnosides, 8-O-α-L-rhamnosyl-β-sorigenin (1), 6-hydroxy-8-O-α-L-rhamnosyl-β-sorigenin (2), and 6-methoxy-8-O-α-L-rhamnosyl-β-sorigenin (3), together with nine (4–12) known compounds. Their structures were established on the basis of spectroscopic data, including IR, MS, 1D, and 2D NMR. All the 12 compounds were tested for their antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, as well as antimicrobial activity. Compounds 1–3 exhibited strong antioxidant activity with IC50 values of 10.5, 13.8, and 15.3 μM, respectively, and modest activity against Staphylococcus aureus (ATCC 29213).

Four new labdane-type diterpenoid glycosides from Diplopterygium laevissimum

Four new labdane-type diterpenoid glycosides, laevissiosides A-D (1–4) were isolated from the 95% ethanol extract of Diplopterygium laevissimum (Christ) Nakai, along with two known analogues, 18- β-D-glucopyranosyl ester-sclareol (5) and 18-hydroxy-sclareol (6). The structures of compounds 1–4 were elucidated by extensive 1D and 2D NMR spectroscopy as well as high-resolution MS analyses. All isolated compounds were evaluated for their cytotoxic effects.

Polycyclic Polyprenylated Acylphloroglucinols and Cytotoxic Constituents of Hypericum androsaemum

Two new polycyclic polyprenylated acylphloroglucinols (PPAPs), androforin A and hyperandrone A (1 and 2, resp.), together with twelve known compounds, were isolated from the aerial parts of Hypericum androsaemum. Their structures were established by detailed spectral analysis. In the cytotoxic assay, 1,4‐O‐diferuloylsecoisolariciresinol (3) showed activities comparable with those of cisplatin, and acetyloleanolic acid (4) exhibited moderate inhibitory effects against HL‐60, SMMC‐7721, A‐549, MCF‐7, and SW480 cancer cell lines.

Triterpenoids from Viburnum betulifolium

Two new triterpenoids, ursa-12-sene-3β,11β-diol 3-O-palmitate (1) and ursa-12-sene-1β,3β,11α-triol 3-O-palmitate (2), were isolated from the 70% aqueous acetone extract of the aerial parts of Viburnum betulifolium, together with the artificial diene derivative of 2, ursa-12-dien-1β,3β-diol 3-O-palmitate (2a). Their structures were characterized by various spectroscopic methods, including 1D NMR, 2D NMR, and HR-ESI-MS.

Onosmanones A and B, two novel quinonoid xanthenes from Onosma paniculatum

Abstract Onosmanones A (1) and B (2), two novel quinonoid xanthenes with two geranyl groups, have been isolated from the whole plants of Onosma paniculatum. Their structures were elucidated on the basis of one- and two-dimensional NMR techniques.