De-Quan Yu

2-Arylbenzofuran derivatives from Morus cathayana.

Four new 2-arylbenzofuran derivatives, cathafurans A (1), B (2), C (3), and D (4), were isolated from the stem bark of Morus cathayana. Their structures were determined by spectroscopic methods. Compounds 2 and 3 exhibited moderate activities against five human cancer cell lines, with IC(50) values ranging from 6.17 to 9.60 microg/mL.

Cytotoxic Triterpenoid Saponins from Lysimachia clethroides

Seven oleanane-type triterpenoid saponins, named clethroidosides A-G (1-7), an ursane-type triterpenoid saponin, clethroidoside H (8), and six known saponins were isolated from the aerial parts of Lysimachia clethroides. The structures of the saponins were elucidated on the basis of physical data analysis (1D and 2D NMR, HR-ESIMS) and chemical evidence. The cytotoxic activities of compounds 1-14 were evaluated against five human tumor cell lines (HT-29, HePG2, BGC-823, A549, and A375). Compounds 3, 4, 6, and 11-13 exhibited moderate cytotoxic activity, with IC50 values of 0.75-2.62 μM, while compound 5 showed selective cytotoxic activity.

Bioactive Sesquiterpenoids from the Rhizomes of Acorus calamus

Eight new sesquiterpenes (1-8) and one new norsesquiterpene (9) named calamusins A-I were isolated from the ethanol extract of Acorus calamus rhizomes. The absolute configuration of compound 8 was determined by comparing its experimental and calculated ECD spectra. The absolute configurations of the other compounds were determined from their CD spectra. Furthermore, in in vitro assays, compounds 3, 4, 7, and 9 (10 μM) exhibited weak hepatoprotective activities against APAP-induced HepG2 cell damage.

Iridal-type triterpenoids with neuroprotective activities from Iris tectorum.

Six novel iridal-type triterpenoids with a previously unreported 3,6-dihydro-2H-pyran moiety, named spirioiridotectals A-F (1-6), were isolated from the ethanol extract of the rhizomes of Iris tectorum. Their structures were elucidated on the basis of extensive spectroscopic analysis. Furthermore, in in vitro bioactivity assays, compounds 1, 2, and 6 exhibited neuroprotective activities against serum-deprivation-induced PC12 cell damage.

A steroidal saponin from the seeds of Allium tuberosum

A steroidal saponin, named tuberoside, together with seven known compounds, were isolated from the seeds of Allium tuberosum Rottl. ex Spreng. Its structure was established by spectroscopic data, hydrolysis, and comparison with spectral data of known compounds to be (2alpha, 3beta, 5alpha, 25S)-2,3,27-trihydroxyspirostane 3-O-alpha-L-rhamnopyranoyl-(1-->2)-O-[alpha-L-rhamnopyranoyl-(1-->4)]-beta-D-glucopyranoside.

Glucokinase-Activating Sesquinlignans from the Rhizomes of Acorus tatarinowii Schott

Three novel sesquinlignans, tatanans A (1), B (2), and C (3), have been isolated from the rhizomes of Acorus tatarinowii Schott. Their structures were established by spectroscopic techniques and single-crystal X-ray analysis. Tatanans A-C potently increase GK enzymatic activity with EC(1.5) values in the range of 0.16-1.85 μM. The potent GK activity and unique structural features of tatanans make them promising leads for therapeutic development of antihyperglycemic drugs.

Two New Caffeyol Glycosides from Forsythia suspensa

Two new caffeoyl glycosides of phenethyl alcohol, suspensaside A (1) and suspensaside B (2), were isolated from the fruits of Forsythia suspensa. Also obtained in this investigation were two known compounds forsythiaside (3) and suspensaside (4). The structures of compounds 1 and 2 were established by ID and 2D NMR techniques and chemical methods.

Four new N-contained iridoid glycosides from flower buds of Lonicera japonica.

Four new N-contained iridoid glycosides, lonijapospiroside A (1), l-phenylalaninosecologanin B (2), l-phenylalaninosecologanin C (3), and dehydroprolinoylloganin A (4), were isolated from the flower buds of Lonicera japonica Thunb. Their structures were established on the basis of UV, IR, MS, and NMR spectral data.

The structure and absolute configuration of Shuangkangsu: a novel natural cyclic peroxide from Lonicera japonica (Thunb.).

A novel cyclic peroxide, shuangkangsu (1), has been obtained from the water extract of the buds of Lonicera japonica (Thunb.). The structure was elucidated as 5,8-divinyl-1,4-dihydro-1,4-di-O-β-d-glucopyranosyl-2,3-dioxane (1) on the basis of the spectral data. Its absolute stereochemistry was determined to be (1S, 4S) by comparison of its CD curves with those of its optically pure analogs 2 and 3, which were synthesized from the phthalaldehyde. The absolute configurations of 2 and 3 were determined to be (1R, 4R) and (1S, 4S) by X-ray analysis and CD spectra, respectively. Compound 1 showed significant antiviral activities against influenza virus in chicken embryo and respiratory syncytial virus in cells.

Two new eudesmanolides from Inula racemosa

Two new eudesmane-type sesquiterpene lactones were isolated from the roots of Inula racemosa and their structures were elucidated as 3β-hydroxy-11α,13-dihydroalantolactone (1) and 11α-hydroxy-eudesm-5-en-8β,12-olide (2). Their cytotoxic activities against five human cancer cell lines had been tested and compound 2 exhibited weak cytotoxic activity against BEL-7402 and HCT-8 cell lines. The anti-inflammatory activities were also tested, but neither of them showed any activities.