Jianqun Liu

Two new pterosin dimers from Pteris mutifida Poir

Two new C₁₄ pterosin dimers, which are a pair of isomers named as bimutipterosins A (1) and B (2), were isolated from the whole plant of Pteris multifida. Their structures have been elucidated on the basis of NMR and MS data. From a biogenetic point of view, these compounds including a cyclobutane basic core should be considered as a [2+2] dimerization product of dehydropterosin Q, which was a known compound and also isolated from this plant. This novel type of pterosin dimer was reported here for the first time. Compounds 1 and 2 showed cytotoxicity against HL 60 cell line (human leukemia) with the IC₅₀ values of 12.8 and 26.6 μM, respectively.

A new alkaloid from the fruit of Nandina domestica Thunb.

A new steroidal alkaloid, (20S,22R,24R)-24-ethyl-3-oxocholest-4-en-22-amino, named as nandsterine (1), together with 10 known alkaloids, palmatine (2), O-methylbulbocapnine (3), nantenine (4), dehydronantenine (5), glaucine (6), didehydroglaucine (7), dehydrocorydaline (8), jatrorrhizine (9), magnoflorine (10) and berberine (11), was isolated from the fruit of Nandina domestica Thunb. Their structures were elucidated by using spectroscopic methods as well as by comparing with the published data. Compound 1 was a new class of steroidal alkaloid isolated from the family Berberidaceae, meanwhile compounds 2, 3, 6–8 and 10 were obtained from N. domestica for the first time. Compound 1 exhibited cytotoxicity against HL-60 cells (human leukaemia) with IC50 values of 52.1 μM.

Three new abietane-type diterpene glycosides from the roots of Tripterygium wilfordii

Three new abietane-type diterpene glycosides named as tripterycoside A (1), tripterycoside B (2), tripterycoside C (3), along with two known ones, 11-O-β-d-glucopyranosyl-neotritophenolide (4), wilfordoside A (5), and nine other known compounds, 5-hydroxymethylmellein (6),1,2-bis-(3-methoxy-4-hydroxyphenyl)-1,3-propanediol (7), leptolepisol C (8), icariol A2 (9), tripfordine A (10), 16α-hydroxy-ent-kauran-19-oic acid (11),wilforine (12), wilfordine (13), 3-acetyloleanolic acid (14),were isolated from the roots of Tripterygium wilfordii. Their structures have been elucidated on the basis of NMR and MS data. To the best of our knowledge, abietane-type diterpene glycosides were rarely reported natural products, especially abietane-type diterpene glycoside containing 7-oxo group (compound 3) was reported here for the first time. Furthermore, compounds 6, 7, 8 and 14 were isolated from this plant for the first time. Compounds 1-5 showed statistically significant inhibitory effects on IL-1β secretion in LPS-induced rat primary synovial fibroblasts at 10μM.

New Benzophenone and Diphenylmethane Glycosides from Psidium littorale

The methanol extract from the fresh leaves of P. littorale was subjected to various column chromatography. This resulted in the isolation of four benzophenone glycoside derivatives: one new benzophenone glycoside, 2,6-dihydroxy-3-methyl-4-O-β-D-glucopyranosyl-benzophenone (1), one new diphenylmethane glycoside, 2,6-dihydroxy-3-methyl-4-O-(6″-O-galloyl-β-D-glucopyranosyl)-diphenylmethane (2), along with two known benzophenones, 2,6-dihydroxy-4-O-β-D-glucopyranosyl-benzophenone (3) and 2,6-dihydroxy-3-methyl-4-O-(6″-O-galloyl-β-D-glucopyranosyl)-benzophenone (4). Their structures were elucidated using data obtained from FAB-MS, 1H, and 13C NMR spectra and correlation experiments (HMQC and HMBC), as well as by comparison with published data. The activity of compounds 1–4 against five fungal species was investigated: the antimicrobial activity of all isolated compounds increased with concentration and varied according to the following rank: 1 ≥ 4 > 3 > 2, thereby showing some structure–activity relationships.