Cheng-Qin Liang

Schicagenins A-C: Three Cagelike Nortriterpenoids from Leaves and Stems of Schisandra chinensis

Schicagenins A-C (1-3), three unprecedented nortriterpenoids characterized with a tetracyclic oxa-cage motif and C(9) side chain, were discovered from the leaves and stems of Schisandra chinensis. Their structures were determined on the basis of extensive spectroscopic analysis, and the absolute stereochemistries were established by single-crystal X-ray diffraction and CD experiments. A plausible biosynthetic pathway of 1-3 was also discussed.

Kadcoccitones A and B, Two New 6/6/5/5-Fused Tetracyclic Triterpenoids from Kadsura coccinea

A pair of new triterpenoid epimers, kadcoccitones A (1) and B (2), together with a new biogenetically related compound kadcoccitone C (3), were isolated from Kadsura coccinea. The epimers featured an unprecedented carbon skeleton with a 6/6/5/5-fused tetracyclic ring system unit and a C(9) side chain. Their structures were determined by spectroscopic data, ECD calculation, and single-crystal X-ray diffraction. Compounds 1 and 3 showed anti-HIV-1 activity with an EC(50) value of 47.91 and 32.66 μg/mL, respectively.

Six new lignans from the leaves and stems of Schisandra sphenanthera

Six new lignans, schisphenlignans F-K (1-6), together with ten known ones, were isolated from the leaves and stems of Schisandra sphenanthera. Their structures were elucidated on the basis of spectroscopic methods, including extensive NMR, MS and CD spectra. In addition, some compounds were tested for their acute activity on insulin sensitivity in 3T3-L1 differentiated adipocytes and anti-HIV-1 activity.

Kadcotriones A-C: Tricyclic Triterpenoids from Kadsura coccinea

Three new triterpenoids, kadcotriones A-C (1-3), together with the biogenetically related lanostane-type triterpenoid (4), were isolated from Kadsura coccinea. Compound 1 features a 12,14β-dimethyl 6/6/6-fused tricyclic skeleton, while 2 and 3 are characterized by a 6/6/5-ring system. Their structures were determined by NMR and electronic circular dichroism spectroscopic methods. Compounds 2 and 4 exhibited anti-HIV-1 activities with EC50 values of 30.29 and 54.81 μM, respectively.

Kadcoccinic Acids A-J, Triterpene Acids from Kadsura coccinea

Eleven triterpene acids including 10 new compounds (kadcoccinic acids A-J, 1-10) were isolated from the stems of Kadsura coccinea. Except for 10, these compounds feature a rearranged lanostane skeleton with a 6/6/5/6 tetracyclic ring system, and compounds 1 and 2 are the first examples of 2,3-seco-6/6/5/6-fused tetracyclic triterpenoids. Their structures were established primarily by spectroscopic and spectrometric methods. Additionally, the absolute configuration of 3 was determined by single-crystal X-ray diffraction. Several of the compounds isolated were tested for their anti-HIV-1 and cytotoxic activities.

Four new indole alkaloids from Plantago asiatica.

Four new indole alkaloids, plasiaticines A-D (1–4), together with two known ones, were isolated from the seeds of Plantago asiatica. The structures of the new compounds were elucidated on the basis of comprehensive analysis of spectroscopic data. All compounds were tested for their cytotoxic activity, and all compounds except 4 were tested for their acetylcholinesterase (AChE) inhibitory activities.Graphical abstract

Isorosthornins A-C, new ent-kaurane diterpenoids from Isodon rosthornii

Three new ent-kauranoids, isorosthornins A-C (1–3), and a new natural product, dihydroponicidin (4), together with five known ones were isolated from the aerial parts of Isodon rosthornii. The structures were determined by means of extensive spectroscopic analysis. All diterpenoids isolated were evaluated for their cytotoxicity against HL-60, SMMC-7721, A-549, MCF-7, and SW480 cell lines, and compounds 5 and 7 showed significant inhibitory effects on all cell lines.

Phenolic constituents from Parakmeria yunnanensis and their anti-HIV-1 activity

Three new phenolic compounds, yunnanensins A–C (1–3), together with fourteen known ones (4–17), were isolated from the leaves and stems of Parakmeria yunnanensis. The structures of new compounds were established on the basis of extensive spectroscopic analyses. Several compounds showed weak anti-HIV-1 activity.

Four new lignans from the leaves and stems of Schisandra propinqua var. sinensis

Four new tetrahydrofuran lignans, schpropinrins A-D (1–4), together with five known ones, were isolated from the leaves and stems of Schisandra propinqua var. sinensis. Their structures, including absolute configurations, were characterized by means of spectroscopic analysis and ECD calculation. Compounds 1–4 featured a ketal or hemiketal substructure at C-7 and all of the isolates were tested for their anti-HIV integrase activity.