Search

Seven new unusual dibenzocyclooctadiene lignans, neglignans A–G (1–7), together with 16 known dibenzocyclooctadiene lignans, were isolated from the stems of Schisandra neglecta. Compounds 1and 2are the first dibenzocyclooctadiene lignans bearing a carboxyl group at C-4, and compounds 3and 4are the first 7,8-seco-dibenzocyclooctadiene lignans found from Nature. The new compounds (1–7) and several of the known compounds were evaluated for their anti-HIV activity and cytotoxicity. Compounds 2and 6showed anti-HIV-1 activities with therapeutic index values greater than 50, and compound 4showed cytotoxicity against the NB4 and SHSY5Y cancer cell lines with IC50values of 2.9 and 3.3 μM, respectively.

Fourteen sesquiterpene and norsesquiterpene derivatives, comprising six different carbon skeletons, were isolated from Sanicula lamelligera. Saniculamoid A1 (1a) is an oxidation product of saniculamoid A (1), created by the transition of a formyl group to a carboxylic acid group after a period of storage in air. The known compounds 5–14were identified in Saniculaplants for the first time. The compounds were evaluated for their anti-HIV-1, cytostatic, and nitric-oxide-production-inhibiting activities using in vitro cellular assays. The results showed that 1,5-naphthalenediol inhibited nitric oxide production in lipopolysaccharide-stimulated RAW 264.7 cells with an IC50value of 28.1 μM and was active toward five cancer cell lines with IC50values in the 31.1–41.6 μM range.

Investigation of whole plants of Euphorbia fischerianaafforded three new tigliane-diterpenoid glycosides, fischerosides A–C (1–3), together with 11 known diterpenoids. Fischerosides A–C (1–3) are the first tigliane-type diterpenoid glucosides. Their structures were determined by a combination of 1D and 2D NMR, MS, and acid hydrolysis. Inhibitory activity against HIV-1 was assessed for compounds 1–5. The new compound 3showed an EC50value of 0.02 μM and a therapeutic index (TI) of 17.50, while prostratin (4) and 12-deoxyphorbol-13,20-diacetate (5) showed significantly greater anti-HIV-1 activity.

Twelve new dibenzocyclooctadiene lignans, marlignans A−L (1−12), together with 16 known compounds, were isolated from the leaves and stems of Schisandra wilsoniana. The structures of 1−12were elucidated by spectroscopic methods including 1D- and 2D-NMR techniques. Compounds 1−12were evaluated for their anti-HIV activities, of which compounds 3, 6, 8, and 12showed modest activities with therapeutic index values of 13.2, 15.6, 17.6, and 16.4, respectively.

Fourteen new lignans, tiegusanins A−N (1−14), together with 13 known compounds were isolated from the aerial parts of Schisandra propinquavar. sinensis. The structures and absolute configurations of 1−13were established using a combination of spectroscopic techniques. Compound 14was obtained as a racemate. When evaluated for inhibitory activity against HIV-1, tiegusanin G (7) showed anti-HIV-1 activity with an EC50value of 7.9 μM and a therapeutic index (TI) of more than 25.

Investigation of an organic extract of Schisandra rubrifloraled to the isolation of three new highly oxygenated nortriterpenoids, named rubriflorins A−C (1−3), together with six related known compounds (4−9). Their structures were elucidated by spectroscopic evidence. Compounds 1−3feature the opening of ring A compared with related known nortriterpenoids isolated from the genus Schisandraand showed anti-HIV-1 activities with EC50values of 10.0, 16.2, and 81.3 g/mL, respectively.

Two new cucurbitacins, endecaphyllacins A ( 1) and B ( 2), together with six known analogues ( 3− 8), were isolated from the tubers of Hemsleya endecaphylla. The structures of 1and 2were elucidated by NMR and MS spectroscopic analysis. The relative stereochemistry of 1was determined by single-crystal X-ray diffraction. Compound 4(cucurbitacin B) showed potent anti-HIV-1 in C8166 cells (EC = 0.09 µg/mL) with a selectivity index of 16.7.