Anti-TMV Effects of Amaryllidaceae Alkaloids Isolated from the Bulbs of Lycoris radiata and Lycoricidine Derivatives

Fifteen known amaryllidaceae alkaloids were isolated from the bulbs of Lycoris radiata.Some of the compounds and lycoricidine derivatives had been screened for the activities against tobacco mosaic virus(TMV)by the conventional halfleaf method.Lycoricidine derivatives were also carried out the assay of effect on systemic infection of TMV by western-blot and RT-PCR analysis.The tested compounds showed moderate inactivation effect,whereas the lycoricidine derivatives showed good protective effect.The protective inhibitory activity of compounds L1(N-methyl-2,3,4-trimethoxyly-coricidine)(60.8%)and L3(N-methyl-2-methoxy-3,4-acetonidelycoricidine)(62.0%)was almost similar to the positive control,Ningnanmycin(66.4%).RT-PCR and Western-blot analysis displayed that compounds L1,L3,L5(N-allyl-2,3,4-triallyloxylycoricidine)exhibited antiviral activity,which was evidenced by reducing TMV-CP gene replication and TMV-CP protein expression.Additionally,defensive enzyme activities confirmed that compound L1 could increase the activity of PAL,POD,SOD to improve disease resistance of tobacco.

β-Carboline alkaloids from Trigonostemon filipes and Trigonostemon lii

Sixβ-carboline alkaloids including three new ones,trifilines A-C(1-3)were isolated from Trigonostemon filipes,along with a newβ-carboline alkaloid,trigonoine C(7)isolated from Trigonostemon lii.Their structures were elucidated by extensive spectroscopic techniques.Trifilines A(1)and B(2)showed weak anti-HIV-1 activity with EC50 values of 54.61μg/mL and 9.75μg/mL,along with TI(Therapeutic index)values of 1.52 and 1.42,respectively.This is the first time to report the chemical constituents of Trigonostemon filipes.

Limonoids and triterpenoids from the twigs and leaves of Dysoxylum hainanense

Four new limonoids,dysohainanins A-D(1-4),and two new triterpenoids,dysohainanins E and F(5 and 6),together with seven known ones were isolated from the twigs and leaves of Dysoxylum hainanense Merr.The structures of the new compounds were determined by a variety of spectroscopic methods.The cytotoxic activities of these compounds were evaluated,and the known compound ent-19-nor-4,16,18-trihydroxy-8(14)-pomaren-15-one(13)showed in vitro cytotoxicity against HL-60,A-549,MCF-7,and SW480 cells,with IC50 values of 24.3,28.1,30.7,and 22.5mM,respectively.Compounds 2 and 3 were tested their insecticidal activities using brine shrimp and both of them were inactive.

Two New C21 Steroidal Glycosides from the Roots of Cynanchum paniculatum

Two new C21 steroidal glycosides,paniculatumosides H and I,together with four known ones were isolated from the roots of Cynanchum paniculatum(Bge.)Kitag.Their structures were identifed by spectroscopic methods including extensive 1D and 2D NMR techniques.All compounds were subjected to detect the anti-tobacco mosaic virus(TMV)activities and their cytotoxities against three human tumor cell lines(SMMC-7721,MDA-MB-231 and A549).The results showed that compounds 1 and 5 exhibited potent protective activities against TMV,while 2,4 and 6 had moderate efects on the SMMC7721 cancer cells viability.

Daphmacrodins A and B, alkaloids from Daphniphyllum macropodum

Two new daphnicyclidin-type Daphniphyllum alkaloids,daphmacrodins A and B(1 and 2)were isolated from the leaves and stems of Daphniphyllum macropodum.Their structures were elucidated by extensive spectroscopic techniques,including 2D NMR spectroscopy and mass spectrometry.The relative configuration of 1 was further confirmed by a single-crystal X-ray diffraction analysis.Their cytotoxic activities against five human cancer cell lines,pesticidal activities against brine shrimp(Artemia salina),and antibacterial activities against five standard bacterial and fungal strains were evaluated.The structure of 1 was successfully transformed to 2 by a chemical method.

Chemical Constituents from the Stems of Manihot esculenta

Two new compounds,maniesculentins A(1)and B(6),together with four known ones were isolated from the stems of Manihot esculenta Crantz.The structures of the new compounds were elucidated by extensive spectroscopic methods including NMR spectroscopy and mass spectrometry.The two new compounds(1,6)were assayed for antibacterial activity against four tested bacteria lines.