Shu-Zhen Mu

Daphnimacropodines A-D, alkaloids from Daphniphyllum macropodum

Ten new yuzurine-type Daphniphyllum alkaloids, daphmacromines A-J (1-10), along with seven known alkaloids 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, and the structure of 1 was confirmed by single-crystal X-ray diffraction. The pesticidal and cytotoxic activities of the isolated alkaloids were evaluated in vitro against brine shrimp (Artemia salina) and five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW480), respectively. This study also suggested structural revisions of oxodaphnigracine, oxodaphnigraciline, and epioxodaphnigraciline.

Daphhimalenine A, a New Alkaloid with an Unprecedented Skeleton, from Daphniphyllum himalense

Daphhimalenine A (1), a novel alkaloid with a rearrangement C-21 skeleton, containing a unique 1-azabicyclo[5.2.1]decane ring system, was isolated from the leaves of Daphniphyllum himalense, along with biogenetically related alkaloids daphhimalenine B (2) and daphnezomine T. Their structures were established on the basis of spectroscopic data, and the absolute configuration of 1 was assigned by computational methods. A plausible biosynthetic pathway of 1 was also proposed.

The limonoids and their antitobacco mosaic virus (TMV) activities from Munronia unifoliolata Oliv.

Five new limonoids, named munronoids K-O (1-5), together with three known limonoids were isolated from Munronia unifoliola Oliv. These limonoids were involved in the skeletons of evodulone, gedunin, and peieurianin types of limonoids, and their structures were established on the basis of spectroscopic data. Compound 5 featuring a γ-lactone ring instead of the β-substituted furan ring was found in the peieurianin type for the first time. The antitobacco mosaic virus (anti-TMV) activities of compounds 1-8 were also evaluated with half-leaf, enzyme-linked immunosorbent assay, and Western blot methods, and limonoids 1, 5, and 8 showed stronger anti-TMV treatment activities than the positive control ningnanmycin. Six compounds (1-5 and 8) exhibited infection inhibition activities against TMV.

Seco-pregnane steroidal glycosides from the roots of Cynanchum atratum and their anti-TMV activity.

Fifteen new seco-pregnane steroidal glycosides cynanosides A-O (1-15) together with twenty-seven known ones were isolated from the roots of Cynanchum atratum. The structures of 1-15 were determined by extensive analysis of spectroscopic data. The anti-tobacco mosaic virus (TMV) activity of these steroidal glycosides was screened by the conventional half-leaf method, enzyme-linked immunosorbent assay, and Western blot methods, most of them showed potent anti-TMV activity. Among them, compounds 1, 7, 13, 28 and 31 showed significantly anti-TMV activity with an IC50 value of 20.5, 18.6, 22.0, 19.2 and 22.2 μg/mL, respectively, and were much more effective than the positive control, ningnanmycin (IC50=49.6 μg/mL).

Alkaloids from Daphniphyllum oldhami

Four new Daphniphyllum alkaloids, daphnioldhanines H-K ( 1- 4), along with 34 known alkaloids, were isolated from Daphniphyllum oldhami. The known alkaloid dehydrodaphnigraciline ( 5) is now reported as a natural product. Their structures were elucidated by spectroscopic methods, especially 2D NMR techniques. The effects against platelet aggregation of compounds 1, 3, and 5 were evaluated, and 3 showed stronger activity against platelet aggregation induced by PAF. This is the first report of quinolizidine alkaloids from the genus Daphniphyllum.

New diterpenoids from the roots of Euphorbia ebracteolata Hayata

Three new diterpenoids, ingenol-5β,20-O,O-isopropylidene-3β-palmitate (1), ingenol-5β,20-O,O-isopropylidene-3β-myristinate (2) and 3β,19-dihydroxy-1(10),15-rosadien-2-one (3), were isolated from the roots of Euphorbia ebracteolata Hayata. Their structures were deduced by spectroscopic means and analytic techniques.

Dapholdhamines A−D, Alkaloids from Daphniphyllum oldhami

Four new Daphniphyllum alkaloids, dapholdhamines A-D (1-4), were isolated from the leaves of Daphniphyllum oldhami. The structures and relative configurations of 1-4 were elucidated on the basis of spectroscopic data.

Daphniphyllum and Diterpenoid Alkaloids from Daphniphyllum longeracemosum

Four new Daphniphyllum alkaloids, daphlongamines A-D (1-4), were isolated from the fruits of Daphniphyllum longeracemosum. Their structures were characterized by spectroscopic methods, especially 2D NMR techniques. A single-crystal X-ray diffraction analysis was used to confirm the stereochemistry of 3. Remarkably, this is the first report of aconitine- and veatchine-type diterpenoid alkaloids from the genus Daphniphyllum.

Schisanhenol derivatives and their biological evaluation against tobacco mosaic virus (TMV).

Schisanhenol (Sol) was isolated from Schisandra rubriflora, and a series of derivatives (1-16, 15a-16a, and 15b-16b) were designed and prepared by chemical modification. The curative and protective effects of these dibenzocyclooctadiene lignan analogues against tobacco mosaic virus (TMV) were evaluated. Most analogues exhibited stronger protective effects than the positive control ningnanmycin. Dibromoschisanhenol (6) at 0.25mM exhibited the strongest protective activity (83.5±1.8% at 0.25mM), and 14-(3, 5-dibenzyloxy)-benzoyloxyschisanhenol (16) showed a significant curative effect (78.0±3.8% at 0.15mM) that was much stronger than that of the commercial virucide ningnanmycin. This study is the first to demonstrate that natural dibenzocyclooctadiene lignans and analogues are active against plant viruses.

Triterpenoids with anti-tobacco mosaic virus activities from Melia Toosendan

Four new triterpenoids, named Toosendansins A-D (1-4), along with nine known ones (5-13) were isolated from the fruits of Melia toosendan Sieb. et Zucc. Their structures were established on the basis of spectroscopic data. The isolation of compounds 1-12 were reported for the first time from this plant. All compounds were analyzed for the anti-Tobacco Mosaic Virus (TMV) activity and protective effect on H2O2-induced damage of SH-SY5Y cells. Compound 7 showed evident anti-TMV activity. Compounds 2 and 9 exhibited modest protection against H2O2-induced damage of SH-SY5Y cells.