Zhen-Yu Li

Sesquiterpenes from the Hainan Sponge Dysidea septosa.

Five new sesquiterpenes, named lingshuiolides A (1) and B (2), lingshuiperoxide (6), isodysetherin (10), and spirolingshuiolide (12), along with several known related analogues (7- 9, 11, and 13- 15), were isolated from the Hainan marine sponge Dysidea septosa. The structures of new compounds 1, 2, 6, 10, and 12 were determined by detailed analysis of 1D and 2D NMR spectra and by comparison with related model compounds. The absolute configuration of lingshuiolide B (2) was established by using the modified Moshers method. Spirolingshuiolide (12) represents the first example of a sesquiterpene with a rearranged drimane skeleton. Compounds 7- 9 and 15 exhibited significant inhibitory activity against human protein tyrosine phosphatase 1B (hPTP1B), an enzyme involved in the regulation of insulin signaling. In particular, 15 showed the most potent effect, with an IC 50 value of 1.9 microg/mL.

Further Daphniphyllum Alkaloids with Insecticidal Activity from the Bark of Daphniphyllum macropodum MIQ.

Two new Daphniphyllum alkaloids, macropodumines J and K (1 and 2, resp.), together with six known structurally related alkaloids, 3–8, were isolated from the bark of Daphniphyllum macropodum Miq. The structures of the new compounds 1 and 2 were elucidated on the basis of a comprehensive analysis of their spectroscopic and chemical data. Macropodumine J (1) contains a CN group which is relatively rare in naturally occurring alkaloids. All isolated compounds were tested for their insecticidal activities against a number of insect species. Daphtenidine C (5) is the most active compound against Plutella xylostella. This is the first report of insecticidal properties of Daphniphyllum alkaloids.

Two New Unprecedented Acetonyl-Bearing Sesquiterpenes from the Hainan Sponge Dysidea fragilis

Two new acetonyl-bearing sesquiterpenes, dysifragilisins A and B (1 and 2, resp.), have been isolated from the Hainan marine sponge Dysidea fragilis. The structures of the new compounds were elucidated on the basis of detailed spectroscopic analyses and by comparison of their NMR data with those of structurally related compounds. A plausible biogenetic pathway is proposed for the origin of compounds 1 and 2.

Two new Daphniphyllum alkaloids from Daphniphyllum macropodum Miq.

Two new Daphniphyllum alkaloids, 4,21-deacetyl-deoxyyuzurimine (1) and macropodumine L (2), together with the two known related alkaloids, have been isolated from the bark of Daphniphyllum macropodum Miq. The structures of the new compounds were elucidated on the basis of the detailed analysis of spectroscopic data, chemical method, and by comparison of the spectroscopic data with those of known compounds. Compounds 2 and 4 exhibited weak cytotoxicity against human carcinoma cell lines SMMC-7721 and HO-8910.

Two New Daphniphyllum Alkaloids from the Stems and Leaves of Daphniphyllum calycinum

Two new Daphniphyllum alkaloids, 9,10-epoxycalycinine A (1) and homodaphniphyllate (2), together with eight known related alkaloids, were isolated from the stems and leaves of Daphniphyllum calycinum. The structures of the new compounds 1 and 2 were elucidated on the basis of in-depth spectroscopic-data analysis, by chemical derivatization, and by comparison of their spectroscopic data with those of known compounds.