Shi-Hui Dong

Daphnane-type diterpenoids from Trigonostemon howii.

Nine new daphnane-type diterpenoids (1-9), named trigohownins A-I, and four known analogues were isolated from Trigonostemon howii. Their structures were elucidated on the basis of extensive NMR and MS analyses. Trigohownins A (1) and D (4) exhibited moderate cytotoxic activity against the HL-60 tumor cell line, with IC50 values of 17.0 and 9.3 μM, respectively.

Constituents of Trigonostemon heterophyllus

Six new diterpenoids, 1-6, a new prenylated sesquiterpenoid, 7, and six known compounds were isolated from Trigonostemon heterophyllus. The structures of 1-7 were elucidated on the basis of NMR and MS analysis. The daphnane diterpenoids trigoheterins A (1) and B (2) possess a rare 4,6-oxetane moiety within this compound class, and trigoheteric acid methyl ester (6) is the first example of a 15,16-dinor-3,4-seco-cleistanthane. Trigoheterin E (5) exhibited cytotoxic activity against the HL-60 (IC₅₀) 1.8 μM) and A-549 (IC₅₀ 10.0 μM) human cancer cell lines.

Angustimine and Angustifolimine: Two New Alkaloids from Daphniphyllum angustifolium

Two new alkaloids, angustimine (1) featuring an unprecedented skeleton, and angustifolimine (2) being a rare diamino Daphniphyllum alkaloid, were isolated from Daphniphyllum angustifolium. Their structures were elucidated by extensive spectroscopic analysis. The biosynthetic origin of 1 was postulated. Cytotoxic activities of 1 and 2 were tested, and all of them were inactive.

Mesendanins A-J, Limonoids from the Leaves and Twigs of Melia toosendan

Ten new limonoids, namely, mesendanins A-J (1-10), together with 14 known compounds, have been isolated from the leaves and twigs of Melia toosendan. Their structures were established on the basis of spectroscopic data analysis.

Onoceranoid-type triterpenoids from Lansium domesticum.

A rare class of onoceranoid-type triterpenoids, represented by lamesticumin A (1), the ethanolysis product of lamesticumin A (2), lamesticumins B-F (3-7), lansic acid 3-ethyl ester (8), and ethyl lansiolate (9), along with four known analogues were isolated from the twigs of Lansium domesticum. Their structures were elucidated on the basis of extensive spectroscopic analysis, and the absolute configuration of C-21 in compound 7 was assigned by using Snatzkes method. Compounds 1-9 exhibited moderate antibacterial activity against Gram-positive bacteria.

Calycinumines A and B, Two Novel Alkaloids from Daphniphyllum calycinum

Two novel alkaloids, calycinumines A (1) and B (2), were isolated from the twigs of Daphniphyllum calycinum. Calycinumine A (1) is the first example of C-22-nor yuzurimine-type alkaloids, and calycinumine B (2) features an unprecedented heteroatom-containing adamantane-like western hemisphere of the alkaloid. Their structures were elucidated by spectroscopic methods, and that of 1 was confirmed by a single-crystal X-ray diffraction.

Chemical constituents from Brucea javanica

Fourteen apotirucallane-type triterpenoids, named brujavanones A-N, were isolated from the twigs of Brucea javanica, along with four known quassinoids and seven known lignans from the seeds of B. javanica. Their structures were elucidated on the basis of extensive spectroscopic data analysis. The structure of a previously reported triterpenoid, bruceajavanin C, was revised as its C-21 epimer. The cytotoxic activities of triterpenoids and quassinoids against two human tumor cell lines, HL-60 and A-549, were evaluated, but all the compounds were inactive (IC₅₀>10 μM).

Sesquiterpenes from Dysoxylum oliganthum and Dysoxylum excelsum

Three new sesquiterpenes (1–3), (6R,7S,11R,10S)-15-hydroxy-sesquisabinene hydrate (1), (6R,7R,11S,10S)-15-hydroxy-sesquisabinene hydrate (2), and (6R,7R,10S)-15-hydroxy-zingiberenol (3), along with three known compounds, were isolated from the stems of Dysoxylum oliganthum; and three new isodaucane (salvionane) sesquiterpenes, namely isodauc-6-ene-10β,14-diol (4), 4-epi-isodauc-6-ene-10β,14-diol (5), and 4-epi-6α,10β-dihydroxy-artabotrol (6) together with 15 known compounds were isolated from the twigs and leaves of D. excelsum. Their structures were established on the basis of extensive spectroscopic analysis and chemical shifts. The absolute configuration of C-10 in compounds 1–3 of a rare class was determined by using Snatzkes method.

New triterpenoids with protein tyrosine phosphatase 1B inhibition from Cedrela odorata

Two new apotirucallane-type triterpenoids, cedrodorols A–B (1 and 2), along with seven known compounds (3–9), were isolated from the twigs and leaves of Cedrela odorata. Their structures were elucidated on the basis of extensive spectroscopic analysis. Compounds 1 and 2 showed significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) with the IC50 values of 13.09 and 3.93 μg/ml, respectively.