Yue-Hu Wang

Three New Indole Alkaloids from Trigonostemon lii

Three unprecedented indole alkaloids, trigonoliimines A-C (1-3) with a unique polycyclic system, were isolated from the leaves of Trigonostemon lii Y. T. Chang. The structures of 1-3 were determined by the spectroscopic, computational, and CD exciton chirality approaches. Trigonoliimine A showed modest anti-HIV-1 activity (EC(50) = 0.95 microg/mL, TI = 7.9).

Anti-Tobacco Mosaic Virus (TMV) Quassinoids from Brucea javanica (L.) Merr.

Two new quassinoids, javanicolide E (1) and javanicolide F (2), along with fifteen known C-20 quassinoids were isolated from the seeds of Brucea javanica (L.) Merr. The antitobacco mosaic virus (TMV) activity of these quassinoids was screened by the conventional half-leaf and leaf-disk method along with Western blot analysis. All of the seventeen quassinoids showed potent anti-TMV activity. Among them, eight compounds, brusatol (3), bruceine B (4), bruceoside B (5), yadanzioside I (6), yadanzioside L (7), bruceine D (8), yadanziolide A (9), and aglycone of yadanziolide D (17), showed strong antiviral activities, with IC(50) values in the range of 3.42-5.66 microM, and were much more effective than the positive control, ningnanmycin (IC(50) = 117.3 microM). The antiviral structure-activity relationships of quassinoids against TMV were also discussed.

Acortatarins A and B, two novel antioxidative spiroalkaloids with a naturally unusual morpholine motif from Acorus tatarinowii.

Acortatarins A (1) and B (2), two novel spiroalkaloids with a naturally unusual morpholine motif, were isolated from the rhizome of Acorus tatarinowii. Their structures with absolute configuration were determined by spectroscopic methods, X-ray diffraction analysis, and Moshers method. Importantly, compound 1 could significantly inhibit reactive oxygen species production in high-glucose-stimulated mesangial cells in a dose- and time-dependent manner.

Antioxidant Lignans from the Fruits of Broussonetia papyrifera.

Nine new lignans, chushizisins A-I (1-9), and three known lignans, threo-1-(4-hydroxy-3-methoxyphenyl)-2-{4-[(E)-3-hydroxy-1-propenyl]-2-methoxyphenoxy}-1,3-propanediol (10), erythro-1-(4-hydroxy-3-methoxyphenyl)-2-{4-[(E)-3-hydroxy-1-propenyl]-2-methoxyphenoxy}-1,3-propanediol (11), and 3-[2-(4- hydroxyphenyl)-3-hydroxymethyl-2,3-dihydro-1-benzofuran-5-yl]propan-1-ol (12), were isolated from the fruits of Broussonetia papyrifera. Their structures were elucidated using spectroscopic methods. Compounds 1, 5, 6, 8, 9, and 11 exhibited antioxidant activities against H(2)O(2)-induced impairment in PC12 cells, while compounds 1, 2, 4, 7, and 11 showed DPPH radical-scavenging activities with IC(50) values of 236.8, 156.3, 273.9, 281.1, and 60.9 microM, respectively.

Cytotoxic Amide Alkaloids from Piper boehmeriaefolium

Eight new amide alkaloids (1-8) and 19 known ones were isolated from the whole plant of Piper boehmeriaefolium. Their structures were determined through spectroscopic data analyses. Cytotoxic activity of these amides against human cervical carcinoma HeLa cells was evaluated, and 1-[(9E)-10-(3,4-methylenedioxyphenyl)-9-decenoyl]pyrrolidine (9) exhibited significant inhibitory activity with an IC(50) value of 2.7 μg/mL.

Pyrrolidinoindoline Alkaloids from Selaginella moellendorfii

Eight new pyrrolidinoindoline alkaloids (1-8) were isolated from the whole plant of Selaginella moellendorfii. Their structures were determined by mass spectrometry, 1D and 2D NMR spectroscopy, and chemical interconversions. These alkaloids have a 3-carboxybut-2-enyl group at C-3a and two methyl groups at N-8. The possible biogenetic route from selaginellic acid (1) to neoselaginellic acid (6) was postulated and chemically mimicked. Tautomerization between 6 and 6a was observed. Selected compounds were evaluated for antibacterial, cytotoxic, and acetylcholinesterase inhibitory activities.

Palhinine A, a Novel Alkaloid from Palhinhaea cernua

Palhinine A, a novel C(16)N-type Lycopodium alkaloid with a unique 5/6/6/9 tetracyclic ring system, was isolated from the whole plant of Palhinhaea cernua L. (Lycopodiaceae). Its structure was elucidated by spectroscopic methods, and the absolute configuration was determined by single-crystal X-ray diffraction analysis using the Flack parameter. Palhinine A is reported as the first example of Lycopodium alkaloids of which C-16 is fused to a new ring through a C-16-C-4 lingkage.

Trigoflavidols A–C, degraded diterpenoids with antimicrobial activity, from Trigonostemon flavidus

Trigoflavidols A (1) and B (2), tetranorditerpenoid dimers possessing a rearrangement skeleton with a spiroketal core moiety, and trigoflavidol C (3), a hexanorditerpenoid, have been isolated from Trigonostemon flavidus along with two known compounds. Compounds 1 and 2 showed moderate antimicrobial activities (MIC values: 3.12-6.25 μg/mL) against Staphylococcus aureus, 8(#)MRSA, and 82(#)MRSA, and 1, 2, and 5 showed weak activities (IC(50) values: 3.75-28.99 μM) against various human tumor cell lines.

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.

Compounds from Acorus tatarinowii: Determination of Absolute Configuration by Quantum Computations and cAMP Regulation Activity

A new cadinane-type sesquiterpenoid, tatarinowin A (1), two phenylpropanoids, tatarinoids A (2) and B (3), and a trinorlignan, tatarinoid C (4), along with 15 known compounds including two pairs of mixtures were isolated from the rhizome of Acorus tatarinowii. The absolute configurations of 1-4 were established by computation of specific rotation values. The isolated compounds were evaluated for their cAMP regulatory activity by the AlphaScreen assay.