Xue-Mei Gao

Antiviral Phenolic Compounds from Arundina gramnifolia

Five new phenolic compounds, gramniphenols C-G (1-5), and eight known compounds (6-13) were isolated from the whole plant of Arundina gramnifolia. Compounds 1, 4, and 5 showed anti-tobacco mosaic virus activity, with IC(50) values of 20.8, 40.8, and 57.7 μM, respectively. Compounds 1-10 were also tested for their anti-HIV-1 activity; compounds 2, 3, and 6 displayed anti-HIV-1 activity with therapeutic index values above 100:1.

Aspergillines A–E, Highly Oxygenated Hexacyclic Indole–Tetrahydrofuran–Tetramic Acid Derivatives from Aspergillus versicolor

Aspergillines A-E (1-5) are highly oxygenated cyclopiazonic acid (CPA)-derived alkaloids bearing a rigid and sterically congested hexacyclic indole-tetrahydrofuran-tetramate scaffold, isolated from the endophytic fungus Aspergillus vesicolor. Apergillines A-C represent a new subclass of CPA-derived alkaloids, and aspergillines B and E possess a butanoic acid methyl ester moiety. The structures, including absolute configuration, were elucidated by interpretation of the NMR, X-ray crystallographic, and circular dichroism data. All compounds displayed anti-TMV and cytotoxic activities.

Compounds from Kadsura heteroclita and related anti-HIV activity.

Phytochemical investigation of the stems of Kadsura heteroclita led to isolation of 16 compounds, including the triterpenoid named longipedlactone J (2), and two dibenzocyclooctadiene type lignans named heteroclitin I and J (3, 4). Compounds 8-10, 14, and 15 were weakly active as anti-HIV agents, whereas compounds 6 and 12 exhibited moderate anti-HIV activity with EC50 values of 1.6 microg/mL, and 1.4 microg/mL, therapeutic index (TI) values of 52.9, and 65.9, respectively. Their structures were established by spectroscopic methods, including application of 2D NMR techniques and CD spectra.

Lignan Derivatives from the Leaves Nicotiana tabacum and Their Activities

Two new lignan derivatives, nicotnorlignan A and nicotlactone A (1, 2), together with two known lignan derivatives (3, 4) were isolated from the leaves of Nicotiana tabacum. Their structures were elucidated by spectroscopic methods, including extensive 1Dand 2D-NMR techniques. Compounds 1-4 were tested for their anti-HIV-1 activity and anti-tobacco mosaic virus activities. The results showed compound 2 has high anti-tobacco mosaic virus activities, and all other compounds have modest anti-HIV-1 activity and anti-tobacco mosaic virus activities. Nicotiana tabacum L. is one of the most commercially valued agricultural crops in the world. Its leaves are the most important row material for cigarette industry. However, N. tabacum is also used as insecticides, anesthetics, diaphoretics, sedatives, and emetic agents in Chinese folklore medicine due to its containing many useful chemical compounds. Therefore, the multipurpose utilization of N. tabacum is an interesting topical, and receives more and more attentions. In previous work, a number of bioactive compounds, such as alkaloids, sesquiterpenes, diterpenoids, phenols, and their homologous, were isolated from the N. tabacum. With the aim of continuing efforts to multipurpose utilization of N. tabacum and identify bioactive natural products from this plants, the phytochemical investigation on N. tabacum was carried out. As a result, four lignan derivatives (with two new one) were isolated from this plant. All of the compounds were evaluated in HETEROCYCLES, Vol. 85, No. 1, 2012 147

Nortriterpenoids and lignans from Schisandra sphenanthera

Nortriterpenoids, sphenadilactone C (1) and sphenasin A (2), together with four known lignans (3-6), were isolated from the leaves and stems of Schisandra sphenanthera. Their structures were elucidated by extensive analysis of 1D and 2D NMR spectroscopic data and compound 2 was further confirmed by single-crystal X-ray diffraction. Compound 1 features a partial enol moiety and an acetamide group in its structure. In addition, compounds 1, 3-6 showed weak anti-HIV-1 activity with EC(50) values in the range of 15.5-29.5 microg/mL.

Lignans from Kadsura angustifolia.

Phytochemical investigation of Kadsura angustifolia led to the isolation and identification of 26 lignans and two triterpenoids, including 11 new lignans named kadangustins A-K ( 1- 11). The structures and stereochemistry of 1- 11 were elucidated by analysis of spectroscopic data. Except for 11 and 20, all the lignans were evaluated for their inhibitory activity against HIV-1. Binankadsurin A ( 19) showed anti-HIV activity with an EC 50 value of 3.86 microM.

Cytotoxic ent-kaurane diterpenoids from Isodon rubescens var. lushiensis.

Ten new ent-kaurane diterpenoids, isolushinins A-J (1-10), together with 20 known compounds, were isolated from the aerial parts of Isodon rubescens var. lushiensis. The structures of 1-10 were elucidated by spectroscopic analysis. Several of the compounds isolated were evaluated for their cytotoxicity against the HL-60, SMMC-7721, A-549, SK-BR-3, and PANC-1 human cancer cell lines, and some exhibited quite potent inhibitory activities.

Antiviral Chromones from the Stem of Cassia siamea

Seven new chromones, siamchromones A-G (1-7), and 12 known chromones (8-19) were isolated from the stems of Cassia siamea. Compounds 1-19 were evaluated for their antitobacco mosaic virus (anti-TMV) and anti-HIV-1 activities. Compound 6 showed antitobacco mosaic virus (anti-TMV) activity with an inhibition rate of 35.3% and IC50 value of 31.2 μM, which is higher than that of the positive control, ningnamycin. Compounds 1, 10, 13, and 16 showed anti-TMV activities with inhibition rates above 10%. Compounds 4, 6, 13, and 19 showed anti-HIV-1 activities with therapeutic index values above 50.

Apoptotic effects of polyprenylated benzoylphloroglucinol derivatives from the twigs of Garcinia multiflora.

With bioassay-guided fractionation, five new polyprenylated benzoylphloroglucinol derivatives, garcimultiflorone D (1), 18-hydroxygarcimultiflorone D (2), garcimultiflorone E (3), garcimultiflorone F (4), and isogarcimultiflorone F (5), and five known compounds, guttiferone E (6), guttiferone F (7), aristophenone A (8), isoxanthochymol (9), and morelloflavone (10), were isolated from the acetone extract of the twigs of Garcinia multiflora. The compounds were evaluated for their apoptotic effects against HeLa-C3 cells, which have been genetically engineered to produce a fluorescent biosensor capable of detecting caspase-3 activation. Compounds 1 and 3-9 activate caspase-3 in HeLa-C3 cells within 72 h after treatment at a concentration of 100 microM or lower. In particular, compounds 6, 8, and 9 showed strong apoptosis-inducing effects at a concentration of 25 microM.

Cytotoxic deoxybenzoins and diphenylethylenes from Arundina graminifolia.

Eight new C-4-alkylated deoxybenzoins (1-8), three new diphenylethylenes (9-11), and five known diphenylethylenes were isolated from Arundina graminifolia. The structures of 1-11 were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. Compounds 9-11 are the first naturally occurring diphenylethylenes possessing a hydroxyethyl unit. Compounds 1-11 were evaluated for cytotoxicity against five human tumor cell lines. Compounds 4, 5, and 9-11 showed significant cytotoxicity against five cancer cell lines, with IC50 values ranging from 1.8 to 8.7 μM.