Browsing by Author "Rasamison, Vincent E."

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  • Antimalarial 5,6-Dihydro-alpha-pyrones from Cryptocarya rigidifolia: Related Bicyclic Tetrahydro-alpha-Pyrones Are Artifacts
    Liu, Yixi; Rakotondraibe, L. Harinantenaina; Brodie, Peggy J.; Wiley, Jessica D.; Cassera, Maria B.; Miller, James S.; Ratovoson, F.; Rakotobe, Etienne; Rasamison, Vincent E.; Kingston, David G. I. (American Chemical Society, 2015-06-01)
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    Antiproliferative Compounds from Cleistanthus boivinianus from the Madagascar Dry Forest
    Liu, Yixi; Young, Kelly; Rakotondraibe, L. Harinantenaina; Brodie, Peggy J.; Wiley, Jessica D.; Cassera, Maria B.; Callmander, Martin W.; Rakotondrajaona, R.; Rakotobe, Etienne; Rasamison, Vincent E.; TenDyke, Karen; Shen, Yongchun; Kingston, David G. I. (American Chemical Society, 2015-07-01)
    The two new lignans 3a-O-(b-D-glucopyranosyl)- desoxypodophyllotoxin (1) and 4-O-(b-D-glucopyranosyl)-dehydropodophyllotoxin (2) were isolated from Cleistanthus boivinianus, together with the known lignans deoxypicropodophyllotoxin (3), (±)-b-apopicropodophyllin (4), (-)- desoxypodophyllotoxin (5), (-)-yatein (6), and b-peltatin-5-O-b-D-glucopyranoside (7). The structures of all compounds were characterized by spectroscopic techniques. Compounds 1, 4, and 5 showed potent antiproliferative activities against the A2780 ovarian cancer cell line, with IC50 values of 33.0 ± 3.6, 63.1 ± 6.7, and 230 ± 1 nM, respectively. Compounds 2 and 7 showed only modest A2780 activities, with IC50 values of 2.1 ± 0.3 and 4.9 ± 0.1 mM, respectively, while compounds 3 and 6 had IC50 values >10 mM. Compound 1 also had potent antiproliferative activity against the HCT116 human colon carcinoma cell line, with an IC50 value of 20.5 nM, and compound 4 exhibited modest antiproliferative activity against the A2058 human caucasian metastatic melanoma and MES-SA human uterine sarcoma cell lines, with IC50 values of 4.6 and 4.0 mM, respectively. In the course of work as part of the Madagascar International Cooperative Biodiversity Group (ICBG) program, an ethanol extract of the stems of Cleistanthus boivinianus (Baill.) Müll. Arg. (Phyllanthaceae) was found to have moderate antiproliferative activity against the A2780 ovarian cancer cell line (IC50 4.5 mg/mL), and was thus selected for evaluation of the presence of novel antiproliferative agents. The genus Cleistanthus is native to Africa, India, and Australia, and comprises approximately 140 species, but only five of these have been investigated chemically: C. collinus, C. patulus, C. schlechteri var. schlechteri, C. gracilis, and C. indochinensis. Arylnaphthalide lignans are major constituents of the genus, while arytetralin, furofuranoid, and dibenzylbutane lignans and terpenoids have also been isolated from them and are known for their cytotoxic properties.
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    Antiproliferative triterpenoid saponins from Leptaulus citroides Baill. from the Madagascar rain forest
    Su, Qingxi; Brodie, Peggy J.; Liu, Yixi; Miller, James S.; Andrianjafy, Naina M.; Antsiferana, Rabodo; Rasamison, Vincent E.; Kingston, David G. I. (Springer, 2016)
    Bioassay-guided fractionation of EtOH extracts obtained from the roots and wood of the Madagascan plant Leptaulus citroides Baill. (Cardiopteridaceae) led to the isolation of ethyl esters of three new triterpenoid saponins (1–3) and the known sesquiterpenoid cinnamosmolide (4). The structures of 1–3 were elucidated by extensive 1D and 2D NMR experiments and mass spectrometry. Compounds 1, 2, and 4 showed moderate cytotoxicity against the A2780 human ovarian cancer cell line with IC50 values of 2.8, 10.2 and 2.0 lM, respectively.
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    Nitrogen-Containing Dimeric nor-Multiflorane Triterpene from a Turraea sp.
    Rasamison, Vincent E.; Rakotondraibe, L. Harinantenaina; Slebodnick, Carla; Brodie, Peggy J.; Ratsimbason, Michael; TenDyke, Karen; Shen, Yongchun; Randrianjanaka, Lucien M.; Kingston, David G. I. (American Chemical Society, 2014-05-16)
    The new triterpene turranoic acid (1) and thenew N-containing nor-triterpene turraenine (2), along with triptocallic acid B (3) and esculentoic acid (4) were isolated from leaves of a Turraea sp. Compounds 1-3 showed weak to moderate in vitro antiplasmodial activity against the chloroquine-resistant Plasmodium falciparum strain FCM29. Compound 1 also displayed weak cytotoxic activity against the non-small lung cancer cell line H522-T1 with an IC50 value of 16.4 μM.