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Antiplasmodial And Antioxidant Isoquinoline Alkaloids From Dehaasia Longipedicellata, Kok Hoong Leong
Antiplasmodial And Antioxidant Isoquinoline Alkaloids From Dehaasia Longipedicellata, Kok Hoong Leong
Kok Hoong Leong
The crude extract of the bark of Dehaasia longipedicellata exhibited antiplasmodial activity against the growth of Plasmodium falciparum K1 isolate (resistant strain). Phytochemical studies of the extract led to the isolation of six alkaloids: two morphinandienones, (+)-sebiferine (1) and (−)-milonine (2); two aporphines, (−)-boldine (3) and (−)-norboldine (4); one benzlyisoquinoline, (−)-reticuline (5); and one bisbenzylisoquinoline, (−)-O-O-dimethylgrisabine (6). Their structures were determined on the basis of 1D and 2D NMR, IR, UV, and LCMS spectroscopic techniques and upon comparison with literature values. Antiplasmodial activity was determined for all of the isolated compounds. They showed potent to moderate activity with IC50 values …
Subditine, A New Monoterpenoid Indole Alkaloid From Bark Of Nauclea Subdita (Korth.) Steud. Induces Apoptosis In Human Prostate Cancer Cells, Kok Hoong Leong
Subditine, A New Monoterpenoid Indole Alkaloid From Bark Of Nauclea Subdita (Korth.) Steud. Induces Apoptosis In Human Prostate Cancer Cells, Kok Hoong Leong
Kok Hoong Leong
In this study, a new apoptotic monoterpenoid indole alkaloid, subditine (1), and four known compounds were isolated from the bark of Nauclea subdita. Complete 1H- and 13C- NMR data of the new compound were reported. The structures of isolated compounds were elucidated with various spectroscopic methods such as 1D- and 2D- NMR, IR, UV and LCMS. All five compounds were screened for cytotoxic activities on LNCaP and PC-3 human prostate cancer cell-lines. Among the five compounds, the new alkaloid, subditine (1), demonstrated the most potent cell growth inhibition activity and selective against LNCaP with an IC50 of 12.2460.19 mM and …
Kingianic Acids A–G, Endiandric Acid Analogues From Endiandra Kingiana, Kok Hoong Leong
Kingianic Acids A–G, Endiandric Acid Analogues From Endiandra Kingiana, Kok Hoong Leong
Kok Hoong Leong
A phytochemical investigation of the methanolic extract of the bark of Endiandra kingiana led to the isolation of seven new tetracyclic endiandric acid analogues, kingianic acids A–G (1–7), together with endiandric acid M (8), tsangibeilin B (9) and endiandric acid (10). Their structures were determined by 1D- and 2D-NMR analysis in combination with HRMS experiments. The structure of compounds 9 and 10 were confirmed by single-crystal X-ray diffraction analysis. These compounds were screened for Bcl-xL and Mcl-1 binding affinities and cytotoxic activity on various cancer cell lines. Compound 5 showed moderate cytotoxic activity against human colorectal adeno-carcinoma (HT-29) and lung …