Introduction ! Malaria is an important parasitic disease trans- mitted to humans by the bite of an infected fe- male mosquito. Approximately 219 million peo- ple worldwide are affected by malaria and 600 000 deaths in 2010 have been reported in the World Malaria Report [1]. Malaria remains one of the most important infectious diseases in the developing world. In Malaysia, the parasites Plasmodium falciparum, P. knowlesi, and P. vivax are recognized as the common cause of malaria. Symptoms of malaria include fever, shivering, joint pain, vomiting, and retinal damage [2]. Global warming could increase malaria by ex- panding the area in which the ambient tempera- ture and climate conditions are suitable. This could lead to the resistance of common antima- larial drugs such as artemisinin-based mono- therapies. Parasite resistance to artemisinin has now been detected in 4 countries: Cambodia, Myanmar, Thailand, and Vietnam [1]. Thus, there Abstract ! The crude extract of the bark of Dehaasia longipe- dicellata 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. Antiplas- modial activity was determined for all of the iso- lated compounds. They showed potent to moder- ate activity with IC 50 values ranging from 0.031 to 30.40 μM. (-)-O-O-dimethylgrisabine (6) and (-)-milonine (2) were the two most potent com- pounds, with IC 50 values of 0.031 and 0.097 μM, respectively, that were comparable to the stan- dard, chloroquine (0.090 μM). The compounds were also assessed for their antioxidant activities with di(phenyl)-(2,4,6-trinitrophenyl)iminoaza- nium (IC 50 = 18.40–107.31 μg/mL), reducing power (27.40–87.40 %), and metal chelating (IC 50 = 64.30 to 257.22 μg/mL) having good to low activity. (-)-O‑O-dimethylgrisabine (6) exhibited a potent antioxidant activity of 44.3% reducing power, while di(phenyl)-(2,4,6-trinitrophenyl) iminoazanium and metal chelating activities had IC 50 values of 18.38 and 64.30 μg/mL, respectively. Thus it may be considered as a good reductant with the ability to chelate metal and prevent pro-oxidant activity. In addition to the antiplas- modial and antioxidant activities, the isolated compounds were also tested for their cytotoxicity against a few cancer and normal cell lines. (-)-Norboldine (4) exhibited potent cytotoxicity towards pancreatic cancer cell line BxPC-3 with an IC 50 value of 27.060 ± 1.037 μM, and all alka- loids showed no toxicity towards the normal pan- creatic cell line (hTERT-HPNE). Abbreviations ! BHA: butylated hydroxyanisole DCE: dichloromethane crude extract DPPH: di(phenyl)-(2,4,6-trinitrophenyl)imi- noazanium EDTA: ethylenediaminetetraacetic acid FRAP: ferric reducing power assay ROS: reactive oxygen species Rf: retention time SOD: superoxide dismutase TLC: thin-layer chromatography Antiplasmodial and Antioxidant Isoquinoline Alkaloids from Dehaasia longipedicellata Authors Azeana Zahari 1 , Foo Kit Cheah 4 , Jamaludin Mohamad 2 , Syazreen Nadia Sulaiman 1 , Marc Litaudon 3 , Kok Hoong Leong 4 , Khalijah Awang 1 Affiliations 1 Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia 2 Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia 3 Institut de Chimie des Substances Naturelles, Centre National de la Recherche Scientifique, Gif-sur Yvette, France 4 Department of Pharmacy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia Key words l " Lauraceae l " Dehaasia longipedicellata l " antiplasmodial l " antioxidant l " cytotoxicity received Sept. 22, 2013 revised February 28, 2014 accepted March 3, 2014 Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1368349 Published online April 10, 2014 Planta Med 2014; 80: 599–603 © Georg Thieme Verlag KG Stuttgart · New York · ISSN 0032‑0943 Correspondence Khalijah Awang Department of Chemistry Faculty of Science University of Malaya 50603 Kuala Lumpur Malaysia Phone: + 60 3 79 67 41 61 Fax: + 60 3 79 67 41 93 khalijah@um.edu.my 599 Zahari A et al. Antiplasmodial and Antioxidant … Planta Med 2014; 80: 599–603 Original Papers Downloaded by: IP-Proxy Univ Malaya, University of Malaya. Copyrighted material.