A new protoberberine alkaloid from Meconopsis simplicifolia (D. Don) Walpers with potent antimalarial activity against a multidrug resistant Plasmodium falciparum strain Phurpa Wangchuk a,b,n , Paul A. Keller b , Stephen G. Pyne b , Wilford Lie b , Anthony C. Willis c , Roonglawan Rattanajak d , Sumalee Kamchonwongpaisan d Q1 a Menjong Sorig Pharmaceuticals, Ministry of Health, Thimphu, Bhutan b School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia c Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia d Medical Molecular Biology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Thailand Science Park, Pathumthani 12120, Thailand article info Article history: Received 9 June 2013 Received in revised form 27 September 2013 Accepted 28 September 2013 Keywords: Meconopsis simplicifolia Simplicifolianine Antimalarial Anticancer Medicinal plant Bhutanese traditional medicine abstract Ethnopharmacological relevance: The aerial components of Meconopsis simplicifolia (D. Don) Walpers are indicated in Bhutanese traditional medicine for treating malaria, coughs and colds, and the infections of the liver, lung and blood. Q4 To validate the ethnopharmacological uses of this plant and also identify potent antimalarial drug leads through bioassays of its crude extracts and phytochemical constituents. Materials and methods: Meconopsis simplicifolia (D. Don) Walpers was collected from Bhutan and its crude MeOH extract was subjected to acid-base fractionation. Through repeated extractions, separations and spectroscopic analysis, the alkaloids obtained were identified and tested for their antimalarial and cytotoxicity activities. Results: Phytochemical studies resulted in the isolation of one new protoberberine type alkaloid which we named as simplicifolianine and five known alkaloids: protopine, norsanguinarine, dihydrosangui- narine, 6-methoxydihydrosanguinarine and oxysanguinarine. Among the five of the alkaloids tested, simplicifolianine showed the most potent antiplasmodial activities against the Plasmodium falciparum strains, TM4/8.2 (chloroquine–antifolate sensitive strain) and K1CB1 (multidrug resistant strain) with IC 50 values of 0.78 μg/mL and 1.29 μg/mL, respectively. The compounds tested did not show any significant cytotoxicity activities against human oral carcinoma KB cells and normal Vero cells of African kidney epithelial cells. Conclusions: This study validated the traditional uses of the plant for the treatment of malaria and identified a new alkaloid, simplicifolianine as a potential antimalarial drug lead. & 2013 Published by Elsevier Ireland Ltd. 1. Introduction Meconopsis (Papaveraceae) comprises about 43–49 species with the majority of these restricted to the Himalaya and only one species, Meconopsis cambrica, being endemic to Europe (Debnath and Nayar, 1986; Zhou et al., 2009). The plants of this genus are prized for their ornamental and medicinal qualities. Many Meconopsis species, such as Macadamia integrifolia, Mecynorrhina torquata, Meconopsis horridula, Muhlenbergia racemosa and Meconopsis quintuplinervia have long been used in Tibetan folk remedies for treating various disorders (Luo et al., 1984; Zhou et al., 2009; Yue et al., 2010). Out of 13 Meconopsis species reported from Bhutan (Grierson and Long, 1984), seven of them (Meconopsis horridula, Murraya paniculata, Meconopsis napaulensis, Meconopsis superba, Mylothris primulina, Meconopsis discigera and Meconopsis simplicifolia) were said to have medicinal properties. However, only two species (Meconopsis horridula and Meconopsis simplicifolia) are currently used in Bhutanese traditional medicine (BTM) for various formulations (Tenzin, 2007; Wangchuk et al., 2008). Meconopsis simplicifolia (D. Don) Walpers is locally known as ud-pel-sngon-po and grows to 30–70 cm tall with narrowly oblon- gated seed capsules, blue flowers, and hairy stems and leaves (Anonymous, 2008). Its aerial parts (stems, leaves, flowers and fruit), in combination with other ingredients, are used for preparing more than eight important BTM multi-ingredient formulations. As an individual plant, it is indicated for treating coughs and colds, fever and infections in the liver, lung and blood which show correlations to the symptoms of cancer, microbial infections and 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jep Journal of Ethnopharmacology 0378-8741/$ - see front matter & 2013 Published by Elsevier Ireland Ltd. http://dx.doi.org/10.1016/j.jep.2013.09.052 n Corresponding Q5 author at: School of Chemistry, University of Wollongong, NSW 2522, Australia. Tel.: þ61 2 4221 4388; fax: þ61 2 4221 4287. E-mail address: phurpaw@yahoo.com (W. Phurpa). Please cite this article as: Phurpa, W., et al., A new protoberberine alkaloid from Meconopsis simplicifolia (D. Don) Walpers with potent antimalarial activity.... Journal of Ethnopharmacology (2013), http://dx.doi.org/10.1016/j.jep.2013.09.052i Journal of Ethnopharmacology ∎ (∎∎∎∎) ∎∎∎–∎∎∎