Sci Research article Pharm www.scipharm.at Open Access Crinum Latifolium Leave Extracts Suppress Immune Activation Cascades in Peripheral Blood Mononuclear Cells and Proliferation of Prostate Tumor Cells Marcel JENNY 1, Angela WONDRAK 2, Elissaveta ZVETKOVA 3 , Nguyen Thi Ngoc TRAM 4, Phan Thi Phi PHI 5, Harald SCHENNACH 6 , Zoran CULIG 7, Florian UEBERALL 2, Dietmar FUCHS * 1 1 Division of Biological Chemistry, Innsbruck Medical University, Fritz-Pregl-Str. 3, 6020 Innsbruck, Austria. 2 Division of Medical Biochemistry, Innsbruck Medical University, Fritz-Pregl-Str. 3, 6020 Innsbruck, Austria. 3 Institute of Experimental Pathology and Parasitology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria. 4 Thien Duoc Company Ltd., 51/4/9 Thanh Thai St. Ward 14, District 10, Ho Chi Minh City, Vietnam. 5 Hanoi Medical University, Ton That Tung Street 1, Hanoi, Vietnam. 6 Central Institute of Blood Transfusion and Immunology, University Hospital Innsbruck, Anichstraße 35, 6020 Innsbruck, Austria. 7 Department of Urology, Innsbruck Medical University, Anichstraße 35, 6020 Innsbruck, Austria. * Corresponding author. E-mail: dietmar.fuchs@i-med.ac.at (D. Fuchs) Sci Pharm. 2011; 79: 323–335 Published: Accepted: April 5th 2011 April 4th 2011 doi:10.3797/scipharm.1011-13 Received: November 30th 2010 This article is available from: http://dx.doi.org/10.3797/scipharm.1011-13 © Jenny et al.; licensee Österreichische Apotheker-Verlagsgesellschaft m. b. H., Vienna, Austria. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Plants of the genus Crinum (Amaryllidaceae) are widely used in folk medicine in different tropical and subtropical regions around the world. The Indian species Crinum latifolium (L.) was traditionally used to treat rheumatism, fistula, tumors, earaches, rubefacient, tubercle and whitlow. In Vietnamese and Chinese traditional medicine Crinum latifolium preparations are used until nowadays because of their antiviral and antitumor properties. In this study, we demonstrate potent in vitro antioxidant activity of an aqueous Crinum latifolium extract by an oxygen radical absorbance capacity (ORAC) value of 1610 ± 150 µmol Trolox equivalents/g. Furthermore, significant anti-inflammatory effects of this extract were shown by its potential to suppress indoleamine 2,3-dioxygenase (IDO) mediated tryptophan degradation in unstimulated- and mitogen-stimulated PBMC at IC50 doses of 241 ± 57 µg/ml and 92 ± 20 µg/ml, respectively. Concentrations of the immune activation marker neopterin were