1 SUPPLEMENTARY MATERIAL Two clerodane diterpenes isolated from Polyalthia longifolia leaves: Comparative structural features, anti-histaminic and anti-Helicobacter pylori activities Martina P. Edmond 1† , Nada M. Mostafa 1† , Mohamed El-Shazly 1,2 * and Abdel Nasser B. Singab 1,3 * 1 Faculty of Pharmacy, Department of Pharmacognosy, Ain Shams University, Cairo, Egypt. 2 Department of Pharmaceutical Biology, Faculty of Pharmacy and Biotechnology, German University in Cairo, Cairo 11835, Egypt. 3 Center for Drug Discovery and Development Research, Ain-Shams University, Abbassia, 11566 Cairo, Egypt. † These authors contributed equally to the work. *Corresponding authors: Abdel Nasser Badawi Singab; Email address: Dean@pharma.asu.edu.eg , Tel.: +201005036231, Fax: +2 0224051107 Mohamed El-Shazly; Email address: mohamed.elshazly@pharma.asu.edu.eg Tel: +20100 140 10 91, Fax: +2 02 2405 1107