1117 0009-3130/17/5306-1117  2017 Springer Science+Business Media New York Chemistry of Natural Compounds, Vol. 53, No. 6, November, 2017 A NEW AMIDE AND ANTIOXIDANT CONSTITUENTS OF Piper taiwanense Jih-Jung Chen, 1,2* Shih-Wei Wang, 3 Chun-Lin Chen, 4 Yueh-Hsiung Kuo, 5,6 Ming-Jen Cheng, 7* Tsung-Hsien Chang, 8 Ping-Jyun Sung, 9 Wen-Lung Kuo, 10 and Yun-Ping Lim 11 A new amide, pipertaiwanamide (1), has been isolated from the aerial part of Piper taiwanense, together with four known compounds, taiwanamide A ( 2), taiwanamide B (3 ), 1-cinnamoylpyrrolidine (4 ), and N-cinnamoyltyramine (5). The structure of the new compound 1 was determined through spectroscopic and MS analyses. Pipertaiwanamide (1) and N-cinnamoyltyramine (5) exhibited free radical scavenging activity, with IC 0.200 values of 12.6  1.4 and 8.5  0.8 M, respectively, in the diphenylpicrylhydrazyl radical (DPPH) decoloration assay. Keywords: Piper taiwanense, Piperaceae, aerial part, amide, antioxidant activity. Piper taiwanense T.T. Lin & S.Y. Lu (Piperaceae) is an endemic scandent plant, distributed in forests at low to medium altitudes throughout Taiwan [1]. Amides [2–5], pyridones [2, 3], benzenoids [2, 4], steroids [2], aristolactams [4], and their derivatives are widely distributed in plants of the genus Piper. Many of these compounds exhibit diverse biological activities, including cytotoxic [2, 3] and antiplatelet aggregation [4, 5] activities. In a preliminary screening, the methanolic extract of the aerial part of this species showed antioxidant activities in vitro. The current phytochemical investigation of the aerial part of this plant has led to the isolation of a new amide, pipertaiwanamide (1), along with four known compounds. The structural elucidation of 1 and antioxidant property of the isolates are described herein. Extensive fractionation of the CH 2 Cl 2 -soluble portion of a MeOH extract of the aerial part of Piper taiwanense using silica gel column chromatography (CC), medium-pressure liquid chromatography (MPLC), and preparative TLC afforded compounds 1–5. 1) Faculty of Pharmacy, School of Pharmaceutical Sciences, National Yang-Ming University, 112, Taipei, Taiwan, e-mail: chenjj@ym.edu.tw; 2) Department of Medical Research, China Medical University Hospital, 404, Taichung, Taiwan; 3) Department of Medicine, Mackay Medical College, New Taipei City 252, Taiwan; 4) Department of Biological Sciences, National Sun Yat-sen University, 804, Kaohsiung, Taiwan; 5) Department of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University, 404, Taichung, Taiwan; 6) Department of Biotechnology, Asia University, 413, Taichung, Taiwan; 7) Bioresource Collection and Research Center (BCRC), Food Industry Research and Development Institute (FIRDI), 300, Hsinchu, Taiwan; 8) Department of Medical Education and Research, Kaohsiung Veterans General Hospital, 813, Kaohsiung, Taiwan; 9) National Museum of Marine Biology and Aquarium, 944, Pingtung, Taiwan; 10) Chung-Jen Junior College of Nursing, Health Sciences and Management, 600, Chiayi, Taiwan; 11) School of Pharmacy, College of Pharmacy, China Medical University, 404, Taichung, Taiwan. Published in Khimiya Prirodnykh Soedinenii , No. 6, November–December, 2017, pp. 949–952. Original article submitted February 14, 2016. 1: R 1 = OH, R 2 = OCH 3 ; 2: R 1 = OH, R 2 = H 3: R 1 = OCH 3 , R 2 = H N O R 1 OCH 3 H R 2 OCH 3 OCH 3 1 - 3 4 5 1 5 7 8' 7' 1' 5' 3' N OH O H 1' 7' 7 5 1 4' 9 N O 7 5 1 9 2' 4' DOI 10.1007/s10600-017-2213-y