紫色狼尾草（Pennisetum purpureum）為狼尾草（Pennisetum spp.）品系之一。本研究分析自臺灣 15 縣市共收集到的 71 收集系，以各縣市地區紫色狼尾草之劍葉以上之葉片為材料，比較來自各地區紫色狼尾草抗氧化能力差異。抗氧化活性及成分含量測定，包括總酚含量(total phenolic content, TPC)、1,1-diphenyl-2-picryl hydrazyl (DPPH)清除自由基能力(DPPH free radical scavenging capacity, DH)、總花青素含量 (total anthocyanin content, TA)。結果顯示 71 個紫色狼尾草收集樣本之抗氧化活性及成分之間經變方分析結果 (ANOVA) 皆有顯著差異，再將 71 個收集系抗氧化活性及成分含量代入 15 地區進行比較地區差異，結果發現 TPC 含量最高及最低之地區分別為宜蘭和桃園，DH 清除率最高及最低分別為台中和台東，TA含量最高及最低分別為宜蘭及台中。綜合上述，紫色狼尾草抗氧化活性方面，TPC 含量最高為宜蘭、DH 清除率最高為台中、TA 含量最高為宜蘭之紫色狼尾草。由結果顯示，上述區域因地區不同及收集系之差異較容易選出高抗氧化能力的紫色狼尾草新品系。

Purple napiergrass is one line of napiergrass (Pennisetum purpureum Schumach). In this study, the antioxidant capacity of 71 purple napiergrass accessions collected from 15 counties in Taiwan was determined. The antioxidative capacity determined included total phenolic content (TPC), 1,1-diphenyl-2-picryl hydrazyl (DPPH), free radical scavenging capacity (DH) and total anthocyanin (TA). ANOVA result showed that antioxidative capacity and antioxidant contents of purple napiergrass were significantly different among 71 accessions. After grouping these 71 accessions into 15 geographic populations, the maximal and minimal contents of TPC were found in accessions from Yilan and Taoyuan, respectively. In addition, the maximal and minimal values of DH were found in accessions from Taichung and Taitung, respectively, and the maximal and minimal contents of TA were found in accessions from Yilan and Taichung, respectively. The accessions with the highest contents of TPC, DH and TA were collected from Yilon and Taichung. It is suggested that the accession of purple napiergrass with high antioxidative capacity might be selected from locations mentined above.