Natural Product Sciences 20(4) : 274-280 (2014) 274 Bioactive Constituents from the n-Butanolic Fraction of Aruncus dioicus var. kamtschaticus Quoc Hung Vo 1,2 , Phi Hung Nguyen 1 , Bing Tian Zhao 1 , Yen Nguyen Thi 1 , Duc Hung Nguyen 1 , Won Il Kim 1 , U Min Seo 1 , Byung Sun Min 1 , and Mi Hee Woo 1, * 1 College of Pharmacy, Catholic University of Daegu, Gyeongsan 712-702, Republic of Korea 2 Department of Pharmacy, Hue University of Medicine and Pharmacy, Hue City, Viet Nam Abstract - Six compounds were isolated from the n-BuOH fraction of the aerial parts of Aruncus dioicus var. kamtschaticus including: sambunigrin (1), prunasin (2), aruncide A (3), aruncide C (4), 1-O-caffeoyl-β-D- glucopyranose (5), and caffeic acid (6). Their structures were confirmed by comparing the spectral data with those reported in the literature. The isolated compounds (1 - 6) were then examined for their cytotoxic effects towards MCF-7, HL-60, and HeLa cancer cell lines, as well as their DPPH radical scavenging activity. The results indicated that compound 4 possessed the strongest inhibitory effect toward HeLa cell line with IC 50 value of 5.38 ± 0.92 μM. Compound 3 possessed selective cytotoxic activity on HL-60 cells with IC 50 value of 6.27 ± 0.17 μM, compound 5 was found as the best in inhibiting proliferation with IC 50 value of 2.25 ± 0.09 μM, and the other compounds showed significant inhibition with IC 50 values ranging from 6.10 to 11.27 μM. Compound 5 also displayed the strongest cytotoxic effect toward MCF-7 cell line (IC 50 4.32 ± 0.15 μM). Both 5 and 6 demonstrated strong radical scavenging activity (IC 50 6.87 ± 0.03 and 4.33 ± 0.22 μM, respectively). Compounds 1 and 5 were isolated for the first time from this plant. Keywords - Aruncus dioicus var. kamtschaticus, Cyanogenic glycosides, Monoterpenes, Caffeoyl glucoside Introduction Increased public interest regarding the efficacy of natural products in the treatment of diseases has inspired pharmaceutical scientists to search for new avenues in drug discovery. Currently, the use of medicinal plants, as well as plant-derived molecules, remain a significant fraction of pharmaceuticals in the clinic. 1 Studies have found that natural products and related drugs are used to treat 87% of all categorized human diseases. 2 Among existing diseases, cancer is a major cause of morbidity and mortality, with approximately 14 million new cases and 8 million cancer-related deaths reported in 2012; the disease affects populations in all countries and all regions. Particularly, breast cancer, which is the most common cancer diagnosis for women in 140 countries and the most frequent cause of cancer mortality in 101 countries, has a considerably higher incidence rate (43.3 per 100,000) than other types of cancer. Cervix is one of the five most common in incident sites of cancer in women which accounts for 7.9% of total. 3 Finally, leukemia ranks as the eleventh highest in terms of cancer incidence, and the tenth most common cause of cancer death. 4 One of the causes of cancer is free radicals, primarily reactive oxygen species (ROS). Increased levels of ROS can damage the structure of biomolecules, alter their functions, and lead not only to cellular dysfunction, but also to cell death. The cumulative effect of increased ROS can increase oxidative stress at a systemic level, and it is manifested in the form of a variety of health problems such as cancer, age-related disease and cardiovascular diseases. Thus, natural antioxidants are known to minimize the adverse effects of free radicals in living system that brings benefits to human health. 5 Therefore, in the interest of promoting drug discovery from natural sources, this research was conducted to identify bio-active compounds from Aruncus dioicus var. kamtschaticus (Rosaceae). This major leafy vegetable, which is cultivated in Ulleungdo - Rep. of Korea, has been proven to possess many bioactivities including antioxidant, 6 antidiabetic, 7 and anti-HIV 8 effects. The herb also has therapeutic value for treating ischemic, *Author for correspondence Mi Hee Woo, College of Pharmacy, Catholic University of Daegu, Gyeongsan 712-702, Republic of Korea Tel: +82-53-8503620; E-mail: woomh@cu.ac.kr