Antioxidant and antitumor activities of water extracts from the root of Actinidia kolomikta

The genus of Actinidia is widely distributed throughout the Asian continent. Specific Actinidia species have been used as health foods and medical products for cancer treatment. Actinidia kolomikta is a species of wild plant that grows in the northern part of Indochina. However, few studies on its bioactivity have been reported. In this study, the polysaccharide and polyphenol contents, the SOD-like activity and the DPPH radical-scavenging activity of water extracts from the root of Actinidia kolomikta produced under different extraction temperatures were investigated. Furthermore, the water extraction-ethanol precipitate (WE-EP) fraction and the water extraction-ethanol supernatant (WE-ES) fraction were used to test the anti-proliferative action on DLD-1 colon cancer cells. Extracts produced using the 100 degrees C extraction procedure revealed higher extraction yields and antioxidant activities than extracts produced using the 40 degrees C extraction procedure. The WE-EP and WE-ES fractions exhibited anti-proliferative effects on the DLD-1 cells. Moreover, the WE-ES polyphenol-enriched fraction possessed more potent anti-proliferative effects on the DLD-1 cells by inducing apoptosis compared to the WE-EP polysaccharide fraction. Medicinal plant extracts are generally considered to be relatively non-toxic at low doses and are not thought to cause major side effects compared to those observed with drugs. Wild A. kolomikta may provide an alternative to currently employed cancer therapies, and may be used as a natural health food with antioxidant actions.