In Vitro Immunomodulatory Effect Of Ipomoea Batatas L. Tuber Bioactives

Bioactives in Ipomoea batatas L. (sweet potatoes) have shown to exhibit radical‐scavenging activity, antimutagenicity, potential chemopreventive properties, and antidiabetic effects. However, bioactions of constituents in the Simon No. 1 (S1) and Tainong 66 (T66) sweet potatoes have not been fully elucidated. Thus, the objective of this study was to investigate the immunomodulatory effect of bioactives extracted from the S1 and T66 tubers harvested from the Chiayi Agricultural Experiment Station, Agricultural Research Institute, Taiwan. Bioactives in the tubers were first extracted with ethanol. After solvent removal with lyophilization, the resulting powder was further fractionated using liquid‐liquid partition to yield ethyl acetate (EAF) and water (WF) fraction. Mice splenocytes were harvested and treated with EAF or WF at concentrations ranging 0–200 μg/mL (w/v) for 24–48 h. EAF of the S1 and T66 increased cell proliferation in a dose‐dependent manner, but not WF. EAF of the T66 and S1 at 200 μg/mL enhanced cytotoxic activity of splenocyte NK cell by 24 and 41%, respectively, compared to control group at an effector cells/target cells ratio of 100. In conclusion, our results showed that bioactives in sweet potatoes exhibit immunomodulatory activities in a cultivar dependent manner. Further studies are warranted to examine underlying mechanism(s) for the modulations and characterize bioactives.