Another mechanism of inhibition of RV by T. esculentum extracts, especially in seed coats, may lie in the inactivation of RV, as shown with enhancement of cell survival after preincubation of rotavirus with T. esculentum extracts. It is herein suggested that the observed inactivation of RV may be through interference with either viral replication or capacity to bind to permissive cells. Clark et al. [36] have shown that some phenolic acids, which were expected to dominate the ethanolic extracts, have inactivation effect against RV. Similar observations were also made with extracts from peppermint, sage, and lemon balm leaves, which were highly inhibitive against HIV [37] . The inhibitive effects of T. esculentum extracts, especially seed coat and cotyledon ethanolic extract (MSCE and MCE) and tuber water extract (MTW) (≥100%), could additionally be due to enhanced release of nitric oxide (NO) from intestinal cells. Nitric oxide has been shown to inactivate RV, mainly by inhibiting replication of the virus [38, 39] . The observed enhancement of nitric oxide release from the human and pig cells was viewed as one of the mechanisms T. esculentum crude extracts can induce a nonspecific immune response in intestinal epithelium.