Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhoea in children and piglets. Infection of ETEC results in fluid secretion and electrolyte losses in the small intestine. In this study the effects of tempeh, a traditional fungal fermented soyabean product, on fluid losses induced by ETEC infection in piglets was investigated. Pairs of ETEC-infected and non-infected small intestinal segments of piglets were perfused simultaneously for 8 h with pre-digested tempeh, its supernatant and saline as an internal control. In saline perfused segments, ETEC infection reduced net fluid absorption by more than 500 μl/cm2, whereas this reduction was significantly less for pre-digested tempeh and its supernatant (75 and 282 μl/cm2, respectively). The supernatant of pre-digested tempeh was also compared with its permeate and retentate fractions. These fractions were created by ultra-filtration and contained respectively low and high molecular weight (>5 kDa) compounds. Again ETEC infection caused a significant reduction of net fluid absorption when perfused with saline (386 μl/cm2) and also with the permeate fraction (300 μl/cm2), but much less with the supernatant and the retentate fraction (125 and 140 μl/cm2, respectively). The reduction in net fluid absorption upon ETEC infection when perfused with supernatant of either undigested or pre-digested tempeh was not different. Therefore from this study it can be concluded that a high molecular weight soluble fraction of tempeh is able to protect against fluid losses induced by ETEC, suggesting that this could play a potential role in controlling ETEC-induced diarrhoea.

Anti-angiogenic strategies are emerging as an important tool for the treatment of cancer and inflammatory diseases. In the present investigation we isolated several isoflavones from a tempeh (fermented soyabean) extract. The isolated isoflavones were identified as 5,7,4′-trihydroxyisoflavone (genistein), 7,4′-dihydroxyisoflavone (daidzein), 6,7,4′-trihydroxyisoflavone (factor 2), 7,8,4′-trihydroxyisoflavone (7,8,4′-TriOH) and 5,7,3′,4′-tetrahydroxyisoflavone (orobol). The effects on angiogenesis of these isoflavones were evaluated in the chicken chorioallantoic membrane assay; their capacity to inhibit vascular endothelial growth factor-induced endothelial cell proliferation and expression of the Ets 1 transcription factor, known to be implicated in the regulation of new blood vessel formation, were also investigated. We found that all isoflavones inhibited angiogenesis, albeit with different potencies. Compared with negative controls, which slightly inhibited in vivo angiogenesis by 6·30 %, genistein reduced angiogensis by 75·09 %, followed by orobol (67·96 %), factor 2 (56·77 %), daidzein (48·98 %) and 7,8,4′-TriOH (24·42 %). These compounds also inhibited endothelial cell proliferation, with orobol causing the greatest inhibition at lower concentrations. The isoflavones also inhibited Ets 1 expression, providing some insight into the molecular mechanisms of their action. Furthermore, the chemical structure of the different isoflavones suggests a structure–activity relationship. Our present findings suggest that the new isoflavones might be added to the list of low molecular mass therapeutic agents for the inhibition of angiogenesis.