In order to identify the component(s) in BE responsible for the antidiabetic activity, our first goal was to confirm that corosolic acid was responsible for the glucose transport stimulatory activity. Since tannins comprise up to 40% of the material in the extract, we were interested in separating it from corosolic acid first. To our surprise, after removing tannins by either gelatin or bovine serum albumin tannin precipitations (29), the remaining extract was not able to induce glucose transport. We concluded that the glucose transport activity was caused by the tannin component of the extract, and not corosolic acid (29) . Furthermore, we tested pure corosolic acid and found that it was not able to stimulate glucose transport in our cell model (Fig. 3) . Although we cannot exclude the possibility that corosolic acid may have some antidiabetic activity, we can eliminate corosolic acid from having the insulin-like glucose transport stimulatory activity found in adipocytes. It should be noted that banaba extracts prepared from banaba leaves from different sources may have different chemical compositions, which in turn may lead to different experimental results (our lab used dried banaba leaves from the Philippines).