Antiproliferative effects of heated Japanese runner bean ( <i>Phaseolus coccineus</i> ) lectins

In this study, we examined the biological properties of lectins isolated from raw and heated Japanese white runner beans (WRB; Phaseolus coccineus). Notably, we studied the agglutination activity of lectins that persisted after both dry and wet heating processes. Raw and heated WRB lectins were fractionated using thyroglobulin-sepharose chromatography. Raw WRB lectins displayed strong specificity for thyroglobulin but weak specificity for fetuin, demonstrated resistance to proteases, and tolerated temperatures of 60°C for 30 min. The antiproliferative effects of WRB lectins on cancer cells were assessed and compared between raw and heated beans. Both raw and heated WRB lectins exhibited significant antiproliferative activity against five cancer cell lines: LM8, B16, HeLa, HepG2, and Colo679. Interestingly, in terms of antiproliferative activity, raw and heated lectins showed no significant differences. Fractionated lectins from raw and heated beans showed strong inhibitory effects against B16 and HeLa cells. Furthermore, crude extracts from raw beans demonstrated anti-inflammatory activity. In summary, our findings highlight that lectin from heated WRB beans retained bioactivity, including anti-inflammatory and anticancer properties, after heating. These results suggest that WRB lectins could be developed as bioactive compounds for medical applications as functional food components. PRACTICAL APPLICATION: Japanese white runner beans (WRB), cultivated in northeastern Japan and traditionally used in confectionery, retain hemagglutination activity under dry and wet heating conditions. Heat-treated WRB lectins demonstrated anticancer activity comparable to that of raw bean lectins, supporting their potential use as bioactive proteins in medical research. WRB lectins may serve as promising candidates for development as anticancer agents or other therapeutic applications.