| Infection from pathogens is one of the major health hazards in higher organisms including plants. To defend against harmful invaders, most plants produce a variety of defense proteins including lectins, protease inhibitors, antifungal proteins, ribonucleases and ribosome-inactivating proteins. They may be present in different organs of the plants, such as leaves, roots, seeds and tubers. Some of the plant defense proteins were found to exhibit a variety of biological activities such as anti-tumor activity, anti-bacterial activity and anti-viral activity that act against various plant pathogens and also some human pathogens. Therefore, some plant defense proteins may have potential for therapeutic applications in human diseases, or protecting the crops from infections.;This study involved purification of defense proteins from different plant sources. The proteins that were successfully isolated included a hemagglutinin from small taro tubers, a lectin from Japanese yam tubers, a lectin and an antifungal peptide from northeast red beans, a lectin, an antifungal peptide and a trypsin inhibitor from brown kidney beans, a lectin from French bean cultivar no. 1 and a trypsin inhibitor from mini pinto beans. The small taro hemagglutinin was found to induce mitogenic response in splenocytes. The Japanese yam lectin and northeast red bean hemagglutinin were found to exert anti-proliferative activity toward some tumor cell lines including MCF7 and CNE2 cells. The brown kidney bean lectin induced a mitogenic response from murine splenocytes as well as inhibited the growth of tumor cell lines including MCF7, HepG2, CNE1 and CNE2 cells, while the brown kidney bean antifungal protein inhibited the growth of several pathogenic fungal species including M. arachidicola, S. turcica and B. maydis. Studying the biological activities of these defense proteins helps to find out their potential applications like therapeutic uses. |
