Purification, Characterization and Bioactivity of a New Homodimeric Lectin From Vicia Altissima (Fabaceae) Seeds

Vicia altissima Desf. (Fabaceae) belongs to subgenus Vicilla, section Pedunculatae. It is a perennial herb that grows in wet ravines with dense vegetation in western Mediterranean countries. The only population that exists in Spain is under critical threat of extinction. Although lectins are abundant in the seeds from several Vicias belonging to subgenus Vicilla, the presence of lectins in section Pedunculatae has not been investigated. Purification of lectins from V. altissima seeds was carried out by albumin extraction according to solubility in water and gel filtration chromatography using a Superose 12 column. SDS-PAGE and native PAGE analyses revealed single bands at 38 and 87 kDa, respectively, indicating that this protein is a homodimer. The lectin exhibited a high affinity for mannose and glucose and inhibited the proliferation of THP-1 cells. Seed lectins from Vicia species belonging to sect. Cracca in subg. Vicilla are, in general, more sensitive to inhibition by N-acetylgalactosamine than to inhibition by glucose or mannose. On the contrary, the seed lectin from V. altissima, belonging to sect. Pedunculatae, has a higher affinity for mannose and glucose than for N-acetylgalactosamine. Our results show the presence of a lectin with antiproliferative activity in the seeds from V. altissima, indicating that this lectin has potential health-promoting and diagnostic applications. These potential applications could have a positive effect on the preservation of this wild legume, which is represented in Spain by only one endangered population.