A new thermostable, non-cytotoxic and non-genotoxic lectin purified from pod of Libidibia ferrea var. ferrea (LifePL)

Abstract

Lectins are proteins capable of binding specifically and reversibly to carbohydrates, allowing several biotechnological applications. In the present study, the lectin from Libidibia ferrea var. ferrea pod (LifePL) was purified and the cytotoxic and genotoxic potentials were evaluated through cell viability and micronucleus in vitro assays. LifePL was isolated by chitin column chromatography followed by elution with 1 M acetic acid. The hemagglutinating activity (HA) of LifePL was determined in the presence of carbohydrates or divalent cations, as well as after heating and incubation at different pH values. In the cytotoxic assay using MTT, human peripheral blood mononuclear cells (PBMCs) were exposed to 10 concentrations of the lectin (ranging from 5 to 200 µg/mL) for 24 h. Genotoxicity was tested using the micronucleus assay at concentrations of 120, 160, and 200 µg/mL to evaluate a previous safety use of lectin. The purified LifePL showed a single band of 8 kDa on SDS-PAGE in the presence or absence of 2-mercaptoethanol or by gel filtration using an AKTA purification system. LifePL agglutinated erythrocytes from humans and rabbits and was inhibited by glycoproteins (e.g., fetal bovine serum). The HA of LifePL remained stable and resistant at temperatures of 30–100 °C. The HA of the lectin was stimulated by ions (Ca2+ and Mg2+), as well as at different pH values ​​ (pH 4.5, 5.0, 5.5 and 7.5). There was no cytotoxicity for the concentrations tested. However, all concentrations increased cell viability (p < 0.05). Regarding genotoxicity, no concentration induced statistically significant changes (p < 0.05). In conclusion, the lectin isolated from L. ferrea var. ferrea pod revealed a good safety profile, since it did not show cytotoxic or genotoxic potential under used conditions.