Novel mannose-binding snail mucus lectins from Lissachatina fulica exhibited antimicrobial, antitumor and insecticidal activities.

Lectins are carbohydrate-binding proteins with diverse biological functions, particularly their roles in innate immunity through the recognition of pathogen-associated molecular patterns and mediation of non-specific immune responses. This study investigates the bioactivities of mucus lectins derived from Lissachatina fulica (LFLs). The LFLs were purified using ion exchange chromatography and analyzed for toxicity, antimicrobial, antioxidant, antitumor, and insecticidal properties. SDS-PAGE experiment revealed protein bands of approximately 70.0 ± 1.0 and 49.0 ± 1.0 kDa. Hemagglutination activity of LFLs was strongly inhibited by D-mannose, whereas galactose and N-acetyl-D-glucosamine showed moderate and mild inhibition, respectively. LFLs exhibited full activity between 20 and 50°C and at pH 7-9. Significant toxicity was observed in the brine shrimp lethality assay (LC50 = 172.3 μg/ml). Antimicrobial assays showed dose-dependent inhibition against Shigella boydii, Shigella sonnei, Bacillus cereus, and Staphylococcus aureus within a concentration range of 50-400 μg/ml. LFLs also exhibited antibiofilm properties targeting Escherichia coli and antifungal efficacy against Aspergillus niger. The DPPH scavenging assay showed moderate antioxidant potential (IC50 = 696.09 μg/ml). In vivo, LFLs inhibited Ehrlich ascites carcinoma (EAC) cell growth by 31.14 % and 55.71 % at doses of 3.0 and 6.0 mg/kg/day, respectively, and improved both mean survival time and hematological parameters. LFLs demonstrated time-dependent larvicidal activity against Culex quinquefasciatus (LC50 reduced from 4.17 to 0.23 mg/ml over 48 h) and insecticidal activity against Callosobruchus chinensis (LD50 reduced from 0.218 % to 0.062 % over 48 h), indicating increased potency with longer exposure. These findings highlight the significant therapeutic and biopesticidal potential of LFLs, supporting further research into their applications.