Toxicity and antitumor activity of the water-soluble lectin from Moringa oleifera Lam. Seeds (WSMoL) in sarcoma 180-bearing mice.

WSMoL, a water-soluble lectin from the seeds of Moringa oleifera, present several biological activities. This work aimed to evaluated the toxicity and antitumor activity of WSMoL. To analyze toxicity, it was determined hematological, biochemical and histological parameters; consumption of water and feed as well as the weight of the animals. Antitumor analysis included evaluation of tumor weight, histology and cytokine levels. Acute toxicity assay revealed 60% mortality of animals treated with lectin at 200 mg/kg i. p. At 100 mg/kg i. p., the animals showed a decreased food and water consumption as well weight gain in comparison with control. However, no animal died and there were no alterations in blood parameters or histological analysis. Antitumor activity evaluated at safe doses (2.5, 5 and 10 mg/kg) showed a significant reduction in tumor weight. Tumor photomicrographs evidenced that WSMoL treatment reduced dissemination of tumor cells. WSMoL (5 and 10 mg/kg) significantly enhance the immune function in the tumor environment as showed by increased the levels of pro-inflammatory (TNF-α, IFN-γ, IL-2, IL-6, and IL-17) and anti-inflammatory (IL-4 and IL-10) cytokines. In conclusion, WSMoL showed in vivo antitumor activity in mice bearing sarcoma 180 tumor, probably by increase the immune response against the tumor.

Antimicrobial potential of Alpinia purpurata lectin (ApuL): Growth inhibitory action, synergistic effects in combination with antibiotics, and antibiofilm activity.

The Alpinia purpurata inflorescence contains a lectin (ApuL), which has immunomodulatory activities on human cells. In the present work, it was evaluated the antibacterial and antifungal effects of ApuL against human pathogens. ApuL showed bacteriostatic activity against non-resistant (UFPEDA-02) and an oxacillin-resistant isolate (UFPEDA-672) of Staphylococcus aureus with minimal inhibitory concentrations (MIC50) of 50 and 400 µg/mL, respectively. In addition, it showed bactericidal effect on the non-resistant isolate (minimal bactericidal concentration: 200 µg/mL). For Candida albicans and Candida parapsilosis, ApuL showed fungistatic effect (MIC50: 200 and 400 µg/mL, respectively). The lectin was able to impair the viability of the microorganism cells, as indicated by propidium iodide (PI) staining. Analysis of growth curves, protein leakage, and ultrastructural changes supported that ApuL acts through distinct mechanisms on S. aureus isolates. Ultrastructural analysis of ApuL-treated Candida cells revealed malformations with elongations and bulges. ApuL-oxacillin combination showed synergistic effect on the oxacillin-resistant isolates UFPEDA-670 and 671, which were not sensitive to lectin alone. Synergism was also detected for ApuL-ceftazidime against a multidrug-resistant isolate of Pseudomonas aeruginosa. Synergistic action of ApuL-fluconazole was detected for C. parapsilosis, which was insensitive to the drug alone. Biofilm formation by S. aureus non-resistant isolate and C. albicans was remarkably inhibited by ApuL at sub-inhibitory concentrations. In conclusion, ApuL showed differential effects on non-resistant and resistant bacterial isolates, was active against Candida species, and showed synergistic action in combination with antibiotics.