Investigating the Therapeutic Potential of Crude Leech Saliva Based on Its Anticancer, Antioxidant, and Anti-Inflammatory Effects

Abstract

Leech therapy is a biotherapeutic approach that has been traditionally used for centuries and is currently being re-evaluated in modern medicine. The efficacy of this treatment is attributed to various bioactive compounds found in leech saliva, which exhibit anticoagulant, anti-inflammatory, antioxidant, and anticancer properties. It has been demonstrated that leech saliva possesses the potential to modulate inflammatory processes and apoptotic mechanisms. In this study, the therapeutic potential of the saliva of Hirudo verbana was evaluated, and its biological and pharmacological effects were comprehensively investigated. The anticancer effects, antioxidant capacity, and anti-inflammatory activity of the crude leech saliva were assessed using human umbilical vein endothelial cells and epithelial ovarian cancer cells. The chemical composition of the saliva was analyzed using gas chromatography–mass spectrometry, while the protein content was determined by the Bradford assay. Antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, inflammatory effects were evaluated by Enzyme-Linked ImmunoSorbent Assay, and cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The findings revealed that crude leech saliva had a minimal effect on healthy cells but showed a selective effect on the viability of ovarian cancer cells. At low concentrations (3.13%), 99.16% of healthy cells remained viable, whereas this rate decreased to 89.25% in cancer cells; at high concentrations (50%), cell viability in cancer cells declined to 63.02%. Gas chromatography–mass spectrometry analysis identified compounds such as gibberellic acid and 6-[(4-methoxyphenyl)methoxy]-4,4,5,7,8-pentamethyl-3H-chromen-2-one, which demonstrated high affinity for the antiapoptotic proteins Bcl-2 and Survivin in molecular docking analyses. In conclusion, the crude leech saliva was confirmed to possess anti-inflammatory, antioxidant, and anticancer properties. However, further biochemical and clinical research is needed to elucidate the underlying mechanisms of these biological effects in greater detail.