Antiangiogenic Potential of Beneficial Sterols from Parotoid Gland Secretion of Indian Common Toads (Duttaphrynus melanostictus) in the Coastal Region of the Indian Subcontinent: An In Vivo to In Silico Approach.

The toxins of the Bufonid toads have been used formerly as ethnomedicine to treat different diseases, including chronic hepatitis, hypertension, and multiple cancers. Thus, toads' venom has a great impact on traditional health care. However, the main emphasis of this study is to identify natural components present in toad parotoid gland secretion and evaluate their antiangiogenic effects. Sterol-rich extracts of parotoid gland secretions were isolated in an ethyl acetate medium from a natural population of Indian common toads (Duttaphrynus melanostictus) from the coastal region (Purba Medinipur, West Bengal) of the Indian subcontinent. The antiangiogenic activity was assessed using a chick embryo chorioallantoic membrane (CAM) assay. Gas chromatography-mass spectrometry (GC-MS) analysis was conducted to determine the chemical composition. In silico molecular docking was subsequently employed to detect putative biologically active substances with antiangiogenic potential. The majority of the sterol components were identified and mainly cholesterol was found at the greatest concentration (31.10%). According to the quantitative analysis Campesterol (15.73%), γ-sitosterol (10.09%), lathosterol (2.79%), stigmasterol (0.933%), and brassicasterol (0.466%) were also present. According to the outcome of the CAM assay, there was 51.62% suppression of blood vessel formation when compared to the untreated. Bonferroni's posthoc test analysis revealed a statistically significant difference at p < 0.001. Using GraphPad Prism software 8.1.2, nonlinear regression analysis yielded EC₅₀ values of 24.27 μg/mL. Following identification, the primary bioactive chemicals in the extract under investigation showed a more robust interaction with vascular endothelial growth factor receptors (VEGFRs) in silico molecular docking experiments. To the best of our knowledge, this is the first-hand report on the ethyl acetate extract (sterol-rich) of parotid gland secretion from the Indian common toad showing antiangiogenic activity by targeting VEGFRs. However, the findings of this study suggest that the bioactive compound from the investigated extract can be considered for the development of antiangiogenic medicine.