Compound Identification and Functional Characterisation of Cane Toad Skin Extracts

Abstract

Amphibians are storehouse of bioactive compounds. Among them, the skin of toad species is rich in biologically active compounds such as peptides, proteins, steroids, alkaloids and opioids. Some of these compounds have found significant therapeutic applications, for example as antibacterials, antifungals, antiprotozoals, antidiabetics, antineoplastics, analgesics and sleep inducing agents. In Traditional Chinese Medicine (TCM) aqueous extracts of Chinese toad skins have been used for centuries to treat pain, swelling, heart failure and several types of cancer with minimal to no side effects, generating a 10 billion USD market in China. Numerous compounds have been identified from these Chinese toad skin extracts, which have reported therapeutic activities in various disease conditions, either as a single compound or as a group of compounds. In Traditional Korean Medicine, toad extracts have also been reported to show potential activity against anxiety and depression. In Australia and America cane toad skins have a history of recreational use for euphoric purposes. This information coupled with knowledge of its use in China and Korea enabled us to hypothesise that Queensland cane toad skin extracts would likely contain similar ‘biologically-active’ compounds in selective extracts. This thesis reports on research work carried out to identify such ‘biologically-active’ extracts and/or compounds, then functionally characterise these in cultured cells for investigation of their therapeutic relevance to neuropsychiatric disorders, especially in obsessive compulsive disorder (OCD) - potentially identifying potent therapeutics for future development.