(Photo : UHN)

Research into the antibiotic and other medicinal properties of crocodiles is not new but given the development of drug-tolerant bacteria and viruses and the waning effectiveness, the research seems to be getting some traction.

The formal study of crocodiles blood is said to have originated from observations of crocodiles in the wild. Biologists observing the behavior of crocodiles noticed that even though crocodiles often engaged in violent territorial behavior and damaging encounters with other animals, very few ever developed fatal infections from their injuries. Even spending most of their time in bacteria-infested swamp water did not seem to affect the healing process. Such natural resistance to bacterial infection is not rare in wild animals, but the blood of crocodiles seemed to be especially resistant.

Samples of crocodiles blood were eventually gathered for serious scientific inquiry and the results surprised many of the researchers. Concentrated human serum and concentrated crocodiles serum samples were each exposed to 23 strains of bacteria, including the one responsible for MRSA. The human blood serum managed to kill off 8 of the 23 bacteria cultures. The crocodiles' blood serum killed all 23 bacteria cultures, including MRSA. It also significantly reduced the overall level of HIV in a sample of infected human blood.

Because of the promising results of these tests, scientists have started to synthesize the chemical structure of the crocodile blood peptides. One identified the first Crocodylus siamensis cathelicidin gene and RN15 peptide derived from cathelin domain to exhibit antibacterial activity (Tankrathok et. al 2019), and yet the most promising result is that of a study conducted by Dr. Donald Branch (TGHRI Affiliate Scientist and PM CCRU Researcher) and Stephen McCarthy (University of Toronto).

Their research team infected human cells with HIV in the presence of crocodile blood and found that the blood suppressed HIV infection. By separating the blood into different components, the researchers identified the exact proteins responsible for this effect; these proteins were analogous to human proteins called histones, which regulate gene expression. While the histones did not prevent HIV from inserting itself into host DNA, they did prevent viral protein expression, a key step in the HIV lifecycle. Despite the fact that human cells have histone proteins, they are still susceptible to HIV infection. To help reconcile this fact, the team looked for histones in the blood of those with HIV. They found that people with HIV produced less histones than those without HIV. "The results of our study suggest that HIV may evade the body's natural defence mechanisms in part by suppressing the production of these protective proteins," says Dr. Branch. "Restoring histones in the blood-by boosting their production or by creating a drug with similar functions-may be a new treatment strategy for HIV."

It has been reported that major pharmaceutical companies in America are already hard at work developing products using crocodile blood and oils, this is according to crocodile researcher Grahame Webb however he was not able to say which companies, for commercial reasons.