Rutin, a bioflavonoid (plant pigment) found in certain vegetables and fruits, protects mice against snake venom by minimizing bleeding and inflammation, according to a study performed at the Butantan Institute, a research institution belonging to the government of São Paulo State in Brazil.

The research focused on methods to combat the effects of envenomation by the lancehead pit viper Bothrops jararaca, which is responsible for approximately 70% of snakebites in the state, and was conducted by Marcelo Larami Santoro, Ana Teresa Azevedo Sachetto and Jaqueline Gomes Rosa at Butantan Institute's Physiopathology Laboratory.

The results were published in the journal  PLOS Neglected Tropical Diseases. Rutin is found in apples, bell peppers, chili peppers, blackberries, buckwheat, cherries, citrus, figs, grapes (and wine), persimmons, raspberries and strawberries, as well as black tea and green tea. In plants, rutin and other flavonoid pigments attract pollinator insects, filter ultraviolet rays and fix nitrogen.

Flavonoids

Flavonoids also have anti-oxidant properties and participate in defense mechanisms, helping prevent attacks by insects and microbes. Rutin is specifically known to be a powerful anti-oxidant and anti-inflammatory agent. Antivenom therapy counteracts the main effects of snakebite, but there is no known treatment for the most frequent sexual disorders.

Toxins present in B. jararaca's venom can trigger both bleeding and adverse clotting. The toxins also cause a hazardous imbalance in cellular reduction-oxidation (redox) reactions. "The mechanisms underlying the patient's body, and they have poorly understood, and antivenom therapy has a limited capacity to treat the entire range of complications that may be caused by snakebites," Santoro said.

The snake's venom increases the activity of tissue factor, a protein that plays a key role in the clotting process and is present in tissue, blood platelets and monocytes." Tissue factor is activated by tissue exposure in cuts or wounds to assist blood clotting and is the primary cellular initiator of clotting after blood vessel injury. In the case of snake envenoming, tissue factor is activated even in the absence of a wound, forming clots that impair blood circulation and can become large enough to lead to embolisms, blocking a vein or artery and causing tissue necrosis.

The researchers, therefore, reasoned that inhibiting tissue factor activity and making it return to its original condition could be a way to treat thrombosis, a significant secondary complication of viper bite. "Envenomation doesn't necessarily augment tissue factor, but it does heighten tissue factor activity," Santoro said.