Coimbatore: Most of us relish cashews. But, did you know that the cashew shells that is often dumped as waste has antibacterial properties. The oil extracted out of cashew shells contains anacardic acid that can cure abscesses and wounds, found a study by professors of Amrita University and University of California, San Diego and Riverside.
"It is known that the oil extracted from cashew shells has antibacterial properties. Cashew nut shell liquid has been used in traditional medicine to heal wounds and treat conditions such as ulcers and tooth abscesses, besides as an anaesthetic for conditions such as leprosy and psoriasis," said the dean of school of biotechnology, Amrita University, Bipin Nair. "But, nobody knows the compound in the oil that has antibacterial properties. So, we extracted anacardic acid from the oil through a one-step method and carried out the research," he further said.
The isolation of anacardic acid and its purification, characterisation and structure elucidation as well as the early studies on antibacterial effects were carried out in the phytochemistry and cell biology laboratories at the Amrita University, Kollam in Kerala. The studies on the bacterial killing properties of the acid were carried out under Victor Nizet, professor of pharmacy at the University of California, San Diego.
The computational studies to demonstrate anacardic acid's specific bactericidal effects were executed by Jefferson Perry, an assistant professor of biochemistry at the University of California, Riverside, USA.
Studies conducted by other groups have demonstrated antibacterial activity of anacardic acid against a number of bacterial species, including Propionibacterium acnes, Staphylococcus aureus and Helicobacter pylori. "In our studies published in the Journal of Biological Chemistry, anacardic acid exhibited antibacterial activity against three different gram positive bacterial species, namely MRSA-the methicillin resistant Staphylococcus aureus, Streptococcus pyogenes and Streptococcus agalactiae. It was not effective against Escherischia coli and Pseudomonas aeruginosa," Professor Victor Nizet said.
Today, many drugs are available in the market to treat abscesses. "There are also other natural compounds such as aloe, quinine, Ashwagandha, clove, ginseng and green tea, with similar antibacterial properties, " Bipin Nair said.
While professors of Amirta and University of California have established antibacterial properties in anacardic acid, there is a long way to go before they develop a drug out of it. "Since there are research works already on this compound, we cannot patent it. But, we are working on developing a new form of the acid and may be use that as a constituent in a drug. The big advantage the Amrita has is its location - Kollam, which is the hub of cashews. Also, no drug in the market (for the treatment of abscesses) today utilises anacardic acid as a constituent," Nair said.
The professors are working out a strategy to utilise cashew nut shells to extract anacardic acid out of it and then use it to prepare a drug for treatment of abscesses. "It also has other properties that can be used for the treatment of cancer and myocardial infaction," Nair added.