Cagliari, May 15 - Sardinian scientists believe they've traced the roots of the 'death-defying' sardonic grin to a plant commonly found on the Italian island.
Greek poet Homer first used the word, an adaptation of the ancient word for Sardininan, to describe a defiant smile or laugh in the face of death.
He was believed to have coined it because of the belief that the Punic people who settled Sardinia gave condemned men a potion that made them smile before dying.
The association with Sardinia has often been disputed, but Cagliari University botanists think they've settled the case - and the plant in question could have beneficial properties too.
The plant, tubular water-dropwart (oenanthe fistulosa), is common in Sardinia, where it is popularly known as 'water celery'.
''Our discovery supports what many cultural anthropologists have said about death rituals among the ancient Sardinians,'' said Cagliari University Botany Department chief Mauro Ballero.
''The Punics were convinced that death was the start of new life, to be greeted with a smile,'' he said.
Ballero's team, whose work appears in the latest edition of the US Journal of Natural Products, have established that a toxic substance in the dropwart plant does, in fact, cause facial muscles to contract and produce a grimace or rictus.
The discovery could have a brighter side, he said, leading to drugs that might help certain conditions where parts of the face are paralysed.
''The good news is that the molecule in this plant may be retooled by pharmaceutical companies to have the opposite effect,'' he said.