An Italian friar has unearthed a document from the pharmacy archives of an ancient convent in Florence describing a medicinal potion made from Bolivian coca leaves and kola nuts, prompting suggestions it could have been a precursor to the famous US soft drink, Coca-Cola.

Father Manuel Russo, rector of the San Marco convent, said he stumbled across the yellowed document, a sort-of promotional flyer, while sorting out the archives.

The flyer details the recipe for an elixir vinoso ricostituente, or restorative wine elixir, made with 10g of Bolivian coca leaves and 30g of kola nut, blended with wine, which the friars who concocted it promoted as a tonic to be used to recuperate the body and mind from fatigue caused by illness and ageing.

The document was not dated, but it is believed to have been produced around the mid-19th century, when the friars plied a brisk trade in Bolivian coca leaves imported to Italy by missionaries, long before they were globally banned in 1961 for containing the natural alkaloid used to make cocaine.

The recipe was similar to the one used by the American pharmacist, John Pemberton, who in 1886 created a sweet syrup by mixing coca leaf extract and kola nuts. Local alcohol laws prevented him from using wine and so he combined the ingredients with carbonated water. Pemberton’s tonic eventually became Coca-Cola.

After learning of Russo’s discovery, some local news outlets pondered whether the soft drink’s origins were, in fact, in Florence and not the US.

But with no evidence demonstrating a link between the friars’ creation and the Coca-Cola recipe, Russo, who also found a couple of empty bottles that contained the potion, is erring on the side of caution.

“I don’t want to attract a lawsuit from Coca-Cola or something like that,” he joked. “Mr Pemberton invented his own recipe, and without alcohol … Plus at that time other people were producing this kind of medicine with coca leaves. It was quite common in Italy and France. The only thing I can say is that San Marco’s pharmacy had its own recipe.”

Kola Coca, an alcoholic syrup made in 1885 by distillers in Valencia, Spain, has also been held up as a potential inspiration for Coca-Cola.

Other documents found by Russo showed that the Florence friars’ concoction, the price for which ranged between 2 and 6 Italian lira – less than a cent in today’s euro currency – was wildly popular among customers.

“Because it had fantastic properties that fought against fatigue, and the fatigue that came with ageing,” said Father Russo. “Up until Bolivian coca leaves were banned – because by that point it was understood that cocaine was a problem more than a cure – I would say that it was one of our bestsellers.”

San Marco convent was founded in 1436 on Via Cavour in Florence, with the pharmacy opening in 1460 to serve the neighbourhood’s poor community.

Russo said the pharmacy, which he describes as “one of the most beautiful things we have at the convent”, still operates – although in 1995 its location was transferred to a different part of the Tuscan city.

However, the original premises are intact, including the remains of a crocodile brought from the Nile River, which has been hanging from the ceiling since the 1600s. Chemists in 19th-century Europe often hung crocodiles and other reptiles from the ceilings of their shops as a way of indicating to customers that they had access to rare, exotic ingredients.

Russo also found labels for pure oxygen, cognac and rectified petroleum spirit. “The inventory in the pharmacy’s archives is incredible,” he said.