The study was carried by scientists from Kanazawa University in Japan who identified kahweol acetate and cafestol- hydrocarbon compounds naturally found in Arabica coffee - which may inhibit growth of prostate cancer.
The findings, published in the journal The Prostate were presented at the 34th European Association of Urology Congress in Barcelona.
Two compounds, kahweol acetate and cafestol, were found to suppress the growth of tumours that are normally resistant to widely used chemotherapy drugs.
Past research has found evidence that coffee drinkers may have a lower risk of developing prostate cancer, and a new study may have figured out what's behind that beneficial effect.
Coffee is a complex mixture of compounds which has been shown to influence human health in both positive and negative ways. One such potential is its ability to reduce the occurrence of certain malignancies, particularly prostate cancer.
Lead scientist Dr Hioaki Iwamoto, from Kanazawa University Graduate School of Medical Science, said: "We found that kahweol acetate and cafestol inhibited the growth of the cancer cells in mice, but the combination seemed to work synergistically, leading to a significantly slower tumour growth than in untreated mice". After 11 days of testing, the animals that received both compounds had their tumors grow by only one and a half times or 167 percent compared to their original size. The coffee-making process has been found to affect whether these compounds remain in coffee after brewing (as with espresso), or whether they are stripped out (as when filtered).
He said: "It is important to keep these findings in perspective".
"This is a pilot study, so this work shows that the use of these compounds is scientifically feasible, but needs further investigation; it does not mean that the findings can yet be applied to humans". The researchers tested the compounds on laboratory mice transplanted with prostate cancer cells.
The growth reduction in transplanted tumour cells were much prominent that in native tumour cells.
"Prostate cancer kills one man every 45 minutes in the United Kingdom and early-stage exploratory research like this is important if we are to find new ways to treat the disease and save more lives". It has not yet been tested in humans...
Despite the potential benefits of coffee drinking on prostate cancer, study co-author Atsushi Mizokami clarified that their findings should not make people change how they consume the beverage. Coffee can have both positive and negative effects (for example it can increase hypertension), so we need to find out more about the mechanisms behind these findings before we can think about clinical applications.