Feijoa, otherwise known as pineapple guava or guavasteen and grown widely across New Zelaand, was especially strong in this regard, the Auckland University academics said.
Along with feijoa and blackberry, blackcurrant, cranberry, elderberry, black and green grapes, mango, pear, plum, red raspberry and strawberry were also assessed.
“Most fruits are good for you and have some anti-oxidant effect, but feijoa and blackberry showed the strongest anti-inflammatory response in the experiments,” said the university’s nutrition and dietetics researcher, Professor Lynn Ferguson.
Chemical pathways
The study identified fruit compounds with an anti-inflammatory effect through certain chemical pathways that could be tested further to develop them as complementary therapies for inflammatory bowel disease and other inflammatory disorders.
“Inflammatory responses are important for coping with damage, but an overactive inflammatory response is also damaging and can create problems,” Ferguson explained.
“These responses can be debilitating for [those] with an inflammatory disease, and these fruits can help to limit the inflammatory response.”
Feijoa and blackberry showed the highest and strongest anti-inflammatory effects in the various test screens carried out for the research. The study also showed that the anti-oxidant action of the feijoa compounds was not a direct effect, but was mediated through inhibitory effects on the enzyme kinase.
Oxidative stress
“Our studies support other results that suggest these fruit extracts could help to regulate oxidative stress and inflammation in cells, both directly and indirectly,” said Ferguson.
“Feijoa is already known to be very high in polyphenols such as flavonoids and these may be responsible for the anti-inflammatory effects. Research to identify the active compounds will be the subject of further studies.”
For the experiments reported in the study, the testing included the skin and pulp of all the fruits.
“In feijoa, the skin has more bio-activity than the pulp,” said Ferguson. “Some Asian cultures eat the skin, but in most western cultures many people find the taste too sour.”
Further testing is required to identify the active compounds and analyse how fruit extracts could be used to help to regulate inflammation in cells.