Researchers have identified the anti-inflammatory mechanism behind a plant used for centuries in traditional Samoan medicine. The new study found the plant, known as matalafi, is as effective at reducing inflammation as ibuprofen.
Psychotria insularum is a small rainforest shrub native to South Pacific regions. Indigenous Samoan communities have used the leaves of the plant as medicine for generations.
Traditional medicinal uses for the matalafi have targeted a variety of inflammatory conditions from fever to swelling and skin infections. The plant’s leaves are traditionally mashed into a paste technically known as a homogenate.
“Matalafi is used in two ways in Samoa—to treat illnesses attributed to ghosts, and to treat various forms of inflammation,” explains indigenous Samoan scientist Seeseei Molimau-Samasoni. “I began my PhD at Te Herenga Waka in 2013, and worked with traditional healers in Samoa to harvest the matalafi and bring it to Aotearoa to find out how and why it works.”
Weaving together nearly a decade of research, the new study uncovers exactly how matalafi could be generating its anti-inflammatory effects. The findings indicate matalafi is an iron chelator. This means matalafi contains compounds that bind to iron essentially helping the body remove excess iron.
Testing matalafi on mammalian cells the research found this iron chelator activity, “decreased proinflammatory and enhanced anti-inflammatory cytokine responses in immune cells.” The anti-inflammatory activity detected in the study was found to rival that seen with ibuprofen, a common over-the-counter anti-inflammatory drug.
The iron chelator activity of matalafi also points to a number of other potential medical uses beyond its general anti-inflammatory attributes. Abnormal iron concentrations in the brain, for example, have recently been hypothesized as playing a role in neurodegenerative diseases such as Alzheimer’s.
Andrew Munkacsi, another researcher working on the new study, says a chemical genomic analysis revealed compounds in the plant interacted with a gene associated with obesity, diabetes, and cardiovascular disease.
“Our findings also highlighted the sensitivity of the RIM101 gene deletion to the P. insularum homogenate.,” says Munkacsi. “This gene is a major regulator of lipotoxicity (cell death due to lipid toxicity), which underlies obesity.”
Two of the primary bioactive compounds in matalafi were highlighted in the study: rutin and nicotiflorin. Both compounds have previously been found to confer anti-inflammatory and neuroprotective effects. However, the researchers do call for further chemical investigation of the Psychotria insularum plant, as there are potentially undiscovered compounds in the mix that could contribute to the overall medicinal effects of matalafi.
“These are traditional medicines our people have been using for hundreds of years, and we are now finding science that supports that there is genuine activity in some of our medicines,” Molimau-Samasoni said recently to New Zealand publication Stuff. “I do want to stress that traditional medicines need to be investigated scientifically before they are administered widely… there are still more steps to be done.”
The new study was published in the journal PNAS.
