There's newfound interest in a little-known fleshy green fruit native to South and Central America, which has long been used in traditional medicine for protection against bacterial infection and even preventing and treating a vast range of cancers. But what exactly is it?
Soursop (Annona muricata) is a flowering tree native to Central and Southern America, but it can now be found in the Pacific Islands, West Africa and Southeast Asia. It's known by many names, but perhaps its most recognized one is graviola, which is commonly used when it comes in supplement form. And for hundreds of years, traditional medicine practitioners have used the spiky green fruit, bark and leaves for everything from managing diabetes to treating infection and cancers.
But there's been new interest in the plant – and its fruit in particular – in the last year, especially from the Western wellness community seeking alternative medicines rooted in traditional therapeutics. However, the science world remains split on its benefits. One thing most experts agree on is that there needs to be more research into it.
"Among all former studies on this plant, the most promising activities are found to be its anticancer, antiparasitic and insecticidal activity," researchers noted in a 2015 review paper in the International Journal of Molecular Sciences. "Further investigations on the biochemical and physiological functions of active compounds and the detailed mechanisms underlying these activities are completely pivotal for the development of pharmaceutical and agricultural products."
What we do know is that the fruit in particular contains bioactive compounds – acetogenins, alkaloids, flavonoids and vitamins – that are generally seen as beneficial, particularly for their cytotoxic effects, or how they work to kill cancer cells. These acetogenins have also been associated with not just blocking cancer growth but cancer prevention. However, a key acetogenin, annonacin, has also been linked to Parkinson's and neurodegenerative diseases.
"The major bioactive compounds identified in Annona Muricata have been classified as Annonaceous acetogenins, which inhibit mitochondrial complex I that leads to a decreased ATP production," researchers found in 2012. "Overall, the compounds that are naturally present in a Graviola extract inhibited multiple signaling pathways that regulate metabolism, cell cycle, survival, and metastatic properties in PC cells. Collectively, alterations in these parameters led to a decrease in tumorigenicity and metastasis of orthotopically implanted pancreatic tumors, indicating promising characteristics of the natural product against this lethal disease."
Plant biologists will recognize that "Annonaceous" refers to the family Annonaceae, which also includes more familiar fruiting trees like the custard apple (Annona reticulata). Both species share some features, like the fruits' creamy white flesh and rather unappealing exteriors, but have a distinct nutritional profile. A cup of soursop fruit has 148 calories, 7.42 g of fiber, 37.8 g of carbohydrates, as well as 30.5 g of sugar, although it has a low glycemic index. The fruit is rich in vitamin C, potassium, magnesium, as well as antioxidants, and potassium. And despite it's appearance, soursop actually tastes pretty good, landing somewhere between strawberry and banana.
While it's been used as a complementary treatment for cancer patients for some time, there's not enough scientific data yet to draw clinical conclusions. Yet another review paper from 2024 found that existing research suggested that there's a reason soursop has been part of traditional medicine for so long.
"This systematic review has identified that Annona muricata extracts exhibits beneficial effect on cancer, demonstrating cytotoxicity effect through inhibitory effect, apoptosis, and selective killing of cancer cells without affecting normal cells," the researchers noted. "Additionally, it has anti-inflammatory effects by activating the anti-inflammatory pathway through the prostaglandin synthesis pathway."
Putting aside its potential antimocribial, antioxidant and anti-inflammatory benefits, it has also been identified as a neurotoxin and may contribute to neurological conditions. So far, researchers believe this is a result of excess consumption.
"High doses of acetogenins can be neurotoxic and may cause neurodegenerative disorders," scientists noted in a 2022 study published in the journal Molecules. "Some alkaloids present in A. muricata are also believed to affect nerve cells. However, research on the neurotoxicity of annonacin states that neurodegenerative conditions caused by these compounds arise due to continuous exposure or consumption. Further research on the toxicity of A. muricata and clinical trials testing the pure compounds are needed to fully elucidate its pharmacological activities and ensure the safety of A. muricata as a potential drug for various diseases."
And while it's been championed as preventing or "curing" cancer, there's little robust scientific evidence to date to back up these claims. Nonetheless, it's still a healthy addition to a salad or smoothie – that is, if you're able to track this exotic fruit down.
