The passion fruit cultivar normally sold in U.S. markets is purple passion fruit (Passiflora edulis), a round or oval fruit smaller than a lemon, with dark purple wrinkled skin and a very moist interior filled with coated seeds. Some passion fruit juice nectars and juice mixtures contain the juice of the other main passion fruit cultivar, yellow passion fruit (Passiflora edulis var. flavicarpa). Passion fruit has not been studied as extensively as fruits more commonly consumed in the U.S. Passion fruit is a good dietary source of vitamin A (through its beta-carotene content), vitamin C, and insoluble fiber.
Passion fruit has been shown to have antioxidant and antifungal properties. Passion fruit seed fiber has been shown to be effective in improving intestinal function and health and may help reduce cholesterol. Purple passion fruit extract has been shown to reduce anxiety-related behaviors in laboratory rats without disrupting memory process. A preliminary screen of 1,220 Brazilian rain forest plant extracts from 352 plants found that passion-flower plant family extracts were among the few that demonstrated cytotoxicity against human prostate cancer cells.
Breast cancer-related effects of consuming passion fruit
A 2007 screen of Brazilian plants found no cytotoxic activity against human ER+/PR+ breast cancer cells by the passion fruit extracts studied. The predominant fatty acid in passion fruit seeds is linoleic acid (comprising approximately 70% of the fatty acid content); the seeds also contain some oleic, palmitic, stearic, and alpha-linolenic acids. Other factors aside, this fatty acid profile does not suggest that the seeds would be likely to prevent breast cancer.
While passion fruit has demonstrated antioxidant activity, it is not impressive compared to that of other fruits known to be associated with reduced breast cancer risk, such as raspberries or grapes. On the other hand, passion fruit contains the anthocyanin cyanidin-3-glucoside, which has been shown to possess both chemopreventive and chemotherapeutic activity and to enhance the treatment effects of Herceptin.
The flesh and seeds of purple passion fruit are edible, but the skin should not be consumed since it contains a small amount of cyanogenic glycosides (a source of cyanide). There are some herbal preparations based on the skin, such as purple passion fruit peel extract (used to treat asthma and high blood pressure), which have been shown to be safe and effective (it is to be hoped that the skin is processed in such as manner as to eliminate the cyanide). However, we would suggest caution in using such products.
Raw passion fruit is strongly acidic. Therefore, commercial passion fruit juice typically has been subjected to deacidification by electrodialysis or other means.
Note that while we are continually searching for new evidence specifically concerning this food, there is not much interest in it among breast cancer researchers, so few studies are available.