Tamanu oil
Cancer
Recent work suggests the anti-cancer potential of C. inophyllum. In a study just over a decade ago, Itogawa et al. examined the potential inhibitory effects of C. inophyllum 4-phenylcoumarin isolates on Epstein-Barr virus early antigen (EBV-EA) activation caused by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All 10 of the isolates displayed inhibitory activity against EBV and no cytotoxicity. The strongest compound tested was calocoumarin-A (5), which also demonstrated a significant capacity to suppress murine skin tumor promotion in a two-stage cancer model. The investigators concluded that some 4-phenylcoumarin constituents of C. inophyllum warrant further study as possible antitumor agents (Cancer Lett. 2001;169:15-19).
C. inophyllum was one of 155 extracts from 93 plant species found on peninsular Malaysia during a screening by Ong et al. in 2009 for in vitro photocytotoxic activity using human leukemia cells (cell line HL60). Further, C. inophyllum was among the 29 plants to lower the in vitro cell viability by more than 50% after exposure to 9.6 J/cm2 of a broad-spectrum light when tested at a concentration of 20 mcg/mL (J. Photochem. Photobiol. B 2009;96:216-22). In addition, Li et al. isolated one new friedelane-type triterpene and seven previously discovered triterpenoids from the stems and leaves of C. inophyllum, and ascertained that they exhibited growth inhibitory activity against human leukemia HL-60 cells (Fitoterapia 2010;81:586-9).
In 2008, Xiao et al. isolated a new prenylated xanthone (caloxanthone) as well as two previously known xanthones from the ethanolic extract of C. inophyllum twigs and reported that two of the constituents (including the new xanthone) demonstrated cytotoxicity against myelogenous leukemia (cell line K562) (J. Asian Nat. Prod. Res. 2008;10:993-7).
C. inophyllum is known to contain an abundance of phytosterols – primarily stigmasterol and beta-sitosterol, which are steroids associated with several healthy benefits (stigmasterol is a potent antioxidant) – as well as delta-tocotrienol, a form of vitamin E that acts as an antioxidant and is associated with anticancer activity, particularly against murine melanoma (Phytochemistry 2005;66:1825-31; J. Nutr. 1997;127:668-74).
Conclusion
Tamanu oil certainly isn’t a passing fad for the numerous traditional societies in the mainly eastern and southern hemispheres who have used the botanical for medicinal and culinary purposes for centuries. As an ingredient in skin care products, though, more research is needed. While modern studies are promising, randomized, placebo-controlled clinical trials are necessary to establish a potential role of C. inophyllum in the large array of topical dermatologic formulations.
Dr. Baumann is chief executive officer of the Baumann Cosmetic & Research Institute in Miami Beach. She has received funding for clinical grants from Allergan, Aveeno, Avon Products, Galderma, Mary Kay, Medicis Pharmaceuticals, Neutrogena, Philosophy, Stiefel, Topix Pharmaceuticals, and Unilever. To respond to this column, or to suggest topics for future columns, write to her at sknews@frontlinemedcom.com.
