Tamanu oil, derived from the seeds of Calophyllum inophyllum, is gaining attention as a natural alternative to chemical sunscreen filters. Beyond its traditional dermatological uses (which I’ll explore in a separate article), both the oil and its pigment extracts show remarkable ability to absorb UVA and UVB rays, while remaining gentle on the skin and environmentally friendly. The publication by Ku and colleagues (2021) deserves a closer look.
Their study shows that crude extracts (C. inophyllum seed extract, CISE) absorb within the UVA (320–400 nm) and UVB (290–320 nm) ranges. However, it’s the pigment extract (C. inophyllum pigment, CIP) that stands out, with an absorption peak at 300 nm—4.5 times higher than that of CISE.
The publication concludes that it’s the pigments in the oil that confer its UV-protective properties. Spectroscopic analyses (UV-Vis, ATR-FTIR) confirm that pigments rich in aromatic and phenolic compounds are the main filtering agents. These molecules interact with UV wavelengths thanks to their specific chemical structures: aromatic rings, hydroxyl groups, and double bonds.
The authors note that the efficacy of pigment extracts (CIP) is dose-dependent. Adding 20% pigment to a neutral base achieves a sun protection factor (SPF) of 50+ and a PA++++ rating—indicating very high UVA protection. These results are comparable to, or even exceed, those of some synthetic UV filters.
From a toxicological perspective, Tamanu extracts show low cytotoxicity. The IC50 index (the concentration at which a compound reduces cell viability by 50%) helps assess toxicity: the higher the value, the lower the toxicity. For example, the crude extract (CISE) has an IC50 of 997.9 ppm—indicating low toxicity. In comparison, some chemical filters have much lower IC50 values, reflecting higher cytotoxicity.
Our oil was tested in vitro by a laboratory at a 3% concentration, diluted in olive oil. Skin samples were exposed to UVA irradiation for 67 minutes. Results observed on treated inserts during exposure revealed:
✅ A fourfold increase in cell viability compared to the positive control*, whose viability was considered completely lost.
🧪 Lactate dehydrogenase (LDH) release—an enzyme indicating cellular damage—was limited to 8.73%, lower than the negative control** (13.71%).
🔥 Expression of the inflammatory marker IL-1α was comparable to the negative control: 15.02 pg/ml versus 14.9 pg/ml, suggesting no significant inflammatory response.
These findings indicate that Tamanu oil offers meaningful photoprotection alongside conventional sunscreens. It demonstrates in vitro its ability to reduce cytotoxic impact and inflammatory responses induced by UVA rays on skin cells.
By potentially reducing reliance on certain sunscreen filters, Tamanu oil could represent a beneficial alternative for the skin… and for coral reefs.
* Positive control = irradiated sample without treatment
** Negative control = non-irradiated sample
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The information presented in this article is for informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Any questions regarding your physical or mental health should be directed to a qualified healthcare professional. The author of this article cannot be held responsible for any use of the information shared herein.
Reference
Ku W-J, Lin C-J, Lin P-H. (2021). UV-Protection Performance of Calophyllum inophyllum Seed Extracts: A Natural Ultraviolet Screening Agent. Natural Product Communications, 16(1). doi:10.1177/1934578X20985650