In addition to the fatty acids that the karanja seed contains, it is also naturally composed of furanoflavonoids, including approximately 2.2% karanjin and less than 1% pongamol. These two active molecules would make karanja oil a natural sun protector. Furthermore, the chemical structure of pongamol is very similar to that of avobenzone, a recognised UVA filter.
To assess its photoprotective properties, laboratory tests were conducted on pure karanja oil. These highlighted its ability to absorb a portion of UV rays, peaking at 350 nm (in ethanol), and to counteract their effects, which are responsible for sunburn and premature skin ageing.
They also demonstrated that it has a Sun Protection Factor (SPF) and a UVA Protection Factor (PF-UVA), scientifically evaluated, making the oily extract of karanja a natural UV filter. A SPF ranging from 15 to 30 depending on the experiments and a PF-UVA of about 9.5 were measured in vitro for pure karanja oil.
However, the ANSM (National Agency for the Safety of Medicines and Health Products) reminded manufacturers in a note published in February 2017 that:
"Sun care products containing only karanja oil with the aim of achieving a protection factor are not in compliance with current regulations and should not be made available on the market";
"In the case of sun protection products composed of authorised ultraviolet filter(s) and karanja oil, it is important to be able to demonstrate that the sun protection factor obtained is due to the authorised ultraviolet filter(s) present in the formula."
Thus, despite the photoprotective properties attributed to karanja oil, it is not officially recognised and listed as a sun filter and does not appear in Annex VI of the cosmetic regulation among the other authorised UV filters. Consequently, its use in a sun protection product to provide a sun protection factor is not in accordance with current regulations.
However, it remains useful to provide support in sun care with authorised ultraviolet filters due to its anti-radical nature. They allow thekaranja oil to partially protect the skin by helping it fight against the accelerated ageing caused by free radicals.