Sun protection factor of vegetable oils used in cosmetics

A study was conducted to evaluate the ultraviolet (UV) absorption capacity of volatile and non-volatile vegetable oils used in sunscreens or cosmetics and to express the same in terms of Sun Protection Factor (SPF) values. ¹

“Sun protection factor is a laboratory measure of the effectiveness of a sunscreen; the higher the SPF, the more protection a sunscreen provides against sunburn-causing ultraviolet radiation. In vitro SPF is determined according to the spectrophotometric method of Mansur et al. Hydroalcoholic dilutions of oils were prepared, and in vitro photoprotective activity was studied by the UV spectrophotometric method in the range of 290 to 320 nm.

It can be observed that the SPF values ​​found for non-volatile oils were between 2 and 8; and for volatile oils, between 1 and 7. Among others, among the fixed oils taken, the SPF value of olive oil was found to be the highest. Similarly, among the essential oils, the SPF value of peppermint oil was found to be the highest.

The study is expected to be useful in selecting oils and fragrances to develop sunscreens with improved safety and a high SPF. Plant oils are more effective at producing a uniform and long-lasting sunscreen film on the skin, and their emollient properties protect the skin from the drying effects of wind and sun exposure. Essential oils are used as fragrances in cosmetics.

Many liquid oils extracted from fruit and vegetable seeds are light and low in viscosity. Their penetrating and conductive properties, as well as their natural content of tocopherols, carotenoids, and essential fatty acids, make them highly valuable. Several naturally based sunscreens, including almond, avocado, coconut, cottonseed, olive, peanut, sesame, and soybean oils, are said to contain UV filters.

Generally, when applied to the skin, vegetable oils are easily absorbed and spread very well. Essential oils contain fragrant ingredients, which are found in various parts of plants, and are used as perfumes and evaporate at room temperature.
Knowing the SPF values ​​of vegetable oils will help in the selection of oils for the formulation of various cosmetic dosage forms, as oil is the most important constituent of creams and lotions. Similarly, the SPF values ​​of essential oils will be useful in the selection of perfumes.

Here is the SPF factor of some selected essential oils commonly used in cosmetics, as indicated in the study.

Peppermint 6.668

Tulsi (Holy Basil) 6,571

Lemongrass 6,282

Lavender 5,624

Orange 3.975

Lemon 2.810

Eucalyptus 2.625

Tea tree 1,702

Pink 0.248

Also on the plant side:

Tocopherol-rich raspberry seed oil has shown absorbance in the UV-B and UV-C ranges with potential for use as a broad-spectrum UV protectant. ² Its SPF factor is reported to be between 28 and 50. ³

Other examples:

Carrot oil between 38 and 40

Shea butter between 6 and 8

Macadamia oil 6

Hemp oil 6

Jojoba 4

Sesame 4

Grapefruit seeds 4

Lawyer 4

Sea buckthorn between 2 and 4

Rice bran 4

Here is a study that puts into context the fact that the harmful effects of UV exposure are often mitigated by the use of UV-blocking lotions and sunscreens. ⁴ However, the toxicity of active ingredients in sunscreens may be of some concern. There is interest in using natural compounds as an alternative to commercial sunscreen.

The study was based on a review of studies on the SPF value of natural compounds. The results demonstrated that several natural compounds, including rutin, caffeine, and ferulic acid, possess UV-blocking properties. Adding these compounds to commercial formulas appears to increase overall SPF levels and, in some cases, may even promote improved skin appearance and health.

In addition, human sebum acts as sun protection. ⁵

Christine Cuisiniez, a pharmacist and expert in Dermo-Cosmetics, gives this advice on her website: For days when our face is not or very little exposed to the sun, we should not choose day creams that have Sun Protection Factors (SPF). A simple serum that contains vegetable oils, some of which have a natural sun protection coefficient of 4 or 5, will be much better for our skin. ⁶

Plant-based sunscreen? A review of the skin-protective effects of carotenoids

Here, a study on carotenoids that exhibit photoprotective, antioxidant, and anti-inflammatory properties. ⁷ These plant pigments are reported to be deposited in the skin and other target tissues following dietary intake and absorption. Since the 1970s, increasing evidence has shown, among other things, improved resistance to sunburn following carotenoid supplementation. This same research suggests that carotenoids may benefit other aspects of skin health, such as reducing lipid peroxidation and other markers of oxidative stress, inhibiting reactive oxygen species and collagen degradation, and benefiting skin hydration, wrinkles, and elasticity. Although research is still emerging, carotenoid bioavailability varies considerably depending on intake (e.g., source, dose, combination of carotenoids, etc.) and host characteristics (e.g., genetics, lifestyle, sex, age, etc.).

References:

1. Kaur CD, Saraf S. In vitro sun protection factor determination of herbal oils used in cosmetics. Pharmacognosy Res. 2010 Jan;2(1):22-5. doi:10.4103/0974-8490.60586. PMID: 21808534; PMCID: PMC3140123. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3140123/pdf/PR-2-22.pdf

2. B.Dave Oomah, Stephanie Ladet, David V Godfrey, Jun Liang, Benoit Girard, Characteristics of raspberry (Rubus idaeus L.) seed oil, Food Chemistry, Volume 69, Issue 2, 2000, Pages 187-193,
ISSN 0308-8146, https://doi.org/10.1016/S0308-8146(99)00260-5 .

3. https://fre.toasthomestylebreakfast.com/natural-oils-that-contain-spf-5585

4. Baswan SM, Klosner AE, Weir C, Salter-Venzon D, Gellenbeck KW, Leverett J, Krutmann J. Role of ingestible carotenoids in skin protection: A review of clinical evidence. Photodermatol Photoimmunol Photomed. 2021 Nov;37(6):490-504. doi:10.1111/phpp.12690. Epub 2021 May 20. PMID: 33955073. https://onlinelibrary.wiley.com/doi/10.1111/phpp.12690

5. https://www.verywellhealth.com/what-is-sebum-1069375#:~:text=Sun%20protection%3A%20Squalene%20has%20been%20shown%20to%20protect,skin%2C%20sebum%20also%20seems%20to%20support%20heart%20health .

6. https://www.oleassence.fr/spf-ou-fps-utiles-cosmetiques

7. Morocho-Jácome AL, Freire TB, de Oliveira AC, de Almeida TS, Rosado C, Velasco MVR, Baby AR. In vivo SPF from multifunctional sunscreen systems developed with natural compounds-A review. J Cosmet Dermatol. 2021 Mar;20(3):729-737. doi: 10.1111/jocd.13609. Epub 2020 Jul 29. PMID: 32649016. https://onlinelibrary.wiley.com/doi/10.1111/jocd.13609

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