Most store-bought sunscreens prevent sunburn by blocking high-energy ultraviolet B (UVB) radiation, but not all offer adequate, lasting protection from low-energy UVA radiation that causes photoaging and skin cancer.
The oil extracted from amaranth is an interesting candidate for a natural sunscreen product, mainly thanks to its high levels of linoleic acid, squalene, and tocopherols.1 Additionally, such herbal sunscreen formulations offer promising results in terms of non-toxicity and skin compatibility.
This study was aimed at determining whether amaranth oil can protect the skin from the effects of UV radiation.
This in vitro study was undertaken by researchers from the Medical University of Bialystok in Bialystok, Poland.
They worked on human fibroblast cells, which were exposed to various concentrations of cold-pressed amaranth oil (0%, 0.1%, 0.25%, 0.5%, and 1%) over the period of 24 hours before and after a 15-minute irradiation under a UVA-emitting lamp.
Researchers studied amaranth oil's protective effects before and after UVA exposure on cell formation as well as collagen and DNA synthesis. The results of this study were published in the Pharmacognosy Magazine.
When cells were treated with amaranth oil before UVA irradiation, cell formation significantly increased, but only in samples treated with 0.1% and 0.25% amaranth oil. Exposure to 0.5% amaranth oil inhibited cell formation. This shows that low concentrations of amaranth oil exert pre-UVA irradiation protective effects.
When cells were treated with amaranth oil after UVA irradiation, cell formation was inhibited in samples that were treated with 0.5% and 1% amaranth oil, but not in those treated with 0.1% and 0.25% oil. This provides evidence that low concentrations of amaranth oil exert post-UVA irradiation protective effects.
UVA has also shown to affect collagen synthesis, which was significantly counteracted by treating the cells with a 0.1% amaranth oil. Other concentrations were not shown to prevent collagen damage by UVA radiation.
Additionally, 0.1% and 0.5% amaranth oil substantially reduced the damaging effects of UVA on DNA synthesis.
What Does this Mean?
As seen in the results of this in vitro study, low concentrations of amaranth oil offer pre- and post-UV protection.
Researchers point out that amaranth oil's effects are not sufficiently strong to serve as sole UV protection. Instead, they encourage its addition to cosmetic formulations, such as sunscreens.
Other herbs whose natural oils have photoprotective abilities include almond, avocado, coconut, olive, and sesame.
- Pharmacognosy Magazine, The Possible Pre- and Post-UVA Radiation Protective Effect of Amaranth Oil on Human Skin Fibroblast Cells, 2017
- Natural Products Chemistry & Research. (2013). Redox Modulation by Amaranth Oil in Human Lung Fibroblasts. Retrieved December 1, 2020 from https://www.longdom.org/open-access/redox-modulation-by-amaranth-oil-in-human-lung-fibroblasts-2329-6836.1000122.pdf