Oriflame Cosmetics discovers citrus fruit-based flavanone naringenin shields skin from UVB exposure and pollution

16 Aug 2023 --- Naringenin, a naturally occurring flavanone found in citrus fruits and known for its antioxidant and anti-inflammatory effects, has been investigated for its photoprotective effects in human skin cells on a lab-grown epidermis. It was discovered to have an anti-inflammatory effect on skin imbalances caused by UVB exposure and pollution.

Both UVB irradiation and air pollution are major extrinsic factors causing premature aging of the skin, including sagging, wrinkles and pigmentation spots.

“Naringenin inhibited the pollution-induced expression of the CYP1A1 gene in human skin keratinocytes,” detail the researchers.

“Topical treatment with naringenin on a pigmented reconstructed epidermis significantly decreased melanin production. In conclusion, this study demonstrates that naringenin could be a valuable ingredient in skin care products, protecting against the detrimental effects of both UVB and pollution on the skin.”

Environmental stressors triggering skin reactivity
The mechanisms underlying the effects of UV radiation and pollution on skin aging are “complex and multifactorial” as phrased by the scientists.

UV radiation generates reactive oxygen species (ROS), which are highly reactive molecules that are formed when oxygen reacts with other molecules in the body. These contribute to the breakdown of collagen and elastin fibers in the skin, resulting in a loss of elasticity and firmness.

Like UV exposure, pollution can also generate ROS and trigger inflammatory pathways, which can further exacerbate the effects of UV radiation and accelerate the aging process, flag the researchers. 

Additionally, air pollution exposure has been shown to be correlated with the development of pigment spots.

“The mechanisms underlying the effects of UV radiation and pollution on skin aging are complex and multifactorial,” say the researchers. “UV radiation generates ROS that contribute to the breakdown of collagen and elastin fibers in the skin, resulting in a loss of elasticity and firmness.”Naringenin specifically inhibits UVB-induced inflammation markers MMP1, MMP3, IL6 and GM-CSF, as well as pollution-induced MMP1 in human skin fibroblasts.

“Exposure to pollution can also generate ROS and trigger inflammatory pathways, which can further exacerbate the effects of UV radiation and accelerate the aging process.”

Photoprotective properties of naringenin
The researchers studied skin melanocytes (melanin-producing and distributing cells) and a pigmented reconstructed epidermis, finding that naringenin significantly downregulated several genes involved in melanogenesis – the process by which the pigment melanin is produced in melanocytes.

The researchers highlight that several animal studies have previously indicated that naringenin holds immense potential in benefiting the skin through its photoprotective, anti-inflammatory, antioxidant and skin-brightening effects.

“Flavonoids have demonstrated their capacity to absorb and scatter UV radiation, thus reducing its penetration into the skin and minimizing its harmful effects,” they note.

The results showed that naringenin specifically inhibits UVB-induced inflammation markers MMP1, MMP3, IL6 and GM-CSF, as well as pollution-induced MMP1 in human skin fibroblasts. 

Functional flavonoids spotlighted
In recent years, there has been growing interest in the use of flavonoids like naringenin in skin care products. Flavonoids are a diverse group of phytochemicals, widely distributed in fruits, vegetables, herbs and medicinal plants, and are known for their various biological activities.

In the realm of skin care, flavonoids – such as quercetin, kaempferol and rutin – are highly regarded for their potent antioxidant and anti-inflammatory properties. 

Among recent studies exploring viable sources of flavonoids for cosmetic applications, oil derived from discarded passion fruit seeds was found to be rich in these compounds.

Other investigated sources include honeysuckle flowers, durian, fermented tea leaves, spiked ginger lily and a special honey sourced from the Azores Islands.

By Benjamin Ferrer