As recently reported by market research and data firm Statista, "the global cosmetic antioxidant market is projected to reach $150.9 million by the end of 2023," and has demonstrated steady growth since 2017. More than ever, consumers demand better-performing anti-aging products with more sustainable ingredients to address fine lines, wrinkles, and dullness.
To better meet consumer demand, cosmetics and personal care product manufacturers searching for innovative new topical ingredients should note a recent study examining cashew leaf extract's efficacy as a cosmetic ingredient. The study examined "the bioactive components of cashew leaf extracts to determine their contents of potential antioxidant, anti-tyrosinase, and anti-collagenase agents as natural sources for skincare products."
What is cashew leaf extract?
Belonging to the Anacardiaceae family, the cashew tree (Anacardium occidentale L.) is commonly found throughout southeast Asia and tropical America. The fruit is edible, and historically, "the leaf, stem and bark extracts are used in traditional medicines to treat inflammation, diarrhea, rheumatic diseases, hypertension, and infectious diseases," treatments that were successful due to the plant's antioxidant and anti-inflammatory properties.
As further detailed in the study, cashew lead extract contains phytochemicals, including "flavonoids, polyphenols, alkaloids, saponins, tannins, coumarin, quinone and cardiac glycoside, indicating the potential bioactivity of plants as antioxidant sources." Plants are already used in various applications in cosmetic and personal beauty products, including skin-lightening and anti-aging moisturizers, sunscreens, and cosmetics.
Anti-tyrosinase & anti-collagenase properties
Natural, plant-based antioxidant ingredients are of particular interest to consumers seeking visible benefits, including "their free-radical-scavenging activity that helps to reduce or prevent skin oxidative stress and can slow down skin aging." Researchers specifically examined cashew leaf extract due to its anti-tyrosinase activity.
Tyrosinase is an enzyme that contributes to the production of melanin in the skin. Over-production of this enzyme can lead to "hyperpigmentation disorders such as age spots, freckles and melisma," and anti-tyrosinase activity benefits those looking to lighten skin to treat these conditions.
Researchers were also interested in examining cashew leaf extract's anti-collagenase activity. According to the study, "collagenase is an enzyme that breaks down collagen, a protein that is found in the connective tissue of the skin."
Further, "collagen is an important component of the skin's structural support, and its degradation can lead to the loss of skin elasticity and the development of wrinkles." Anti-collagenase activity is beneficial to those looking to support skin elasticity and prevent fine lines from forming.
Different types of testing and confirmed results
Researchers first prepared the extract by sourcing and drying the cashew leaves before creating three extract types: 95% ethanol (DEN), 95% ethyl acetate (DEA), and distilled water (DDW). Each extract type was then tested to determine total phenolic and flavonoid content.
Once phenolic and flavonoid content was established, researchers performed two assays on each extract composition to measure their antioxidant properties. Following these results, additional testing was performed to determine each extract's tyrosinase and collagenase inhibitory activity. Finally, researchers prepared and tested the formulation and stability of different cashew leaf extractions into a facial cream to determine the potential compatibility as a topical ingredient.
In their conclusion, researchers determined that the data collected demonstrated that "the cashew leaves extracted with ethanol (DEN) showed substantial antioxidant activities and the highest inhibition of the crucial enzymes involved in skin aging such as tyrosinase and collagenase, with the potential for cosmeceutical product development for anti-aging, skin-whitening and antioxidant applications."
Further, their testing of the facial cream revealed that cashew lead extract can successfully be incorporated into a topical cream as "the stability and physical properties of the facial skin cream were satisfactory under various storage conditions."
As consumers continue to seek out beauty products formulated with clean or plant-based ingredients, it will be interesting to see if cashew leaf extract becomes a trending ingredient in cosmetic skin care products in the coming months.
2023; 10(1):17. https://doi.org/10.3390/cosmetics10010017
Title: “Collagenase and Tyrosinase Inhibitory Activities and Stability of Facial Cream Formulation Containing Cashew Leaf Extract”
Authors: Srisuksomwong P. et al.