The study, conducted by researchers at Rangsit University, Walailak University, Prince of Songkla University, and Chulalongkorn University, found this benefit especially strong when the cashew apple extract (CAE) was placed inside tiny, protective spheres called liposomes.
This helped keep its key nutrients, including vitamin C, stable, and boost its ability to be absorbed into the skin.
Lab tests found the CAE to be a strong antioxidant that encouraged the skin to make more collagen, protected skin cells (fibroblasts) from damage, and helped close artificial wounds.
When delivered in liposomes, the absorption of vitamin C into the skin roughly doubled, and the vitamin degraded much more slowly under challenging storage conditions.
Turning farm waste into cosmetic ingredient
Cashew apples are the large, fleshy “false fruits” attached to the cashew nut, and are grown in large quantities in places like Brazil, Africa, and South East Asia.
However, because they taste bitter and spoil quickly, they are often discarded. The Thai research team aimed to take this underused material and turn it into a valuable raw material for cosmetics.
The researchers gathered ripe cashew apples, mashed them up, and used alcohol to extract their active components. This liquid was then dried to obtain the CAE. The final product was a sticky, brown liquid with a sweet, fruity scent and a pH level of around 5, making it ideal for most facial products.
When they assessed the chemicals inside, the team found that every gramme of CAE contained about 0.9mg of vitamin C (or ascorbic acid), as well as a large amount of polyphenols and other antioxidants.
The presence of these beneficial substances, including flavonoids, suggested that the extract worked via a combination of actions rather than just a single molecule.
Antioxidant, collagen-boosting effects
In standard tests designed to measure how well a substance can fight harmful free radicals, CAE showed good antioxidant strength. While it was not as strong as pure vitamin C, the researchers expected this because vitamin C was only a small part of the extract and the overall benefit came from the wide variety of compounds present.
Crucially, for skin applications, CAE was found to be safe for cells in the lab. Skin cells and immune cells stayed nearly 100% alive even at high extract levels, indicating that there was a wide margin of safety for future product development.
The team also looked at how it affected collagen production. Treating skin cells with CAE led to Type I collagen production increasing once the concentration reached a certain level. This continued to rise as more extract was added.
This result supported the idea that CAE could be used in products aimed at firming skin and improving skin structure.
Damage protection and wound healing
To test how the extract protected against damage, researchers exposed skin cells to hydrogen peroxide, a common way to cause oxidative stress that usually kills most of the cells.
However, cells pre-treated with non-toxic amounts of CAE before the damage saw a significantly greater number of survivors among them. This meant the extract helped keep the skin cells alive under attack, displaying a genuine cell-protective effect that went beyond simple test-tube antioxidant activity.
The next step was to examine whether this protection could aid wound-healing. Using a scratch test (where a small wound is created in a dish of cells), a CAE solution sped up cell movement to close the gap, compared to untreated samples.
According to the researchers, this was linked to the extract’s ability to stimulate collagen, alongside its rich profile of compounds known to support tissue repair.
From an immune perspective, CAE did not cause inflammation. It neither increased the levels of a key inflammatory marker — nitric oxide (NO) — in immune cells, nor strongly reduced existing inflammation. This suggested that its main role was in protection and repair, and not as a powerful anti-inflammatory agent.
On the other hand, the extract was weak at skin whitening. In a test measuring the inhibition of tyrosinase, CAE was over 100 times less effective than kojic acid. This suggested that it was unlikely to be used on its own for whitening, though its protective qualities may still help even skin tone over time.
Liposomes improve vitamin C protection and skin entry
As vitamin C is a key indicator of the cashew apple’s beneficial potential and is easily broken down, the researchers wrapped the CAE inside liposomes to keep it safe and help it penetrate the skin.
The liposomes were found to be highly effective at capturing the vitamin C, protecting about 85% of it successfully.
In a test using artificial skin (Strat-M), the CAE-loaded liposomes delivered a steady flow of vitamin C into the skin at about 16.5µg/cm2, compared to 7.8µg/cm2 from the free extract. In other words, the liposomes approximately doubled the amount of active ingredient that the skin absorbed.
Furthermore, solutions containing either the free CAE or liposome-loaded CAE were found to be skin-friendly, easy to spread, and stable when kept cold.
The most important difference was in vitamin C stability. After three months of storage at 30°C, the simple CAE solution lost over 80% of its vitamin C. In contrast, the CAE-loaded liposome solution kept a much higher amount of its original vitamin C. This confirmed that using liposomes was a highly effective way to protect the unstable vitamin C in cashew apple-based products.
Limitations and future indications
The research highlighted CAE as a promising upcycled plant-based ingredient with a strong scientific foundation and benefits rooted in antioxidant defence, collagen stimulation, cell protection, and wound healing.
However, the researchers stressed that these were early-stage results based only on animal cells and artificial skin, and human safety or effectiveness studies had not yet been conducted.
Also, as the vitamin C content was not extremely high, CAE should be promoted as a complex, multi-component plant extract, not just a vitamin C substitute.
The study’s authors concluded: “Future research should focus on long-term stability evaluations, and clinical trials that can validate the efficacy and safety of CAE formulations as potential alternatives for anti-ageing skin care products.”
Source: Cosmetics
“Anti-Aging and Wound Healing Activity of Cashew Apple (Anacardium occidentale) Extract and Its Liposomal Development to Enhance Skin Permeability and Ascorbic Acid Stability”
https://doi.org/10.3390/cosmetics12060246
Authors: Narumon Changsan, et al.
