Cosmeceutical potential of cashew leaf extract in facial creams targeting anti-aging

24 Jan 2023 --- A Thailand-based study has uncovered cosmeceutical applications for anti-aging, skin-whitening and antioxidant applications of cashew leaf extract as it showed “substantial” antioxidant activities with the highest inhibition of skin aging enzymes such as tyrosinase and collagenase.

The researchers examined a facial cream containing the extract for its stability and physical properties, finding it to be “satisfactory” under various storage conditions.

What’s in the leaf?
The cashew leaf was extracted using ethanol (DEN), ethyl acetate (DEA) and distilled water (DDW), which, in the same order, yielded 22.76%, 1.82% and 24.97%.

The results found significant phytochemicals (bioactive plant nutrients) that were high in polarity and soluble in water.Collagenase is an enzyme that can degrade collagen, thus, weakening it in the underskin or the dermis layer, which leads to wrinkles.

“The most common phenolic compounds found in the cashew leaves were flavonol glycosides consisting of major components such as kaempferol 3-O-glucoside, kaempferol 3-O-arabinofuranoside, quercetin 3-O-glucoside, quercetin 3-O-galactoside and chlorogenic acid, while quercetin was the dominant flavonoid,” share the authors.

Phenolic compounds
The DDW extract had the highest total phenolic content, while the DEN extract had the highest total flavonoid content.

“Phenolic compounds are usually mainly responsible for the antioxidant properties of plants and most of these compounds are classified as hydrophilic antioxidants...phenolic compounds have an important influence on the antioxidant activity of plant extracts,” they continue.

Additionally, phenolic compounds are anti-bacterial and anti-inflammatory, protect the skin from UV radiation and have anti-carcinogenic properties.

Tyrosinase inhibition
Tyrosinase is an enzyme that catalyzes the production of melanin in the skin and hair bulbs.

The natural compounds, namely the antioxidants from cashew leaf extract, showed to inhibit the activity of tyrosinase – which can be a useful mechanism to combat hyperpigmentation, dull skin or dark spots.

“The compounds from the various parts of cashew fruits, namely anacardic acids, 2-methyl cardols, cardol triene and cardols, exhibited tyrosinase inhibitory activity,” detail the researchers.

In a recent study, P. lactiflora flowers were found to contain many flavonoids, phenolic acids, tannins and alkaloids.

Suppressing collagenase
Collagenase is an enzyme that can degrade collagen, thus, weakening it in the underskin or the dermis layer, which leads to wrinkles.Tyrosinase is an enzyme that catalyzes the production of melanin in the skin and hair bulbs.

“Incubating DEA, DDW and DEN extracts at concentrations of 100, 200 and 400 µg/mL in the collagenase inhibition test gave collagenase activities of 50.1 ± 3.6, 20.6 ± 2.0 and 2.9 ± 1.1% for the DEA extract, while the DDW and DEN extracts recorded no activity at all the studied concentrations,” note the researchers.

“DDW and DEN extracts at concentrations of 100, 200 and 400 mg/mL inhibited the enzyme’s activity. Therefore, the extract concentrations were reduced to 10, 20 and 40 µg/mL. The DEN extract at 40 µg/mL showed the highest inhibition of collagenase activity, which was recorded at zero percent.”

The flavonol group of chemicals, including quercetin and kaempferol in the extract, are noted to give the plant its strong anti-collagenase activity. The antioxidants in the ethanol-sourced extract also inhibited the collagenase enzyme activity.

Similarly, Egypt-based researchers have found that coriander oil in pharmaceutical dosage forms has been found to possess anti-wrinkle properties that improve external signs of aging and UV light-induced stress.

Stability test
The skin cream was tested for its stability in different temperatures of 4°C and 45°C for three months and under alternating hot and cold conditions for six heating/cooling cycles.

The cream was kept at 45°C for 24 hours, alternating to 4°C for the next 24 hours. The product’s texture, color, odor, stratification and acid base (pH) were found to be stable with “satisfactory physical characteristics.”

The basic formula and smell remained consistent although the color became darker but did not stratify. Its viscosity changed slightly and the pH increased at 45°.

By Venya Patel

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