Synergistic anti-hyperpigmentation power of arbutin and kaempferol compound from upcycled rambutan seeds

13 Dec 2023 --- The ongoing search for natural beauty solutions leads to a breakthrough study that looks into the untapped potential of agricultural by-products. Researchers explore the seeds of Nephelium lappaceum L., commonly known as rambutan, to determine their efficacy against melanin inhibition and tyrosinase activity.

Hyperpigmentation contributes to various skin disorders and requires effective and safe solutions. Common treatments often have undesirable side effects, prompting research of safer and more potent melanogenic inhibitors. 

Rambutan, a fruit large in agricultural waste, may offer a solution rooted in sustainability.

Melanin protects the skin from UV rays, regulates skin pigmentation and maintains skin integrity, underscore the authors. However, excess melanin can lead to melasma, hyperpigmentation, freckles and undesirable dark spots.

Potent anti-melanogenic activity
Among the four flavonoid glycosides evaluated, kaempferol-7-O-α-L-rhamnopyranoside (3) emerges as a standout performer. 

Demonstrating the highest potency with anti-melanogenic and anti-tyrosinase activities, the compound showcases its potential in skin whitening formulations.

“Thailand is renowned for its agricultural prominence, and rambutan is one of the economically significant crops in Thailand. In addition to commercial fresh fruits, rambutan is industrially processed into cans, juice, jam, jelly and spread. This processing produces a large amount of seed waste, a yearly average of 1900 metric tons discarded,” note researchers.Color of the formulation F1 and F2 in the accelerated storage period (Image Credit: Study).

Synergistic efficacy with arbutin
The effect of compound 3 with arbutin, a widely recognized tyrosinase inhibitor, was also explored with the results, in Nature, unveiling a synergistic impact in inhibiting melanin production and tyrosinase activity. That is seen as setting the stage for an effective combination in cosmetic formulations.

The formulation was stable under “accelerated storage conditions,” where compound 3 and arbutin levels were above 90% after one month of storage. “Determination of the formulation’s shelf life using the Q10 method, estimating it to be approximately  five months from the date of manufacture,” write the authors. 

Formulation for the future
The researchers developed a cosmetic formulation (F1) incorporating compound 3 and arbutin as active ingredients. F1 demonstrated physical stability, maintaining color, odor, and texture and exhibited consistent pH values. 

However, a comparative formulation (F2) experienced color changes attributed to specific formulation components. This formula consists of: “Compound 3 (0.005% w/w), glycerin (2.00% w/w), propylene glycol (1.00% w/w), hydroxyethyl cellulose (0.5% w/w), Acrylates/C10-30 Alkyl Acrylate Crosspolymer (0.10% w/w), triethanolamine (0.05% w/w), phenoxyethanol (0.5% w/w) and water (95.845% w/w).”

In addition to physical stability, F1 showcased chemical stability over an accelerated storage period. Compound 3 and arbutin levels remained above 90% after one month, affirming the formulation’s efficacy. The Q10 method estimated a shelf life of approximately 5.2 months from the date of manufacture.

F1 is made of: “Compound 3 (0.005% w/w), glycerin (3.00% w/w), propylene glycol (3.00% w/w), xanthan gum (0.5% w/w), ActiveProtecTMOX (Sodium Diethylenetriamine Pentamethylene Phosphonate, Disodium EDTA, Sodium Metabisulfite, Sodium Gluceptate) (0.60% w/w), arbutin (0.20% w/w), phenoxyethanol (0.5% w/w) and water (92.195% w/w).”In Thailand, 1900 metric tons of rambutan seeds are annually discarded.

Hyperpigmentation solutions
Ashland recently unveiled Perfectyl biofunctional, its chamomile extract crafted with AI to predict the skin care functions of its active compounds. Perfectyl targets flaws induced by external and lifestyle stresses, such as post-inflammatory hyperpigmentation and sebum overproduction.

Additionally, scientists at Northwestern University, US, designed a skin cream that heals damage throughout the day when exposed to sunlight or environmental toxins using synthetic, biomimetic melanin. 

Researchers in Thailand found that bamboo mushroom (Phallus indusiatus) extracts can decrease melanin content caused by cellular tyrosinase activity while also possessing antioxidant activity.

In a recent multi-million research fund, Boots, No7 Beauty and the University of Manchester, UK, will “redress the historical imbalance in the existing body of skin research,” which previously focused on lighter skin tones, with darker skin tones underrepresented or “overlooked completely.” 

By Venya Patel