The study conducted by Mae Fah Luang University revealed that combining pumpkin seed oil and Japanese pumpkin polysaccharides within a specific emulsion structure can significantly improve skin barrier function.
This research highlighted a growing trend in the cosmetics industry — repurposing of agricultural by-products into high-value functional ingredients.
The team focused on the Japanese pumpkin, Cucurbita maxima, a crop widely cultivated in Thailand. While the flesh is a food staple, the seeds and specific carbohydrate chains, known as polysaccharides, contain bioactive compounds that the researchers believed could be harnessed for dermatological benefits.
To deliver these ingredients effectively, they turned to ultra-micro liquid crystal (ULC) emulsions.
The science of biomimetic delivery
Traditional lotions often sit on the surface of the skin, but liquid crystal emulsions are designed to mimic the natural structure of human skin lipids. These formulations create a lamellar structure — alternating layers of oil and water — that resembles the stratum corneum.
The researchers tested various emulsifiers and thickening agents to find the most stable and effective combination. They discovered that an emulsifier based on alkyl polyglucosides (APGs), specifically Emulgade PL 68/50, was superior at creating a dense network of these biomimetic structures.
Under polarised light microscopy, these structures appear as distinct Maltese cross patterns, a hallmark of a well-formed lamellar phase.
The novelty of this work lies in the synergistic triple-action mechanism. The formulation combined a lipid lamellar structure, which acted as a water reservoir, with emollients from the pumpkin seed oil and humectants from the pumpkin polysaccharides.
This three-pronged approach ensured that moisture was not only added to the skin, but also locked in by a reinforced physical barrier.
Optimising the formula
The study identified a specific formulation, labelled F9, as the most promising candidate for commercial application. This version contained 4.5% emulsifier, 0.3% xanthan gum as a thickener, 2.0% pumpkin seed oil, and 0.1% pumpkin polysaccharides.
A key technical achievement was keeping the particle size of the emulsion droplets to approximately 4 micrometres. These ultra-micro particles provided better stability and a more refined skin feel than larger droplets.
Wide-angle X-ray diffraction (WAXD) confirmed that the cream maintained an “alpha-gel” phase, which helped the product remain stable over time and during temperature fluctuations.
This crystalline structure gave the cream its unique ability to hold onto water molecules and release them slowly into the skin.
The F9 cream underwent six rigorous heating and cooling cycles, ranging from 4°C to 45°C. The results showed no phase separation, colour change, or significant loss of viscosity, suggesting a long shelf life for potential retail products.
The researchers noted that while many natural formulations struggled with consistency, the ULC framework provided a robust architecture for botanical actives.
Proven clinical results
To validate the laboratory findings, the researchers conducted clinical trials with 33 healthy volunteers aged 30 to 50.
Using a closed patch test, where the cream was applied to the skin under a small chamber for 24 hours, the team found the pumpkin-based ULC emulsion was non-irritating. The Mean Irritation Index (MII) was well below the threshold for concern, making it suitable even for sensitive skin.
The efficacy of the cream was measured using two industry-standard devices: the Corneometer, which measures skin hydration, and the Tewameter, which calculates transepidermal water loss (TEWL).
In short-term tests, a single application of the F9 cream increased skin hydration by more than 50% within 15 minutes. The long-term results over 14 days were even more notable.
By the end of the two-week period, the F9 formulation reached the highest hydration levels among all tested groups. It also significantly reduced the amount of water escaping through the skin barrier, a process known as TEWL.
The data showed that while the base emulsion (placebo) provided a significant boost in moisture, the addition of pumpkin seed oil and polysaccharides created a statistically superior result over a 14-day period.
This suggested that the pumpkin components worked to repair the skin over time, rather than just providing a temporary surface-level fix.
Market potential for sustainable cosmetics
The researchers noted that pumpkin seed oil is rich in unsaturated fatty acids and antioxidants like vitamin E and beta-carotene, which help repair the skin barrier. Meanwhile, polysaccharides act as humectants, drawing moisture from the environment into the skin.
The successful integration of pumpkin-derived actives into a stable ULC system provided a safe and effective approach for advanced moisturising skin care.
This study also provided a roadmap for utilising agricultural waste, specifically from the Thai pumpkin industry, which has an economic impact exceeding USD12m.
By transforming these by-products into sophisticated delivery systems, manufacturers can meet the increasing consumer demand for green chemistry and clean beauty without sacrificing clinical performance.
The researchers concluded: “The unique combination of pumpkin-derived bioactive compounds within a liquid crystal system offers a promising, safe, and natural alternative for advanced moisturising skin care. These findings demonstrate the potential for utilising agricultural by-products in the development of high-performance cosmeceutical delivery systems.”
Source: Cosmetics
“Effective Skin Hydration Using an Ultra-Micro Liquid Crystal Emulsion Containing Pumpkin Seed Oil and Polysaccharides”
https://doi.org/10.3390/cosmetics13020049
Authors: Setinee Chanpirom, et al
