UNILIPO Publishes Research on Pterostilbene Microcapsule Delivery in the Journal of Molecular Liquids

Research on UNILIPO R&D Lab’s proprietary pterostilbene microcapsule delivery technology has been published in the Journal of Molecular Liquids. The paper refers to the patented material as Mat-IL-MicCap@PTB; UNILIPO markets the ingredient as UNISOUL® Reborn.

Why Develop This Technology?

Pterostilbene is a key active compound in Pterocarpus bark extract and a naturally occurring dimethylated analog of resveratrol. Research has explored its anti-aging potential and its ability to inhibit tyrosinase activity and melanin accumulation. In one laboratory assay, it inhibited tyrosinase more strongly than kojic acid.

However, pterostilbene presents several formulation challenges.

Sensitivity to light and heat. In UNILIPO’s stability tests, concentrated pterostilbene degraded and turned brown when exposed to elevated temperatures or light, affecting the formulation’s appearance.

Limited skin penetration. After eight hours, approximately 5-6 μg/cm² of unencapsulated pterostilbene was retained in the skin. Achieving an effective dose therefore required higher concentrations or additional penetration enhancers, potentially increasing the risk of irritation. 

These challenges led the team to develop a carrier designed to improve stability and skin penetration while remaining suitable for daily skincare use.

Pterostilbene Lipid Microcapsule Technology

UNILIPO’s R&D team combined microencapsulation with ionic-liquid treatment to improve pterostilbene’s stability and water solubility. Comparative testing evaluated the encapsulated and unencapsulated forms across six areas: stability, cytotoxicity, skin delivery, antioxidant activity, anti-wrinkle potential, and brightening activity. The resulting ingredient is marketed as UNISOUL® Reborn.

Stability Under Stress

After 90 days of storage at 45°C and −25°C, UNISOUL® Reborn retained 95% of its pterostilbene content, indicating stability under the tested conditions.

Stability samples and measurements of particle size and pterostilbene content over 90 days under the tested storage conditions.

Dynamic light scattering (DLS) measurements showed a uniform particle-size distribution without large aggregates. The negative zeta potential was also consistent with stability in water.

Particle characterization showed a mean size of 154.5 ± 3.4 nm and a zeta potential of −30.8 mV.

Cytotoxicity Profile

Encapsulated pterostilbene showed low toxicity toward HKF cells while producing a stronger inhibitory effect on G361 cells than unencapsulated pterostilbene.

Cell-viability testing in HKF cells and G361 melanoma cells.

Transdermal Delivery

Unencapsulated pterostilbene showed limited skin penetration after four hours. Within 30 minutes, skin retention with the microcapsule formulation was more than twice that of the unencapsulated form and remained higher at every measured time point. After eight hours, retention was 7.7 times that of the unencapsulated control.

Confocal images and skin-retention measurements comparing unencapsulated pterostilbene with the microcapsule formulation.

Antioxidant and Brightening Activity

Laboratory testing reported 2.5-fold greater DPPH radical-scavenging activity and 33-fold greater ABTS radical-scavenging activity for encapsulated pterostilbene compared with the unencapsulated form.

Caption: DPPH and ABTS radical-scavenging assays comparing free pterostilbene with UNISOUL® Reborn.

Melanin inhibition improved by 4.8% and 11.9% at the same concentration, respectively, indicating a stronger brightening profile for the encapsulated form.

Comparison of melanin inhibition with encapsulated and unencapsulated pterostilbene.

Anti-Wrinkle and Firming Effects

At concentrations of 0.0156%, 0.0313%, and 0.0625% (v/v), encapsulated pterostilbene increased type I collagen levels in fibroblasts more than the unencapsulated form, suggesting greater anti-wrinkle and firming potential.

Effects on type I collagen levels and MMP-1 expression in fibroblasts.

After 14 days of use, the three measured wrinkle parameters decreased by 8.27%, 12.95%, and 48.07%. After 28 days, the corresponding reductions were 14.60%, 18.01%, and 55.78%. VISIA analysis also showed improvements in crow’s feet, pigmentation, dark spots, and overall skin tone.

Caption: VISIA facial images captured at baseline, day 18, and day 28 of product use.

The study reported antioxidant, anti-wrinkle, brightening, and repair-related activity for encapsulated pterostilbene, along with findings supporting its potential use in daily skincare.

Product Applications

UNILIPO has incorporated UNISOUL® Reborn into products such as the VC/VA/Pterostilbene Serum, with additional applications planned.

UNILIPO’s R&D Lab continues to evaluate its key ingredients and formulation technologies through preclinical and clinical research, with the goal of supporting skin health.