Research
Research Publication
First-author peer-reviewed publication by Sirinda (Pammy) Chalermthiralert in Cosmetics (MDPI), a Scopus Q1 journal (CiteScore 4.1), demonstrating the development of a reef-friendly sunscreen formulation utilizing Perilla frutescens seed extract.
Formulation of Broad-Spectrum Ultraviolet Protection and Reef-Friendly Sunscreen Containing Perilla Seed Extract
Sirinda Chalermthiralert, Witchuda Sukjoi, Sutatip Thonglem,
& Narongrit Lahpun, (2026). Cosmetics, 13(3), 126.
This study explored Perilla frutescens (perilla) seed extract as a natural, sustainable booster for sun protection. The extract — rich in omega-3 linolenic acid and high in antioxidant activity — was incorporated into a reef-safe sunscreen formula free from coral-harming filters like oxybenzone and octinoxate. The final formulation achieved SPF 29.5, PA++++, and a critical wavelength of 382 nm (true broad-spectrum protection), while clinical testing on human volunteers confirmed it was non-irritating and showed a mild skin-brightening effect after sun exposure. The research demonstrates that botanical ingredients like perilla can deliver effective, eco-conscious photoprotection without compromising safety for skin or marine ecosystems.
This research is conducted under the guidance of
Asst. Prof. Narongrit Lahpun, Faculty of Science and Technology, Phranakhon Rajabhat University, who serves as the consultant for this research project.
Extract Procedure and UV Absorption Analysis
Perilla seed extracts were prepared into 3 samples using ethanol (50%, 70%, 95%) to identify the most efficient method. Perilla seed samples were sealed, shaken, and left to ferment, then filtered and concentrated using a rotary evaporator at 15°C to obtain purified extracts.
The resulting extracts showed strong UV absorption under UV-VIS analysis, highlighting their potential as natural, coral-safe alternatives to traditional substances in sunscreens.
Sunscreen Base Formulation
A balanced oil-in-water emulsion was developed to serve as the base for Parilla Guard sunscreen. The water phase (with Carbopol 940 and Butylene Glycol) provides moisture and stability, while the oil phase (with Emulgade 165, Olive Oil Extract, Lipid Soft SPF, and Silica Sunsphere H53) enhances UV protection and texture.
Both phases were heated to 75 °C and blended using a high-speed homogenizer to achieve a smooth, stable cream ready for SPF testing.
Stability & SPF Testing
Two sunscreen formulas — one base and one with 1% Perilla seed extract — were mixed at 3,000 rpm for 15 minutes and analyzed for pH, viscosity, color, and cream stability (CI). SPF values were measured to determine UV-protection efficacy. Results showed that the 95% ethanol extract achieved the highest SPF, confirming a greater concentration of natural UV-absorbing compounds.
Parilla Guard sunscreen achieved SPF 32.06 ± 9.03, providing broad-spectrum, UV protection verified by laboratory testing.
Skin Safety Test
To ensure both skin safety and consumer acceptance, Parilla Guard underwent comparative patch testing on human volunteers. Two cream samples — one with and one without Perilla seed extract — were applied on marked skin sections under transparent patches.
Measurements of skin redness, moisture loss, and color variation were recorded using precision instruments including the Mexameter MX18, Tewameter TM300, and Skin-Colorimeter CL400.
Results showed no irritation or allergic response, and participants reported a light, comfortable texture. These findings support the extract’s suitability as a biocompatible, eco-safe ingredient in next-generation sunscreens.
