Pterostilbene has dermal medicinal benefits such as anti-inflammatory, antioxidative effects and photoprotective properties against UVB radiation. The purpose of this study was to evaluate the dermal toxicity of pterostilbene via skin irritation and sensitisation. A skin irritation test was done according to the Organization Economic Co-operation and Development 404 guideline with the scoring of irritation based on erythema and oedema in 5 albino rabbits were observed up to 14 days. The sensitisation test using the Buehler Test in accordance with the ISO 10993-10 guideline was used to study the sensitisation effect of pterostilbene on the skin surface of albino guinea pigs. According to the primary dermal irritation index (PDII), the positive control group was classified with severe irritation (scorings of 7.71). No irritation was observed for the negative control and the 5% pterostilbene treated groups. But, a slight irritation reaction with PDII scorings of 0.86 was observed in the 10% pterostilbene treated group. The sensitisation study indicated that pterostilbene did not produce any sensitisation signs, thus classified as a non-sensitiser agent according to the Magnusson & Kligman classification. Pterostilbene-treated skin also did not indicate any signs of irritation and sensitisation. In conclusion, pterostilbene did not cause dermal toxicity upon application on the skin.

Wound care management is incredibly challenging for chronic injuries, despite the availability of various types of wound care products in the market. However, most current wound-healing products do not attempt to mimic the extracellular matrix (ECM) and simply provide a barrier function or wound covering. Collagen is a natural polymer that involves a major constituent of the ECM protein, thus making it attractive to be used in skin tissue regeneration during wound healing. This study aimed to validate the biological safety assessments of ovine tendon collagen type-I (OTC-I) in the accredited laboratory under ISO and GLP settings. It is important to ensure that the biomatrix will not stimulate the immune system to produce any adverse reaction. Therefore, we successfully extracted collagen type-I from the ovine tendon (OTC- I) using a method of low-concentration acetic acid. The three-dimensional (3D) skin patch of spongy OTC-I was a soft and white colour, being tested for safety and biocompatibility evaluations based on ISO 10993-5, ISO 10993-10, ISO 10993-11, ISO 10993-23, USP 40 <151>, and OECD 471. For the dermal sensitisation and acute irritation test, none of the tested animals displayed any erythema or oedema effects (p > 0.005). In addition, there were no abnormalities detected in the organ of the mice after being exposed to OTC-I; additionally, no morbidity and mortality were observed in the acute systemic test under the guideline of ISO 10993-11:2017. The grade 0 (non-reactive) based on ISO 10993-5:2009 was graded for the OTC-I at 100% concentration and the mean number of the revertant colonies did not exceed 2-fold of the 0.9% w/v sodium chloride compared to the tester strains of S. typhimurium (TA100, TA1535, TA98, TA1537), and E. coli (WP2 trp uvrA). Our study revealed that OTC-I biomatrix does not present any adverse effects or abnormalities in the present study’s condition of induced skin sensitization effect, mutagenic and cytotoxic towards cells and animals. This biocompatibility assessment demonstrated a good agreement between in vitro and in vivo results regarding the absence of skin irritation and sensitization potential. Therefore, OTC-I biomatrix is a potential medical device candidate for future clinical trials focusing on wound care management.