Assessment of Acute Dermal Toxicity of Lignosus rhinocerus TM02® (Agaricomycetes) Sclerotium and Its Potent Cold Water Extract (xLr®)

The tiger milk mushroom (Lignosus rhinocerus), a Southeast Asian medicinal mushroom, has traditional uses for respiratory ailments, wound healing, and general health. This study evaluated the acute dermal toxicity of L. rhinocerus sclerotium (TM02Ŵ) and cold-water extract (xLrŴ) for safe topical application. Healthy female Sprague Dawley rats were topically administered TM02Ŵ or xLrŴ at 2000 mg/kg body weight, while physiological saline served as a control. Visual toxicity observations, body and organ weight measurements, food and water intake, hematological and serum biochemical analyses, and histological examinations were performed. Findings were contextualized with prior oral toxicity studies of L. rhinocerus. Both TM02Ŵ and xLrŴ demonstrated excellent dermal safety with no observed mortality, behavioural abnormalities, or significant differences in food or water intake, body weight, or organ weights compared with controls. Hematological and biochemical parameters remained within normal ranges, and histopathology of the skin and major organs revealed no adverse effects. Consistent with earlier chronic oral toxicity studies, the preparations showed no evidence of systemic toxicity or organ damage. TM02Ŵ and xLrŴ are classified as Category 5/Unclassified under the Globally Harmonized System (GHS) criteria, affirming their suitability for topical use. These findings, coupled with earlier oral toxicity studies, highlight the safety of L. rhinocerus as a versatile ingredient for therapeutic and cosmetic applications. Further research on chronic dermal exposure is recommended to reinforce its use in skincare.