A 26-week repeated dose toxicity evaluation of sporoderm-removed Ganoderma lucidum spores in rats

Ganoderma lucidum spore powder is a traditional Chinese medicine with a variety of health benefits. Sporoderm-removed Ganoderma lucidum spores (RGLS) can be more effectively absorbed and utilized by the body. Due to the extensive clinical application and lack of long-term (>30 days) safety evaluation of RGLS, it is necessary to evaluate its repeated dose toxicity during a longer administration period. Here, we conducted a 26-week repeated dose toxicity test of RGLS in Sprague‒Dawley (SD) rats. The male and female rats were orally administered RGLS at doses of 0, 0.4, 1.2, and 4.0 g/kg once daily for a period of 26 weeks. The safety profile of RGLS was assessed through in vivo observations of survival, body weight, and food consumption; hematological, biochemical, and urine analyses; immunotoxicity assays; and histopathological examinations. The results showed that no significant systemic toxicity was observed following 26 weeks of repeated RGLS administration. Our data showed a no-observed adverse effect level (NOAEL) of 4.0 g/kg, which is approximately 20 times higher than the human equivalent dose. Our results support that RGLS can be considered a safe medicinal or food product that can be added to a healthy diet.