Subacute Oral Toxicity Study of Astragalus Root Water Extract in Rats

Astragalus membranaceus has a long-standing history of use in traditional Chinese medicine (TCM). Despite its extensive historical application and the emerging scientific evidence supporting its medicinal value, the safety of its extracts, particularly concerning subchronic toxicity, remains inadequately characterized.

This study conducted a subchronic toxicity assessment of Astragalus root water extract (AWE) in Sprague-Dawley rats to evaluate its safety profile.

The safety of AWE was evaluated through a 90-day repeated-dose toxicity study, administering a constant daily dose of 47 g of crude drug per kilogram of body weight. The animals were assessed for body weight, food consumption, rectal temperature, and rotarod performance, alongside hematological and biochemical parameters, bone marrow and immune parameters, and underwent gross necropsy and histopathological examination.

No treatment-related mortality, clinical abnormalities, or gross/histopathological changes were observed. Hematological evaluations, clinical biochemical analyses, bone marrow cytology assessments, and spleen immune typing did not reveal any adverse changes. Compared to the control group, rats treated with AWE exhibited a transient decrease in food intake across five different 24-h intervals, as well as a significant reduction in rectal temperature on Day 90. On the 90th day, the latency period on the rotating rod decreased significantly; however, during the subsequent 30-day recovery phase, all parameters returned to baseline levels. Additionally, absolute and relative organ weights, weight gain, and fat mass remained unaffected.

The high-dose administration of AWE did not exhibit significant toxic effects in Sprague-Dawley rats, thereby supporting its safety within a certain dose range.