Evaluation of the Effect of Astragalus membranaceus Saponins Administration on Knee Function and Cartilage Biomarkers in Healthy Subjects with Knee Discomfort.

OBJECTIVE

This study aimed to evaluate the effects of 12 weeks of Astragalus membranaceus saponins (AMS) supplementation on functional performance, knee joint mobility, self-reported outcomes, and biomarkers of inflammation and cartilage in healthy subjects with knee discomfort.

METHODS

A randomized, double-blind, placebo-controlled trial was conducted in healthy subjects aged 20-70 years with knee discomfort but without clinically diagnosed knee osteoarthritis. Participants were assigned to receive one capsule of AMS or a placebo once daily for 12 weeks. The pre-specified primary endpoints were the SLSD step count and knee ROM; KOOS total score was a key secondary endpoint; serum biomarkers were exploratory. The results included functional performance assessed by the Single Leg Step Down (SLSD) test, knee range of motion (ROM), and self-reported outcomes using the Knee injury and Osteoarthritis Outcome Score (KOOS). Knee ROM was measured with a goniometer and recorded as both active ROM and passive ROM for knee flexion and extension. Serum biomarkers of inflammation (IL-8, IL-1β, MIP-1α), cartilage degradation (CTX-II, COMP, MMP-13, COL2A1), and cartilage synthesis (PIINP) were evaluated at baseline and Week 12.

RESULTS

Within the AMS group, SLSD step count increased significantly by 16.83% (Δ = +12.78 steps; p < 0.05) and recovery time decreased significantly by 19.12% (Δ = -108.91 s; p < 0.05) compared with baseline, whereas the placebo group showed smaller, non-significant changes (+4.48 steps and -56.48 s, respectively); however, neither between-group difference in change scores reached statistical significance. Significant improvements in active and passive knee ROM were observed in both flexion and extension (all p < 0.05) within the AMS group, whereas the placebo group showed no significant changes. KOOSs improved significantly in all domains within the AMS group, with the largest gains observed in sport/recreation (+22.23%) and quality of life (+18.38%). In the exploratory biomarker analysis, several inflammation and cartilage-related biomarkers changed after AMS supplementation showed within-group reductions (IL-8, COMP, MMP-13) and PIINP increased.

CONCLUSIONS

12 weeks of AMS supplementation was associated with improvements in selected functional, mobility, and outcomes in generally healthy adults with self-reported knee discomfort. AMS was also associated with changes in selected circulating biomarkers related to inflammation and cartilage metabolism. These findings should be interpreted as a preliminary, safe, complementary strategy to support joint health in healthy subjects with knee discomfort.