Centella asiatica triterpenes for diabetic neuropathy: a randomized, double-blind, placebo-controlled, pilot clinical study

Background: Diabetic neuropathy (DN), a common complication of diabetes mellitus, results from hyperglycemia, poor microcirculation and attendant nerve damage. Currently available treatments relieve symptoms, but do not modify the neurodegeneration underlying DN. Centella asiatica (CA) triterpenes improved microcirculation in earlier clinical studies, and showed neurotropic effects in preclinical models suggesting a potential disease modifying effect in DN. This 52-week, randomized, double-blind, placebo-controlled trial examined the effects of CAST, a standardized CA extract containing triterpenes, on neuropathy symptoms in Type II diabetic subjects.

Patients and methods: The study enrolled patients with a history of Type II diabetes, with evidence of symptomatic symmetrical DN with total symptom score (TSS) ≥4, and stable HbA1c level <8. The primary outcome measure was TSS, which assessed intensity and frequency of parasthesia, numbness, pain and burning symptoms self-reported by patients. Secondary measures were nerve conduction, neurological impairment score, and quantitative sensory testing.

Results: Comparing CAST (n=21) and Placebo (n=22) groups, significant reductions from baseline for TSS (p<0.01) and paresthesia (p<0.01) were seen only in CAST treated groups. Numbness increased from baseline only in the Placebo group (p<0.05) and was significantly higher than for the CAST group (p<0.001). Burning sensation was reduced in both groups (p<0.01). Plasma triterpene levels in patients treated with CAST mirrored neurotropic concentrations in vitro.

Conclusions: CAST is a potential oral treatment for diabetic neuropathy, as it is well tolerated and effective in reducing the severity of DN symptoms in patients with Type II diabetes.