Clinical and electrophysiological efficacy of leaf extract of Gingko biloba L (Ginkgoaceae) in subjects with diabetic sensorimotor polyneuropathy

Abstract

Purpose: To investigate the health benefits of Gingko biloba L. leave extract EGb 761 in patients with diabetic sensorimotor polyneuropathy (DSP).

Method: In a randomized, double-blind, placebo trial, patients (n = 156) received Gingko biloba (120 mg/day) or placebo for 6 months. Efficacy of Gingko biloba extract EGb 761 was assessed on the reduction in the scores of “Short-Form McGill Pain Questionnaire” (SF-MPQ) and improvements in latency, amplitude and conduction velocity of four sensory (ulnar, median, peroneal and sural) and four motor (ulnar, median, peroneal and tibial) nerves.

Results: Gingko biloba significantly improved the mean scores of sensory, affective, visual analogue score (VAS) and present pain intensity (PPI) of SF-MPQ on 3 and 6 month post-treatment. At the start of experiment in the Gingko biloba-treated group, scores for sensory, affective, VAS and PPI domains were 12.90 ± 7.21, 4.40 ± 1.79, 4.38 ± 1.69 and 3.24 ± 0.78 respectively. After 6-months treatment with Gingko biloba, scores for sensory, affective, VAS and PPI domains were reduced (p < 0.01) to 7.24 ± 4.91, 3.11 ± 1.81, 3.37 ± 1.35 and 2.45 ± 0.65 respectively. Contrarily, in the placebo-administered group, sensory domain was (p < 0.01) deteriorated after 6 month (4.70 ± 1.87) compared to the baseline (4.04 ± 1.67). Gingko biloba extract EGb 761 failed to influence the electrophysiological measures when compared with the placebo group. The common adverse effects observed with Gingko biloba were somnolence and dryness of mouth compared with the placebo-treated patients

Conclusion: Gingko biloba extract EGb 761 seems to be an effective and safe drug for reducing symptoms of DSP without any apparent effect on the electrophysiological attributes of sensorimotor nerves.

Keywords: Diabetic polyneuropathy, Diabetes mellitus, Electrophysiological parameters, Gingko biloba, Sensorimotor nerves, Short-Form McGill Pain Questionnaire