Response surface optimization and antioxidant activity of total proanthocyanidins fraction from Abutilon theophrasti Medic. leaves

The extraction procedure and antioxidant activity were investigated for total proanthocyanidins extracts from Abutilon theophrasti Medic. leaves collected in August, September and October. The maximum extraction yield was achieved with 90% ethanol, 80oC of heating reflux temperature, 149.94 min of extraction time and 60(ml/g) of the ratio of solvent and material, which were optimized by Box-Behnken Design of response surface method. Spectrophotometric study displayed that total proanthocyanidins content was (0.44±0.02)% (0.52±0.01)% and (0.59±0.01)% for August, September and October samples, respectively. The proanthocyanidins extracts exhibited much stronger antioxidant activity to scavenge ABTS and DPPH free radicals, and reduce ferric power than the control synthetic antioxidant BHT. The present findings suggest that the proanthocyanidins extract from Abutilon theophrasti Medic. leaves was a very interesting candidate for the research and development of natural and healthy antioxidant for the pharmaceutical and food industries.