Assessment of eight Morus indica cultivars for 1-deoxynojirmycin content, antioxidant and anti-diabetic potential: optimization of ultrasound assisted process for bioactive enriched leaf extract

The present study evaluates the in vitro antioxidant, anti-diabetic potential and 1-deoxynojirimycin content in hydro-ethanolic leaf extracts of eight Indian mulberry cultivars (V-1, K-2, S-36, S-13, BER-779, BER-763, BER-1 and Anantha). Subsequently, for the selected variety ultrasound-probe assisted extraction parameters (power, liquid to solid ratio and time) were optimized using response surface methodology. UHPLC-QTOF accurate mass spectrometry was performed for phytochemical characterization of the optimized extract. Total phenolic content among cultivars varied from 8.90 +/- 0.18 to 12.27 +/- 0.22 GAE mg/g, and total flavonoids from 9.94 +/- 0.41 to 15.09 +/- 0.41 RE mg/g. In general, antioxidant composite index of cultivars, inclusive of ABTS and DPPH scavenging assay, reducing power, inhibition of lipid peroxidation, NO radical and OH radical scavenging activities was in order V-1 > S-13 > S-36> Anantha > K-2 > BER-763 > BER-779 > BER-1. The extracts from cultivars showed differences in inhibition of alpha-glucosidase (65.6 +/- 1.88 to 82.26 +/- 1.87%) and alpha-amylase (17.99 +/- 0.55 to 25.82 +/- 1.273%) enzymes. 1-Deoxynojirimycin content varied from 0.74 +/- 0.01 to 2.12 +/- 0.02 mg/g. Under optimized extraction parameters of power, ratio and time, the recovery of 1-DNJ, TPC and TFC were 2.53 +/- 0.06 mg/g, 13.12 +/- 0.14 mg GAE/g, and 15.89 +/- 0.23 mg RE/g, respectively, for the selected cultivar V-1. Mass spectrometry analysis of V-1 leaf extract confirmed presence of 14 important phytochemicals, ascertaining a synergistic contribution to bioactivities. Our findings suggest a huge potential of leaf extracts from Morus indica L. V-1 cultivar to address multimodal health disparities and aid in better management of diabetes. [GRAPHICS] .