Teeraporn Katisart^1,2, Kanitsara Magnussen¹, Ampa Konsue³, Luchai Butkhup⁴, Chirapha Butiman⁵

Abstract

Purpose: To determine the phytochemical compounds, in leaves, branches and roots of two mulberry cultivars, Monnoi and Buriram 60 (Br.60). Methods: Both cultivars were grown under organic conditions. Extraction of plant parts was done using either distilled water (autoclave), 50 % ethanol or 95 % ethanol and the proximate chemical analysis including 1-Deoxynojirimycin (DNJ) content, total flavonoid (TFC) and total phenolic contents (TPC), antioxidant and α-glucosidase inhibitory properties of the plant extracts were analyzed. Results: The proximate analysis showed that both cultivars had high protein content in leaves (21 – 25 %) compared to branches and roots. The carbohydrate content was high in all parts of both cultivars (32 – 50 %) and the DNJ content of all parts using 50 % ethanol extraction was higher compared to the other two methods, ranging from 10 – 17 mg/g Ext. Total phenolic content (TPC) in Monnoi branches extracted with distilled water (autoclave) was 13.45 ± 0.26 mg GE/g Ext while Br.60 roots with distilled water extraction (autoclave) showed the highest total flavonoid content (TFC) at 1.55 ± 0.02 mg QE/g Ext. Antioxidant activities of the extract on FRAP, DPPH radical and ABTS were high for both cultivars but the IC50 value was higher and significantly different (p < 0.05) compared to two standards used as controls (Trolox and Ascorbic acid). The α-glucosidase assay showed that the leaves and branches of Monnoi had IC50 values of 2.21 ± 0.09 and 2.45 ± 0.1, respectively, with the potential to reduce enzymatic activity but less than the standard substance Acarbose with an IC50 of 0.31 ± 0.01. Conclusion: Two mulberry cultivars, Monnoi and Br.60, show high potential for diabetes treatment owing to their bioactive compounds. Extraction with 50 % ethanol gives the highest yield. Further isolation and characterization and possible mechanism of action of phytoactive constituents such as 1- deoxynojirimycin (DNJ) would be necessary.