Hypoglycemic potential of mulberry leaf extract – red palm oil emulsion: extraction, formulation, and bioactivity assessment

Both mulberry leaf extract (MLE) and red palm oil (RPO) have been reported to help regulate blood sugar levels, attributed to the 1-deoxynojirimycin (1-DNJ) in MLE and tocopherols and carotenoids in RPO. This study aims to investigate the potential hypoglycemic effects of an MLE-RPO emulsion, which have not been previously explored. The results prove that cellulase-assisted ultrasound extraction improved the recovery of 1-DNJ by 6.5-fold to 2.97 ± 0.01 mg/g, and enhanced α-amylase and α-glucosidase inhibition activities by 10-20%. Combining MLE and RPO into an emulsion at a ratio of 5.25:1 further increased α-glucosidase inhibition activity to 90.26 ± 0.73%. However, the MLE-RPO emulsion at a 1:1 ratio exhibited superior antioxidant and anti-inflammatory activities and was more effective than the 5.25:1 ratio in modulating the pattern of reducing sugar release during rice digestion. This study provides insights into the potential of the MLE-RPO emulsion as a functional food additive for modulating carbohydrate digestion.