Exploring Bioactive Potential of Mulberry Leaf Extract – Red Palm Oil Emulsion for In Vitro Hyperglycemia Regulation

Chew, Huei Chin (2025) Exploring Bioactive Potential of Mulberry Leaf Extract – Red Palm Oil Emulsion for In Vitro Hyperglycemia Regulation. Masters thesis, Tunku Abdul Rahman University of Management and Technology.

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Abstract

This research aimed to develop a bioactive emulsion with enhanced anti-diabetic potential using mulberry leaf extract (MLE) and red palm oil (RPO). Initially, the effectiveness of cellulase pretreatment and lactic acid bacteria fermentation was investigated to enhance MLE's bioactivities. Using central composite response surface methodology, the extraction process conditions were optimized, selecting the MLE with the highest bioactivities for further studies. An MLE-RPO emulsion was then formulated and analyzed to determine the interplay between MLE and RPO on the emulsion's chemical and bioactive properties through Simplex Lattice mixture design . The MLE-RPO emulsions with the highest bioactivities and stability were chosen to investigate the effects of simulated in vitro digestion on their bioactivities when added to the white rice and Basmathi rice. The study showed that MLE produced from cellulase-assisted ultrasound extraction (C-MLE) had the highest 1-DNJ content, and α-amylase and α-glucosidase inhibition activities. MLE produced from lactic acid bacteria fermentation (L-MLE) exhibited the highest antioxidant activity. Therefore, C-MLE was selected for the next phase of the study to formulate the MLE-RPO emulsion. Simplex Lattice mixture design optimized the emulsion formulation, leading to two variants: Emulsion 1 (E1) with a 1:1 ratio and Emulsion 2 (E2) with a 1:5.25 ratio of RPO to MLE. E1 showed the highest anti-inflammatory activity, while E2 demonstrated superior antioxidant and anti-diabetic activities. The findings suggested that combining MLE and RPO could produce an emulsion with the bioactivities of both ingredients. Both emulsions were then selected to proceed to the simulated digestion experiments. Results showed that E2 maintained higher stability and effectiveness against digestive enzymes compared to E1, which exhibited better oxidative stability but decreased α-glucosidase activity post-intestinal digestion. These findings suggest E2 as a promising antioxidative and anti-diabetic additive for diabetes management. Subsequent in vitro gastrointestinal digestion tests indicated that fortifying white rice and Basmathi rice with these emulsions enhances DPPH scavenging and FRAP antioxidant activities, with E1 significantly inhibiting α-glucosidase. Both emulsions also improved the anti-inflammatory properties and moderated sugar digestion, demonstrating potential health benefits when combined with white or Basmathi rice. E1 is better for slower sugar digestion, while E2 supports sustained energy release. Overall, E1 combined with either white rice or Basmathi rice demonstrated health benefits. This study provides insights into the advantages of combining RPO and MLE in preparing a stable, bioactive emulsion with potential for diabetes management. Keyword: Mulberry leaf extract, red palm oil, bioactive emulsion, anti-diabetic activity, antioxidant activity, anti-inflammatory activity.