Date of Award

12-2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Food Technology

Committee Chair/Advisor

Vivian Haley-Zitlin

Committee Member

Alexis Stamatikos

Committee Member

Jonathan H. Crane

Committee Member

William C. Bridges

Committee Member

Feng Chen

Abstract

Diabetes and obesity are metabolic diseases that have a serious impact on morbidity, disability, and mortality globally. The majority of treatments for diabetes and obesity are expensive and frequently have adverse effects. Finding an alternate treatment option that addresses concerns about current treatments while being safer and more affordable is crucial. Mangoes have long been a desirable source of nutrients and pharmacological therapeutics. Bioactive substances found in the mango plant (Mangifera indica L.) may have anti-diabetic activities. Mango leaf is a wasted by-product of the mango tree that has potential medicinal properties due to its’ many bioactive compounds that may enhance human health. The main chemical compound in mango leaf, mangiferin (MGF), has purported anti-diabetic and antioxidant assets.

We conducted a systematic review to explore the anti-diabetic properties of the various parts of the mango plant in the management of type 2 diabetes mellitus (T2DM) in animal models and humans. The electronic databases searched included the Web of Science, PubMed, FSTA, MEDLINE, CINAHL, and Cochrane Library. The publication date limit was up to December 2020. Twenty-eight of a total of 1001 studies met the inclusion criteria. Mango leaf, flesh, seed-kernel, peel, stem-bark, and by-product were assessed. Results support the glucose-lowering properties of mango in both animals and humans. Several proposed anti-diabetic mechanisms of action have been proposed. Additional studies are needed, especially in humans.

Subsequently, a chemical and sensory evaluation was conducted on five teas made from mango leaves (‘Tommy Atkins’, ‘Keitt’, ‘Kensington Pride’, ‘Carabao’, and commercial tea). Total polyphenols, tannins, and antioxidants were assessed. Significant differences (p < 0.05) in total polyphenols were observed in all varieties except commercial tea and Tommy Atkins; the most was in Carabao. The highest antioxidant activity belonged to Carabao, commercial tea, and Kensington Pride. Tannin levels were highest in Tommy Adkins and Keitt cultivars. Mangiferin was highest in commercial tea and Carabao. The sensory evaluation was performed using a 9-point hedonic scale with 61 untrained participants. All individual varieties of mango leaf tea were statistically significant for higher overall acceptability compared to green tea control or commercial mango tea.

The anti-adipogenic efficacy of mango leaf tea (MLT) and mangiferin (MGF) in 3T3-L1 cells was assessed. Cell viability, lipid accumulation levels, adiponectin, and glucose uptake were analyzed. Changes in the mRNA expression of genes involved in fat metabolism in 3T3-L1 cells were determined using quantitative real-time PCR. The results showed MLT and MGF inhibited adipogenesis accompanied by decreased triglyceride accumulation, increased adiponectin, increased glucose uptake, diminished gene expression of ACC, and elevated FOXO1 and ATGL gene expression in 3T3-L1 cells.

Available for download on Saturday, May 31, 2025

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