Antioxidant and anti-diabetic activities in commercial and homemade pomegranate molasses in Lebanon

Abstract

Pomegranate fruit and its derived products are rich sources of bioactive compound that were shown to have many biological activities. Pomegranate molasses (PM) is a thick traditional Middle Eastern syrup used in many recipes for international cuisines from around the world, including the Lebanese cuisine. It is considered to be a highly nutritious product which makes it of great interest to researchers. The purpose of this study is to assess the phytochemical composition, antioxidant and anti-diabetic properties of homemade and commercial PM consumed in Lebanon using samples collected from households in rural areas (n=4) and the market (n=28), respectively. The objectives of this study are to determine their total phenolic content using the Follin-Ciocalteu method, their total flavonoid content using aluminum chloride method, their antioxidant activity using DPPH radical scavenging as well as ferrous ion chelating assays and their anti-diabetic activity using α-amylase and α-glucosidase inhibitory activities while using acarbose, a known anti-diabetic drug as the standard reference. Homemade PM samples exhibited a higher antioxidant activity than commercial samples, with the most active homemade PM having IC₅₀ of DPPH: 0.09 mg/ml and % of chelation: 46.78. Also, homemade PM samples were found to have a higher anti-diabetic activity than commercial samples, with the most active homemade PM having IC₅₀ against α-amylase: 0.63 mg/ml and IC₅₀ against α-glucosidase: 0.405 mg/ml and being almost as active as acarbose with both enzymes (1.5 times). Significant inverse strong/moderate correlations were observed between total phenols content (r=-0.542)/total flavonoids content (r=-0.483) and IC₅₀ of DPPH scavenging activity and significant negative moderate correlations were observed between total phenols/flavonoids contents and alpha amylase inhibitory activity (r: -0.436, p-value: 0.013 and r: -4.445, p-value: 0.011 respectively). Further investigation should be performed in order to identify and isolate the bioactive metabolites responsible for each activity.