Inhibition of the in vitro Activities of α-Amylase and Pancreatic Lipase by Aqueous Extracts of Amaranthus viridis, Solanum macrocarpon and Telfairia occidentalis Leaves

Abstract

Inhibition of digestive enzymes such as α-amylase and pancreatic lipase (PL) is a promising therapeutic strategy for the treatment and management of chronic health conditions such as diabetes and obesity. Therefore, the aim of this work was to determine the enzyme inhibitory activity of polyphenol-rich aqueous extracts of Amaranthus viridis (AV), Solanum macrocarpon (SM) and Telfairia occidentalis (TO) leaves, which were harvested from plants produced using multiple urea fertilizer doses (0–80 kg N/ha). Fertilizer application was applied at two time points (at planting or 2 weeks after seedling emergence). Leaf extracts were obtained using aqueous extraction (1:20, leaves:water) for 4 h at 60°C followed by centrifugation and freeze-drying of the supernatant. Results showed that the extracts inhibited α-amylase, and pancreatic lipase dose-dependently with TO extracts having significantly (p < 0.05) higher inhibitory activities for both enzymes. Fluorescence intensity and circular dichroism spectra in the presence and absence of leaf extracts indicate significant changes to the enzyme protein secondary and tertiary conformations. We conclude that the leaf extracts, especially from TO are potential agents for reducing calorie intake as a preventive or treatment tool against chronic diseases such as diabetes and obesity.

A 96-Well-Plate–based Method for the Estimation of Alpha-Amylase Activity Using Miniaturises 3,5-Dinitrosalicylic Acid (Dnsa) Colorimetric Method

“…Figure 3a revealed a significantly higher (p<0.05) product produced from the α-amylase enzyme reaction incubated at 50 °C temperature as compared with the room and 37 °C temperatures. This is in contrast with the most reported papers including Keharom et al (2016), Simair et al (2017), and Oluwagunwa et al (2021) which showed the ability of alpha-amylase enzyme to react at the range of 37-39 °C temperatures. However, Xiao et al (2006) demonstrated that the alpha-amylase enzyme was mostly active after 30 min of incubation at 50 °C.…”

“…The validated proposed method was employed to determine the optimum condition for α-amylase enzyme reaction. The conditions tested were the concentrations of the enzyme (2, 4, 6, 8, 10 U/mL) and starch (1, 2, 3, 4, 5% w/v) incubated at three different temperatures, including room temperature (Oyedemi et al, 2017), 37 °C (Oluwagunwa et al, 2021) and 50 °C (Xiao et al, 2006). An amount of 20 µL of 0.02 M sodium phosphate buffer containing 0.006 M of sodium chloride (pH 6.9) was mixed with 20 µL of soluble starch and 20 µL of α-amylase enzyme solution.…”

Characterization, Antioxidant Activities, and Pancreatic Lipase Inhibitory Effect of Extract From the Edible Insect Polyrhachis vicina

“…The inhibition of PL mitigates excessive fat deposition in the adipose tissue ( 3 ). The results of PL inhibitory activity of the P. vicina extract with or without shaking are shown in Figure 3A .…”

“…Obesity, which is characterized by excessive accumulation of body fat and aberrant lipid metabolism, is associated with an increased risk of disability. Thus, the enzymes, including pancreatic lipase (PL), involved in lipid metabolism are potential therapeutic targets for obesity ( 3 ). Oxidative stress, a major source of free radicals, is the etiological factor for various chronic diseases, such as type 2 diabetes mellitus, cardiovascular disease, chronic inflammation, cancer and metabolic dysfunction ( 4 ).…”

In vitro inhibition of acetylcholinesterase activity by yellow field pea (Pisum sativum) protein-derived peptides as revealed by kinetics and molecular docking

“…The far and near UV spectra of the enzyme -peptide complexes were determined as described by Oluwagunwa et al (21). The final assay solution (200 µl) was a mixture of enzyme (100 and 350 µg/ml for far and near-UV, respectively), peptide (12.5 -50 µg/ml), which were all prepared in 0.1 M phosphate buffer (pH 7.4).…”