Effect of <i>Agave americana</i> L. on the human, and <i>Aspergillus oryzae</i> S2 α-amylase inhibitions

<p>Among phenolic compounds, <i>Agave americana</i> L. extract contained puerarin (38.4%) and <i>p</i>-coumaric acid (12.29%) (pCa). From the Lineweaver–Burk plots, pCa and puerarin demonstrated a competitive and a non competitive inhibitions towards human α-amylase activity, respectively. PCa exhibited a higher human inhibitory activity with an IC₅₀ of 98.8 μM which was about 2.3 times than acarbose. Puerarin (IC₅₀ = 3.87 μM) and pCa (IC₅₀ = 10.16 μM) also showed an excellent inhibition for <i>Aspergillus oryzae</i> S2 α-amylase activity. The inhibitions of the described biocatalysts compounds towards both amylases were significantly decreased when they were pre-incubated with starch. The binding modes of these compounds were evaluated <i>in silico</i>. The binding efficiency order of these molecules in terms of polar contact numbers for both enzymes was in agreement with the <i>in vitro</i> studies<i>.</i> These findings provided a rational reason to establish the isolated compounds capability as therapeutic target for hyperglycaemia modulation and antifungal therapy.