Improved Synthesis of Lysine- and Arginine-Derived Amadori and Heyns Products and in Vitro Measurement of their Angiotensin I-Converting Enzyme Inhibitory Activity

The l-lysine- and l-arginine-derived Amadori and Heyns products consisting of <i>N</i>-(1-deoxy-d-fructos-1-yl)­amino acid and <i>N</i>-(2-deoxy-d-glucos-2-yl)­amino acid were prepared by reaction of d-fructose and d-glucose with l-lysine hydrochloride and l-arginine hydrochloride using commercial zinc powder as deprotonating reagent and also as catalyst precursor in a simple synthetic route in high yield. These compounds were screened for angiotensin I-converting enzyme (ACE) inhibitory activity using a high-throughput colorimetric assay (utilizing porcine kidney ACE). The IC₅₀ values fall in the range of 1030–1175 μM, with <i>N</i>^α-(1-deoxy-d-fructos-1-yl)­arginine showing the best IC₅₀ value (1030 ± 38 μM). This study demonstrates an improved synthetic method for simple Amadori and Heyns products and their moderate ACE inhibitor activity

Antiaflatoxigenic and Antimicrobial Activities of Schiff Bases of 2‑Hydroxy-4-methoxybenzaldehyde, Cinnamaldehyde, and Similar Aldehydes

2-Hydroxy-4-methoxybenzaldehyde (HMBA) is a nontoxic phenolic flavor from dietary source Decalipus hamiltonii and Hemidesmus indicus. HMBA is an excellent antimicrobial agent with additional antiaflatoxigenic potency. On the other hand, cinnamaldehyde from cinnamon is a widely employed flavor with significant antiaflatoxigenic activity. We have attempted the enhancement of antiaflatoxigenic and antimicrobial properties of HMBA, cinnamaldehyde, and similar molecules via Schiff base formation accomplished from condensation reaction with amino sugar (d-glucamine). HMBA derived Schiff bases exhibited commendable antiaflatoxigenic activity at the concentration 0.1 mg/mL resulting in 9.6 ± 1.9% growth of Aspergillus flavus and subsequent 91.4 ± 3.9% reduction of aflatoxin B₁ with respect to control