Thermal decomposition of matrix metalloproteinase inhibitors: evidence of solid state dimerization

Waste-derived biocatalysts for pesticide degradation

A green approach to produce a cellulose-derived biocatalyst containing hydroxamic acids targeted for the neutralization of toxic organophosphates is shown. The cellulose source, rice husk, is among the largest agricultural waste worldwide and can be strategically functionalized, broadening its sustainable application. Herein, rice husk was oxidized in different degrees, leading to carboxylic acid-based colloidal and solid samples. These were functionalized with hydroxamic acids via amide bonds and fully characterized. The hydroxamic acid derived biocatalysts were evaluated in the cleavage of toxic organophosphates, including the pesticide Paraoxon. Catalytic increments reached up to 10⁷-fold compared to non-catalyzed reactions. Most impressively, the materials showed P atom-selectivity and recyclability features. This guarantees only one reaction pathway that leads to less toxic products, hereby, detoxifies. Overall, highly sustainable catalysts are presented, that benefits from waste source, its green functionalization and is successfully employed for the promotion of chemical security of threatening organophosphates. To the best of our knowledge, this is the first report of a hydroxamate-derived rice husk (selectively modified at the C6 of cellulose) and its application in organophosphates reaction.

Cytotoxicity Analysis of Active Components in Bitter Melon (Momordica charantia) Seed Extracts Using Human Embryonic Kidney and Colon Tumor Cells

Bitter melon (Momordica charantia) seed extracts (BMSE) have been used as traditional medicine for treating various ailments, although in many cases, the active component(s) are unidentified. In this study, bitter melon seeds were extracted in water, ethanol, or ethanol: water (1:1). The aqueous seed extracts (BMSE-W) exhibited marked cytotoxicity towards human embryonic kidney 293T (HEK293T) and human colon tumor 116 (HCT116) cells. The activity in BMSE-W was unaffected by heat and proteinases treatments, and eluted in the total volume of size-exclusion HPLC, suggesting the small, organic nature of the active component(s). Gas chromatographic-mass spectrometic (GC-MS) analysis of the HPLC fractions identified methoxy-phenyl oxime (MPO) as a major active component. Acetophenone oxime, a commercially available structural homolog of MPO, demonstrated cytotoxicity comparable with that of the BMSE-W. The oxime functional group was found to be critical for activity. Increased poly-(ADP-ribose)-polymerase and β-actin cleavage, and chromatin condensation observed in treated cells suggested apoptosis as a plausible cause for the cytotoxicity. This study, for the first time, identified a cytotoxic oxime in BMSE-W.