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BACKGROUND: Green tomato extracts, an agro‐food industry waste, are rich in the glycoalkaloid tomatine, which presents activity against several diseases. High‐performance liquid chromatography (HPLC) with ultraviolet (UV) detection is one of the most used techniques for quantification of bioactive compounds. The aim of this study was to optimize and validate a selective HPLC method with diode array detector (DAD) for the quantitative analysis of tomatine extracted from green tomatoes by subcritical water. RESULTS: Chromatographic runs were performed on a InertSustain Phenyl (250 mm × 4.6 mm, 5 μm) analytical column, at a wavelength of 205 nm. A concentration range of 50–580 μg mL−1 was used. The validation process was performed considering the linearity, precision, trueness, limit of detection (LOD) and limit of quantitation (LOQ) of the method. The selected mobile phase composed of acetonitrile and a solution of 20 mmol L−1 potassium dihydrogen phosphate (KH2PO4) pH 3, resulted in suitable retention times and a standard calibration curve with adequate linearity (R2 = 0.9999). The method trueness was evaluated by the recovery assay, obtaining a mean recovery of 105% and the precisions were 1.4% and 0.9% (percentage relative standard deviation, RSD%) for the tomatine standard and extract samples, respectively. The inter‐day variability was 2.7–9.0% (RSD%) for the standards and 6.9% (RSD%) for extract. The LOD and the LOQ of the method were determined at 8.0 and 24.1 μg mL−1, respectively. CONCLUSION: The herein described method was successfully used for the quantification of tomatine in a tomato‐derived extract. Furthermore, the method constitutes a simple and rapid analytical approach able to be used as a routine protocol. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The 4-oxo-ββ-lactams (azetidine-2,4-diones) are potent acylating agents of the human leukocyte elastase (HLE), a neutrophil serine protease that plays a key role in several inflammatory diseases. A novel 4-oxo-ββ-lactam containing a N-(4-(phenylsulphonylmethyl)phenyl) group, 3, was designed as a potential mechanism-based inhibitor capable of undergoing elimination of phenylsulphinate upon Ser-195 acylation. Compound 3 was found to be a potent slow-tight binding inhibitor of HLE, presenting a remarkable second-order rate constant of 1.46 ×× 106 M−−1s−−1 and displaying selectivity over the proteinase 3 and cathepsin G. However, liberation of phenylsulphinate was not observed in the hydrolysis of 3 in both pH 7.4 phosphate buffer and human plasma. The Cmax values of 1207 μμg/total blood, 179 μμg/g spleen and 106 μμg/g lung were determined by HPLC, following a single 30 mg/kg dose of 3 given intraperitoneally to NMRI mice, suggesting that the inhibitor distributes well into tissues. Although being a powerful selective inhibitor of HLE, 4-oxo-ββ-lactam 3 has a limited stability, being susceptible to off-target reactions (plasma and liver enzymes). [ABSTRACT FROM AUTHOR]