S-allyl-L-cysteine

Changes in chemical composition during food processing and handling are crucial for the alteration of food flavor and function, and accurate characterization of key chemical reaction pathways in complex food matrices is one of the core challenges in food chemistry research. Here, this study attempts to establish a strategy for sensitive characterization of chemical reactions during food processing based on on-line extraction electrospray ionization mass spectrometry (oEESI-MS). The process of making garlic into black garlic, a traditional global flavor food, was chosen as an exemplary research template. The direct MS characterization of raw garlic as well as black garlic samples with different processing times was achieved by using the self-constructed oEESI-MS device. Benefiting from the high tolerance of oEESI-MS to complex matrix interferences, all samples can be fingerprinted directly without any pre-processing or pre-separation. As a result, oEESI-MS achieved a sensitive characterization of the changes of key substances during the preparation of black garlic. Further, a new chemical reaction pathway, the degradation of γ-L-glutamyl-S-allyl-L-cysteine to S-allyl-l-cysteine, was completely demonstrated by analyzing the differential substances before and after the treatment, and verified by standard substances and chemical theory calculations. In conclusion, a complete oEESI-MS-based strategy for tracking the substance changes in food processing was established in this study, which has a widely applicable prospect for the precise setting of food processing time and parameters, and the innovation of processing technology.

Atherosclerotic plaques, which are characterized by endothelial oxidative stress, lipid metabolism disorders and persistent inflammation, can induce serious cardiovascular diseases. However, the pharmacotherapies currently used to treat atherosclerosis (AS), such as lipid-lowering and antithrombotic drugs, can regulate only a single pathological feature of AS, and there is still a dearth of integrated platforms for the multifaceted regulation of AS progression. Herein, we developed a synergistic combination of endogenous H₂S gas therapy with a multienzyme-like nanozyme (named ^LyP-1Lip@HS) for the treatment of AS. The high affinity of the LyP-1 peptide for macrophages and foam cells within plaques allows ^LyP-1Lip@HS to actively target atherosclerotic lesions. After cavitation was induced by low-intensity focused ultrasound (LIFU), the lipid membrane of ^LyP-1Lip@HS was disrupted, thereby "unlocking" the enzyme-like activity of hollow mesoporous Prussian blue (HMPB) and facilitating the release of the endogenous H₂S donor S-allyl-L-cysteine (SAC). Notably, H₂S endogenously generated by enzymatic catalysis plays multiple roles, upregulating the ATP-binding cassette transporter A1 in foam cells to increase lipid efflux and promote the conversion of M1 macrophages to M2 macrophages. Moreover, the high level of reactive oxygen species in the inflammatory microenvironment of the plaque was mitigated. Overall, ^LyP-1Lip@HS provides a specific and controlled treatment to prevent oxidative stress, inflammation and lipid metabolism disorders, making it a candidate for AS treatment.