HR-μMAS NMR-Based Metabolomics: Localized Metabolic Profiling of a Garlic Clove with μg Tissues

The localization of metabolic profiles within a tissue sample is of particular interest when the sampling size is considerably small, i.e., in the order of a microgram (μg) scale. Small sampling size is inevitable when the sample availability is limited, or when different metabolic profiles are suspected in small disparate sample regions. Capitalizing a recently introduced high-resolution micro-MAS probe (HR-μMAS) for its capability of high-quality NMR data acquisition of μg samples, this study explores the localized metabolic NMR profiling of a single garlic clove and compares the methodology and results with the standard HR-MAS. One advantage of HR-μMAS is the feasibility of analyzing homogeneous μg samples within a large heterogeneous tissue. As a result, the sampling mass (<0.5 mg) allows to selectively profile four homogeneous anatomical garlic regions by HR-μMAS (skin, flesh, inner epidermis, and sprout), in contrast to three regions (skin, flesh, and core ≡ inner epidermis and sprout) by HR-MAS, wi...