Bioactive Potential of “Jaspeado Garlic” (Allium sativum) from Northwestern Mexico: In Vitro Antioxidant and Bacteriostatic Effects

Background/Objectives: Garlic (Allium sativum) has long been valued for its rich constellation of organosulfur and phenolic compounds, molecules that underpin its many recognized biological activities. Despite its deep roots in traditional medicine, the functional profile of garlic is far from uniform; it shifts notably depending on how its bioactive components are extracted. Most scientific attention has gravitated toward ethanolic extracts, leaving the behavior of aqueous-buffer preparations relatively unexplored. In this study, we evaluated the antioxidant, antimicrobial, and exploratory immunometabolic effects of extracts obtained with phosphate-buffered saline (PBS) and 50% ethanol in PBS (EtOH:PBS; 50:50, v/v), using a regional garlic variety (“Jaspeado”) cultivated in northwestern Mexico. Methods: Their antioxidant potential was profiled through DPPH, ABTS, and ORAC assays; phenolic content was quantified using the Folin–Ciocalteu method, and a broader chemical fingerprint was obtained through UPLC-ESI-TQ-MS/MS. Furthermore, we analyzed their antimicrobial action against Escherichia coli, Salmonella spp., and Staphylococcus aureus, and examined their immunometabolic influence in LPS-stimulated 3T3-L1 adipocytes. Results: The extracts showed distinct, solvent-dependent patterns of antioxidant activity. The PBS extract displayed the highest ORAC values, whereas the EtOH:PBS extract showed a stronger DPPH and ABTS activity and a higher phenolic recovery. The PBS extract exhibited a broader bacteriostatic effect, inhibiting the growth of all strains, and selectively modulated antioxidant gene expression and influenced cytokine changes in adipocytes. Conclusions: Overall, this regional garlic variety exhibits solvent-dependent antioxidant and antimicrobial activities, while the PBS extract provided a biocompatible preparation for exploring relationships between chemical composition and biological activities.