Targeted Metabolomic Analysis Reveals Solvent-Dependent Phenolic Variation and Associated Antioxidant and Antibacterial Activity in Coriander Seeds (Coriandrum sativum L.)

<i>Coriandrum sativum</i> L. (coriander) seeds have long been used as a traditional medicine and a spice worldwide. Despite its abundant use, bioactive properties of coriander seeds, correlated with the antioxidant and phenolic data, have not been fully studied systematically. This study evaluated the phenolic data, antioxidant capacity, and antibacterial activity of coriander seed extracts obtained using solvents of differing polarity. Higher total phenolic content (TPC) and antioxidant activity were observed in the polar extracts, while moderate and non-polar extracts possessed higher antibacterial activity. Acetone extract (Ace) had the highest antibacterial activity, with an inhibition zone diameter (IZD) of 16.2 ± 0.2 mm against <i>B. subtilis</i>, and a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 1 and 2% (<i>w</i>/<i>v</i>), respectively. The MBC/MIC ratio between 1 and 4 was observed for the active extracts of coriander seeds, indicating their bactericidal behavior. The liquid chromatography and tandem mass spectroscopy (LC-MS/MS) system using multiple reaction monitoring (MRM) targeted analysis identified 13 phenolic compounds: gallic acid, ellagic acid, gentisic acid, caffeic acid, vanillic acid, o-coumaric acid, sinapinic acid, chlorogenic acid, salicylic acid, ferulic acid, rutin, trans-cinnamic acid, and quercetin. Quantitative differences were observed in the phenolic compounds across the different coriander seed extracts. The TPC was significantly (<i>p</i> ≤ 0.01) and positively correlated with cupric-reducing antioxidant capacity (CUPRAC) (r = 0.92), as well as with ferric-reducing antioxidant power (FRAP) (r = 0.98); furthermore, it showed that the higher level of antioxidant capacity of the coriander seed extracts was significantly (<i>p</i> ≤ 0.05) associated with phenolic compounds such as gallic acid, chlorogenic acid, gentisic acid, ferulic acid, and rutin. However, antibacterial activity and phenolic/antioxidant content were negatively correlated, suggesting that non-polar compounds may impact antibacterial activity.