Role of model equations and energy dynamics in understanding bioactive compounds of olive leaf extract by LC-MS/MS; their evaluation using a cluster approach

This study investigated the effects of phenolic composition in olive leaf extract (OLE) obtained using microwaveassisted extraction (MAE) and conventional extraction (CE). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and response surface methodology (RSM) were applied to mathematically model and optimize extraction parameters. The study aims to enhance bioactive yields, antioxidant activity, total phenolic content (TPC), and total flavonoid content (TFC) for potential applications in the food and pharmaceutical industries. Olive leaf extract (OLE) was obtained using MAE (250-350 watt, 30-90 min) and CE (30-90 min). Response surface methodology identified optimal conditions at 300 W for 60 min (MAE; desirability: 0.962) and 90 min for CE (desirability: 0.998). Linear models most accurately described thymoquinone, total phenolic compounds (TPc) (P < 0.01), hydroxycinnamic acid (P < 0.05), fumaric acid, caffeic acid, hydroxybenzoic acid, and total hydrolyzed tannins (THT) (P > 0.05) under CE. Oleuropein, quercetin, total condensed tannins (TCT) (P < 0.0001), and luteolin (P > 0.05) were best fitted to quadratic models, while caffeic acid, hydroxybenzoic acid, and thymoquinone under MAE required quadratic fits, with cubic models for remaining compounds (P > 0.05). Antioxidant assays (DPPH, ABTS) showed stronger radical scavenging for maceration (Mc) compared to CE and MAE. Optimizing extraction parameters enhances bioactive compound yield in OLE. MAE produces more phenols and flavonoids, while CE is more energy-efficient and can sometimes achieve antioxidant activity comparable to Mc. Systematic modeling improves phytotherapy research, ensuring more accurate prediction of extraction efficiency.