## 2 Materials and Methods
### The Effect of Alkaloid Extracts on TDH in PC-12 Cells Induced by OS with H\({}_{2}\)O\({}_{2}\)  
The supernatant was prepared as outlined in Section 2.7. The determination of TDH was carried out using both native thiol and total thiol assays (both from Rel Assay, Gaziantep, Turkey) following the manufacturer's guidelines. For TDH, reducible disulfide bonds were converted into free functional thiol groups. Any excess sodium borohydride, a reductant, was neutralized and removed using formaldehyde. Subsequently, all thiol groups, including the newly reduced and the native ones, were measured after reacting with 5,5\({}^{\prime}\)-dithiobis-(2-nitrobenzoic) acid (DTNB). The dynamic disulfide quantity was calculated by taking half the difference between the total and native thiols. Once the native and total thiols were established, the amounts of disulfides were ascertained [43]. Determination of the Effect of Alkaloid Extracts on Total Oxidant Status (TOS), Total Antioxidant Status (TAS), and OS Index (OSI) Levels in PC-12 Cells Induced by OS with H\({}_{2}\)O\({}_{2}\)  
Cells were seeded in a 6-well plate at a concentration of 1 \(\times\) 10\({}^{6}\) cells per well. The PC-12 cells were then exposed to alkaloid extracts at concentrations of 100, 250, and 500 ug/mL, dissolved in 2 mL of cell culture medium. This was incubated at 37 \({}^{\circ}\)C in an atmosphere containing 5% CO\({}_{2}\) for 18 h. Subsequently, the cells underwent a 24 h incubation with a medium infused with 200 uM H\({}_{2}\)O\({}_{2}\). Cells maintained under standard conditions without H\({}_{2}\)O\({}_{2}\), or alkaloid extract treatments served as controls. Post-treatments, cells were gently washed with cold PBS. They were then covered with 2 mL of cold PBS and detached using a cell scraper (Corning Star). The detached cells were then gathered in a sterile centrifuge tube and spun at 10,000 rpm for 5 min at 4 \({}^{\circ}\)C. It is crucial to note that all the following steps were conducted in a cold environment. The resultant cell pellets were suspended in 500 uL of cold lysis buffer containing 1 M Tris buffer (pH 7.2), 2 M sodium chloride (NaCl), 1 M magnesium chloride (MgCl\({}_{2}\)), and 1% Triton X-100. The mix was kept at 4 \({}^{\circ}\)C for 15 min, with intermittent vortexing every 5 min. Post-incubation, cell debris was discarded by centrifuging the tubes at 10,000\(\times\)\(g\) for 30 min at 4 \({}^{\circ}\)C. The clear supernatant was then used to evaluate the TOS and TAS levels using respective assay kits (Rel Assay). The TOS levels were assessed spectrophotometrically at 530 nm, correlating the color intensity to the oxidant quantity within each test group. The results were calibrated using H\({}_{2}\)O\({}_{2}\) and expressed in terms of umol H\({}_{2}\)O\({}_{2}\) equivalent per liter [44; 45]. TAS levels were determined by assessing the reducing ability of antioxidants against 2,2\({}^{\prime}\)-azino-bis(3-ethylbenzothazoline-6-sulfonic acid) (ABTS) at 660 nm, with outcomes expressed as mmol Trolox equivalent/L [44; 46]. Additionally, the OSI (Oxidative Stress Index) was derived by computing the TOS to TAS ratio using the following formula: OSI = TOS (umol H\({}_{2}\)O\({}_{2}\) equivalent/L) divided by TAS (umol Trolox equivalent/L) [47]. Determination of the Effect of Alkaloid Extracts on Paraoxanase-1 (PON1), Superoxide Dismutase (SOD), Catalase (CAT), and Glutathione Peroxidase (GPx) Enzyme Levels in PC-12 Cells Induced by OS with H\({}_{2}\)O\({}_{2}\)  
The supernatant was prepared as outlined in Section 2.7. The levels of enzymes PON1, ARE, SOD, CAT, and GPx were measured using their respective kits: PON1 (Rel Assay),ARE (Rel Assay), SOD (FineTest, Boulder, Colorado, USA), CAT (FineTest), and GPX (FineTest), in line with the instructions provided by the manufacturers. PON1 activity was evaluated based on the increase in absorbance at 412 nm at 25 \({}^{\circ}\)C, which results from the formation of \(p\)-nitrophenol. The rate of paraoxon hydrolysis was used for this assessment.