## 4 Discussion  
Recent advances in pharmacognostics have revealed that a wide range of bioactive compounds are present in medicinal herbs. Of these, phytochemical studies have identified numerous volatile compounds (e.g., gernal and neral), polyphenolic compounds (e.g., rosmarinic acid, luteolin, and naringin), and terpenoids (e.g., unsolic acid) in lemon balm [5]. Similarly, numerous polyphenolic compounds (e.g., chicoric acid, chlorogenic acid, luteolin, and isorhamnetin), terpenoids (e.g., taraxacinic acids), and alkaloids (e.g., taraxacine and taraxafolin) have been isolated from the aerial parts of dandelion [8]. The vast majority of antioxidant and anti-inflammatory activities of herbs are attributed to the presence of polyphenols. Two such compounds, rosmarinic acid and chicoric acid are both enriched in lemon balm and dandelion [6,22] and are effectively solubilized in MLD (e.g., 34.07 \(\pm\) 0.55 mg/g rosmarinic acid and 2.26 \(\pm\) 0.01 mg/g chicoric acid) [23]. Because it has been reported that the aforementioned polyphenolic compounds can attenuate oxidative stress-mediated liver injury [24, 25, 26, 27, 28, 29], not only the presence of these polyphenols but also other unidentified compounds in MLD may collaboratively contribute to protect the liver against CCl\({}_{4}\)-induced acute liver damage. Further studies are warranted to elucidate the major bioactive compounds in MLD. The results presented here indicated that MLD synergistically prevented CCl\({}_{4}\)-mediated increases in hepatocyte degeneration characterized by ballooning, fatty vacuole formation, and eosinophil cell death. In addition, MLD significantly reduced the serum activities of ALT and AST that were released from injured hepatocytes into the bloodstream, suggesting that MLD protects hepatocytes from CCl\({}_{4}\)-mediated acute injury effectively. Although centrilobular necrosis of hepatocytes has been identified as the predominant form of pathological death induced by CCl\({}_{4}\)[30], other types of programmed cell death (e.g., pyproptosis, necroptosis, and apoptosis) are also associated with CCl\({}_{4}\)-induced liver injury [16, 25, 31, 32]. Mitochondria, core subcellular organelles for the activation of the intrinsic apoptotic pathway, are the primary organelles targeted by CCl\({}_{4}\). Exposure to CCl\({}_{4}\) has been shown to downregulate mitochondrial membrane potential and promote the opening of transition pores, leading to the release of Ca\({}^{2+}\) and membrane proteins (e.g., cytochrome c) into the cytoplasm, thereby facilitating the cleavage of initiator caspases through the activation of the apoptosome complex [30,32]. In addition, it has been reported that CCl\({}_{4}\) activates the death receptor-dependent extrinsic apoptotic pathway by increasing the expression of Fas, Fas ligand, and the Fas-associated death domain in the liver [33,34]. Cleavage of executor caspases (e.g., caspase-3) caused by the activation of both apoptotic pathways facilitates the disruption of the nuclear envelope, inactivation of DNA repair enzymes (e.g., PARP), and fragmentation of chromosomes [35]. Although the effects of MLD on other types of cell death will require further study, the results presented here showing that MLD decreased the number of cleaved caspase-3- and cleaved PARP-positive cells in the hepatic tissues provide clear evidence that MLD-dependent hepatic protection from CCl\({}_{4}\) can be attributed to the inhibition of apoptosis. CCI\({}_{4}\) absorbed by hepatocytes is primarily metabolized by cytochrome P450 2E1, producing trichloromethyl and trichloromethylperoxyl radicals in the process, which in turn accelerates lipid peroxidation by extracting hydrogen from polyunsaturated fatty acids [30]. Among the major oxidation products, 4-hyroxynonenal preferentially reacts with thiol-containing redox signaling proteins, resulting in mitochondrial dysfunction via the inactivation of mitochondrial ATPase [36].