## 4 Discussion  
The extraction of bioactive compounds, such as phenols, from natural products or plant material is influenced by their method of extraction, chemical structure, and the time and conditions of storage [44]. A growing number of studies show that most medicinal plants exhibit antioxidant and anticancer properties due to the presence of chemical components. Antioxidants protect against infections  
Figure 8: Apoptosis-related genes were upregulated by _Pyracantha_ and _Paullinia_ in cancer cells. (**A**-**G**) Detection of the mRNA expression levels of _Casp3_, _Casp7_, _BAX_, _Cytc_, _p53_, _Puma_, and _Parp_ in HEPG2 cells treated with two different concentrations (40 or 320 \(\upmu\)g-mL-1) of _Pyracantha_ and _Paullinia_ after 72 h. *\(p<0.05\); **\(p<0.01\); ***\(p<0.001\). Non-significance is denoted as ns. Untreated samples were used as controls for all tested plant extracts. Figure 9: Determination of phytochemical components and antioxidant activity in _Pyracantha_ and _Paullinia_ extracts. Analysis of phenolic compounds (**A**), flavonoids (**B**), and antioxidant scavenging activity (**C**) in _Pyracantha_ and _Paullinia_ extracts. (**D** and **E**) Intracellular reactive oxygen species (ROS) levels in HEPG2 cancer cells following treatment with _Pyracantha_ and _Paullinia_ extracts at the indicated concentrations. (**F**) qPCR analysis of _CAT_ and _SOD2_ (_MnSOD_) antioxidant levels in HEPG2 cancer cells following treatment with _Pyracantha_ and _Paullinia_ extracts at the indicated concentrations. *\(p<0.05\); **\(p<0.01\); ***\(p<0.001\). and disease in humans by neutralizing the effects of free radicals. In particular, phenols possess a structural component for free radical scavenging and thus have antioxidant potential [45; 46]; as a result, phenols have attracted considerable interest in the field of medicine. Many research studies have proven the antioxidant and anticancer potential of several natural plant extracts in a wide variety of human systems and animal models with relevance to disease [47]. Extracted phenolic compounds show strong protective effects via anti-inflammatory, anti-mutagenic, and anticancer activities [48]. Free radicals play a key role in a wide range of cellular processes by damaging proteins and DNA, leading to many fatal diseases, including cancer [49; 50]. Antioxidants can be used for effectively inhibiting cellular proliferation, promoting cell apoptosis, inhibiting gene expression, enhancing detoxification enzymes, and scavenging ROS. Thus, by suppressing oxidative stress and free radicals, phenols and flavonoids promote the amelioration of DNA damage, decreasing the amount of abnormal cell division [51]. In this way, many antioxidant-rich plants exhibit anticancer potential [52; 53]. Antioxidants, particularly polyphenols, have been demonstrated as promising agents that can delay cancer initiation and progression [54]. It is believed that flavones may exert their anticancer effects via several possible mechanisms, such as the alteration of cancer cell signaling pathways, removal of carcinogenic agents, antioxidant enzymatic actions, cell cycle arrest, and induction of apoptosis [55]. Most of the anticancer properties correlated with flavanols are supposed to be facilitated by the flavanol epigallocatechin gallate, which has been revealed to prevent cancer cell growth by modifying the expression of cyclin proteins involved in the cell cycle, as well as the activity of cellular signaling proteins involved in proliferation and transformation [56]. In our study, most of the tested medicinal plant extracts protected against breast carcinoma and hepatocellular carcinoma-induced cytotoxicity at a higher concentration (320 \(\upmu\)g\(\cdot\)mL\({}^{-1}\)). However, _Pyracantha_ and _Paullinia_ showed the maximum level of inhibition against two different cancer cell types (Figures 2 and 3). It is worth mentioning that both these extracts had no toxic effects on the normal counterparts of the cancer cells, as confirmed in mammary epithelial MCF10A cells (Figure 4).