**5. Conclusions**

This study shows that plant cells produce a variety of compounds, mainly secondary metabolites, for defense mechanisms against bacteria, fungi, antioxidants, and cancer. Secondary metabolites with antibacterial, antifungal, antioxidant, and anticancer effects are sources of natural bioactive molecules, which control diseasecausing pathogens in plants and humans. In addition, the different plant families have shown a unique combination of secondary metabolites; therefore, exhibiting different antibacterial, antifungal, antioxidant, and anticancer activities. The emerging research on identifying secondary metabolites is ongoing, and further research is encouraged to advance our knowledge about these compounds. Secondary metabolites can help treat infectious diseases that have increased resistance to current antibiotics. They can offer alternative medical therapy to individuals, particularly in developing nations where people may not access health care.
