**1.6 Uses and benefits of medicinal plants for medicine**

Previous studies by researchers on medicinal plants have claimed that plants have been used for medicine about 60 thousand years ago, which paved the way for more discoveries of medicinal plants [83]. The use of medicinal plants for medication is progressively becoming a primary type of medication, mainly in tropical and underdeveloped countries. Medicinal plant utilisation has been adopted to prevent infectious diseases and avoid death in humans. Whereas, inadequate application of these plants may cause resistance to bacteria, resulting in the antibiotic crisis, along with the limited development of novel molecules [84].

The medicinal applications have been conducted with aid of some medicinal plants. For example, stevia extracts were used as intravenous infusions in rats to reveal their effect on glucose metabolism, diuresis, organ weights, and endocrine function anti-androgenic activity. Stevia extracts have shown some health benefits since they serve as antioxidants and blood pressure and hypertension reducers [85]. The Monarda plant acts against pathogenic and microbial spoilage of food and promotes health. Examples of such organisms that this plant attacks include; Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, and others Salmonella typhimurium or Pseudomonas aeruginosa [86, 87].

Medicinal leaf extracts have antibacterial and fungicidal properties, with an inhibitory effect on the growth of such bacteria as S. aureus, Streptococcus mutants, Bacillus subtilis, and E. coli [88]. Stevia's antihypertensive, anti-inflammatory, anticancer, antidiarrheal, diuretic, and immunomodulatory properties have been shown to this extent [70]. Rhodiola plant extracts are utilised traditionally in tonics and adaptogens and are incorporated in antidepressant and anti-inflammatory drugs [89, 90].
