Principles of phytochemicals | Antimicrobial ability against multidrug resistant pathogens

 Principles of phytochemicals | Antimicrobial ability against pathogens 

1.1 Introduction - 

Phytochemicals are chemical compounds found in medicinal plants that have different functions, such as deterring herbivores and inhibiting the growth of bacterial or fungal pathogens. While these active principles may provide health benefits, they are not essential nutrients that the human body requires for survival in the same way as vitamins and minerals. 

Nevertheless, these secondary plant products play a crucial role in the use of medicinal plants for therapeutic purposes.

Phytochemicals are responsible for the characteristic colors, tastes, and smells of fruits, vegetables, and herbs.

Phytochemicals are also believed to play a significant role in plant defense mechanisms against pathogens, herbivores, and other environmental stresses.

In recent years, phytochemicals have gained considerable attention for their potential health benefits, including their antimicrobial activity against multidrug-resistant pathogens.

1.2 Multidrug-resistant pathogens -

Multidrug-resistant pathogens are Microorganisms such as bacteria, fungi, or viruses that have become resistant to multiple drugs or classes of drugs(Antimicrobial agent). This resistance can be acquired through genetic mutations, horizontal gene transfer, or selective pressure from the overuse of antibiotics. Multidrug-resistant pathogens are a major concern for public health, as they pose a significant threat to the effective treatment of infectious diseases.

1.2.1 Here is a list of some of the most common MDR pathogens:

• Methicillin-resistant Staphylococcus aureus (MRSA)
• Vancomycin-resistant Enterococcus (VRE)
• Extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae (such as E. coli and Klebsiella)
• Carbapenem-resistant Enterobacteriaceae (CRE)
• Acinetobacter baumannii
• Pseudomonas aeruginosa
• Mycobacterium tuberculosis (MDR-TB)
• Candida auris (an emerging fungal pathogen with multidrug resistance)

These MDR pathogens pose a significant threat to public health, as they are associated with increased morbidity, mortality, and healthcare costs. Effective management of these infections requires a multidisciplinary approach, including infection prevention and control measures, antimicrobial stewardship, and the development of new antimicrobial agents

1.3 Principles or constituents (phytochemicals) - 

Phytochemicals are chemical compounds found in plants that are not essential nutrients, but have been shown to provide health benefits. Here are some general principles of phytochemicals:

• They are naturally occurring compounds found in plants, including fruits, vegetables, and herbs.

• They are not considered essential nutrients required for survival, but they have been shown to provide health benefits and may play a role in disease prevention.

• They can have a variety of functions, including acting as antioxidants, anti-inflammatory agents, and antimicrobial agents.

• The amount and type of phytochemicals present in a plant can vary based on factors such as the plant species, growing conditions, and harvesting methods.

• Phytochemicals can be extracted from plants and used in dietary supplements or pharmaceuticals.

• Consumption of a diverse range of plant foods has been associated with health benefits, which may be due in part to the presence of phytochemicals.

These are some general principles of phytochemicals, but the specific properties and functions of individual phytochemicals can vary widely.

1.3.1 Classification of phytochemicals (secondary metabolites) -

• Alkaloids
• Glucosinolates
• Terpene polymers
• Monoterpenes
• Diterpenes
• Triterpenes cardiac glycosides
• Sesquiterpenes
• Sterols
• Phenolic acids
• Coumarins
• Lignans
• Flavonoids
• Tennins
• Lignin

1.4 Antimicrobial ability of phytochemicals against pathogens -

The antimicrobial activity of phytochemicals is based on their ability to disrupt various cellular processes and structures in bacteria, fungi, and viruses. Phytochemicals can inhibit bacterial growth by damaging the cell membrane or cell wall, disrupting energy metabolism, inhibiting DNA synthesis, and interfering with protein synthesis. Additionally, some phytochemicals can stimulate the immune system, making it more effective in fighting infections.


Fortunately, phytochemicals have shown promising antimicrobial activity against multidrug-resistant pathogens. Some of the most effective phytochemicals against multidrug-resistant pathogens include alkaloids, flavonoids, phenolic acids, terpenes, and essential oils. These phytochemicals have been shown to inhibit the growth of multidrug-resistant bacteria such as Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE), and multi-drug resistant Pseudomonas aeruginosa.

1.4.1 For example -

• The phytochemicals found in tea tree oil have been shown to have antimicrobial activity against multidrug-resistant strains of Staphylococcus aureus and Escherichia coli. 
• Similarly, berberine, a plant alkaloid found in plants such as goldenseal and Oregon grape, has been shown to have antimicrobial activity against multidrug-resistant strains of bacteria, including MRSA and VRE.

Phytochemicals that possess antimicrobial activity against various microorganisms, including multidrug-resistant (MDR) pathogens.

 1.4.2 Here are some examples of phytochemicals that have been shown to work against MDR pathogens:

• Allicin: 

A phytochemical found in garlic that has been shown to possess broad-spectrum antimicrobial activity against various microorganisms, including MDR bacteria such as methicillin-resistant Staphylococcus aureus (MRSA).

• Curcumin: 

A phytochemical found in turmeric that has been shown to possess potent antimicrobial activity against various microorganisms, including MDR pathogens such as Pseudomonas aeruginosa and Acinetobacter baumannii.

• Berberine: 

A phytochemical found in goldenseal and barberry that has been shown to possess antimicrobial activity against various microorganisms, including MDR bacteria such as E. coli and Klebsiella pneumoniae.

• Epigallocatechin gallate (EGCG): 

A phytochemical found in green tea that has been shown to possess antimicrobial activity against various microorganisms, including MDR bacteria such as MRSA.

• Resveratrol: 

A phytochemical found in grapes and red wine that has been shown to possess antimicrobial activity against various microorganisms, including MDR bacteria such as Staphylococcus aureus and Escherichia coli.

• Quercetin:

 A phytochemical found in onions and apples that has been shown to possess antimicrobial activity against various microorganisms, including MDR bacteria such as MRSA.

• Ursolic acid:

 A phytochemical found in herbs such as rosemary and thyme that has been shown to possess antimicrobial activity against various microorganisms, including MDR bacteria such as Staphylococcus aureus and Escherichia coli.

These are just some examples of phytochemicals that have been studied for their antimicrobial activity against MDR pathogens. Further research is needed to fully elucidate the potential of phytochemicals as antimicrobial agents against MDR pathogens

1.5 Conclusion - 

In conclusion, phytochemicals are a diverse group of naturally occurring compounds that have shown promising antimicrobial activity against multidrug-resistant pathogens. The use of phytochemicals as an alternative or complementary therapy for infectious diseases may provide new options for the effective treatment of multidrug-resistant infections. Further research is needed to fully understand the mechanisms of action and potential applications of phytochemicals in the treatment of infectious diseases.

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