The Management of Infectious and Chronic Diseases
Novel Bioactive Phytocompounds Against Multidrug-Resistant Bacteria/Fungi:
The Management of Infectious and Chronic Diseases
Long before the discovery of the existence of microbes, the idea that certain plants
had healing potential, indeed, that they contained what we would currently charac-
terize as antimicrobial principles, was well accepted. Since antiquity, humans have
used plants to treat common infectious diseases, and some of these traditional
medicines are still included as part of the habitual treatment of various maladies.
For example, the use of bearberry (Arctostaphylos uva-ursi) and cranberry juice (Vac-
cinium macrocarpon) to treat urinary tract infections is reported in different manu-
als of phytotherapy, while species such as lemon balm (Melissa officinalis), garlic
(Allium sativum), and tee tree (Melaleuca alternifolia) are described as broad-spec-
trum antimicrobial agents. That being said, it has generally been the essential oils
of these plants rather than their extracts that have had the greatest use in the treat-
ment of infectious pathologies in the respiratory system, urinary tract, gastrointes-
tinal, and biliary systems, as well as on the skin. In the case of Melaleuca alternifolia,
for example, the use of the essential oil (tee tree oil) is a common therapeutic
tool to treat acne and other infectious troubles of the skin.
Antimicrobial resistance is one of the biggest challenges facing global public
health. Although antimicrobial drugs have saved many lives and eased the suffer-
ing of many millions, poverty, ignorance, poor sanitation, hunger and malnutri-
tion, inadequate access to drugs, poor and inadequate health care systems, civil
conflicts and bad governance in developing countries have tremendously limited
the benefits of these drugs in controlling infectious diseases. The development of
resistance in the responsible pathogens has worsened the situation, often with very
limited resources to investigate and provide reliable susceptibility data on which
rational treatments can be based as well as the means to optimize the use of anti-
microbial agents. The emergence of multidrug-resistant isolates in tuberculosis,
acute respiratory infections, and diarrhea, often referred to as the diseases of pov-
erty, has had its greatest toll in developing countries. The epidemic of HIV/AIDS,
with over 30 million cases in developing countries, has greatly enlarged the popu-
lation of immunocompromised patients. The disease has left these patients at
great risk of numerous infections and even greater risk of acquiring highly resist-
ant organisms during long periods of hospitalization.
Antibiotic resistance can occur via three general mechanisms: prevention of
interaction of the drug with target, efflux of the antibiotic from the cell, and direct
1.5 Novel Bioactive Phytocompounds Against Multidrug-Resistant Bacteria/Fungi 17
destruction or modification of the compound. The emergence of multidrug resis-
tance in human and animal pathogenic bacteria as well as undesirable side-effects
of certain antibiotics has triggered immense interest in the search for new antimi-
crobial drugs of plant origin.
Ahmad and Beg [41] tested alcoholic extracts of 45 traditionally used Indian me-
dicinal plants against drug-resistant bacteria and fungi (C. albicans) both related to
the critical prognosis and treatment of infectious diseases in immunocomprom-
ised, AIDS and cancer patients. Of these, 40 plant extracts showed varied levels of
antimicrobial activity against one or more test bacteria. Anticandidal activity was
detected in 24 plant extracts. Overall, broad-spectrum antimicrobial activity was ob-
served in 12 plants (L. inermis, Eucalyptus sp., H. antidysentrica, H. indicus, C. equi-
stifolia. T. belerica, T. chebula, E. officinalis, C. sinensis, S. aromaticum and P. grana-
tum). Several other studies have also demonstrated the importance of new bioac-
tive phytocompounds against multidrug-resistant bacteria/fungi.
Useful antimicrobial phytochemicals can be divided into several categories sum-
marized in Table 1.1. Scientists from divergent fields are investigating plants anew
with an eye to their antimicrobial usefulness. A sense of urgency accompanies the
search as the pace of species extinction continues. Laboratories of the world have
found literally thousands of phytochemicals which have inhibitory effects on all
types of microorganisms in vitro. More of these compounds should be subjected to
animal and human studies to determine their effectiveness in whole-organism sys-
tems, including in particular toxicity studies as well as an examination of their ef-
fects on beneficial normal microbiota. It would be advantageous to standardize
methods of extraction and in vitro testing so that the search could be more system-
atic and interpretation of results facilitated. Also, alternative mechanisms of infec-
tion prevention and treatment should be included in initial activity screenings. Dis-
ruption of adhesion is one example of an anti-infection activity not commonly
screened currently. Attention to these issues could usher in a badly needed new era
of chemotherapeutic treatment of infection by using plant-derived principles.
Novel Bioactive Phytocompounds Against Multidrug-Resistant Bacteria/Fungi:
The Management of Infectious and Chronic Diseases
Long before the discovery of the existence of microbes, the idea that certain plants
had healing potential, indeed, that they contained what we would currently charac-
terize as antimicrobial principles, was well accepted. Since antiquity, humans have
used plants to treat common infectious diseases, and some of these traditional
medicines are still included as part of the habitual treatment of various maladies.
For example, the use of bearberry (Arctostaphylos uva-ursi) and cranberry juice (Vac-
cinium macrocarpon) to treat urinary tract infections is reported in different manu-
als of phytotherapy, while species such as lemon balm (Melissa officinalis), garlic
(Allium sativum), and tee tree (Melaleuca alternifolia) are described as broad-spec-
trum antimicrobial agents. That being said, it has generally been the essential oils
of these plants rather than their extracts that have had the greatest use in the treat-
ment of infectious pathologies in the respiratory system, urinary tract, gastrointes-
tinal, and biliary systems, as well as on the skin. In the case of Melaleuca alternifolia,
for example, the use of the essential oil (tee tree oil) is a common therapeutic
tool to treat acne and other infectious troubles of the skin.
Antimicrobial resistance is one of the biggest challenges facing global public
health. Although antimicrobial drugs have saved many lives and eased the suffer-
ing of many millions, poverty, ignorance, poor sanitation, hunger and malnutri-
tion, inadequate access to drugs, poor and inadequate health care systems, civil
conflicts and bad governance in developing countries have tremendously limited
the benefits of these drugs in controlling infectious diseases. The development of
resistance in the responsible pathogens has worsened the situation, often with very
limited resources to investigate and provide reliable susceptibility data on which
rational treatments can be based as well as the means to optimize the use of anti-
microbial agents. The emergence of multidrug-resistant isolates in tuberculosis,
acute respiratory infections, and diarrhea, often referred to as the diseases of pov-
erty, has had its greatest toll in developing countries. The epidemic of HIV/AIDS,
with over 30 million cases in developing countries, has greatly enlarged the popu-
lation of immunocompromised patients. The disease has left these patients at
great risk of numerous infections and even greater risk of acquiring highly resist-
ant organisms during long periods of hospitalization.
Antibiotic resistance can occur via three general mechanisms: prevention of
interaction of the drug with target, efflux of the antibiotic from the cell, and direct
1.5 Novel Bioactive Phytocompounds Against Multidrug-Resistant Bacteria/Fungi 17
destruction or modification of the compound. The emergence of multidrug resis-
tance in human and animal pathogenic bacteria as well as undesirable side-effects
of certain antibiotics has triggered immense interest in the search for new antimi-
crobial drugs of plant origin.
Ahmad and Beg [41] tested alcoholic extracts of 45 traditionally used Indian me-
dicinal plants against drug-resistant bacteria and fungi (C. albicans) both related to
the critical prognosis and treatment of infectious diseases in immunocomprom-
ised, AIDS and cancer patients. Of these, 40 plant extracts showed varied levels of
antimicrobial activity against one or more test bacteria. Anticandidal activity was
detected in 24 plant extracts. Overall, broad-spectrum antimicrobial activity was ob-
served in 12 plants (L. inermis, Eucalyptus sp., H. antidysentrica, H. indicus, C. equi-
stifolia. T. belerica, T. chebula, E. officinalis, C. sinensis, S. aromaticum and P. grana-
tum). Several other studies have also demonstrated the importance of new bioac-
tive phytocompounds against multidrug-resistant bacteria/fungi.
Useful antimicrobial phytochemicals can be divided into several categories sum-
marized in Table 1.1. Scientists from divergent fields are investigating plants anew
with an eye to their antimicrobial usefulness. A sense of urgency accompanies the
search as the pace of species extinction continues. Laboratories of the world have
found literally thousands of phytochemicals which have inhibitory effects on all
types of microorganisms in vitro. More of these compounds should be subjected to
animal and human studies to determine their effectiveness in whole-organism sys-
tems, including in particular toxicity studies as well as an examination of their ef-
fects on beneficial normal microbiota. It would be advantageous to standardize
methods of extraction and in vitro testing so that the search could be more system-
atic and interpretation of results facilitated. Also, alternative mechanisms of infec-
tion prevention and treatment should be included in initial activity screenings. Dis-
ruption of adhesion is one example of an anti-infection activity not commonly
screened currently. Attention to these issues could usher in a badly needed new era
of chemotherapeutic treatment of infection by using plant-derived principles.
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