Plant Products as Antimicrobial Agents

INTRODUCTION .......................................................................................................................................................564 Brief History ............................................................................................................................................................565 MAJOR GROUPS OF ANTIMICROBIAL COMPOUNDS FROM PLANTS ...................................................565 Phenolics and Polyphenols ....................................................................................................................................565 Simple phenols and phenolic acids ..................................................................................................................565 Quinones ..............................................................................................................................................................568 Flavones, flavonoids, and flavonols ..................................................................................................................568 Tannins.................................................................................................................................................................569 Coumarins............................................................................................................................................................571 Terpenoids and Essential Oils..............................................................................................................................571 Alkaloids...................................................................................................................................................................572 Lectins and Polypeptides .......................................................................................................................................572 Mixtures ...................................................................................................................................................................572 Other Compounds...................................................................................................................................................573 EXPERIMENTAL APPROACHES...........................................................................................................................573 Extraction Methods ................................................................................................................................................573 Efficacy......................................................................................................................................................................574 In vitro experiments ...........................................................................................................................................574 (i) Bacteria and fungi.....................................................................................................................................574 (ii) Viruses .......................................................................................................................................................574 (iii) Protozoa and helminths .........................................................................................................................575 In vivo testing of phytochemicals .....................................................................................................................575 Clinical trials in humans...................................................................................................................................575 PLANTS WITH EFFICACY AGAINST HUMAN IMMUNODEFICIENCY VIRUS.........................................577 COMMERCIAL AVAILABILITY AND SAFETY OF COMPOUNDS.................................................................577 CONCLUSIONS AND FUTURE DIRECTIONS....................................................................................................577 ACKNOWLEDGMENTS ...........................................................................................................................................577 REFERENCES ............................................................................................................................................................577