It is estimated that there are 250,000 to 500,000 species of plants on Earth. A relatively small percentage (1 to 10%) of these are used as foods by both humans and other animal species. It is possible that even more are used for medicinal purposes. In the first century A.D., Dioscorides wrote De Materia Medica, a medicinal plant catalog which became the prototype for modern pharmacopoeia
We have two reasons to be interested in the topic of antimicrobial plant extracts. First, it is very likely that these phytochemicals will find their way into the arsenal of antimicrobial drugs prescribed by physicians; several are already being tested in humans. It is reported that, on average, two or three antibiotics derived from microorganisms are launched each year. After a downturn in that pace in recent decades, the pace is again quickening as scientists realize that the effective life span of any antibiotic is limited. Worldwide spending on finding new anti-infective agents. New sources, especially plant sources, are also being investigated.
Second, the public is becoming increasingly aware of problems with the overprescription and misuse of traditional antibiotics. In addition, many people are interested in having more autonomy over their medical care. A multitude of plant compounds (often of unreliable purity) is readily available over-the-counter from herbal suppliers and natural-food stores, and self-medication with these substances is commonplace. The use of plant extracts, as well as other alternative forms of medical treatments, is enjoying great popularity in the late 1990s.
MAJOR GROUPS OF ANTIMICROBIAL COMPOUNDS FROM PLANTS
Plants have an almost limitless ability to synthesize aromatic substance, most of whict are phenols or their oxygen-substituted derivatives. Most are secondary metabolites. in many cases, these substance serve as plant defense mechanisms againt predation by microorganisms, insect and herbivores. some , such as terpenoids give plants their odors; other like quinones and tannins are respnsiblefor plant pigmen. useful antimicrobial phytochemicals can be divided into several categories, Phenolics and Polyphenols, Terpenoids and essential olis, Alkaloids, Lectin and Polypeptides
Cowan. 1999. Plant Product as Antimicrobial Agent. Clin.Microbiol.Rev. 12: 564-582
We have two reasons to be interested in the topic of antimicrobial plant extracts. First, it is very likely that these phytochemicals will find their way into the arsenal of antimicrobial drugs prescribed by physicians; several are already being tested in humans. It is reported that, on average, two or three antibiotics derived from microorganisms are launched each year. After a downturn in that pace in recent decades, the pace is again quickening as scientists realize that the effective life span of any antibiotic is limited. Worldwide spending on finding new anti-infective agents. New sources, especially plant sources, are also being investigated.
Second, the public is becoming increasingly aware of problems with the overprescription and misuse of traditional antibiotics. In addition, many people are interested in having more autonomy over their medical care. A multitude of plant compounds (often of unreliable purity) is readily available over-the-counter from herbal suppliers and natural-food stores, and self-medication with these substances is commonplace. The use of plant extracts, as well as other alternative forms of medical treatments, is enjoying great popularity in the late 1990s.
MAJOR GROUPS OF ANTIMICROBIAL COMPOUNDS FROM PLANTS
Plants have an almost limitless ability to synthesize aromatic substance, most of whict are phenols or their oxygen-substituted derivatives. Most are secondary metabolites. in many cases, these substance serve as plant defense mechanisms againt predation by microorganisms, insect and herbivores. some , such as terpenoids give plants their odors; other like quinones and tannins are respnsiblefor plant pigmen. useful antimicrobial phytochemicals can be divided into several categories, Phenolics and Polyphenols, Terpenoids and essential olis, Alkaloids, Lectin and Polypeptides
Cowan. 1999. Plant Product as Antimicrobial Agent. Clin.Microbiol.Rev. 12: 564-582
