micro

R eview A r ticle

The Journal of Venomous Animals and Toxins including Tropical Diseases
ISSN 1678-9199 | 2010 | volume 16 | issue 3 | pages 402-413

Biological properties of medicinal plants: a review of their antimicrobial
activity
Silva NCC (1), Fernandes Júnior A (1)

(1) Department of Microbiology and Immunology, Botucatu Biosciences Institute, São Paulo State University (UNESP –Univ Estadual Paulista), Botucatu, São Paulo State, Brazil.

Abstract: Plants have been used for thousands of years to flavor and conserve food, to treat health
disorders and to prevent diseases including epidemics. The knowledge of their healing properties
has been transmitted over the centuries within and among human communities. Active compounds
produced during secondary vegetal metabolismare usually responsible for the biological properties of
some plant species used throughout the globe for various purposes, including treatment of infectious
diseases. Currently, data on the antimicrobial activity of numerous plants, so far considered empirical,
have been scientifically confirmed, concomitantly with the increasing number of reports on pathogenic
microorganisms resistant toantimicrobials. Products derived from plants may potentially control microbial
growth in diverse situations and in the specific case of disease treatment, numerous studies have aimed to
describe the chemical composition of these plant antimicrobials and the mechanisms involved in microbial
growth inhibition, either separately or associated with conventional antimicrobials. Thus, in the presentwork, medicinal plants with emphasis on their antimicrobial properties are reviewed.
Key words: medicinal plants, phytochemistry, antimicrobial activity, plant extracts, essential oils, synergism.

INTRODUCTION
The use of plants for treating diseases is as old
as the human species. Popular observations on the
use and efficacy of medicinal plants significantly
contribute to the disclosure oftheir therapeutic
properties, so that they are frequently prescribed,
even if their chemical constituents are not always
completely known. All over the globe, especially
in South American countries, the use of medicinal
plants has significantly supported primary health
care (1). From 250 to 500 thousand plant species
are estimated to exist on the planet, and only
between 1 and 10% are usedas food by humans
and other animals (2). Brazil has the world’s
highest biodiversity, accounting for over 20% of
the total number of known species. This country
presents the most diverse flora, with more than 55

thousand described species, which corresponds
to 22% of the global total. Such biodiversity is
followed by a wide acceptance of the medicinal
plant use (3). Most of theBrazilian population
(80%) consumes only 37% of the commercially
available drugs and depend almost exclusively
on medicines of natural origin (4). Thus,
phytotherapics entered the market promising
a shorter and cheaper production, since basic
requirements to use medicinal plants do not
involve strict quality control regarding safety and
efficacy compared to the other types of drugs (5).Infectious diseases represent an important
cause of morbidity and mortality among the
general population, particularly in developing
countries. Therefore, pharmaceutical companies
have been motivated to develop new antimicrobial
drugs in recent years, especially due to the

Silva NCC, Fernandes Júnior A. Biological properties of medicinal plants: a review of their antimicrobial activity

constantemergence of microorganisms resistant
to conventional antimicrobials. Apparently,
bacterial species present the genetic ability to
acquire and transmit resistance against currently
available antibacterials since there are frequent
reports on the isolation of bacteria that are known
to be sensitive to routinely used drugs and became
multiresistant to other medications available
on the...