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Rodrigues and Samuels (1999) reported
the endophytic fungi
Colletotrichum gloe-
osporioides,
and
Guignardia
and
Phomopsis
species from leaf blades and bark of
Spondias mombin
collected from Pará and
Rio de Janeiro states of Brazil. Further, they
studied the antimicrobial activity of extract
of
Guignardia
sp.,
Phomopsis
sp. and
Pestalotiopsis guepinii
against pathogenic
bacteria. Rodrigues
et al.
(2000) reported
endophytic
Guignardia
and
Phomopsis
spe-
cies and
Pestalotiopsis guepinii
isolated
from
S. mombin
. They screened for com-
pounds with antimicrobial activity on actin-
omycetes, Gram-negative, Gram-positive
bacteria, yeast and filamentous fungi. Lv
et al.
(2010) isolated endophytic species of
Cylindrocarpon, Phoma
and
Fusarium
from
Saussurea involucrata
. They also studied
antimicrobial activity of these fungi against
pathogenic microorganisms. Guimaraes
et al
. (2008) recovered endophytes from
Viguiera arenaria
and
Tithonia diversifolia.
Moreover, they screened their antimicro-
bial, antiparasitic and anti-tumour activity.
antioxidants. Tejesvi
et al.
(2008) isolated
endophytic
Pestalotiopsis
species from
Terminalia arjuna, Terminalia chebula,
Azadirachta indica
and
Holarrhena anti-
dysenterica
. Furthermore, they studied
antioxidant and antihypertensive activity
by measuring 1, 1-diphenyl-2-picrylhydrazyl
inhibitory activity, lipid peroxidation and
angiotensin-converting enzyme inhibition
activity. Endophytic
Xylaria
sp. isolated
from the medicinal plant
Ginkgo biloba
contains compounds showing antioxidant
activities (Liu
et al
., 2007). Kajula
et al
.
(2010) studied the extracellular production
of siderophore and antibacterial and anti-
oxidant compounds by endophytic fungi of
Scots pine (
Pinus sylvestris
L.) and Labrador
tea (
Rhododendron tomentosum
Harmaja).
Huang
et al
. (2007) observed that the anti-
oxidant capacities of the endophytic fungal
cultures were correlated with their total
phenolic contents, and suggested that phe-
nolics were also the major antioxidant con-
stituents of the endophytes. They also
suggested that some of the endophytes were
found to produce metabolites possessing
strong antioxidant activities. The authors
concluded that the metabolites produced
by a wide diversity of endophytic fungi in
culture can be a potential source of novel
natural antioxidants.
5.2.5 Mycoendophytes
and antioxidant activity
Antioxidant compounds in food play an
important role as a health-protecting factor.
Scientific evidence suggests that antioxi-
dants reduce the risk of chronic diseases
including cancer and heart disease. An anti-
oxidant is a molecule that inhibits the oxi-
dation of other molecules. Oxidation is a
chemical reaction that transfers electrons or
hydrogen from a substance to an oxidizing
agent. Oxidation reactions can produce free
radicals. In turn, these radicals can start
chain reactions. When the chain reaction
occurs in a cell, it can cause damage or
death to the cell. Antioxidants terminate
these chain reactions by removing free-radical
intermediates and inhibit other oxidation
reactions. Naturally occurring antioxidant
compounds are commonly found in vegeta-
bles, fruits and medicinal plants. It has
been observed, however, that endophytes
are also a potential source of novel natural
5.3
Future Perspectives
Some endophytes produce phytochemicals
that were originally thought of as characteris-
tic of the host plant. Genetic interaction or
horizontal gene transfer between the endo-
phyte and the host has occurred over evolu-
tionary time (Tan and Zou, 2001). This concept
was proposed to explain why
Taxomyces
andreanae
produces taxol. The cultured
endophytes can be induced to produce the
same rare and important bioactive com-
pounds as when associated with their host
plants. This would reduce the need to harvest
slow-growing and possibly rare plants. It
would also help to preserve the world's
ever-diminishing biodiversity. Furthermore, a
microbial source of a high-value product is
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