16 Afra Khiralla, Rosella Spina, Sakina Yagi et al.
isolated from at least three endophytes genera including Fusarium,
Nothapodytes, Neurospora (Zhao et al., 2010; Amna et al., 2006).
However, around six genera of endophytic fungi: Alternaria,
Fusarium, Monilia, Penicillium, Phialocephala, Trametes were found
to be capable to produce podophyllotoxin, the potent compound with
anticancer, antiviral, antioxidant, antibacterial, immunostimulation
and anti-rheumatic activities. In addition, this compound has been
used as a precursor for chemical synthesis of the anticancer drugs like
etoposide, teniposide and etopophose phosphate (Zhao et al., 2010).
2) Endophytes from plants with ethnobotanical history might have
interesting biological activities. Yu et al., (2010) screened the
presence of endophytes and revealed antimicrobial agents into
medicinal plants and different plants in special environments
frequently. They found that 35% of endophytes which were isolated
from the medicinal plants had an antimicrobial activity, 29% from
crops, while 18% from plants in special environment. However,
Strobel and Daisy (2003) pointed out also the significance of plants in
special environments. For example, Strobel et al., (1999a) studied an
aquatic plant Rhyncholacis penicillat collected from a river system in
Southwest Venezuela. They postulated that, aquatic environment
created many portals through which common phytopathogenic
oomycetes could enter into the plant. Still, the plant population
appeared to be healthy, possibly due to protection from an endophytic
product. Eventually, an endophytic fungus Serratia marcescens which
recovered from R. penicillat founded to produce oocydin A a potent
antioomycetous compounds.
3) The diversity of the biological activities could be obtained by the
same fungal endophyte strain isolated from different medicinal plants,
increasing the opportunities to isolate a plenty of new compounds.
Added to that, the various natural products produced by endophytic
fungi possess unique structures, thus representing a huge reservoir
which offers an enormous potential for exploitation in agricultural and
industrial areas (Tan and Zou, 2001).
4) Bioprospecting from endophytic fungi and their natural products is
one avenue for the discovery of novel pharmaceuticals. A great
number of novel compounds were isolated from endophytes
possessing several potent properties including antioxidant, anticancer,
antimicrobial, antifungal and antiviral activities (Strobel and Daisy,
2003; Huang et al., 2007; Kharwar et al., 2011; Yu et al., 2010).
Table 1 presents a summary of some isolated bioactive agents from
endophytic fungi associated with medicinal plants.