Endophytic Fungi 15Several other compounds belonging to different chemical classes have
been reported such as: aldehydes, chromones, cyclohexanones, esters,
lactones, xanthones (Kharwar et al., 2011).
7. SIGNIFICANCE OF ENDOPHYTES ASSOCIATED
WITH MEDICINAL PLANTS
Many of the pharmaceuticals currently available to physicians have a long
history of use as herbal remedies, including opium, aspirin, digitalin, and
quinine. According to World Health Organization (WHO) estimation, 80% of
the population of some Asian and African countries presently use herbal
medicine for some aspect of primary health care (Alves and Rosa, 2007). In
recent years a lot of efforts have been employed to identify novel molecules
derived from natural sources that exhibit a range of clinical and
pharmacological activities. This thus led to an extensive research on organic
substances synthesized by various plants and microorganisms, growing in
diverse habitats and displaying a range of habit. Endophytic fungi of medicinal
plants are considered as an attractive source of novel bioactive compounds.
This ability is of great importance, it provides an alternative strategy for
reducing the need to harvest slow growing and possibly rare plants, also help
to preserve the world’s ever diminishing biodiversity. Moreover, the
production of a high value phytochemical by exploiting a microbial source is
easier and more economical and it leads to increased availability and the
reduced market price of the product (Strobel et al., 2004). The significance of
endophytic fungi associated with medicinal plants spouts from different
approaches:
1) Some endophytes produce the same natural products as their host
plants (Tan and Zou, 2001; Strobel and Daisy, 2003). Such is the case
of paclitaxel-producing fungus, Taxomyces andreanae, from the yew
Taxus brevifolia (Stierle et al., 1993). At least nineteen genera of
endophytic fungi (Alternaria, Aspergillus, Botryodiplodia, Botrytis,
Cladosporium, Ectostroma, Fusarium, Metarhizium, Monochaetia,
Mucor, Ozonium, Papulaspora, Periconia, Pestalotia, Pestalotiopsis,
Phyllosticta, Pithomyces, Taxomyces, Tubercularia) were screened to
have the ability to produce paclitaxel and its analogues (Zhao et al.,
2010). Alternaria sp. an endophyte vinblastine-producing was isolated
from Catharanthus roseus (Guo et al., 1998). Camptothecin was