Endophytic Fungi 116.2.3. Steroids
Many steroids are produced by endophytes, but most of the isolated
compounds showed moderate antimicrobial activities. Along with ergosterol,
3β,5α,6β-trihydroxyergosta-7,22-diene; 3β-hydroxyergosta- 5 - ene; 3 -
oxoergosta-4,6,8, 22 - tetraene; 3β-hydroxy-5α,8α-epidioxyergosta-6,22-diene;
3β-hydroxy-5α,8α-epidioxyergosta-6,9, 22 - triene and 3-oxoergosta- 4 - ene, two
new steroids, 3β,5α-dihydroxy-6β-acetoxyergosta-7,22-diene and 3β,5α-
dihydroxy-6β-phenyl- acetoxyergosta-7,22-diene were characterized from the
liquid culture of an fungal endophyte Colletotrichum sp. of Artemisia annua.
Some of these metabolites were shown to be antifungal against some crop
pathogens Gaeumannomyces graminis var. tritici, Rhizoctonia cerealis,
Helminthosporium sativum and Phytophthora capisici (Lu et al., 2000; Yu et
al., 2010).
6.2.4. Terpenoids
Sesquiterpenes, diterpenoids and triterpenoids are the major terpenoids
isolated from endophytes (Yu et al., 2010). In period of 2006-2010, sixty five
sesquiterpenes, fourty five diterpenes, five monoterpenes and twelve other
terpenes, amounting to 127 terpenoids were isolated from endophytic fungi
and all have biological activity such as anti-microbial, anti-cancer and anti-
protozoa (Souza et al., 2011).
Three novel eremophilane-type sesquiterpenes were isolated from the
endophyte Xylaria sp. associated with Licuala spinosa. The three compounds,
eremophilanolide 1, 2 and 3 exhibited moderate cytotoxic activity with IC 50
values of 3.8– 21 μM against cancer cell lines KB, MCF-7, and NCI-H187
(Isaka et al., 2010). Two ent-eudesmane sesquiterpenes, ent-4(15)-eudesmen-
11 - ol- 1 - one and ent-4(15)-eudesmen-1R, 11-diol were isolated from the
endophytic fungus Eutypella sp. BCC 13199 from the plant Etlingera littoralis
(Earth ginger) (Isaka et al., 2009). Four cytotoxic sesquiterpene compounds, 8-
deoxytrichothecin, trichothecolone, 7α-hydroxytrichodermol and 7α-
hydroxyscirpene, were isolated from fungal isolate KLAR 5, a mitosporic
Hypocreales found in a healthy twig of the Thai medicinal plant Knema
laurina. Also, tauranin, merulin A and C, sesquiterpene compounds, were
isolated from endophytic fungi with cytotoxic activity (Kharwar et al., 2011).
Two insect toxins of a pimarane diterpene framework were isolated from
the broth of an unidentified endophyte from a needle of the balsam fir Abies
balsamea (Tan and Zou, 2001). Subglutinol A and B, immunosuppressive but
noncytotoxic, were produced by Fusarium subglutinans, an endophytic fungus
from the perennial twining vine Tripterygium wilfordii (Lee et al., 1995).