68 Khaled A. Selim, Mohamed M. S. Nagia and Dina E. El. Ghwas
Penicillium sp. as endophytic fungi found commensalistic with higher
plants and marine algae are considered an interesting source of new natural
compound and metabolites belonging to different chemical classes among
which steroids are of great importance. Penicisteroids A (47) and B (48) are
two novel highly oxygenated steroids with uncommon structure contains
tetrahydroxy and C- 16 - acetoxy groups. They were isolated from the
Penicillium chrysogenum isolated from red algae (Gao et al., 2011). From the
same species found associated to the traditional Chinese herb Huperzia serrata
three new steroids possess a unique C 25 steroid with a bisnor C-atom side
chain, namely norcyclocitrinol A (49), erythro-11α-hydroxyneocyclocitrinol
(50) and pseudocyclocitrinol A (51) (Ying et al., 2014). Related structures
were isolated very recently in 2016 from another Penicillium sp. from
Saccharum arundinaceum for example, erythro- 23 - O-Methylneocyclocitrinol
(52) and its threo- isomer (Deng et al., 2016). Penicillium sp. GD6 derived
from Chinese mangrove Bruguiera gymnorrhiza produced a novel acetylated
steroid (53) (Zhou et al., 2014b). Very recently in 2016, Penicillium sp. from
Saccharum arundinaceum produced novel steroids with the unprecedented C 25
structure.
Other species contribute also to the production of steroids from
endophytes. Globosterol (54) is a polyhydroxylated C 29 steroid. It was firstly
reported from Chaetomium globosum isolated from Ginkgo biloba along with
already identified ergosterol derivative (Qin et al., 2009). Three novel steroids
designated as ergosta-5, 7, 22-trienol (55), 5α, 8α-epidioxyergosta-6, 22-dien-
3β-ol (56) and ergosta-7, 2 2 - dien-3β,5α,6β-triol (57) were identified from the
culture extracts of Pichia guilliermondii derived from the medicinal plant
Paris polyphylla along with one nordammarane triterpenoid (Zhao et al.,
2010). Culture broth of Phomopsis sp. isolated from Aconitum carmichaeli
contained two novel steroids, namely (14β, 22E)-9, 14-dihydroxyergosta-4, 7,
22 - triene-3, 6-dione (58) and (5α, 6β, 15β, 22E)- 6 - ethoxy-5, 1 5-
dihydroxyergosta-7, 22-dien- 3 - one (59) their antifungal activity was screened
(Wu et al., 2013). Figure (7) summarizes the diversity of steroidal metabolites
isolated from endophytic fungi (structures from 44-59).
10.6. Terpenoids
Terpenoids are a large group of organic natural products formed by the
assembly of a number of C 5 isoprene units. Arisugacins I (60) and J (61) are
two novel compounds belonging to the subgroup meroterpenoids that were