62 Khaled A. Selim, Mohamed M. S. Nagia and Dina E. El. Ghwas
professor Peter Proksch (Xu et al., 2009). Recently a new coumarine, 4, 6-
dihydroxy- 7 - formyl- 3 - methylcoumarin (20) was isolated from the endophyte
Pestalotiopsis versicolor along with other known compounds (Yang et al.,
2015).
Novel metabolite has the isocoumarin nucleus with uncommon
substitution pattern, namely (4S)-(+)-ascochin (21) from Ascochyta sp was
isolated in 2007. Associated with Meliotus dentatus its absolute configuration
was confirmed by integration of X-ray diffraction and solid state TDDFT CD
(Krohn et al., 2007).
From the herbaceous plant Fagonia cretica associated endophyte
Microdochium bolleyi three Monocerin related isocoumarins were isolated
compounds (22-24). Compound (24) is considered as an open ring analogue
(Zhang et al., 2008). The absolute configuration of these compounds was
identified by modified Mosher’s method (Ohtani and Mosher, 1991).
A number of isocoumarins and isocoumarin derivatives had been isolated
from endophytic fungi associated with mangrove plants. (3R, 4S)-6, 8-
dihydroxy-3, 4, 7-trimethylisocoumarin (25) was isolated from Penicillium sp.
091402 in 2009 (Han et al., 2009). From Cephalosporium sp., a novel
prenylated dihydroisocoumarin was identified as 5-(3'-methylbut-2'-enyloxy)-
3, 4-dihydro 8-hydroxy- 3 - methylisochromen- 1 - one (26) (Wei et al., 2010).
Recently six new isocoumarin derivatives representative compounds are
shown (27-28) were isolated from Talaromyces amestolkiae YX1 along with
another nine previously reported compounds. Two of these compounds
showed antibacterial effects against different strains of bacteria and four
exhibited α-glucosidase inhibitory activity (Chen et al., 2016). Their absolute
configuration was assigned using modified Mosher’s method (Ohtani and
Narisada, 1991).
The dihydroisocoumarin (3R, 4R)-3,4-dihydro-4,6-dihydroxy- 3 - methyl- 1 -
oxo-1H-isochromene- 5 - carboxylic acid (29) was isolated from Xylaria sp., a
fungus associated with Piper aduncum (Piperaceae) was proved to have
antifungal and acetyl cholinesterase (AChE) inhibitory activities in vitro
(Oliveira et al., 2011). Tenuissimasatin (30) is a new dihydroisocoumarin
produced by the endophytic fungus Alternaria tenuissima Wiltshire isolated
from the bark of Erythrophleum fordii Oliver (Fang et al., 2012). Figure (4)
summarize the diversity of coumarins and isocoumarins derivatives isolated
from endophytic fungi (structures from 18-30).