336
metabolites that make them ideal candidates in drug-screening programs
(Manivasagan et al. 2013). Extensive research on marine flora led to the discovery
of novel genera of actinomycetes (Claverias et al. 2015), adding to the diversity of
potential bioactive compounds. Efforts are being taken to cultivate marine flora
(Joint et al. 2010) which would certainly make the screening process easy due to the
easy availability of samples.
Wide array of secondary metabolites produced by the cyanobacteria (blue green
algae) are interesting candidates of pharmaceutical importance due to their selective
activity against various types of organisms including bacteria, fungi, and viruses
(Lopes et al. 2010). Cyanobactins are small cyclic peptides produced by cyanobacteria. Some of the cyanobactins are reported to have antimalarial activity (Sivonen
et al. 2010). Another metabolite Viridamide A, obtained from a blue green algae of
genus Oscillatoria, showed antitrypanosomal and antileishmanial activity with IC
50 as low as <2 μM in both cases (Simmons et al. 2008b).
Due to their abundance, great species diversity, and rich secondary metabolites,
marine fungi hold an important position as a source of antimicrobial compounds
(Swathi et al. 2013; Xu et al. 2015). Sansalvamide A isolated from Fusarium sp.
showed inhibitory effect on topoisomerase enzyme. This compound was found to be
active against pox virus Molluscum contagiosum that causes pink rashes in humans
(Hwang et al. 1999). Zofimarin and griseofulvin are antifungal agents isolated from
marine fungi Zopfiella marina and Penicillium waksmanii, respectively (Mayer
et al. 2013; Pietra 1997). Compounds isolated from marine fungi are diverse. They
have not only antifungal and antiviral properties but antibacterial (e.g., pestalone
and sumiki’s acid), antihelminthic (e.g., nafuredin), and antimalarial (e.g., aigialomycin D and halorosellinic acid) activities too (Bugni and Ireland 2004; Overy et al.
2014). Zopfiellamides A and B are two compounds identified to have antimicrobial
activities during the early 2000s (Daferner et al. 2002). A number of novel compounds are still being identified, e.g., fumigaclavine (antifungal) from Penicillium
viridicatum, 3-phenyl-2-propenoic acid, cyclo-(Phe-Pro) and cyclo-(Val-Pro) (antibacterial) from Cladosporium sp., 6-methoxyspirotryprostatin B (antiparasitic)
from Aspergillus fumigatus, and nodulisporacid A (antiplasmodial) from
Nodulisporium sp., etc. (Swathi 2013).
Marine algae comprise a diverse group of organisms classified into two major
categories based on their size – microalgae and macroalgae. Microalgae are small
photosynthetic organisms that could be seen only with the help of a microscope.
These tiny organisms are shown to have antibiotic, antimycotic, and antiviral properties (Patterson et al. 1994). Macroalgae, commonly called seaweeds, include
members of red, green, and brown algae. Crude preparations of marine algae have
traditionally been used against diseases due to iodine deficiency, intestinal disorders, etc. (El Gamal 2010). A polyunsaturated fatty acid, eicosapentaenoic acid
(EPA), isolated from a diatom (a type of microalga) was effective against a range of
both Gram positive and Gram negative bacteria including methycillin-resistant
Staphylococcus aureus (MRSA) (Desbois et al. 2009). The viral infections that
microalgae are active against include viral hemorrhagic septicaemia virus (VHSV)
and African swine fever virus (ASFV) (Fabregas et al. 1999). A number of
Lini Nirmala and D.P. Zyju
metabolites that make them ideal candidates in drug-screening programs
(Manivasagan et al. 2013). Extensive research on marine flora led to the discovery
of novel genera of actinomycetes (Claverias et al. 2015), adding to the diversity of
potential bioactive compounds. Efforts are being taken to cultivate marine flora
(Joint et al. 2010) which would certainly make the screening process easy due to the
easy availability of samples.
Wide array of secondary metabolites produced by the cyanobacteria (blue green
algae) are interesting candidates of pharmaceutical importance due to their selective
activity against various types of organisms including bacteria, fungi, and viruses
(Lopes et al. 2010). Cyanobactins are small cyclic peptides produced by cyanobacteria. Some of the cyanobactins are reported to have antimalarial activity (Sivonen
et al. 2010). Another metabolite Viridamide A, obtained from a blue green algae of
genus Oscillatoria, showed antitrypanosomal and antileishmanial activity with IC
50 as low as <2 μM in both cases (Simmons et al. 2008b).
Due to their abundance, great species diversity, and rich secondary metabolites,
marine fungi hold an important position as a source of antimicrobial compounds
(Swathi et al. 2013; Xu et al. 2015). Sansalvamide A isolated from Fusarium sp.
showed inhibitory effect on topoisomerase enzyme. This compound was found to be
active against pox virus Molluscum contagiosum that causes pink rashes in humans
(Hwang et al. 1999). Zofimarin and griseofulvin are antifungal agents isolated from
marine fungi Zopfiella marina and Penicillium waksmanii, respectively (Mayer
et al. 2013; Pietra 1997). Compounds isolated from marine fungi are diverse. They
have not only antifungal and antiviral properties but antibacterial (e.g., pestalone
and sumiki’s acid), antihelminthic (e.g., nafuredin), and antimalarial (e.g., aigialomycin D and halorosellinic acid) activities too (Bugni and Ireland 2004; Overy et al.
2014). Zopfiellamides A and B are two compounds identified to have antimicrobial
activities during the early 2000s (Daferner et al. 2002). A number of novel compounds are still being identified, e.g., fumigaclavine (antifungal) from Penicillium
viridicatum, 3-phenyl-2-propenoic acid, cyclo-(Phe-Pro) and cyclo-(Val-Pro) (antibacterial) from Cladosporium sp., 6-methoxyspirotryprostatin B (antiparasitic)
from Aspergillus fumigatus, and nodulisporacid A (antiplasmodial) from
Nodulisporium sp., etc. (Swathi 2013).
Marine algae comprise a diverse group of organisms classified into two major
categories based on their size – microalgae and macroalgae. Microalgae are small
photosynthetic organisms that could be seen only with the help of a microscope.
These tiny organisms are shown to have antibiotic, antimycotic, and antiviral properties (Patterson et al. 1994). Macroalgae, commonly called seaweeds, include
members of red, green, and brown algae. Crude preparations of marine algae have
traditionally been used against diseases due to iodine deficiency, intestinal disorders, etc. (El Gamal 2010). A polyunsaturated fatty acid, eicosapentaenoic acid
(EPA), isolated from a diatom (a type of microalga) was effective against a range of
both Gram positive and Gram negative bacteria including methycillin-resistant
Staphylococcus aureus (MRSA) (Desbois et al. 2009). The viral infections that
microalgae are active against include viral hemorrhagic septicaemia virus (VHSV)
and African swine fever virus (ASFV) (Fabregas et al. 1999). A number of
Lini Nirmala and D.P. Zyju