338
than 3300 antibiotics and other bioactive compounds. Marine sponges have always
been organisms of antimicrobial research interest since the discovery of pharmaceutically important nucleosides spongothymidine and spongouridine in the early
1950s (Heider et al. 2010; Min et al. 1998). In addition to the nucleoside molecules,
various types of compounds isolated form marine sponges have also shown to have
therapeutic properties. These include fatty acids, sterols, alkaloids, peptides, amino
acid derivatives, etc. (Laport et al. 2009; Sagar et al. 2010). A myriad of compounds
of therapeutic interest is isolated from sponges that are active against both bacteria
and fungi. These fall under various chemical groups such as alkaloids, terpenes,
cyclical compounds, etc. (Perdicaris et al. 2013). Alkaloids isolated from marine
sponges Agelas mauritiana and Lotrochota purpurea (halogenated) exhibited antibacterial and antifugal properties (Shen et al. 2012; Yang et al. 2012), while cyclic
compounds isolated from the Haliclona sp. showed antibacterial activity against
Gram positive strains (Lee et al. 2012). Diterpenes and pentacyclic ingamine alkaloids isolated from various marine sponges were found to have antimalarial activity
(Chanthathamrongsiri et al. 2012; Ilias et al. 2012). One of the psammaplysin derivatives (19-hydroxypsammaplysin E) identified from the Indonesian marine sponge
Aplysinella strongylata also showed promising antimalarial activity (Mudianta
et al. 2012). Research was focused more toward control of HIV and compounds
such as clathsterol, dehydrofurodendin, crambescidin, mirabamides, etc. isolated
from various marine sponges were found to be very effective anti-HIV molecules.
Clathsterol and dehydrofurodendin act against HIV by inhibiting the reverse transcriptase enzyme while crambescidin and mirabamides act by inhibiting HIV-1
envelop fusion with host cells (Chang et al. 2003; Shoshana et al. 1999; Plaza et al.
2007; Rudi et al. 2001). Microspinosamide, petrosins, and neamphamide were also
proved to be active against this deadly virus (Oku et al. 2004; Rashid et al. 2001;
Venkateshwar Goud et al. 2003).
Cnidaria is another phylum which needs to be explored well for antimicrobial
compounds. As this group of organisms are very diverse and known to have developed defense mechanisms to combat pathogenic microbes in the sea, the possibility
of them producing therapeutically important compounds would be high. Efforts for
identification of compounds from cnidarians began after the discovery of prostaglandins from corals in the late 1960s. Soft corals are promising sources of bioactive compounds as they rely on chemical substances for defending themselves from
microbial attack, while the bony corals seem to have developed other mechanisms.
Ceramideas from Lobophytum crassum (Vanisree and Subbaraju 2002) and desoxyhavannahine from Xenia macrospiculata (Kelman et al. 2006) are examples of antimicrobial compounds isolated from soft corals.
Molluscs are another interesting group of organisms under the radar of scientists
in search of novel antimicrobials. Development of potential antibacterial drugs were
suggested from the findings in the late 1990s that the egg capsule extract of the
gastropod Rapana rapiformis exhibited significant activity against bacterial pathogens (Amruthalakshmi and Yogamoorthi 2015). Recent findings of broad spectrum
antibacterial effect of whole body extracts of Nerita albicilla and N. oryzarum and
egg mass extracts of Chicoreus virgineus and C. ramosus underscore the importance
Lini Nirmala and D.P. Zyju
than 3300 antibiotics and other bioactive compounds. Marine sponges have always
been organisms of antimicrobial research interest since the discovery of pharmaceutically important nucleosides spongothymidine and spongouridine in the early
1950s (Heider et al. 2010; Min et al. 1998). In addition to the nucleoside molecules,
various types of compounds isolated form marine sponges have also shown to have
therapeutic properties. These include fatty acids, sterols, alkaloids, peptides, amino
acid derivatives, etc. (Laport et al. 2009; Sagar et al. 2010). A myriad of compounds
of therapeutic interest is isolated from sponges that are active against both bacteria
and fungi. These fall under various chemical groups such as alkaloids, terpenes,
cyclical compounds, etc. (Perdicaris et al. 2013). Alkaloids isolated from marine
sponges Agelas mauritiana and Lotrochota purpurea (halogenated) exhibited antibacterial and antifugal properties (Shen et al. 2012; Yang et al. 2012), while cyclic
compounds isolated from the Haliclona sp. showed antibacterial activity against
Gram positive strains (Lee et al. 2012). Diterpenes and pentacyclic ingamine alkaloids isolated from various marine sponges were found to have antimalarial activity
(Chanthathamrongsiri et al. 2012; Ilias et al. 2012). One of the psammaplysin derivatives (19-hydroxypsammaplysin E) identified from the Indonesian marine sponge
Aplysinella strongylata also showed promising antimalarial activity (Mudianta
et al. 2012). Research was focused more toward control of HIV and compounds
such as clathsterol, dehydrofurodendin, crambescidin, mirabamides, etc. isolated
from various marine sponges were found to be very effective anti-HIV molecules.
Clathsterol and dehydrofurodendin act against HIV by inhibiting the reverse transcriptase enzyme while crambescidin and mirabamides act by inhibiting HIV-1
envelop fusion with host cells (Chang et al. 2003; Shoshana et al. 1999; Plaza et al.
2007; Rudi et al. 2001). Microspinosamide, petrosins, and neamphamide were also
proved to be active against this deadly virus (Oku et al. 2004; Rashid et al. 2001;
Venkateshwar Goud et al. 2003).
Cnidaria is another phylum which needs to be explored well for antimicrobial
compounds. As this group of organisms are very diverse and known to have developed defense mechanisms to combat pathogenic microbes in the sea, the possibility
of them producing therapeutically important compounds would be high. Efforts for
identification of compounds from cnidarians began after the discovery of prostaglandins from corals in the late 1960s. Soft corals are promising sources of bioactive compounds as they rely on chemical substances for defending themselves from
microbial attack, while the bony corals seem to have developed other mechanisms.
Ceramideas from Lobophytum crassum (Vanisree and Subbaraju 2002) and desoxyhavannahine from Xenia macrospiculata (Kelman et al. 2006) are examples of antimicrobial compounds isolated from soft corals.
Molluscs are another interesting group of organisms under the radar of scientists
in search of novel antimicrobials. Development of potential antibacterial drugs were
suggested from the findings in the late 1990s that the egg capsule extract of the
gastropod Rapana rapiformis exhibited significant activity against bacterial pathogens (Amruthalakshmi and Yogamoorthi 2015). Recent findings of broad spectrum
antibacterial effect of whole body extracts of Nerita albicilla and N. oryzarum and
egg mass extracts of Chicoreus virgineus and C. ramosus underscore the importance
Lini Nirmala and D.P. Zyju