About 29% of the planet Earth is covered by land
having vast biodiversity. From which a
very high population belongs to plants and
microorganisms. Plants are essential member of
diversity with various uses. Of the 2, 50,000 higher
plant species present, more than 80,000
are medicinal plants Joy P. P., et al., 1998. The
medicinal properties of the plant are
determined by the presence of certain
phytochemicals. These phytochemicals incurs the plant
with its characteristic colour, flavour, odour which
are part of defence system of the plant.
Phytochemicals are bioactive, non-nutrients
compounds in fruits, vegetables, grains and other
parts of the plant. These compounds (eg.
isoflavones, anthocyanins, and flavonoids) serves as
photoprotectants as they have the ability to repel
other harmful organisms Pandya k., et al.,
Nanoparticles have a surprisingly long history.
Proteins, polysaccharides, viruses among
others are the organic nanoparticles occurring
naturally whereas iron oxyhydroxides, metals
are examples of inorganic nanoparticles. The
inorganic nanoparticles are produced due to
weathering, volcanic eruptions or microbial
processes. This is how we know that
nanoparticles have been existing in nature for a
long time and not just produced in the
laboratories by modern synthesis Heiligtag F.C. and
Niederberger M., 2013.
Its history dates back to the 9th Century
in Mesopotamia, the artisans used nanoparticles to
generate a glittery effect on the surface of pots.
This lustre over pots was due to a metallic
film that was placed over its surface. This lustre
is seen due to the presence of silver and
copper nanoparticles present in the film. The
nanoparticles were made by adding cooper and
silver salts and oxides together with vinegar, ochre
and clay on the surface of the pot Dr.
Mandal A., 2014.
In nature variety of nanomaterials are synthesised
naturally by biological processes. For
example, the magneto tactic bacteria synthesis
interacellular magnetite or greigite
nanocrystallites, diatoms synthesises siliceous
materials and s-layer bacteria produces
gypsum and calcium carbonate layers R. Nithya and
R. Ragunathan, 2009.