Plants in addition to primary metabolites produce secondary metabolites
which are of immense pharmaceutical importance and other industrial uses. Secondary
metabolites are produced due to the stress experienced by plants in response to external
triggers/agents like elicitors. Elicitation involves two types of elicitors namely biotic
and abiotic. Elicitors have a vital role in plant tissue culture as these improve secondary
metabolite content in cultures. Other culture conditions including volume and types of
medium, duration, etc., also affect the yield of alkaloids. Extensive research has been
carried out for the enhanced level of alkaloids in in vitro cultured plants. Various
common elicitors used in media are methyl jasmonate (MeJA), yeast extract (YE),
fungal extract, ions from various salts like CdCl2, heavy metal ions, and ionic, nonionic
radiations, etc. The fungal cell wall components oligosaccharides and peptides have
also been used as elicitors for the induction/enhancement of secondary metabolites in
plant cell/organ cultures. The influence of sample representation of biotic and abiotic
elicitors, i.e., YE, Aspergillus flavus, MeJA, CdCl2
, CaCl2
, has been discussed taking a
few medicinals and oil yielding plants from authors’ laboratory. A direct link of stress
with elicitors including plant growth regulators (PGRs) has been established showing
over accumulation of proline, protein, SOD, APX and other antioxidant enzyme
activity with increased levels of elicitation. Increasing demand forces researchers to
conduct further investigation in this area for the production of phyto-compounds and
even for viable commercial exploitation.
Keywords: Alkaloids, Catharanthus roseus, Colchicum luteum, Colchicine, Elicitor.
