817-825 In the present investigation an attempt has
been made to enhance rosmarinic acid level in plants, grown<i style="mso-bidi-font-style:
normal"> in vitro, of
2 species of Mentha in presence of 2
precursors in the nutrient media during culture. For <i style="mso-bidi-font-style:
normal">in vitro culture establishment and shoot bud multiplication, MS
basal media were used supplemented with different concentrations and
combinations of different growth regulator like NAA (α-napthaleneacetic acid),
BAP (6-benzylaminopurine). The medium containing NAA (0.25 mg/L) and BAP (2.5
mg/L) gave the highest potentiality of shoot formation (average 58.0 numbers of
shoots) per explant for Mentha piperita
L. and the medium containing BAP (2.0 mg/L) gave the highest potentiality of
shoot (average 19.2 numbers of shoots) formation per explant for Mentha arvensis L. The complete plants
were regenerated in above mentioned media after 8 weeks of subculture. For in vitro enhancement of rosmarinic acid
production, the 2 precursors tyrosine (Tyr) and phenylalanine (Phe) were added
in the nutrient media at different levels (0.5 mg/L to 15.0 mg/L). Tyrosine was
found to be very effective for augmenting rosmarinic acid content in Mentha piperita L. It nearly increased the production up to 1.77 times. In case of Mentha arvensis L., phenylalanine significantly affected the production of rosmarinic
acid and the production was nearly 2.03 times more than the control. No
significant increase in biomass was observed after addition of these precursors
indicating that the added amino acids acting as precursors for rosmarinic acid
synthesis were readily utilized in producing rosmarinic acid without promoting
growth. Total protein profile also revealed the presence of a specific band in
polyacrylamide gel electrophoresis