فهرست مطالب rezvan ramezannezhad

Lactuca undulata Ledeb. is a medicinal plant belonging to the Asteraceae family. Chicoric acid is one of the main derivatives of caffeic acid, with various pharmacological and biological properties. This study was conducted to optimize cell suspension culture and enhance chicoric acid production in L. undulata by eliciting secondary metabolites using silver nitrate (AgNO3) and silver nanoparticles (AgNPs). Seeds were cultured on ½ MS medium to produce sterile seedlings. In order to produce callus, leaf and root explants were obtained from 2 months old sterile seedlings and placed on ½ MS medium containing 2 mg/L 2,4-D/ plus 0.5 mg/L Kin and 2 mg/L 2,4-D/ plus 2 mg/L Kin, respectively. Cell suspension cultures from leaf and root-derived calluses were established and treated with different concentrations (0, 2, and 4 mg/L) of AgNO3 and AgNPs during the logarithmic growth phase. Then cells were harvested after 24, 48, and 72 hours. Overall, elicitation by AgNPs was more effective on chicoric acid production compared to AgNO3. The highest amounts of chicoric acid (9.7 ± 0.48 mg/g DW) and caffeic acid (15.3 ± 0.8 mg/L) were found in leaf and root cell suspension cultures after 48 hours of exposure to 4 and 2 mg/L AgNPs, respectively. In contrast, 4 mg/L of AgNO3 stimulated the greatest accumulation of chlorogenic acid (4.56 ± 0.3 mg/g DW) in root cell culture at 72 h after elicitation. The current results revealed that the use of AgNPs can be an efficient strategy to improve cichoric acid accumulation in cell suspension culture.

As a valuable industrial compound, cichoric acid has antiviral, antioxidant, and anti-inflammatory properties. It is effectively used in obesity prevention and for neuroprotective purposes. Here, we aimed to compare the effects of plant growth regulators and UV-B radiation on the induction of cichoric acid production under tissue culture conditions. For this purpose, Lactuca undulata, an herbaceous medicinal plant, was used as a new source of cichoric acid. Leaf explants were initially cultured on ½ MS (Murashige and Skoog) medium containing 0.1, 1 mg/L Kinetin (Kin) and 2,4-Dichlorophenoxyacetic acid (2,4-D). The callus was then exposed to different UV-B exposure times (0, 20, 40, and 60 min) and was harvested after 5, 10, and 15 days. The highest amounts of total phenol, cichoric acid, chlorogenic acid, and caffeic acid were achieved in callus samples that were treated with 20 and 40 minutes of UV-B radiation for 10 days. Cichoric acid content reached an amount of 6.15±0.292 mg/g DW after 20 min of radiation. Pearson’s correlation coefficient analysis (PCC) showed that Phenylalanine Ammonia Lyase (PAL) activity did not correlate with the production of caffeic acid derivatives. These results suggested that UV-B irradiation can be used as an elicitor to induce the production of cichoric acid in Lactuca undulata callus cultures.

Echinacea purpurea belongs to the family of Asteraceae which has different medicinal properties. The main goal of current research was optimization of callus induction and biomass production by using Response Surface Method (RSM). For this purpose, root and leaf explants were cultured in the ½ MS medium supplemented with different concentrations (0, 1 and 2 mg/L) of Kin either alone or with 2,4-D and NAA. Also, callus production and biomass were considered as dependent variable and different concentrations of plant growth regulators were used as optimizing parameters. Meanwhile Central Composite Design was used for optimization of callus production parameters. Correlation analysis of regression model determined a polynomial second degree which used for optimizing of callus induction and biomass production. The obtained data showed that both root and leaf explants produced callus in all investigated treatments. But the highest amount of callus induction and biomass production was achieved in leaf derived callus in medium containing 1.05 and 0.94 mg/L NAA and Kin, respectively. On the other hand, the maximum fresh weight was obtained in leaf derived callus in medium supplemented with 1.07 and 1.15 mg/L 2,4-D and Kin. The current results were almost in consistency with predicted data. The fit model was suitable and RSM was successful for optimization of callus induction and biomass production.