الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Background: Plant tissue culture systems have provided a reliable and continuous source of plant pharmaceuticals. Cynara scolymus L. (Artichoke) has attracted the attention of various researchers due to its nutritional and therapeutic values. Method: The present study utilized tissue culture technique to modify the secondary metabolite profile of C. scolymus L. and studied the effect of different phytohormones and methyl jasmonate elicitation on C. scolymus culture regarding the accumulation of certain flavonoids, sesquiterpene lactones, lignans and phenolic acids using HPLC/UV analysis technique. In addition, the present study reported phytochemical investigation of the methylene chloride fraction of leaf extract of C. scolymus L. using ordinary chromatographic techniques. The structures of the isolated compounds were determined via spectroscopic analysis. Results: A new sesquiterpene lactone 4,11,13,15-tetrahydrocynaropicrin (H1-a) along with other four known compounds 11,13-dihydrocynaropicrin (H1-b), Cynarinin B sesquiterpene lactone (G6), Luteolin flavonoid (G5) and Pinoresinol lignan (H4) were isolated from fresh leaves of Cynara scolymus L. In addition, the present study reported a reliable protocol for in vitro callus induction of C. scolymus L. from leaves and bracts. In vitro culture of Cynara scolymus L. was induced from bracts and leaves, using different phytohormone combinations. The most suitable one was 1-naphthaleneacetic acid: 6-benzylaminopurine (NAA-BAP), 3:1 mg/L. Modification of different phytohormone combinations altered the profile of C. scolymus L. secondary metabolites. Rutin was recorded at 1.77 mg/g DW in leaf callus extract (not detected in cultivated leaves extract). After addition of 100 µM of methyl jasmonate (MeJA) as elicitor, 1.20 mg/g DW of cynarin was recorded in bract-derived callus and 1.18 mg/g DW in leaf-derived callus extract (not detected in cultivated leaves and bracts extracts). Leaf callus enriched with NAA-BAP (3:1 mg/L) showed more elevated levels of rutin, cynarin, cynaropicrin, and pinoresinol as compared to the cultivated artichoke. Moreover, elicitation of this callus by addition of 50 µM MeJA elevated luteolin, quercetin, cynarin, and chlorogenic acid levels relative to the initial callus. Higher Total Phenolics Content (TPC) was recorded in leaf and bract calluses compared to leaves and bracts of cultivated plants. Conclusion: In vitro callus culture along with MeJA elicitation can potentially enhance the profile and the production level of the biologically active phytochemicals of artichoke.