الفهرس 
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Abstract
In this study seeds of Balanites aegyptiaca L. were germinated in vitro and shoots were cut to obtain internode segments and leaves each alone to use as explants. These explants were cultured on MS medium supplemented with different concentrations (0.0, 0.25, 0.5, 1.0 or 2.0 mg/l) of 2,4-D or NAA in order to induction of calls. After six weeks fresh weight of callus (g), antioxidant activity (%), content of total flavonoids (mg QE/g extract) and yield (mg QE), content of total phenolic compounds (mg gallic acid/g extract) and yield (mg gallic acid) as well as total saponins content (mg/g) and yield (mg) were determined. Internode segments (the best explant type) was cultured on MS medium supplemented with 2 mg/l 2,4-D (the best treatment for callus growth and secondary metabolites production) combined with some precursors i.e.; phenylalanine, tryptophan, glutamine or peptone at different concentrations (0, 5, 10, 20 or 40 mg/l) or some elicitors i.e.; chitosan (0, 5, 10, 20 or 40 mg/l), yeast extract (0.00, 0.25, 0.50, 1.0, 2.0 or 4.0 g/l), salicylic acid (0, 5, 10, 20 or 40 mg/l) or methyl jasmonate (0, 1, 2, 4 or 8 mg/l) in order to induction of calls and improving secondary metabolites production and accumulation. After six weeks, the abovementioned parameters were recorded. The obtained results showed that inoculation of internode segments on MS medium supplemented with 2,4-D at 2.0 mg/l recorded the ultimate values of the abovementioned parameters. Also, results proved that in most cases the maximum values of callus fresh weight and active ingredients (antioxidant activity as %, total flavonoids, total phenolic compounds and total saponins contents and yields) were recorded by supplementation the medium with the highest concentration of each precursor compound alone, except peptone which the lowest concentration (5 mg/l) recorded the highest values of most active ingredients. Concerning the impact of elicitors, our findings demonstrate that in most cases the maximum total flavonoids, total phenolic compounds and total saponins contents and yields were belonged to the highest concentration of each elicitor alone. Among different tested elicitors, salicylic acid surpassed all other elicitor concerning antioxidant activity (%) as well as total flavonoids and total phenolic compounds contents and yields. While, the ultimate total saponins content and yield were discovered when medium was fortified with the highest concentration of yeast extract or salicylic acid each alone. Overall evaluation of the above-mentioned results shows that glutamine at the highest concentration (40 mg/l) seems to be the most effective treatment for improving callus growth and secondary metabolites production.