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Abstract
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Silver birch (Betula pendula Roth) is a medicinally important woody plant. This plant produces a range of biologically active terpenoids such as betulin and betulinic acid. These triterpenes have been used for their medicinal properties. Recent clinical studies have shown that betulin was effective against a variety of tumors [1, 2]. The biotechnological techniques for the production of terpenoids using cell cultures, is a good strategy to enhance the yield of these natural compounds. The objective of the present study was to evaluate effect of different concentration of chlorocholine chloride and exposure time on the cell culture and growth index. In this research cell cultures of B. pendula was established on NT-based medium [3] with hormonal concentration of 2.5 mg L-1 2,4-D and 0.5 mg L-1 BAP. Then the effect of chlorocholine chloride (with final concentration 0, 0.5, 1, 2 and 3 mg L-1) on cell suspension cultures was investigated. chlorocholine chloride was added to the 8-day-old cell cultures and cell growth, betulin and betulinic acid content were monitored at 1, 2, 3, 5 and 7 days after feeding. The results showed that cell viability in the fed cells were decreased compared to controls. Also maximum increase in growth index was obtained on the 5 days after feeding with 0.5 mg L-1 chlorocholine chloride. The accumulation of betulinic acid in cells 3 days after feeding by 2 mg L-1 chlorocholine chloride was increased about 1.7- fold (3 mg g-1 DW) compared to controls. Moreover, betulin accumulation was enhanced 7 days after feeding by 2 mg L-1 chlorocholine chloride about 149.3-fold (19.4 mg g−1 DW). In conclude, although the low concentration of chlorocholine chloride (0.5 mg L-1) was resulted the highest increased cell growth but interestingly, betulin production can be increased by high concentration of chlorocholine chloride (2 mg L-1).
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