Detection of ginkgolide A in Ginkgo biloba cell cultures

Abstract

Ginkgo biloba cells were cultured in two 500 mL shake flasks and in 2 L and 6 L immobilization bioreactors using MS medium supplemented with 1 mg.L⁻¹ NAA, 0.1 mg.L⁻¹ K and 30 g.L⁻¹ sucrose. Specific growth rates were 0.06 d⁻¹, 0.11 d⁻¹ and 0.07 d⁻¹ for the 2 L and 6 L bioreactors and shake flask cultures, respectively. Extracellular phosphate, nitrate, ammonium and carbohydrate uptake rates of the bio reactor cultures were approximately 17 to 39% slower than those of shake flask cultures. The specific oxygen uptake and carbon dioxide transfer rates of immobilized Ginkgo biloba cells ranged from 0.027 to 0.041 mmol O₂.g⁻¹.d.w.hr⁻¹ (maximum uptake at 14 days) and 0.020 to 0.057 mmol CO₂g. ⁻¹.d.w.hr⁻¹ (maximum production at 14 days). Extracts from the biomass of the two immobilized and shake flask suspension cultures were analysed for ginkgolide A by GC-MS. Yields of 7, 17, 19 and 7 ng.g. ⁻¹d.w. of ginkgolide A were determined for shake flask 1, shake flask 2 and the 2 L and 6 L immobilized cultures, respectively. Traces of ginkgolide B were detected with the signal to noise ratio, however, being too low for positive confirmation of this last product.