Bioproduction of diosgenin in callus cultures of Balanites aegyptiaca:: Effect of growth regulatorsi explants and somatic embryogenesis

This study describes the effects of plant growth regulators, explants, and somatic embryogenesis on in vitro production of the steroidal sapogenin, diosgenin, in callus cultures of the Balanites aegyptiaca (L.) Del.(desert date). Root, shoot, hypocotyl, and epicotyl callus culture of B. aegyptiaca, were raised on MS basal media supplemented with various combinations of either 2,4-D and NAA alone, or with BAP. The diosgenin content (on a dry weight basis) was found to be highest when calli were cultured in MS basal medium supplemented with 1.0 mg 1(-1) 2,4-D alone and/or in combination with 0.5 mg 1(-1) BAP. However, the callus growth was highest in media supplemented with 2.5 or 3.0 mg 1(-1) 2,4-D. MS basal media supplemented with 2,4-D 2.5 mg 1(-1) alone and in combination with 0.5 mg 1(-1), BAP induced pre-embryogenic callus formation on root cultures. When these pre-embryogenic callus cultures were used to establish cell suspension cultures, two growth densities were obtained in embryogenic suspension cultures, inducing clusters of somatic embryos at various stages of development. The maximum number of somatic embryos were obtained at the fifth week on the medium supplemented with 1.0 mg 1(-1) 2,4-D. However, the diosgenin content in these somatic cells was found to be lower compared to the explant calluses. This study revealed that production of diosgenin in callus cultures of B. aegyptiaca is possible, but the amount is significantly affected by the growth regulators, type of explants, and somatic embryogenesis.