Effect of various composition of medium on antioxidants and antioxidation capacity in sweet potato (Ipomoea batatas Lam.) suspension culture

[[abstract]]Sweet potatoes (Ipomoea batatas L.) are rich in dietary fibre, minerals, vitamins, and antioxidants, such as phenolic acids, anthocyanins, tocopherol and β-carotene. Besides acting as antioxidants, carotenoids and phenolic compounds also provide sweet potatoes with their distinctive flesh colours. In this research, by changing growth hormone, cytokines, sucrose, iron ions and organic nitrogen concentration, the changes of phenol, flavonoid contents and the anti-oxidation ability were studied. Because the total phenolic compounds and flavonoid contents from the cells in B5 suspension culture were higher than the ones from MS medium, the B5 medium was used as base medium for further studies. Results show that increasing content of sucrose and KNO3 in the medium resulted in significant improvement of total phenolic compounds and flavonoids content as well as cell growth. Changing the NH4+ and FeSO4 concentration in B5 medium could cause the same effects except increase in cell growth. The potato cells in the suspension culture containing NAA had higher total phenolic compound and flavonoid contents. 6mg gallic acid eq./g D.W in total phenolic compounds from sweet potato cells in the culture with 0.4mg NAA/L, and 0.3mg Kinetin/L were obtained, in which the total phenolic compound contents was 3 times higher than the ones from original medium. Meanwhile, the contents of flavonoid from cells in B5 medium with 0.6mg NAA/L and 0.5mg Kinetin/L increase 9 times than the ones from the original B5 medium. However, the cells from the previous medium have higher anti-oxidation ability. Addition of 60mg/L and 120mg/L FeSO4 in the B5 medium with 0.4mg NAA/L, and 0.3mg Kinetin/L and the one with 0.6mg NAA/L and 0.5mg Kinetin/L respectively could result in even higher contents of total phenolic compounds and flavonoids in potato suspension cell cultures. The suspension cell culture from the later medium has the highest total phenolic compound contents, 9.5mg, and flavonoid contents, 132.7 ug, respectively; and it has the highest anti-oxidation ability in this research, too. A potato suspension cell culture with high phenolic compound contents, high flavonoid contents and high anti-oxidation ability was obtained, it could be used in further study in the potato breeding