Effect of growth hormones in induction of callus, antioxidants, and antibacterial activity in Nerium odorum

Nerium odorum is an imperative species with worldwide therapeutic and commercial uses. N. odorum has been considered as a potentially important plant for industrial and pharmacological applications. Callus induction potential of N. odorum was assessed from leaf explants cultured on Murashige and Skoog’s medium using different plant hormonal treatments. A range of different concentrations of 6-benzylaminopurine, 1-naphthaleneacetic acid, 2,4-dichlorophenoxyacetic acid (2,4-D), indole-3-acetic acid (IAA), and kinetin (0.5–5.0 mg/L) have been incorporated in the culture medium to investigate the biomass, polyphenols production and oxidizing and antibacterial activity of the callus. The results showed highest callus induction at 2.0 mg/L in growth hormone combination of IAA and 2,4-D. The total phenolic content was 92.14 mg GA/g dry weight (DW). In addition, the 2,2-diphenyl-1- picrylhydrazyl activity and 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) activities were 46.7 μg/mL DW and 19.9 μg/mLDW, respectively. Interestingly, the explants produced hard calli using combination of IAA and 2,4- D presented a higher phenolic content and antioxidant capacity when compared to individual growth hormones of either IAA or 2,4-D. Altogether, these results demonstrate the extraordinary effect of different growth hormones on polyphenols production, antioxidant, and antibacterial activities in N. odorum.