In vitro propagation of Senecio candicans DC and comparative antioxidant properties of aqueous extracts of the in vivo plant and in vitro-derived callus

Abstract

Senecio candicans DC is an endemic sub-shrubby climber and the hot water extract of this plant is being used traditionally for the treatment of gastric ulcer. The first objective of the present study was to design a standardized protocol for in vitro regeneration of S. candicans from leaf explants and compare the antioxidant activities of aqueous extracts of in vitro calluses and in vivo leaves by three different methods. Callus was initiated on Murashige and Skoog's (MS) basal media supplemented with various concentrations (0.5mgL−1 to 2.0mgL−1) and combinations of auxins and cytokinins under dark incubation for 2weeks. The percentage of callus induction (PCI) and the fresh weights were recorded after 28days of culture. The fresh weights were again recorded after 4weeks of sub-culture to determine the relative fresh weight growth (RFWG). The highest PCI of 87% and RFWG of 3.245 were obtained on an MS medium supplemented with 6-benzyl amino purine (BA) 2mgL−1 and indole-3-acetic acid (IAA) 2mgL−1. The callus obtained after 28days of culture were inoculated on MS medium supplemented with different growth regulators. The maximum average shoot length (4.28±0.27cm) and maximum percentage of shoot induction (81%) was observed on MS medium supplemented with BA (2.0mgL−1)+IAA (1.0mgL−1). The maximum root induction percentage (90%) from shoots was observed on half strength MS medium fortified with 3.0mgL−1 α-naphthalene acetic acid (NAA) alone. The antioxidant activity of in vivo leaf was significantly high compared to the in vitro callus in all the three antioxidant assays. A linear correlation between antioxidant activity and the total phenolic content was observed. The current protocol for in vitro regeneration would pave the way for further research on the isolation of bioactive compounds including antioxidants by cell suspension culture.