The synergistic effects of sucrose and plant growth regulators on morphogenesis and evaluation of antioxidant activities in regenerated tissues of Caralluma tuberculata

Caralluma tuberculata (C. tuberculata) is a very important medicinal plant with a range of anti-diabetic and weight reduction properties. This high-valued medicinal plant is nowadays considered as endangered due to its unsustainable elimination from wild habitats. There is lack of research efforts on its propagation to overcome escalating demand. In this research study, an effort has been made to optimize protocol for large-scale mass propagation and production of natural antioxidants. Highest callogenic response (87.2 %) was observed from shoot tip explants on Murashige and Skoog (MS) medium containing 30 g l−1 sucrose and combination of 2, 4-D (2.0 mg l−1) and BA (1.0 mg l−1). During shoot morphogenesis, 50 g l−1 sucrose along with BA (2.0 mg l−1) and GA3 (1.0 mg l−1) enhanced shoot regeneration (91.3 %), mean shoot length (2.6 cm) and shoots per explant (24.5) as compared to control. The combination of IBA and IAA (2.0 mg l−1) was found optimum for root induction (74.98 %), mean root length (4.1 cm) and roots per shoot (6.9) as compared to control. The plantlets were successfully acclimatized in plastic cups and various tissues were investigated for accumulation of antioxidant secondary metabolites including phenolics, flavonoids, stress enzymes and antioxidant activities. The superoxide dismutase enzyme was higher in shoots; protein content was higher in callus cultures; phenolics, DPPH and protease activity were higher in plantlets, while flavonoids, peroxidase, reducing power and total antioxidant activities were higher in wild plants. This simple protocol is very useful for commercial production of consistent plantlets and metabolites of interest.