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This study aimed to evaluate the in vitro growth and biochemical activity of Curcuma longa explants using different MS medium formulations and growth regulators. In all the experiments, plants were grown in MS medium supplemented with agar (6.5 g L-1) and pH adjusted to 5.8. In the first assay, the MS culture medium at 70% strength, supplemented with 30 g L-1 of sucrose, and without the addition of activated carbon, resulted in the highest number of shoots. The sucrose concentration of 60 g L-1, combined with the addition of actived charcoalin half-strength MS medium, resulted in the increased root dry mass, root collar diameter, and relative chlorophyll index. In the second assay, the highest root collar diameter and dry matter of shoots and roots were found in the MS medium supplemented with 4.44 BAP, 0.46 KIN, and 1.08 NAA. The MS medium with 8.88 BAP, 0.92 KIN, and 2.16 μM NAA resulted in the highest number of shoots (7.75), number of leaves (35), and shoot length (88.57 mm). The antioxidant activity was significantly higher in the treatments that resulted in better plantlets growth performance, demonstrating that the antioxidant activity is related to other factors such as a possible role of growth regulators on the elicitation of compounds in plants. Superoxide dismutase had a high enzymatic activity in both assays, whereas the enzymatic activity of catalase and ascorbate peroxidase was dependent on the culture media used.

Curcuma longa L. is a plant widely used for its pharmacological and medicinal properties, however, does not have a conclusive micropropagation protocol.  The objective was to evaluate how growth regulators, sucrose and potassium influence the growth and biochemical activity of Curcuma longa seedlings grown in vitro.  Shoots were inoculated in culture medium supplemented with 6-benzylaminpurine - BAP (8.88 and 17.76 μM), Kinetin - KIN (0.92 and 2.16 μM) and naphthalene acetic acid - NAA (2.16 and 7.20 μM), potassium iodide KI (25 and 50 μM) and sucrose (30 and 60 gL-1). Growth regulators at the lowest concentration and 30 gL-1 sucrose promoted increases in growth of C. longa. Antioxidant activity was high in all treatments. The activity of the enzymes catalase and ascorbato peroxidase were increased in the two treatments that contained the highest concentrations of growth regulators. It is concluded that the addition of growth regulators such as cytokinins and auxins are fundamental to increase the number of leaves and growth of shoots in C. longa. Since the best concentrations are in the range of 4.44 to 8.88 μM of (BAP) and 2.16 of NAA. The addition of supplemental potassium in the culture medium is not necessary, and the beneficial effects of doubling the usual sucrose concentration are nullified if other constituents of the medium are altered. The antioxidant activity and enzymes had their activity altered, especially in treatments that did not contain growth regulators.