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Obtaining cells of Physalis pubescens is of interest for studies of primary and secondary metabolic pathways, in the search for new active molecules. Our objectives were to evaluate the regeneration potential of explants from different parts of the plant, growth regulators to be used, and the determination of the growth curve of the callus. We used explants of leaf, root, stem and petiole, cultured on Murashige and Skoog medium with different concentrations of 6-benzylaminopurine and naphthaleneacetic acid. The explants from stem and petiole had a higher regeneration potential of the shoot to the treatment with 0.5 mg L-1 6-benzylaminopurine, and the explants of leave and root emitted more roots, with lower production of callus. The tests showed that the regeneration of the whole plant should be done in two steps: cultivation for shoot regeneration and transplantation to a new rooting medium. The growth of callus showed five distinct phases, with accumulation of phenols in the final stages of growth. The levels of soluble sugars increased with age, while reducing sugars showed variations, with higher concentrations in the initial stages of cultivation, with fall and rise again at the final evaluation (28 th day).

The performance of the pomegranate peel extract against the synthetic antioxidant additives on the oxidation stability of commercial biodiesel B100 derived from soybean was evaluated. The experimental extraction was conducted under 200 bar, 35, 45, and 55 C, and 0.0, 2.5, and 5.0 mL of ethanol as co-solvent. Due to the rich in squalene and α-tocopherol composition, all extracts presented high antioxidant capacity, 16.70 to 1.68 μg mL À1 . In the oxidation stability tests, the addition of 1000 ppm of the supercritical extracts of pomegranate peel to biodiesel resulted in the increment of the induction time of pure biodiesel by up to 1.83. In contrast, the biodiesel added at 1000 ppm with commercial antioxidants increased the times up to 1.58 and 1.79, respectively for butylated hydroxyanisole and butylated hydroxytoluene. Biodiesel added with supercritical extract of pomegranate peel, obtained under 35 C and with 5.0 mL of ethanol, presented higher efficiency in the prevention of the oxidative process and was in accordance with norm European Standard EN 14214. The findings revealed that the extract is a promising natural antioxidant for biodiesel, that, besides being eco-friendly, is an additive that can substitute commercial synthetic antioxidants, extending biodiesel stability.

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