Lupeol acetate production and antioxidant activity of a cell suspension culture from Cnidoscolus chayamansa leaves

Cnidoscolus chayamansa (‘Tree spinach’ or Chaya) produces lupeol acetate (LUAC) naturally. Cell culture may represent a viable alternative production method to sustainably use of natural resources. No studies have reported LUAC production in vitro or in Chaya cell culture. The aim of the study was to establish a C. chayamansa cell suspension culture, quantify LUAC production and evaluate the extract's antioxidant and antibacterial activity. To induce callus, immature leaves were cultured in Murashige and Skoog (MS) culture medium supplied with different combinations of auxin (2,4-dichlorophenoxyacetic acid, 2,4-D; α-naphthalene-acetic acid, NAA; indole-3-acetic acid, IAA or indole-3-butyric acid, IBA) and cytokinin (6-benzylaminopurine, BAP; or kinetin, KIN) at concentrations of 0.5, 2.5, and 5.0 mg/L. The higher percentage of callus induction (75.0%) and the best friable characteristic were exhibited when combining NAA (2.5 mg/L) and BAP (5.0 mg/L). This callus was used to establish a cell suspension culture, quantify LUAC production and evaluate the antioxidant and antibacterial activity. The maximum dry biomass (DW) of the cell suspension culture was 9.2 g/L at 40 days, growth index 5.63; specific growth rate (μ) of 0.082 days; and doubling time (td) at 8.45 days. Cells growth was related with D-glucose culture medium concentration. Cell suspension culture produced 38.1 mg LUAC/g extract at 40 days of culture, which was greater than the production in wild plant leaves (2.9 mg LUAC/g extract). Extracts exhibited moderate antioxidant activity (EC50 16.60 mg/mL) and antibacterial activity against Staphylococcus aureus, Listeria monocytogenes and Staphylococcus coagulase. Although the extracts exhibited only moderate biological activity, these produced a large amount of LUAC. Therefore, C. chayamansa cell suspension culture represents an alternative LUAC source instead of using the wild plant.