Antioxidant, Cytotoxic, and Toxic Activities of Propolis from Two Native Bees in Brazil: Scaptotrigona depilis and Melipona quadrifasciata anthidioides

Propolis is a natural mixture of compounds produced by various bee species, including stingless bees. This compound has been shown to exhibit antioxidant, antiproliferative, and antitumor activities. The present study aimed to determine the chemical constituents as well as the antioxidant, cytotoxic, and toxic activities of ethanol extracts of propolis obtained from the stingless bees Scaptotrigona depilis and Melipona quadrifasciata anthidioides, which are found in Brazil. Phytosterols, terpenes, phenolic compounds, and tocopherol were identified in the ethanol extracts of propolis (EEPs) in different concentrations. The compounds stigmasterol, taraxasterol, vanilic acid, caffeic acid, quercetin, luteolin, and apigenin were found only in EEP-M. The EEPs were able to scavenge the free radicals 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and protected human erythrocytes against lipid peroxidation, with the latter effect being demonstrated by their antihemolytic activity and inhibition of malondialdehyde formation. The EEPs showed cytotoxic activity against erythroleukemic cells and necrosis was the main mechanism of death observed. In addition, the concentrations at which the EEPs were cytotoxic were not toxic against Caenorhabditis elegans. In this context, it is concluded that EEP-S and EEP-M show antioxidant and cytotoxic activities and are promising bioactive mixtures for the control of diseases associated with oxidative stress and tumor cell proliferation.