Chemical characterization, cytotoxicity, antimicrobial and antioxidant potential of Justicia pectoralis Jacq and Croton jacobinensis Baill extracts

Abstract In this research, aqueous and ethanolic extracts from Justicia pectoralis Jacq and Croton Jacobinensis Baill were characterized. The UPLC-QTOF-MSE analysis was performed on the extracts identified, predominantly, flavonoids, tannins and acids. The extracts did not indicate toxicity in human epithelial cells. C. jacobinensis presented a concentration of phenolics 60.5% higher than J. pectoralis in all scenarios evaluated and, for both samples, the hydroalcoholic extract at 70% exhibited the best efficiency in the extraction (14501.3 and 32521.5 mg GAE 100 g-1 for J. pectoralis and C. jacobinensis, respectively). The antioxidant activity presented a positive correlation with the concentration of phenolics, being 1.186,1 and 1.507,9 µM of Trolox for J. pectoralis and C. jacobinensis at 70% of ethanol; however, it was not verified statistical difference between the ethanolic solutions (p < 0.05). The antimicrobial activity of J. pectoralis extracts was highlighted once was the most effective against gram-positive bacteria. The results suggest that both J. pectoralis and C. jacobinensis extracts present the potential to be applied as natural additives due to their antioxidant and antimicrobial activity and safety. Thus, it is suggesting the development of studies that could investigate the interaction of these plant extracts with food matrices is required

UPLC–QTOF–MS and NMR analyses of graviola (Annona muricata) leaves

ABSTRACT Graviola leaves (Annona muricata L., Annonaceae) are used by some people to try to treat or even cure cancer, even though over-consumption of the fruit, which contains the neurotoxins annonacin and squamocin has caused an atypical form of Parkinson's disease. In previous analyses, the fruits were extracted with methanol under ambient conditions before analyses. In the present study, UPLC–QTOF–MS and NMR were used to analyze freeze-dried graviola leaves that were extracted using dry methanol and ethanol at 100 ºC and 10 MPa (100 atm) pressure in a sealed container. Methanol solubilized 33% of the metabolites in the lyophilized leaves. Ethanol solubilized 41% of metabolites in the lyophilized leaves. The concentrations of total phenolic compounds were 100.3 ± 2.8 and 93.2 ± 2.0 mg gallic acid equivalents per g of sample, for the methanolic and ethanolic extracts, respectively. Moreover, the toxicophore (unsaturated γ-lactone) that is present in neurotoxic acetogenins was found in the lipophilic portion of this extract. The concentrations of the neurotoxins annonacin and squamocin were found by UPLC–QTOF–MS to be 305.6 ± 28.3 and 17.4 ± 0.89 µg/g-dw, respectively, in the dried leaves. Pressurized methanol solubilized more annonacin and squamocin than ethanol. On the other hand, a hot, aqueous infusion solubilized only 0.213% of the annonacin and too little of the squamocin to be detected. So, graviola leaves contain significant amounts of the neurotoxins annonacin and squamocin, as well as some potentially healthy phenolic compounds. Finally, the potential neurotoxicity of whole leaves in dietary supplements could be much higher than that of a tea (hot aqueous infusion) that is made from them.