Elicitação microbiana e análise de betalaínas em Pereskia aculeata Miller

Abstract

Pereskia aculeata Miller, from the botanical family Cactaceae, is a plant cultivated in tropical regions, recognized for its medicinal and nutritional value due to its richness in nutrients and bioactive phytochemicals, with various biomedical and technological applications.. This study comprises two investigations: The first study aimed to evaluate the effect of plant growth-promoting bacteria inoculation (Azospirillumbrasilense, Bacillus subtilis, Rhizobium tropici) on the concentration of total phenolic compounds, mineral composition, antioxidant activity, and chemical profile in P. aculeata leaves. The experiment was conducted in a greenhouse using a completely randomized design with four treatments and six replicates. The total phenolic compound content was determined using the Folin-Ciocalteu method, antioxidant activity was assessed through the DPPH radical scavenging method, mineral composition was analyzed by inductively coupled plasma optical emission spectrometry, and the chemical profile was determined by high-performance liquid chromatography. The results indicated that rhizobacteria inoculation significantly increased the total phenolic compound concentration, with R. tropici and A. brasilense showing the highest values. Inoculation with A. brasilense and B. subtilis increased nitrogen and iron levels. Antioxidant activity was significantly higher in plants inoculated with A. brasilense, R. tropici, and B. subtilis, and the chromatograms showed greater band density in inoculated plants. Among the treatments, R. tropici and A. brasilense were the most promising elicitors of phytochemicals in P. aculeata.The second study aimed to identify the presence of betalains in apical leaves of P. aculeata, optimize the extraction conditions, evaluate color stability and spectral characteristics under different pH conditions, and determine the antioxidant potential of the extract. The extraction was optimized using the Box-Behnken design, considering the following factors: mass/solvent ratio, solvent temperature, and extraction time. The optimized extract was compared with a betalain standard using high-performance liquid chromatography and UV-Vis absorbance spectroscopy, while antioxidant activity was assessed using the DPPH radical scavenging method. Chromatographic and spectrophotometric analyses demonstrated equivalence between the optimized extract and the reference standard. The optimized extract exhibited antioxidant potential and color change under alkaline conditions.The findings reinforce the medicinal value of this species due to its rich composition of bioactive compounds, minerals, and high antioxidant capacity, highlighting its potential for technological and medicinal applications, With emphasis on sustainable production techniques that enhance the utilization of this species.