Eulalia Vargas Tapia

Urban medicinal plant markets preserve traditional knowledge, but information on the quality and chemical characteristics of commercial plant materials remains limited. This study combined a descriptive cross-sectional survey of 48 medicinal plant vendors at Gamarra Market, Lima, Peru, with selected physicochemical, elemental, and phytochemical analyses of commercial leaves of Aristeguietia ballii (Oliv.) R.M.King & H.Rob., Borago officinalis L., Senecio canescens (Bonpl.) Cuatrec., and Eucalyptus globulus Labill. The survey documented plant names, reported medicinal uses, plant parts, preparation methods, and routes of administration. Laboratory analyses included proximate composition, arsenic (As), lead (Pb), and mercury (Hg) determination, preliminary phytochemical screening, spectrophotometric estimates of total phenolic content (TPC) and total flavonoid content (TFC), and DPPH and ABTS radical-scavenging assays. A. ballii had the highest concentrations of As (2.18 mg/kg) and Pb (2.54 mg/kg) among the materials analyzed, while Hg was below the detection limit in all samples. E. globulus yielded positive reactions in the greatest number of qualitative screening assays and the highest TPC in its hydroethanolic extract (53.22 ± 1.00 mg GAE/g DS) and TFC in its chloroform-derived extract (21.92 ± 0.41 mg QE/g DS). Hydroethanolic B. officinalis had the highest DPPH response (33.39 ± 0.63 mg TE/g DS), whereas aqueous E. globulus had the highest ABTS response (63.60 ± 1.19 mg TE/g DS). These findings characterize the interviewed vendors’ reports and the commercial samples analyzed. Convenience sampling and one composite commercial sample per species limit generalizability, and the chemical assays do not establish respiratory efficacy or overall toxicological safety.

Peru’s agro-industrial activities generate lignocellulosic residues that can be valorized as sources of cellulose-based materials. This study aimed to obtain TEMPO-oxidized cellulosic material (T-OCM) from bleached purple corn cob pulp. Spent purple corn cob (SPCC) was characterized and conditioned through washing, drying, grinding, and sieving, followed by treatment with acidified ethanol (0.01% HCl) to remove anthocyanins. Cellulose was obtained via alkaline delignification (6% NaOH) and bleaching with 4% H₂O₂. T-OCM was then produced using TEMPO-mediated oxidation (2,2,6,6-tetramethylpiperidine-1-oxyl, 98%) with NaBr, testing NaClO concentrations of 10, 20, and 30 mmol/g over a 6 h reaction time. Characterization included FTIR, particle size analysis (zeta sizer), scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetry (TGA). SPCC showed 5.76 ± 0.08% moisture, 1.66 ± 0.06% ash, 2.62 ± 0.02% extractives, 41.81 ± 0.34% cellulose, 36.06 ± 0.34% hemicellulose, and 17.85 ± 0.05% lignin, comparable to unprocessed samples. The cellulose reached a purity of 91.05%, while the maximum yield of T-OCM was 58% at 20 mmol of NaClO/g, with a carboxylate content of 1.60 mmol/g, which increased with the dosage. The resulting T-OCM exhibited zeta potential −45.1 mV and hydrodynamic particle diameter 134.12 nm. The crystallinity index increased from 65.53% in cellulose to 73.7% in the T-OCM. In conclusion, SPCC can be valorized to obtain highly purified cellulose and TEMPO-oxidized cellulosic material.

Açai (Euterpe precatoria Mart.) is a fruit with tremendous bioactive potential, but its high perishability necessitates the use of technologies to improve its stability and further enhance its bioactivity, such as microencapsulation by spray drying. Maltodextrin (MD) and gum Arabic (GA) are commonly used encapsulants in spray drying, but their combination for the microencapsulation of açai extract has not been studied. This study aimed to optimize the microencapsulation of açai extract using spray drying, evaluating its effect on the physicochemical and functional properties of the microparticles (MPs). Optimization was performed using response surface methodology with a central composite rotatable design, considering inlet air temperature (IAT) and polymer ratio (GA:MD) as factors. The optimal conditions were 135 °C IAT and a 50:50 GA:MD, under which a process yield of 76.05%, total phenolic compounds of 2791.83 mg GAE/100 g, and hygroscopicity (HYG) of 7.28% were obtained. Solubility (WSI) and total anthocyanin content (TAC) were not optimized due to lack of fit (p < 0.05). The experimental validation showed precise agreement between predicted and experimental values, with relative errors of less than 5%. The MPs presented spherical forms with rough surfaces. The effectiveness of the microencapsulation process demonstrates the potential of açai MPs as possible functional ingredients for future food applications.

Background: Propolis has been used as a natural health product mainly due to the presence of polyphenols, flavonoids, phenolic aldehydes, amino acids, vitamins and others bioactive constituents. To this natural substance are attributed different biological and pharmacological properties which are influenced by its chemical composition and organoleptic properties. The aim of this work was to evaluate the physicochemical properties and parameters of green propolis collected during a period of six years (2008-2013) in the state of Minas Gerais, located at the southeastern region of Brazil. Methods: The methodology were in accordance with Brazilian legislation on the identity and quality standards of propolis. The evaluated parameters of hydroalcoholic from green propolis were total flavonoids, antioxidant activity - DPPH method, oxidation index, wax content, humidity and insoluble impurities. Results: Propolis samples collected in different seasons during the years 2008 to 2013 presented mean values of total flavonoids (3.4 ± 0.11 mg/g), antioxidant activity DPPH (4.76 ± 0.16 μg/mL), oxidation index (3, 4 ± 0.33 seconds) and wax (15.14 ± 0.78% m/m), which are in accordance with Brazilian legislation. Conclusion: Green propolis did not show abrupt seasonal changes during the six years of investigation, and may be considered as an adequate functional ingredient.

To verify the chemical quality of polar extract of green propolis produced in Minas Gerais, Brazil, were analyzed by means of RP-HPLC, the concentration of eleven flavonoids, artepillin C and p-coumaric acid. Samples were collected in February, March, May, July, September, and October, during a period of six years (2008 to 2013) and the results compared with purchased standards. Artepillin C was the main constituent (80-90%) found in all samples. Lower concentrations of p-coumaric acid, chrysin and kaempferide were observed in March, and of ricin and galangin in September. Respectively, these months correspond to the end of summer and spring period in Brazil. The variation in concentration of the analyzed constituents always occurred in the same month of the six years of evaluation period. All thirteen constituents of green propolis were detected throughout the study period, and the average concentration of each one was similar in relation to the same moment of collection. Due to similarities among chemical constituents of green propolis with those present in B. dracuncufolia, this plant was identified as being the principal source of green propolis.

In this work we performed assays for the genetic improvement of the oleaginous yeast Lipomyces starkeyi DSM 70296 focusing on its utilization for lipid biosynthesis from renewable sources. The genetic optimization was carried out by random mutagenesis by ultraviolet irradiation and mutant selection by cerulenin, a compound displaying inhibitory effects on lipid biosynthesis. Mutants demonstrating normal growth in presence of cerulenin were considered as good candidates for further studies. Using this strategy, we selected 6 mutants for further studies, in which their productivities were evaluated by fermentation in shaken flasks and bioreactor. The evaluation of the fermentative performance of mutants was carried out using xylose as sole carbon source; the fermentation of wild-type strain was used as reference. Using this strategy it was possible to identify one mutant (termed A1) presenting a significant increase in the productivity rates of both biomass and lipid in comparison to wild-type strain. A1 mutant was further studied in bioreactor using the same fermentation parameters optimized for L. starkeyi lipid production from a mixed carbon source (xylose:glucose), as previously determined by other studies in our laboratory. A1 presented a productivity increase of 15.1% in biomass and 30.7% in lipid productivity when compared to the wild-type strain with a similar fatty acid composition, despite a slight increase (approx. 7%) on the unsaturated fraction. Our work demonstrates the feasibility of the random mutagenesis strategy coupled with mutant selection based on cerulenin screening for the genetic improvement of the oleaginous yeast L. starkeyi.