Abstract Fridericia caudigera and Cuspidaria convoluta (Bignoniaceae) species, which grow in the northwest of Argentina, have shown antibacterial effect against strains isolated from skin infections, and each one displayed synergism with commercial antibiotics. The aims of this work were to evaluate the antibacterial activity and toxicity of the combination of these two plant species, and to design a stable gel for topical use including the blend of extracts. The combination of extracts was evaluated for synergistic effects (chequerboard assay), genotoxicity (Ames test) and cytotoxicity (Artemia salina test). A gel was subsequently formulated with the combination of extracts using carboxymethylcellulose as a polymer. The following physico- chemical characteristics of the gel formulation: pH, viscosity, spreadability and total phenol content, as well as resistance to severe temperature changes, biological activity (diffusion in agar), in vitro permeation (Franz cells) and primary dermal irritation (Draize test) were analyzed. The combination of extracts showed a synergistic effect on pathogenic bacteria and was not toxic in the in vitro tests. The gel was stable and retained the antimicrobial activity of the original extracts. The formulation proposed in this work could constitute an alternative for primary skin infections since it proved to be safe for topical administration.

RESUMEN El presente trabajo tiene como objetivo aprovechar el aceite de las semillas de Cucurbita argyrosperma C. Huber (sin. Cucurbita mixta Pangalo), como fitoingrediente en la elaboración de productos cosméticos. El aceite empleado se obtuvo por extracción con soxhlet y se realizó su caracterización fisicoquímica. Se elaboraron emulgeles (O/W) variando el agente viscosante y emulgente. Las formulaciones logradas se valoraron mediante la evaluación de las propiedades organolépticas (color, olor, brillo), fisicoquímicas (pH, conductividad) y extensibilidad y fueron sometidas a estudios de estabilidad. Se obtuvieron productos tipo emulgel de color amarillento con ligero olor ceroso, con pH aceptable para la piel. Todas las formulaciones resultaron estables. Los resultados demostraron que las formulaciones propuestas permitieron incorporar el aceite de origen vegetal logrando un preparado cosmético de características y estabilidad aceptables.

SUMMARY The objective of this work is to take advantage of the oil of the seeds of Cucurbita argyrosperma C. Huber (sin. Cucurbita mixta Pangalo), as a phytoingredient in the elaboration of cosmetic products. The oil used was obtained by extraction with soxhlet and its physicochemical characterization was carried out. Emulgels (O/W) were prepared by varying the viscosifying and emulsifying agent. The formulations achieved were evaluated by evaluating the organoleptic properties (color, odor, brightness), physicochemical (pH, conductivity) and extensibility and were subjected to stability studies. Emulgel type products with yellowish color with slight waxy odor were obtained, with acceptable pH for the skin. All the formulations were stable. The results showed that the proposed formulations allowed incorporating the oil of vegetable origin achieving a cosmetic preparation of acceptable characteristics and stability.

Aloysia polystachya is popularly used to treat various conditions. The aim of the study was to evaluate the chemical composition, some physicochemical properties and in vitro antioxidant activity of an ethanolic extract of the species. Extracts retain a higher content of essences that infusions or decoctions. It was detected five groups of metabolites (two of them as traces) and the physicochemical properties were similar to those of the employed solvent. It was quantified total phenols (2.32 ± 0.16 mg GAE/mL E), total flavonoids (0.37 ± 0.01 mg QE/mL E) and in vitro antioxidant activity by UV-visible spectrophotometry. The free radical scavenging capacity would be about three times smaller than the reference substance and the total antioxidant activity equivalent to 0.83 mg of Trolox/mL extract.

Aloysia polystachya se usa popularmente para tratar diversas afecciones. El objetivo del estudio fue evaluar la composición química, algunas propiedades fisicoquímicas y la actividad antioxidante in vitro de un extracto etanólico de la especie. Los extractos conservan un mayor contenido de esencias que las infusiones o decocciones. Se detectaron cinco grupos de metabolitos (dos de ellos como trazas) y las propiedades fisicoquímicas resultaron similares a las del solvente. Se cuantificaron fenoles totales (2,32 ± 0,16 mg EAG/ml E), flavonoides totales (0,37 ± 0,01 mg EQ/ml E) y actividad antioxidante in vitro por espectrofotometría. La capacidad de captar radicales libres sería aproximadamente tres veces menor que la sustancia de referencia y la actividad antioxidante total equivaldría a 0,83 mg de Trolox/ml de extracto.