Evaluation of the antibacterial synergism of two plant extracts belonging to Bignoniaceae family and development of a topical formulation

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.

Actividad antioxidante de cuatros especies vegetales del nordeste argentino / Antioxidant activity of four plant species in the Argentine Northeast / Atividade antioxidante de quatro espécies de plantas no Nordeste argentino

RESUMEN Objetivos: Determinar la composición fitoquímica y evaluar la actividad antioxidante de los extractos hidroalcohólicos de S. haematospermum; P. niruri; P. tenellus; E. serpens. Metodología: La composición fitoquímica se analizó por cromatografía en capa fina y la actividad antioxidante se observó de modo cualitativo por ensayo autográfico. Los fenoles totales se cuantificaron con el método de Folin-Ciocalteu y flavonoides totales con la reacción de complejación de aluminio. Para determinar la actividad antioxidante se utilizaron las técnicas de decoloración del radical libre DPPH• (2,2- difenil-1-picrilhidracilo) y del radical catión ABTS•+ (ácido 2,2'-azino-bis (3-etilbenzotiazolin)-6-sulfónico) y del poder reductor del catión hierro (III). Resultados: El estudio fitoquímico evidenció en todas las especies la presencia de metabolitos bioactivos. El contenido de fenoles totales osciló entre: 627,71 ± 1,45 y 369,8±52,6 mg EAG/g muestra y de flavonoides totales fue de 12,2 ± 0,1 hasta 4,5 ± 0,3 mg Q/g muestra. Las especies S. haematospermum y P. tenellus presentaron mayor contenido de polifenoles. Los ensayos de actividad antioxidante permitieron reconocer que S. haematospermum y P. tenellus tienen capacidad de mayor inhibición de los radicales libres probados y mostraron mayor poder reductor los extractos hidroalcohólicos S. haematospermum y P. niruri.

SUMMARY Objectives: To determine the phytochemical composition and evaluate the anti-oxidant activity of the hydroalcoholic extracts of S. haematospermum; P. niruri; P. tenellus; E. serpens. Methodology: The phytochemical composition was analyzed by thin layer chromatography and the antioxidant activity was observed qualitatively by autographic assay. Total phenols were quantified with the Folin-Ciocalteu method and total flavonoids with the aluminum complexation reaction. To determine the antioxidant activity, the discoloration techniques of the free radical DPPH• (2,2-diphenyl-1-picrilhydracil) and of the cation radical ABTS•+ (2,2-Azino-bis-3-ethylbenzothiazolin-6-sulfonic acid) and the reducing power of the iron (III) cation. Results: The phytochemical study showed the presence of bioactive metabolites in all species. The total phenol content ranged from: 627.71 ± 1.45 to 369.8 ± 52.6 mg EAG / g sample and total flavonoids was 12.2 ± 0.1 to 4.5 ± 0.3 mg Q / g sample. The species S. haematospermum and P. tenellus presented higher content of polyphenols. The antioxidant activity tests allowed recognizing that S. haematospermum and P. tenellus have a capacity for greater inhibition of the tested free radicals and the hydroalcoholic extracts S. haematospermum and P. niruri showed greater reducing power.

RESUMO Objetivos: Determinar a composição fitoquímica e avaliar a atividade antioxidante dos extratos hidroalcoólicos de S. haematospermum; P. niruri; P. tenellus; E. serpens. Metodologia: A composição fitoquímica foi analisada por cromatografía em camada delgada e a atividade antioxidante foi observada qualitativamente por ensaio autográ-fico. Fenóis totais foram quantificados pelo método de Folin-Ciocalteu e flavonóides totais pela reação de complexação de alumínio. Para determinar a atividade antioxidante, as técnicas de descoloração do radical livre DPPH• (2,2-difenil-1-picrilhidracil) e do radical catiônico ABTS•+ (2,2-azino-bis-3-etilbenzotiazolin-6-sulfônico ácido) e o poder redutor do cátion ferro (III). Resultados: O estudo fitoquímico mostrou a presença de metabólitos bioativos em todas as espécies. O conteúdo total de fenol variou de: 627,71 ± 1,45 a 369,8 ± 52,6 mg EAG / g amostra e flavonóides totais foi de 12,2 ± 0,1 a 4,5 ± 0,3 mg Q / g amostra. As espécies S. haematospermum e P. tenellus apresentaram maior teor de polifenóis. Os testes de atividade antioxidante permitiram reconhecer que S. haematospermum e P. tenellus apresentam maior capacidade de inibição dos radicais livres testados e os extratos hidroalcoólicos S. haematospermum e P. niruri apresentaram maior poder redutor.

Formulación de productos cosméticos con aceite de semillas de Cucurbita argyrosperma C. Huber / Formulation of cosmetic products from Cucurbita argyrosperma C. Huber seed oil

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.