P. orbicularis aqueous extract protects human cells against UVB damage. This protective effect is through the modulation of DNA repair effectiveness.

The ultraviolet (UV) component of sunlight is high on the earth surface, especially at low latitudes, raising the risk of skin diseases, including cancer. The use of natural compounds is a strategy to protect people against UV damage. Seaweeds are becoming increasingly influential in the food industry, and are also used in the pharmacy and cosmetic industries, due to several bioactive demonstrated properties. This work analyzed the genotoxic and photoprotective effects of the aqueous extracts of two seaweed species: Bryothamnion triquetrum and Halimeda incrassata. A cell-free plasmid DNA assay was employed, allowing detection of DNA breaks. The plasmids were exposed to increasing concentrations of aqueous extracts. DNA break was produced at concentrations of 2.0 and 4.0 mg/mL in both seaweed extracts and, consequently, a genotoxic effect is postulated. This effect arises with higher exposure times. Additionally, different combinations of plasmid DNA, restriction enzymes (Eco RI, Bam HI, and Pvu II) and extracts were assayed. The extracts did not produce an interference effect in the reconnaissance of the specific restriction target sequences of each enzyme. Photoprotective activity of the extracts was evaluated in UVC-irradiated plasmids. None of the extracts displayed DNA protective effects in this assay.

Cymbopogon citratus (DC) Stapf is consumed as a popular decoction owing to its nice flavor and hypotensor property. Its aqueous extract radioprotector and antimutagenic properties have been experimentally demonstrated. In addition, its DNA protective activity against UV light has been proved in plasmid DNA and bacterial models. The fractioning process is important in order to identify phytocompounds responsible for this activity. In this work, the toxicity of three fractions obtained from Cymbopogon citratus (essential oils, butanolic and aqueous fractions) were tested using the SOS Chromotest in Escherichia coli. Cymbopogon citratus chemical fractions possess cytotoxic properties in E. coli in the following order butanolic > aqueous > essentials oils. Genotoxic properties were detected in any of the fractions.

Objetivo: Evaluar el efecto protector del extracto acuoso de Cymbopogon citratus (DC) Stapf, ante el daño inducido por las radiaciones UVC. Material y Métodos: Para evaluar si el extracto acuoso de C. citratus era capaz de inducir roturas de cadenas en el ADN, moléculas de plásmido pBluescript SK II fueron tratadas con diferentes concentraciones del extracto (0,01 - 4,0 mg/mL), en los tiempos de exposición: 30, 60 y 90 min. El efecto fotoprotector fue evaluado aplicando el extracto vegetal antes, durante, y después de la irradiación del ADN plasmídico con 200 J/m2 de UVC. La actividad enzimática de T4 endonucleasa V fue empleada para detectar formación de CPDs. Las formas superenrollada y relajada de las moléculas de plásmido fueron separadas electroforéticamente en gel de agarosa. Adicionalmente, se midió la transmitancia del extracto acuoso a la DO de 254 nm. Resultados: Ninguna de las concentraciones evaluadas resultó genotóxica con 30 min de tratamiento. Las concentraciones ≥ 2 mg/mL indujeron roturas de cadenas a los 90 min de incubación. El extracto de C. citratus a concentraciones ≥ 0,5 mg/mL protegió al ADN frente a las radiaciones UVC. Conclusiones: En nuestras condiciones experimentales, el extracto acuoso de C. citratus protege al ADN frente a la genotoxicidad inducida por la luz UVC, previniendo la generación de CPDs, pero no es capaz de eliminarlas una vez formadas.