Isolation of acetylated bile acids from the sponge Siphonochalina fortis and DNA damage evaluation by the comet assay.

From the organic extracts of the sponge Siphonochalina fortis, collected at Bahía Bustamante, Chubut, Argentina, three major compounds were isolated and identified as deoxycholic acid 3, 12-diacetate (1), cholic acid 3, 7, 12-triacetate (2) and cholic acid, 3, 7, 12-triacetate. (3). This is the first report of acetylated bile acids in sponges and the first isolation of compound 3 as a natural product. The potential induction of DNA lesions by the isolated compounds was investigated using the comet assay in lymphocytes of human peripheral blood as in vitro model. The results showed that the administration of the bile acid derivatives would not induce DNA damages, indicating that acetylated bile acids are nontoxic metabolites at the tested concentrations. Since the free bile acids were not detected, it is unlikely that the acetylated compounds may be part of the sponge cells detoxification mechanisms. These results may suggest a possible role of acetylated bile acids as a chemical defense mechanism, product of a symbiotic relationship with microorganisms, which would explain their seasonal and geographical variation, and their influence on the previously observed genotoxicity of the organic extract of S. fortis.

Aqueous extracts of Lippia turbinata and Aloysia citriodora (Verbenaceae): assessment of antioxidant capacity and DNA damage.

The aim of the present work was to make a contribution to the knowledge of aqueous extracts of Lippia turbinata and Aloysia citriodora (Verbenaceae; infusion and decoction) in relation with the establishment of its antioxidant activity and lack of DNA damage, for its potential use in therapeutics. The cytogenotoxic profile was evaluated through genotoxic biomarkers such as mitotic index, cellular proliferation kinetics, sister chromatid exchanges, single-cell gel electrophoresis assay, and micronucleus test in human peripheral blood lymphocyte cultures. No statistical differences were found (P > .05) between control and exposed cultures, even between both aqueous extracts. The total antioxidant capacity was shown to be higher in the decoction than in the infusion and both aqueous extracts protected against protein carbonylation and lipid peroxidation, the decoction being more efficient than the infusion (P < .005). These results suggest the safe use of these medicinal plants as chemoecologic agents in therapeutics.

Análisis de polifenoles, actividad antioxidante y genotoxicidad en especies argentinas de Lippia y Aloysia (Verbenaceae) / Survey on polyphenols, antioxidant activity and genotoxicity on Argentinean species of Lippia and Aloysia (Verbenaceae)

Three species and a variety from the Verbenaceae belonging to the argentinean flora were analyzed: Aloysia gratissima var. gratissima (Gill. Et Hook) Tronc., Aloysia gratissima var. schulziana (Moldenke) Botta, Aloysia polystachya (Griseb.) Moldenke and Lippia integrifolia (Griseb.) Hieron., the first two known as “cedrón del monte”, the third as “yerba del burro” and the other as “incayuyo”. Their leaves are used as digestive in folk medicine. The research was performed on quantification of polyphenols (total phenols, total flavonoids and total hydroxicinnamic acids) and on determination of antioxidant and genotoxic activities. L. integrifolia showed the highest total phenol concentration and A. polystachya the lowest, but with the highest concentration of hydroxicinnamic acids. When flavonoids were quantified, A. polystachya showed the lowest concentations and A. gratissima var. schultziana the highest. According to quantification of total polyphenols, the lowest antioxidant activity was measured in A. polystachya extracts, followed by those from A. gratissima var. gratissima and A. gratissima var. schulziana, while extracts from L. integrifolia showed the highest antioxidant activity. No genotoxic activity was detected by means of the comet-assay for any of the species. This absence of genotoxicity, added to the relevant antioxidant activity, could justify the use of leaves infusions and decoctions from these species in treatments of those pathologies where antioxidants play an important role. These studies suggest their sure use in folk medicine, in which people include them among their medicinal plants.

Se analizaron 3 especies y una variedad de la familia Verbenaceae de la flora argentina: Aloysia gratissima var. gratissima (Gill. Et Hook) Tronc., Aloysia gratissima var. schulziana (Moldenke) Botta, Aloysia polystachya (Griseb.) Moldenke y Lippia integrifolia (Griseb.) Hieron., conocidas como “cedrón del monte” las dos primeras, “yerba del burro” la tercera e “incayuyo” la restante. De todas ellas se emplean las hojas en la medicina popular como digestivas. Se investigaron los contenidos de polifenoles (fenoles totales, flavonoides totales y ácidos hidroxicinámicos totales) y se determinó la capacidad antioxidante y genotoxicidad de las preparaciones acuosas (infusiones y cocimientos). L. integrifolia fue la especie con mayor contenido de fenoles totales y A. polystachya la menor. En el análisis de los hidroxicinámicos, A. polystachya fue la que mayor concentración mostró. En cuanto a los flavonoides, A. polystachya fue la que poseyó menor concentración en tanto que A. gratissima var. schultziana fue la más rica en estos compuestos. A. polystachya es la especie que presenta los menores valores de actividad antioxidante, seguida por A. gratissima var. gratissima y A. gratissima var. schulziana, mientras que L. integrifolia es la especie con mayor actividad antioxidante, en correlación con los valores de polifenoles totales. Ninguna de las especies analizadas demostró actividad genotóxica en el ensayo del cometa. La ausencia de genotoxicidad, sumada a una marcada actividad antioxidante, justificarían el empleo de las infusiones y cocimientos en el tratamiento de aquellas patologías donde los agentes antioxidantes juegan un importante rol terapéutico. Estos estudios sugieren el empleo seguro en la medicina tradicional de los pueblos y comunidades que las incluyen entre sus plantas medicinales.