Cytotoxic activity of halogenated sesquiterpenes from Laurencia dendroidea.

Red algae of the genus Laurencia J. V. Lamouroux are found in tropical and subtropical regions throughout the world and are an extremely rich source of active secondary metabolites with diverse structural features. In the present study, 6 sesquiterpenes (obtusol, (-)-elatol, dendoidiol, debrome-elatol, triquinane, and obtusane) isolated from Laurencia dendroidea were investigated for their cytotoxicity, using 4 cancer cell lines (U937, Jurkat, B16F10, and Colo-205). Among all sesquiterpenes tested, obtusol and (-)-elatol showed a promising activity in the treatment of Colo-205 strain, with IC50 of 1.2 ± 1.4 and 2.5 ± 1.3 µg/ml, respectively. In addition, fluorescence microscopy results indicated that, at 100 µg/ml, obtusol induced apoptosis at 79% and (-)-elatol at 95%. Activation of Caspases 2, 4, 6, and 8 showed to be involved in (-)-elatol activity and only Caspase 6 in obtusol activity. These data demonstrated the effective apoptosis-inducing activity of the sesquiterpene (-)-elatol and obtusol in the treatment of Colo-205 strain. Therefore, more studies should be done so that the sesquiterpenes (-)-elatol and obtusol might become promising chemotherapy.

Therapeutic potential of treatment with the flavonoid rutin after cortical focal ischemia in rats.

Flavonoids have known anti-inflammatory and antioxidative actions, and they have been described as neuroprotective and able to reduce damage in CNS diseases. We evaluated the action of the flavonoid rutin in an animal model of focal cortical ischemia induced by unilateral thermocoagulation of superficial blood vessels of motor (M1) and somatosensory (S1) primary cortices. Ischemic rats were submitted to daily injections (i.p.) for five days, starting immediately after induction of ischemia. We tested two doses: 50mg/kg or 100mg/kg of body weight. Sensorimotor tests were used to evaluate functional recovery. Bioavailability in plasma was done by chromatographic analysis. The effect of treatment in lesion volume and neurodegeneration was evaluated 48 h and 72 h after ischemia, respectively. We observed significant sensorimotor recovery induced by rutin, and the dose of 50mg/kg had more pronounced effect. Thus, this dose was used in further analyses. Plasma availability of rutin was detected from 2h to at least 8h after ischemia. The treatment did not result in reduction of lesion volume but reduced the number of degenerated neurons at the periphery of the lesion. The results suggest rutin as an efficient drug to treat brain ischemia since it was able to promote significant recovery of sensorimotor loss, which was correlated to the reduction of neurodegeneration in the periphery of cortical injury. Increasing studies with rutin and other flavonoids might give support for further clinical trials with these drugs.