The production of reactive oxygen species (ROS) takes place in all organisms. ROS regulate the cell cycle and other biological phenomena that make them essential for life. However, when there is a ROS excess and/or the antioxidant system is reduced, oxidative stress is induced. During this process, ROS can attack various biomolecules and generate oxidative damage. The hydroxyl radical is a highly reactive ROS that can react with guanine in deoxyribonucleic acid (DNA), generating the molecule 8-hydroxy-2’-deoxyguanosine (8-OHdG), a marker of oxidative damage to DNA. Some research have shown that cancer patients or mouse models of cancer have elevated levels of 8-OHdG in serum, urine, saliva, and tissues. This literature review summarizes the main findings of 8-OHdG in several types of cancer and shows the evidence for the potential use of 8-OHdG as a biomarker of oxidative DNA damage in cancer.

Abstract. Laelia furfuracea is an endemic orchid from Mexico, with antioxidant activity. The objective of this study was to evaluate the effect of hydroethanolic extract and fractions obtained from the orchid leaves on the clotting times of patients with venous thromboembolic disease (VTD) and to identify their tentative compounds. The anticoagulant activity was evaluated by determining prothrombin (PT), thrombin (TT) and, activated partial thromboplastin (APTT) times. Identification of the compounds was carried out using a chromatographic technique with an ultra-high-performance liquid chromatographic analyzer coupled with electrospray ionization with quadrupole time of flight-mass-mass spectrometry. The extract prolonged the clotting times depending on the concentration-response (5-60 mg / mL); 25 mg/mL prolonged the PT (33.2 ± 2.3 s) and TT (33.1 ± 0.3 s); and APTT (61.8 ± 3.4 s) at a concentration of 15 mg/mL. The main groups tentatively identified were xanthine, carboxylic acid, amino acid, and phenolic compounds. These compounds or the synergy between them prolong clotting times. Laelia furfuracea is an orchid with research potential in the search for new anticoagulant agents.   Resumen. Laelia furfuracea es una orquídea endémica de México, la cual posee actividad antioxidante. El objetivo de este estudio fue evaluar el efecto del extracto hidroetanólico y fracciones obtenidas de hojas de la orquídea sobre los tiempos de coagulación de pacientes con enfermedad tromboembólica venosa (ETV) e identificar sus posibles compuestos. La actividad anticoagulante se evaluó determinando los tiempos de protrombina (TP), trombina (TT) y tromboplastina parcial activada (TTPA). La identificación de los compuestos se realizó usando una técnica cromatográfica con un analizador cromatográfico líquido de Ultra Alta Resolución con Ionización por electroespray acoplado a espectrometría de masas con Cuadrupolo y Tiempo de Vuelo. El extracto prolongó los tiempos de coagulación dependiente de la concentración-respuesta (5-60 mg/mL); 25 mg/mL prolongó el TP (33.2±2.3 s) y TT (33.1±0.3 s); y TTPA (61.8±3.4 s) a una concentración de 15 mg/mL. Los principales grupos de posibles compuestos identificados fueron xantina, ácido carboxílico, aminoácido y compuestos fenólicos. Estos compuestos o la sinergia entre ellos prolongan los tiempos de coagulación. Laelia furfuracea es una orquídea con potencial en investigación para la búsqueda de nuevos agentes anticoagulantes.