ARTÍCULO ORIGINAL abstractThe hydro-alcoholic extract from Calendula officinalis petals, was evaluated showing beneficial effects against oxidative stress and therefore on diseases associated to inflammatory processes. The content of polyphenols of the extract was determined by TLC and HPLC-UV-DAD and the antioxidant efficiency estimated from Fe 3+ /Fe 2+ reducing power, Cu 2+and Fe 2+ chelation,• OH radical scavenging, ABTS [2, 2´-azino bis (3 ethylbenzothiazoline-6-sulphonic acid)] and DPPH (2,2´diphenyl-1-picrylhydrazyl) assays. The in vitro growth inhibition (IC 50 ) in human cancer cell breast (MDA-MB-231), uterine cervix (HeLa), lung (A-549), colon (HT-29) and (Caco-2) was determined by MTT method. The extract showed that the polyphenols content in the hydro-alcoholic extract was 37.01±0.015 mg GAE g -1 , being rutin the most abundant one. ABTS TEAC and DPPH TEAC tests showed a high antioxidant capacity. The antioxidant activity profile displayed high reducing capacity and ability to chelate Cu 2+ and Fe 2+ as well as good• OH radical scavenging capacity. The extract showed a cytotoxic effect on human cancer cell lines of colon (HT-29) and (Caco-2), breast (MDA-MB-231), uterine cervix (HeLa), and lung (A-549) (IC 50 = 10.84, 11.73, 11.26, 11.53, and 11.96 µg mL -1 , respectively). The correlation analysis suggests that the Calendula officinalis polyphenols are directly related to the antioxidant efficiency of the extract and inversely to the cell viability.Key Words: Calendula officinalis, polyphenols, antioxidant, cytotoxicity. OH, y ensayos ABTS [2, 2´-azino-bis (3 etilbenzotiazolin-6-sulfónico) y DPPH (2,2´difenil-1-picrilhidracilo). La inhibición del crecimiento in vitro (IC 50 ) en células cancerosas humanas de mama (MDA-MB-231), de cuello uterino (HeLa) , pulmón (A-549) , y colon (HT-29 y Caco-2), fue determinado por el método de MTT. El extracto mostró que el contenido total de polifenoles fue de 37.01±0.015 mg GAe g -1 , siendo la rutina la más abundante. Las pruebas ABTS TEAC y DPPH TEAC mostraron una alta capacidad antioxidante. El perfil de actividad antioxidante mostró buena capacidad reductora y capacidad para quelar Cu 2+ y Fe 2+, así como una buena capacidad de eliminación de radicales • OH. El extracto también mostró efecto citotóxico en células de colon (HT-29 y Caco-2) , de mama (MDA-MB-231), de cuello uterino (HeLa) y pulmón (A-549) (IC 50 = 10.84, 11.73, 11.26, 11.53 y 11.96 μg mL -1 , respectivamente). El análisis de correlación sugiere que los polifenoles de Calendula officinalis están directamente relacionados con la capacidad antioxidante del extracto y se asocian inversamente con la viabilidad celular.Palabras Clave: Calendula officinalis, polifenoles, antioxidante, citotoxicidad.

One of the most important causes of disease and premature death in the world is environmental pollution. The presence of pollutants in both water and air contributes to the deterioration of the health of human populations. The Mexico City Metropolitan Area is one of the most populous and affected by air pollution worldwide; in addition, in recent years there has been a growing demand for water, so urban reservoirs such as the Madin dam are vital to meet the demand. However, this reservoir is highly polluted due to the urban settlements around it. Therefore, the aim of the present study was to evaluate oxidative stress in clinically healthy subjects by means of the degree of lipoperoxidation, as well as the modification of serum enzyme levels, such as alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase associated with air and drinking water pollutants from three zones of the Mexico City Metropolitan Area, two of them related to Madin Dam. This descriptive cross-sectional study was conducted between March 2019 and September 2021 in 142 healthy participants (age range 18-65 years). Healthy subjects were confirmed by their medical history. The results showed that chronic exposure to air (SO 2 ) and water pollutants (Al and Fe) was significantly associated with elevated levels of lipoperoxidation. There was evidence that contamination from the Madín dam can generate oxidative stress and affect the health status of people who receive water from this reservoir or who consume fish that inhabit it.