Executive summary on the treatment of type 2 diabetes mellitus in elderly or frail individuals. 2022 update of the 2018 consensus document "Treatment of type 2 diabetes mellitus in the elderly".

The population with type 2 DM (DM2) is highly heterogeneous, representing an important challenge for healthcare professionals. The therapeutic choice should be individualized, considering the functional status, frailty, the occurrence of comorbidities, and the preferences of patients and their caregivers. New evidence on the cardiovascular and renal protection of specific therapeutic groups and on the usefulness of new technologies for DM2 management, among other aspects, warrant an update of the consensus document on the DM2 in the elderly that was published in 2018.

[Control of cardiovascular risk factors in type 2 diabetes in a specialized diabetic clinic]. / Control de los factores de riesgo cardiovascular en diabetes tipo 2 en una consulta monográfica.

BACKGROUND: Achieving an adequate control of glycaemic and cardiovascular risk factors (CVRFs) is essential in patients with type 2 diabetes mellitus (T2DM). However, several studies have shown that the percentage of patients achieving these goals is scarce. We evaluated the degree of control of CVRFs target goals in T2DM patients who regularly attend a specialized diabetic clinic. METHODS: We studied T2DM patients who attended the specialized Diabetic Unit at the Department of Endocrinology of Clínica Universitaria de Navarra with a minimum follow-up of one year. Clinical characteristics, chronic complications and treatments were collected and patients were classified into groups according to the fulfilment of target glycated haemoglobin (HbA1c), LDL cholesterol and blood pressure (BP) levels, predefined according to the presence of different comorbidities and the duration of T2DM. RESULTS: We analysed 137 patients (75% men) with T2DM, with an average age of 67 years and a 12.7 year duration of diabetes. During follow-up, 83.9% of the patients were within the individualized HbA1c target, 76.6% considering BP and 67.2% in terms of LDL-cholesterol. In addition, 68% had concomitantly the three main variables within the target. CONCLUSIONS: In our population of T2DM, HbA1c, LDL cholesterol and BP targets were achieved in a substantial proportion of patients (67-91%). Perhaps the intense and individualized care offered through a specialized diabetes unit may explain these results.

Review of basal-plus insulin regimen options for simpler insulin intensification in people with Type 2 diabetes mellitus.

AIMS: To identify simple insulin regimens for people with Type 2 diabetes mellitus that can be accepted and implemented earlier in primary and specialist care, taking into consideration each individual's needs and capabilities. METHODS: Using randomized clinical trials identified by a search of the PubMed database, as well as systematic reviews, meta-analyses and proof-of-concept studies, this review addresses topics of interest related to the progressive intensification of a basal insulin regimen to a basal-plus regimen (one basal insulin injection plus stepwise addition of one to three preprandial short-acting insulin injections/day) vs a basal-bolus regimen (basal insulin plus three short-acting insulin injections per day) in people with Type 2 diabetes. The review explores approaches that can be used to define the meal for first prandial injection with basal-plus regimens, differences among insulin titration algorithms, and the importance of self-motivation and autonomy in achieving optimum glycaemic control. RESULTS: A basal-plus regimen can provide glycaemic control equivalent to that obtained with a full basal-bolus regimen, with fewer injections of prandial insulin. The first critical step is to optimize basal insulin dosing to reach a fasting glucose concentration of ~6.7 mmol/l; this allows ~40% of patients with baseline HbA1c >75 mmol/mol (9%) to be controlled with only one basal insulin injection per day. CONCLUSIONS: Compared with a basal-bolus regimen, a basal-plus insulin regimen is as effective but more practical, and has the best chance of acceptance and success in the real world.

Dissociation of body mass index, excess weight loss and body fat percentage trajectories after 3 years of gastric bypass: relationship with metabolic outcomes.

BACKGROUND/OBJECTIVES: Body weight, body mass index (BMI) and excess weight loss (EWL) are the most frequently used measures to analyse bariatric surgery outcomes. However, these measurements do not provide accurate information on body composition (BC) with body fat (BF), importantly determining the levels of cardiometabolic risk factors. Our aim was to analyse the evolution of BC after Roux-en-Y Gastric Bypass (RYGB) and its influence on the changes of cardiometabolic risk factors in comparison to BMI and EWL. SUBJECTS/METHODS: A group of 81 obese Caucasian patients (19 males/62 females) aged 44.9±1.3 years undergoing RYGB between January 2006 and December 2011 was prospectively followed up for a period of 3 years. BC was determined by air-displacement plethysmography. Visceral adiposity, physical activity and cardiometabolic risk factors were measured. RESULTS: BF was markedly (P<0.001) reduced after the first year, increasing progressively during the second and third years after RYGB, following a different trajectory than body weight, BMI and EWL that decreased up to the second year post surgery. Markers of glucose homeostasis decreased during the first month and continued to decrease during the first year (P<0.05), remaining stabilised or slightly increased between the second and third years following RYGB. However, markers of lipid metabolism decreased (P<0.05) markedly during the first 12 months, increasing thereafter in parallel to the changes observed in BC, with the exception of high-density lipoprotein-cholesterol, which increased progressively throughout the whole period analysed. CONCLUSIONS: The adverse switch in the changes in BC between the first and the second years after RYGB may underlie the changes observed in cardiometabolic risk factors. Tracking of adiposity during the follow-up of bariatric/metabolic surgery yields clinically relevant information to better identify patients in need of increased lifestyle advice or treatment intensification.

Antioxidant capacity of (+)-catechin visible-light photoirradiated in the presence of vitamin B2.

OBJECTIVES: Catechins are important components of human diet and have received special attention due to their antioxidant capacity. The purpose of this paper was to study the antioxidant action of (+)-catechin (CTQ) in the presence of vitamin B2 (riboflavin) as light-absorbing agent. Furthermore, two model compounds, catechol (CTC) and resorcinol (RSC), were selected in order to elucidate the reactive target of the CTQ molecule. The influence of pH-medium was investigated. METHODS: Stationary photolysis, polarographic detection of dissolved oxygen, reactive oxygen species (ROS)-scavengers, time-resolved near-IR phosphorescence detection, stationary, and time-resolved fluorescence and laser flash photolysis techniques were employed. RESULTS: CTQ interacts with riboflavin under visible-light photoirradiation as well as with different ROS which are generated in this mechanism. Radical-scavenging activity increases with increasing of pH-medium. DISCUSSION: pH-effect of the medium on radical-scavenging activity comes from the increased electron-donating ability of CTQ upon deprotonation. These results are very interesting due to the fact that the pH of the food products displays important variations. The [Formula: see text]-scavenging ability of CTQ, would be equal to the additive contribution of each reactive center, CTC, and RSC, present at the molecule of CTQ. However, CTQ would have a moderate ability to removal of [Formula: see text]-species at pH 7.

[Consensus on the detection and management of prediabetes. Consensus and Clinical Guidelines Working Group of the Spanish Diabetes Society]. / Consenso sobre la detección y el manejo de la prediabetes. Grupo de Trabajo de Consensos y Guías Clínicas de la Sociedad Española de Diabetes.

In Spain, according to the Di@bet.es study, 13.8% of the adult population suffers from diabetes and 14.8% from some form of prediabetes (impaired glucose tolerance, impaired fasting glucose or both). Since early detection of prediabetes can facilitate the implementation of therapeutic measures to prevent its progression to diabetes, we believe that preventive strategies in primary care and specialized clinical settings should be agreed. Screening for diabetes and prediabetes using a specific questionnaire (FINDRISC) and/or the measurement of fasting plasma glucose in high risk patients leads to detecting patients at risk of developing diabetes and it is necessary to consider how they should be managed. The intervention in lifestyle can reduce the progression to diabetes and reverse a prediabetic state to normal and is a cost-effective intervention. Some drugs, such as metformin, have also been shown effective in reducing the progression to diabetes but are not superior to non-pharmacological interventions. Finally, an improvement in some cardiovascular risk factors has been observed although there is no strong evidence supporting the effectiveness of screening in terms of morbility and mortality. The Consensus and Clinical Guidelines Working Group of the Spanish Diabetes Society has issued some recommendations that have been agreed by the Sociedad Española de Endocrinología y Nutrición, Sociedad Española de Endocrinología Pediátrica, Sociedad Española de Farmacia Comunitaria, Sociedad Española de Medicina Familiar y Comunitaria, Sociedad Española de Médicos Generales, Sociedad Española de Médicos de Atención Primaria, Sociedad Española de Medicina Interna, Asociación de Enfermería Comunitaria and Red de Grupos de Estudio de la Diabetes en Atención Primaria.

[Consensus on the detection and management of prediabetes. Consensus and Clinical Guidelines Working Group of the Spanish Diabetes Society]. / Consenso sobre la detección y el manejo de la prediabetes. Grupo de Trabajo de Consensos y Guías Clínicas de la Sociedad Española de Diabetes.

In Spain, according to the Di@bet.es study, 13.8% of the adult population suffers from diabetes and 14.8% from some form of prediabetes (impaired glucose tolerance, impaired fasting glucose or both). Since early detection of prediabetes can facilitate the implementation of therapeutic measures to prevent its progression to diabetes, we believe that preventive strategies in primary care and specialized clinical settings should be agreed. Screening for diabetes and prediabetes using a specific questionnaire (FINDRISC) and/or the measurement of fasting plasma glucose in high risk patients leads to detecting patients at risk of developing diabetes and it is necessary to consider how they should be managed. The intervention in lifestyle can reduce the progression to diabetes and reverse a prediabetic state to normal and is a cost-effective intervention. Some drugs, such as metformin, have also been shown effective in reducing the progression to diabetes but are not superior to non-pharmacological interventions. Finally, an improvement in some cardiovascular risk factors has been observed although there is no strong evidence supporting the effectiveness of screening in terms of morbility and mortality. The Consensus and Clinical Guidelines Working Group of the Spanish Diabetes Society has issued some recommendations that have been agreed by the Sociedad Española de Endocrinología y Nutrición, Sociedad Española de Endocrinología Pediátrica, Sociedad Española de Farmacia Comunitaria, Sociedad Española de Medicina Familiar y Comunitaria, Sociedad Española de Médicos Generales, Sociedad Española de Médicos de Atención Primaria, Sociedad Española de Medicina Interna, Asociación de Enfermería Comunitaria and Red de Grupos de Estudio de la Diabetes en Atención Primaria.

[Consensus on the detection and management of prediabetes. Consensus and Clinical Guidelines Working Group of the Spanish Diabetes Society]. / Consenso sobre la detección y el manejo de la prediabetes. Grupo de Trabajo de Consensos y Guías Clínicas de la Sociedad Española de Diabetes.

In Spain, according to the Di@bet.es study, 13.8% of the adult population suffers from diabetes and 14.8% from some form of prediabetes (impaired glucose tolerance, impaired fasting glucose or both). Since early detection of prediabetes can facilitate the implementation of therapeutic measures to prevent its progression to diabetes, we believe that preventive strategies in primary care and specialized clinical settings should be agreed. Screening for diabetes and prediabetes using a specific questionnaire (FINDRISC) and/or the measurement of fasting plasma glucose in high risk patients leads to detecting patients at risk of developing diabetes and it is necessary to consider how they should be managed. The intervention in lifestyle can reduce the progression to diabetes and reverse a prediabetic state to normal and is a cost-effective intervention. Some drugs, such as metformin, have also been shown effective in reducing the progression to diabetes but are not superior to non-pharmacological interventions. Finally, an improvement in some cardiovascular risk factors has been observed although there is no strong evidence supporting the effectiveness of screening in terms of morbility and mortality. The Consensus and Clinical Guidelines Working Group of the Spanish Diabetes Society has issued some recommendations that have been agreed by the Sociedad Española de Endocrinología y Nutrición, Sociedad Española de Endocrinología Pediátrica, Sociedad Española de Farmacia Comunitaria, Sociedad Española de Medicina Familiar y Comunitaria, Sociedad Española de Médicos Generales, Sociedad Española de Médicos de Atención Primaria, Sociedad Española de Medicina Interna, Asociación de Enfermería Comunitaria and Red de Grupos de Estudio de la Diabetes en Atención Primaria.

Consensus on the detection and management of prediabetes. Consensus and Clinical Guidelines Working Group of the Spanish Diabetes Society. / Consenso sobre la detección y el manejo de la prediabetes. Grupo de Trabajo de Consensos y Guías Clínicas de la Sociedad Española de Diabetes.

In Spain, according to the Di@bet.es study, 13.8% of the adult population suffers from diabetes and 14.8% from some form of prediabetes (impaired glucose tolerance, impaired fasting glucose or both). Since early detection of prediabetes can facilitate the implementation of therapeutic measures to prevent its progression to diabetes, we believe that preventive strategies in primary care and specialized clinical settings should be agreed. Screening for diabetes and prediabetes using a specific questionnaire (FINDRISC) and/or the measurement of fasting plasma glucose in high risk patients leads to detecting patients at risk of developing diabetes and it is necessary to consider how they should be managed. The intervention in lifestyle can reduce the progression to diabetes and reverse a prediabetic state to normal and is a cost-effective intervention. Some drugs, such as metformin, have also been shown effective in reducing the progression to diabetes but are not superior to non-pharmacological interventions. Finally, an improvement in some cardiovascular risk factors has been observed although there is no strong evidence supporting the effectiveness of screening in terms of morbility and mortality. The Consensus and Clinical Guidelines Working Group of the Spanish Diabetes Society has issued some recommendations that have been agreed by the Sociedad Española de Endocrinología y Nutrición, Sociedad Española de Endocrinología Pediátrica, Sociedad Española de Farmacia Comunitaria, Sociedad Española de Medicina Familiar y Comunitaria, Sociedad Española de Médicos Generales, Sociedad Española de Médicos de Atención Primaria, Sociedad Española de Medicina Interna, Asociación de Enfermería Comunitaria and Red de Grupos de Estudio de la Diabetes en Atención Primaria.

Cardiotrophin 1 protects beta cells from apoptosis and prevents streptozotocin-induced diabetes in a mouse model.

AIMS/HYPOTHESIS: Cardiotrophin 1 (CT-1) is a recently described cytokine originally isolated from the heart where it has been shown to play an important role in apoptotic protection of cardiomyocytes and heart hypertrophy. Its beneficial properties have also been described in other organs such as liver and neuromuscular tissue. In the present study, we investigated whether CT-1 can confer protection against pro-apoptotic stimuli in pancreatic beta cells, and its role in insulin secretion and diabetes development. METHODS: The effects of CT-1 on apoptosis and function were studied using MIN6B1 cells and freshly isolated murine pancreatic islets. The impact on the development of diabetes was evaluated in Ct1-null (Ct1 (-/-)) mice (the gene Ct1 is also known as Ctf1) using two streptozotocin (STZ)-induced models of diabetes. RESULTS: CT-1 has a protective effect in MIN6B1 cells and murine islets under the pro-apoptotic stimulus of serum deprivation, which correlates with the expression of B cell lymphoma-extra large, or following exposure to a mixture of cytokines. In addition, CT-1 enhances glucose-stimulated insulin secretion in MIN6B1 cells and this was repressed by inhibitors of phospholipase C. Furthermore, Ct1 (-/-) mice were more prone to develop diabetes, and their glucose tolerance test showed impaired plasma glucose clearance which correlated with decreased pancreatic insulin secretion. CONCLUSIONS/INTERPRETATION: The results obtained from both in vitro and in vivo experiments show that CT-1 improves beta cell function and survival, and protects mice against STZ-induced diabetes.

Body mass index classification misses subjects with increased cardiometabolic risk factors related to elevated adiposity.

CONTEXT: Body mass index (BMI) is widely used as a measure of overweight and obesity, but underestimates the prevalence of both conditions, defined as an excess of body fat. OBJECTIVE: We assessed the degree of misclassification on the diagnosis of obesity using BMI as compared with direct body fat percentage (BF%) determination and compared the cardiovascular and metabolic risk of non-obese and obese BMI-classified subjects with similar BF%. DESIGN: We performed a cross-sectional study. SUBJECTS: A total of 6123 (924 lean, 1637 overweight and 3562 obese classified according to BMI) Caucasian subjects (69% females), aged 18-80 years. METHODS: BMI, BF% determined by air displacement plethysmography and well-established blood markers of insulin sensitivity, lipid profile and cardiovascular risk were measured. RESULTS: We found that 29% of subjects classified as lean and 80% of individuals classified as overweight according to BMI had a BF% within the obesity range. Importantly, the levels of cardiometabolic risk factors, such as C-reactive protein, were higher in lean and overweight BMI-classified subjects with BF% within the obesity range (men 4.3 ± 9.2, women 4.9 ± 19.5 mg l(-1)) as well as in obese BMI-classified individuals (men 4.2 ± 5.5, women 5.1 ± 13.2 mg l(-1)) compared with lean volunteers with normal body fat amounts (men 0.9 ± 0.5, women 2.1 ± 2.6 mg l(-1); P<0.001 for both genders). CONCLUSION: Given the elevated concentrations of cardiometabolic risk factors reported herein in non-obese individuals according to BMI but obese based on body fat, the inclusion of body composition measurements together with morbidity evaluation in the routine medical practice both for the diagnosis and the decision-making for instauration of the most appropriate treatment of obesity is desirable.

Recomendaciones para el tratamiento del dolor neuropático / Recommendations for the treatment of neuropathic pain

Con la introducción y el desarrollo de nuevos productos que han demostrado ser eficaces en el dolor neuropático (DN), se ha generado una clara necesidad de tener un algoritmo basado en la evidencia para tratar las diferentes condiciones del DN. El objetivo de este artículo es elaborar unas recomendaciones para el tratamiento del DN que estén avaladas por la evidencia científica y que estén consensuadas por un grupo multidisciplinario de expertos en metodología y en tratamiento del dolor. La evidencia se ha obtenido de estudios de metanálisis que recogen la mayor información disponible para cada tipo de DN. La búsqueda bibliográfica se llevó a cabo por 5 revisores, que se centraron individualmente en las diferentes formas de presentación del DN. Las bases de datos consultadas fueron la Cochrane Library, EMBASE (año 2000 en adelante) y PUBMED(año 2000 en adelante), y se seleccionaron metaanálisis y ensayos clínicos aleatorizados y controlados. Finalmente, los autores, especialistas en dolor, evaluaron e hicieron las recomendaciones clínicas para el tratamiento del DN. En algunos tipos de DN, de los cuales no hay suficiente información, se han incluido recomendaciones basadas en publicaciones científicas sin evidencia, con el objetivo de que estas recomendaciones proporcionen la mayor información posible acerca de su tratamiento. Se han revisado estudios de eficacia y seguridad de neuralgia postherpética (NPH), neuropatía diabética dolorosa (NDD) y neuralgia del trigémino(NT) como paradigmas de DN periférico, y también se ha recogido la escasa información existente acerca del DN central(DNC) y el dolor simpático (DS). Con los resultados obtenidos con este estudio bibliográfico y las evidencias extraídas, se ha elaborado un algoritmo de decisión con los fármacos disponibles actualmente en la farmacopea española para la NPH y la NDD; por otro lado, y de forma independiente, para la NT y, finalmente, para el DNC y el DS.

The introduction and development of new products with demonstrated efficacy in neuropathic pain has generated a clear need for an evidence-based algorithm to treat the different types of neuropathic pain. The present article aims to provide recommendations on the treatment of neuropathic pain supported by the scientific evidence and agreed on by consensus by a multidisciplinary group of experts in methodology and pain management. The evidence was obtained from meta-analyses including the greatest amount of information available for each type of neuropathic pain. The literature search was performed by 5 reviewers, who focussed individually on the distinct forms of presentation of neuropathic pain. The databases consulted were the Cochrane Library, EMBASE (from 2000 onwards), and PUBMED (from 2000 onwards). Meta-analyses and randomized, controlled clinical trials were selected. Finally, retrieved articles were evaluated and clinical recommendations for the treatment of neuropathic pain were designed by the pain specialists. For some types of neuropathic pain, there is insufficient information. In these types of pain, recommendations based on scientific publications without evidence were included to provide the reatest possible amount of information on their treatment. Studies of safety and efficacy in postherpetic neuralgia (PHN), painful diabetic neuropathy (PDN), and trigeminal neuralgia (TN) were reviewed as paradigms of peripheral neuropathic pain. The scarce available information on central neuropathic pain (CNP) and sympathetic pain (SP) was also gathered. Based on the results obtained with this literature review and the evidence extracted, a decision algorithm was designed with the drugs currently available in the Spanish pharmacopeia for PHN and PDN, and separate decision algorithms were designed for TN and finally for CNP and S P.

Singlet molecular oxygen [O2(1Deltag)]-mediated photodegradation of tyrosine derivatives in the presence of cationic and neutral micellar systems.

The kinetics of rose bengal-sensitized photooxidation of tyrosine and several tyrosine-derivatives (tyr-D) named tyrosine methyl ester, tyrosine ethyl ester and tyrosine benzyl ester was studied in buffered pH 11 water, and buffered pH 11 micellar aqueous solutions of 0.01 M cetyltrimethylammonium chloride (CTAC) and 0.01 M-octylphenoxypolyethoxyethanol [triton X100 (TX100)]. Through time-resolved phosphorescence detection of singlet molecular oxygen (O(2)((1)Delta(g))) and polarographic determination of oxygen consumption, the respective bimolecular rate constants for reactive (k(r)) and overall (k(t)) quenching of the oxidative species by tyr-D were evaluated. Both rate constants behave in different fashion depending on the particular reaction medium. k(r)/k(t) values, increase in the sense CTAC<

[New therapeutic strategies for type 1 diabetes mellitus]. / Nuevas estrategias terapéuticas en diabetes mellitus tipo 1.

The main determinant of the risk of complications from type 1 diabetes mellitus is the total lifetime blood glucose levels. To impact on the health and quality of life of individuals with diabetes, safe and effective methods of achieving and maintaining normoglycemia are needed. Unfortunately, intensive insulin therapy does not achieve normal levels of blood glucose, is difficult to implement for many patients, and limited by the accompanying increased frequency of severe hypoglycemia. Hence, the only way at present to restore permanently normoglycemia without hypoglycemia is to provide the patient with additional beta-cells. This can be achieved by transplanting an intact pancreas, or by transplanting islets. The shortage of functional beta-cells from available donors is one of the major limiting factors for the treatment of diabetes by islet transplantation. Therefore, methods to preserve or even promote regeneration of the beta-cell mass are dearly needed. Significant progress has been made over the last decade in stem cell biology. However, the quest for identification of stem cells has been hampered by the lack of appropriate research tools including assays that allow assess their differentiation potential in vitro and in vivo. Therefore, new techniques are necessary in order to develop new therapeutic strategies based on stem cells for the treatment of diabetes mellitus type 1.

Differential regulation of gonadotropins and glycoprotein hormone alpha-subunit by IGF-I in anterior pituitary cells from male rats.

IGF-I has been demonstrated to stimulate basal and GnRH-induced gonadotropin release. IGF-I also elicites alpha-subunit secretion in human pituitary tumor cells. The aims of this study were to evaluate both the effect of IGF-I on gonadotropin LH-beta and FSH-beta mRNA levels and glycoprotein alpha-subunit gene expression in cultured rat anterior pituitary cells. The exposure of pituitary cells to recombinant human IGF-I (rhlGF-I; 2 microg/ml) for 72 h markedly stimulated basal LH and FSH release whereas their mRNA levels remained unmodified. IGF-I elicited a-subunit release from pituitary cells (p < 0.01) and augmented its mRNA levels. Exposure to IGF-I consistently reduced GH release from pituitary cells. This study shows that the gonadotropin-releasing effects of IGF-I are not paralleled by changes in their mRNAs whereas IGF-I stimulates not only alpha-subunit release but also its mRNA levels. This study provides the first observation of alpha-subunit regulation by IGF-I in normal pituitary cells, where a differential regulation between release and synthesis for gonadotropin a-and 1-subunits is also shown.

Photodegradation of the herbicide Norflurazon sensitised by Riboflavin. A kinetic and mechanistic study.

The kinetics and mechanism of the Riboflavin (Rf)-promoted photochemical degradation with visible light of the herbicide Norflurazon (NF) has been studied by time-resolved and stationary techniques. Using light of wavelength higher than 400 nm--a region where NF is totally transparent--and with concentrations of Rf and NF of ca. 0.02 and 1 mM, respectively, only the excited triplet state of Rf ((3)Rf*) is quenched by NF, in competition with dissolved ground state triplet oxygen, O(2)((3)Sigma(g)(-)). NF degradation mainly occurs by reaction with superoxide radical anion O(2)(-) formed through two electron transfer steps: from NF to (3)Rf*, yielding Rf radical anion, and from this anion to O(2)((3)Sigma(g)(-)), regenerating ground state Rf. Although singlet molecular oxygen is also produced, NF only quenches this oxidative species in a physical mode. The global result is the photoprotection of the sensitiser and the photodegradation of NF.

Kinetic study of the riboflavin-sensitised photooxygenation of two hydroxyquinolines of biological interest.

4-Hydroxyquinoline (4-OHQ) and 8-hydroxyquinoline (8-OHQ), two compounds of interest because of their bioactivity and their structural relation with bioactive products, are effectively photooxygenated when irradiated with visible light in the presence of riboflavin (Rf) (vitamin B2) in solution in air-saturated water-methanol (9:1). Rf behaves as a dye-sensitiser, since both quinolines are transparent to visible light. 8-OHQ degrades about five times faster than 4-OHQ. Kinetic data obtained through time-resolved and stationary detection of Rf-electronically excited states indicate that a superoxide radical anion-mediated mechanism exclusively operates for 4-OHQ, whereas singlet molecular oxygen--mainly--plus superoxide radical anion is the species that reacts with 8-OHQ. The sensitiser Rf, which is known to photodegrade under visible-light aerobic irradiation, is regenerated in the presence of any of the quinolines through an electron transfer process that produces superoxide radical anion. The overall picture indicates that both quinolines act as sacrificial scavengers of the photogenerated oxygen species, thus preventing the photodegradation of Rf.