Toxicological aspects of the use of phenolic compounds in disease prevention

The consumption of a diet low in fat and enhanced by fruits and vegetables, especially rich in phenolic compounds, may reduce risks of many civilization diseases. The use of traditional medicines, mainly derived from plant sources, has become an attractive segment in the management of many lifestyle diseases. Concerning the application of dietary supplements (based on phenolic compounds) in common practice, the ongoing debate over possible adverse effects of certain nutrients and dosage levels is of great importance. Since dietary supplements are not classified as drugs, their potential toxicities and interactions have not been thoroughly evaluated. First, this review will introduce phenolic compounds as natural substances beneficial for human health. Second, the potential dual mode of action of flavonoids will be outlined. Third, potential deleterious impacts of phenolic compounds utilization will be discussed: pro-oxidant and estrogenic activities, cancerogenic potential, cytotoxic effects, apoptosis induction and flavonoid-drug interaction. Finally, future trends within the research field will be indicated

Dietary anthocyanins: are they micronutrients?

Dietary anthocyanins might be seen as micronutrients. Even though they are abundant in fruits and vegetables, and thus also in our diet, they occur in plasma and tissues only in trace amounts. However, they profoundly af ect cellular metabolism, organ functioning, and have strong clinical-epidemiological evidence supporting their health-promoting ef ects

Prognostic model for predicting hearing recovery in idiopathic sudden sensorineural hearing loss

Hypothesis: To aid in realistic counseling of patients at the time of their first visit concerning their chances for recovery, we created a simple prognostic model for predicting hearing recovery in idiopathic sudden sensorineural hearing loss (ISSHL). Background: An important element of research on ISSHL is to identify prognostic factors for this disease. Many studies have described predictive indicators to identify patients with a good prognosis needing no or minimal treatment. Only a few of these studies have included a model for calculating the probability for patient recovery, which may be important for clinical work, but these prognostic tables have not achieved widespread use clinically. Methods: Evaluation of an electronic patient data base of 541 patients with ISSHL. The standard treatment was carbogen inhalation (95% O2 and 5% CO2 8 times per day in duration of 30 min) and prednisone orally (100 mg in 1 morning dose) for 7 days. Factors that were analyzed included the patient's age, the interval between the onset of symptoms and beginning of treatment, the presence or absence of vertigo and tinnitus, audiometric patterns, the severity of hearing loss, and hearing in the opposite ear. Hearing gain was expressed either as absolute hearing gain or as relative hearing gain. Significant recovery of hearing was defined as the final pure-tone audiometry of 30 dB or less (or the same as the pure-tone audiometry of the opposite ear). Results: The absolute hearing gain was 15.1 dB. The mean relative hearing gain was 47%. Three hundred one (57%) patients had significant recovery of hearing, and 228 (43%) did not have significant recovery of hearing. Using step-wise multiple linear regression analysis, the most important factors for prognosis included severity of hearing loss, presence of vertigo, time between onset and treatment, the hearing of the other ear, and the audiogram shape ([beta] coefficient was -0.216, -0.231, 0.211, 0.113, and -0.064, respectively; constant, 0.968). A recovery expectancy table was developed using the data from this study. Conclusion: Based on a retrospective analysis, prognostic indicators for hearing recovery in ISSHL were found to be severity of hearing loss, presence of vertigo, time between onset and treatment, the hearing of the other ear, and the audiogram shape. We created a model for calculating the probability for hearing recovery based on the analysis of 529 patients with unilateral ISSHL

Bioavailability of flavonoids: The role of cell membrane transporters

Dietary flavonoids play an important role in the prevention of diseases related to oxidative stress in living systems. Although much attention has been focused on studying the protective functions of flavonoids, so far only limited biochemical research was done to tackle the fundamental issue of how flavonoids enter cells. Flavonoids have limited bioavailability, and consequently low plasma concentrations. Thus, in order to enter the intracellular compartment of cells in target tissues, flavonoids must exploit specific cell membrane transporter systems. This interaction between flavonoids and the proteins that mediate their transmembrane transport is of critical importance since it affects both the pharmacokinetic and pharmacodynamic properties of the flavonoids. Extensive knowledge of cell membrane transporters is therefore essential to fully understand the mechanisms of flavonoid-mediated protective activity in the cardiovascular, renal, hepatic, and central nervous systems, and also to elucidate flavonoid-drug interactions

Oxidative stress-based cytotoxicity of delphinidin and cyanidin in colon cancer cells.

Colorectal cancer is the second most frequent cause of cancer death in the western world. Although the prognosis has improved after the introduction of newer anticancer drugs, the treatment of metastatic colorectal cancer still remains a challenge due to a high percentage of drug-resistant tumor forms. We aimed at testing whether anthocyanidins exerted cytotoxicity in primary (Caco-2) and metastatic (LoVo and LoVo/ADR) colorectal cancer cell lines. Both cyanidin and delphinidin, though neither pelargonidin nor malvidin, were cytotoxic in metastatic cells only. The cell line most sensitive to anthocyanidins was the drug-resistant LoVo/ADR. There, cellular ROS accumulation, inhibition of glutathione reductase, and depletion of glutathione could be observed. This suggests that anthocyanidins may be used as sensitizing agents in metastatic colorectal cancer therapy