[Study on Effects and Mechanisms of Phytochemicals in Vegetables and Fruits in Preventing and Treating Lung Cancer]

Assessment of Methodological Pipelines for the Determination of Isothiocyanates Derived from Natural Sources

Isothiocyanates are biologically active secondary metabolites liberated via enzymatic hydrolysis of their sulfur enriched precursors, glucosinolates, upon tissue plant disruption. The importance of this class of compounds lies in their capacity to induce anti-cancer, anti-microbial, anti-inflammatory, neuroprotective, and other bioactive properties. As such, their isolation from natural sources is of utmost importance. In this review article, an extensive examination of the various parameters (hydrolysis, extraction, and quantification) affecting the isolation of isothiocyanates from naturally-derived sources is presented. Overall, the effective isolation/extraction and quantification of isothiocyanate is strongly associated with their chemical and physicochemical properties, such as polarity-solubility as well as thermal and acidic stability. Furthermore, the successful activation of myrosinase appears to be a major factor affecting the conversion of glucosinolates into active isothiocyanates.

The Associations of Fruit and Vegetable Intake with Lung Cancer Risk in Participants with Different Smoking Status: A Meta-Analysis of Prospective Cohort Studies

The results of epidemiological studies on the relationship between fruit and vegetable intake and lung cancer risk were inconsistent among participants with different smoking status. The purpose of this study was to investigate these relationships in participants with different smoking status with prospective cohort studies. A systematic literature retrieval was conducted using PubMed and Scopus databases up to June 2019. The summary relative risks (RRs) and the corresponding 95% confidence intervals (CIs) were calculated by random-effects model. The nonlinear dose-response analysis was carried out with restricted cubic spline regression model. Publication bias was estimated using Begg’s test. Nine independent prospective studies were included for data synthesis. Dietary consumption of fruit was negatively correlated with lung cancer risk among current smokers and former smokers, and the summery RRs were 0.86 (95% CI: 0.78, 0.94) and 0.91 (95% CI: 0.84, 0.99), respectively. Consumption of vegetable was significantly associated with reduced risk of lung cancer for current smokers (summary RR = 87%; 95% CI: 0.78, 0.94), but not for former smokers and never for smokers. Dose-response analysis suggested that risk of lung cancer was reduced by 5% (95% CI: 0.93, 0.97) in current smokers, and reduced by 4% (95% CI: 0.93, 0.98) in former smokers with an increase of 100 grams of fruit intake per day, respectively. Besides, dose-response analysis indicated a 3% reduction in lung cancer risk in current smokers for 100 gram per day increase of vegetable intake (95% CI: 0.96, 1.00). The findings of this study provide strong evidence that higher fruit consumption is negatively associated with the risk of lung cancer among current smokers and former smokers, while vegetable intake is significantly correlated with reducing the risk of lung cancer in current smokers. These findings might have considerable public health significance for the prevention of lung cancer through dietary interventions.