Structure-activity relationship of flavonoids and its application in pulmonary inflammatory diseases / 中草药

As polyphenolic compounds in nature, flavonoids are classified into flavones, flavanones, flavonols, flavanonols, isoflavones, isoflavanones, flavan-3-ols, anthocyanidins, and chalcones according to their chemical structures. In general, flavonoids with different structures always have different biological activities. Many studies have shown that flavonoids exhibit a wide range of pharmacological effects, such as anti-oxidant, antimutagenic, antitumor, anti-inflammatory, antibacterial, antiviral, and immunomodulatory activities. The anti-inflammatory and anti-oxidant properties of flavonoids make them likely to be candidates for prevention and treatment of pulmonary inflammatory diseases. Thus, this review focuses on the application of flavonoids in pulmonary inflammatory diseases, as well as establishes some structure-activity relationships between this biological potential and chemical profile of these compounds, which can provide the references for the development and utilization of flavonoids.

Dietary flavan-3-ols intake and metabolic syndrome risk in Korean adults

Flavan-3-ols are a subclass of flavonoids found in a variety of foods including teas. The effects of flavan-3-ols on the risk of metabolic syndrome (MetS) have been investigated, generally focusing on tea catechins or individual flavan-3-ol rich foods, but there is little information on dietary flavan-3-ols intake and risk of MetS in population-based studies. In this cross-sectional study, we examined the association between dietary flavan-3-ols intake and the risk of MetS in Korean adults. Subjects comprised 1,827 men and 2,918 women aged 20-69 years whose data was included in the 2008 Korean National Health and Nutrition Examination Survey. This survey was conducted between January 2008 and December 2008. Total flavan-3-ols intakes were calculated from 24-hour dietary recalls using a flavonoids database. Thirty percent of the male subjects and 24% of the female subjects were reported as having MetS. In the female subjects, flavan3-ols intake was inversely associated with the risk of MetS after adjusting for potential confounders (5th vs. 1st quintile, OR = 0.64, 95% CI = 0.45-0.91, P for trend = 0.384). The main food source of flavan-3-ols was green tea followed by apples and grapes. Among MetS components, flavan3-ols intake was inversely associated with the risk of high blood pressure after adjusting for potential confounders (5th vs. 1st quintile, OR = 0.64, 95% CI = 0.45-0.90, P for trend = 0.005). No significant association between flavan-3-ols intake and risk of MetS was found in the male subjects. After stratified analysis by obesity (BMI > or = 25 or BMI < 25), however, flavan3-ols intake was inversely related to the risk of hypertension in non-obese men. These results suggest that dietary flavan-3-ols intake may have beneficial effects on MetS risk by reducing the risk of hypertension. The effects of flavan-3-ols intake dependent on obesity need further investigation.

Development of flavonoid database for commonly consumed foods by Koreans

Flavonoids have been hypothesized to reduce the risk of chronic diseases, but the lack of a flavonoid database hampered epidemiological studies addressing this issue in Korea. In this study, we developed a flavonoid database, based on a systematic review. A total of 1549 food items containing flavonoids were selected using the Korean Nutrient Database. Among them, flavonoid contents for only 649 food items were evaluated with analytical values and the remaining 900 items were replaced with adaptations or calculations from similar items. The developed flavonoid database covered 93.2% of fruits and fruit juices, 76.1% of vegetables, 98.4% of legumes and legume products, and 85.0% of all plant foods overall (1,549 items) as reported by the 24-hr dietary recall method regarding the 2008 Korean National Health and Nutrition Examination Survey. We found that this flavonoid database, overall, included 95.6% of all mainly consumed plant foods by Koreans. This flavonoid database is expected to be useful in regards to the correlation study of flavonoid intake and chronic diseases.