Bioactive flavonoid from apple trees eases asthma symptoms: Taiwan study

They found Phloretin (PT), assisted in reducing severe airway hyper-responsiveness, airway inflammation and oxidative stress in mice with induced asthma.

Researchers from Chang Gung University of Science and Technology in Taiwan noted: “We found that PT significantly reduced goblet cell hyperplasia and eosinophil infiltration, which decreased AHR, inflammation, and oxidative responses in the lungs of ovalbumin (OVA)-sensitized mice,”​ they wrote in Frontiers in Immunity​.

“These findings suggested that PT alleviated pathological changes, inflammation, and oxidative stress by inhibiting Th2 cytokine production in asthmatic mice.”​

In the study, mice were randomly assigned to the five experimental groups: normal controls; OVA-induced asthmatic mice; and OVA-induced mice injected with three PT doses of 5, 10, or 20 mg/kg.

“On days 14, 17, 20, 23, and 27, the mice were challenged with inhalations of 2% OVA for 30 minutes. One hour before the OVA inhalation challenge, mice were treated with or without intraperitoneal injections of PT.”​

Airway hyper responsiveness was then measured by Penh value to assess airway function after the mice inhaled aerosolised methacholine, which is used to diagnose asthma.

 “At 40 mg/ml of inhaled methacholine, PT-treated asthmatic mice showed significantly lower Penh values compared to asthmatic mice in the OVA-sensitized group. Hence, PT could significantly diminish AHR in asthmatic mice.”​

Fewer inflammatory cells

The asthmatic mice treated with PT also reported reduced numbers of inflammatory cells and had an increased expression of the antioxidant heme oxygenase (HO-1), which previous studies showed decreases lung damage during oxidative stress. 

PT is found in the fruit, leaves, and bark of apple trees and has previously been found to regulate glucose transporters, promote apoptosis in tumor cells, and enhance lipid metabolism to defend against obesity.

The research team involved in the current study also previously found that found that it reduced inflammatory and oxidative stress in LPS-induced acute lung injury mice.

Now they have also concluded that PT could lessen local asthma symptoms in the lungs.

“PT acted by blocking the inflammatory response and alleviating oxidative stress,”​ researchers concluded. “​It showed therapeutic potential for ameliorating asthma symptoms in the future.”​

Source: Frontiers in Immunity​

DOI: 10.3389/fimmu.2017.00134​

“Phloretin attenuates allergic airway inflammation and Oxidative stress in asthmatic mice”​

Authors: Wen-Chung Huang, Li-Wen Fang, et al​.