Citrus junos Tanaka Peel Extract and Its Bioactive Naringin Reduce Fine Dust-Induced Respiratory Injury Markers in BALB/c Male Mice

Abstract

Particulate matter (PM) 10 refers to fine dust with a diameter of less than 10 µm and induces apoptosis and inflammatory responses through oxidative stress. Citrus junos Tanaka is a citrus fruit and contains bioactive flavonoids including naringin. In the present study, we aimed to identify the preventive effect of Citrus junos Tanaka peel extract (CPE) against PM10-induced lung injury. As a proof of concept, NCI-H460 cells were treated with CPE (800 μg/mL, 12 h) in conjunction with PM10 to examine intracellular antioxidative capacity in the pulmonary system. In an in vivo model, male BALB/c mice (n = 8/group) were randomly assigned into five groups: NEG (saline-treated), POS (PM10 only), NAR (PM10 + naringin, 100 mg/kg), CPL (PM10 + CPE low, 100 mg/kg), and CPH (PM10 + CPE high, 400 mg/kg). Intervention groups received dietary supplementations for 7 days followed by PM10 exposure (100 mg/kg, intranasal instillation). Compared to the NEG, the CPE decreased to 22% of the ROS generation and significantly increased cell viability in vitro. The histological assessments confirmed that pulmonary damages were alleviated in the PM10 + CPL group compared to the POS. Pro-inflammatory cytokines and NF-κB/apoptosis signaling-related markers were decreased in the PM10 + CPL group compared to the POS. These results indicated that CPE showed promising efficacy in preventing pulmonary injuries in vivo. Such protection can be explained by the anti-oxidative capacity of CPE, likely due to its bioactives, including naringin (7.74 mg/g CPE). Follow-up human intervention, as well as population-level studies, will further shed light on the preventive efficacy of CPE against pulmonary damage in humans.

Nomilin from Yuzu Seed Has In Vitro Antioxidant Activity and Downregulates Melanogenesis in B16F10 Melanoma Cells through the PKA/CREB Signaling Pathway

“…Another study evaluated the toxicity of citron peel extract and reported that it was safe at <800 µg/mL. In this study, nomilin was isolated from the yuzu seed husk, and the non-toxic concentration was found to be <100 µg/mL [ 51 ]. These results suggest that the range of toxicity may appear differently depending on the yuzu seed extraction method and cell types.…”

Ameliorative Effect of Citrus junos Tanaka Waste (By-Product) Water Extract on Particulate Matter 10-Induced Lung Damage

“…The CJBs used in this study were obtained from the Goheung Agricultural Cooperative Federation (Goheung, Korea) and extracted through the methods used by Lee et al [ 20 ], with some modifications. The material was ground using a blender and extracted (70 °C) with 10 volumes of distilled water for two hours.…”

“…The naringin and hesperidin contents in the samples were determined using the method of Lee et al, with some modifications [ 20 ]. The Shiseido Nanospace SI-2 (Shiseido; Tokyo, Japan) was equipped with a quaternary pump, an online degasser, an auto plate-sampler, and a UV/Vis detector with a CapcellPAK C18 UG120 column (4.6 × 250 mm, 5 µm particle size), which was used for the separation.…”

“…Saline was nasally administered to the CON mice. After six hours of exposure to PM10, the mice were euthanized by an intraperitoneal injection of tribromoethanol (200 mg/kg; Sigma-Aldrich), and their serum, bronchoalveolar lavage fluid (BALF), and lung tissues were immediately collected and stored at −80 °C [ 20 ]. All animal care and experimental procedures were approved by the ethics committee of Korea University (approval number: KUIACUC-2020-0044).…”

“…The increasing annual prevalence of PM10-induced diseases imposes enormous multidimensional burdens on patients and healthcare systems, necessitating the exploration of newer, safer substances for treatment, such as natural products. Our previous studies [ 20 ] demonstrated the potent antioxidant effect of CJ peel extract in PM10-exposed mouse lungs. The purpose of this study was to reuse CJ by-products (CJBs), which have more abundant nutritional bioactives than CJ peel alone, to minimize environmental stress.…”