Respiratory Protective Effects of Perilla Leave Varieties (Perilla frutescens) Against Fine Particulate Matter (PM2.5)-induced Damage in Human Nasal Cells

Abstract

Fine particulate matter (PM2.5) is known to exacerbate chronic respiratory disorders, primarily by inducing inflammatory responses and mucus overproduction. Perilla leaves are reported to have significant health benefits, such as antioxidant, antibacterial, and antiallergic properties, attributed to phenolic compounds that vary depending on genetic diversity. In this study, flavonoid-rich extracts (FRE) from 56 perilla leaf varieties and genetic resources were prepared and screened using a mass screening system. The screening focused on evaluating their anti-inflammatory, mucus-reducing, and respiratory protective effects against PM2.5-induced damage in human nasal cells (RPMI2650). Parameters such as cell viability, nitric oxide (NO) levels, and mucus secretion factor (MUC5AC) concentrations were assessed. Among the 56 varieties, Perilla frutescens var. crispa (YCPL706), sourced from Ulleung Island, Korea, exhibited the highest cell viability (112.50%, 100 μg/mL), lowest NO concentration (9.98 μM, 100 μg/mL), and MUC5AC level (78.65 ng/mL, 100 μg/mL). Further evaluation of YCPL706 FRE demonstrated significant respiratory protective effects, including the inhibition of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), MUC5AC, and oxidative stress factors (MDA and ROS), compared to the control cultivar Namcheon. YCPL706 also showed strong antibacterial activity against Pseudomonas aeruginosa (minimum inhibitory concentration: 5 mg/mL). These findings suggest that the genetic resource YCPL706 is a promising candidate for combating PM2.5-induced respiratory damage due to its potent anti-inflammatory, antioxidant, and antibacterial properties.

Keywords: Perilla leaf; fine particulate matter; genetic resource; respiratory disease; varieties.

FIGURE 1

Fifty‐six leaf varieties in different cultivars (cvs), elite lines (ELs), and genetic resources (GRs) of perilla (Perilla frutescens L.) for mass screening of potential respiratory improvement effects.

FIGURE 2

Distribution of (A) antioxidant compounds (polyphenols and flavonoids) and (B) antioxidant activities (2,2‐azinobis (3‐ethyl benzothiazoline)‐6‐sulfonic acid [ABTS] and 1,1‐diphenyl‐2‐picrylhydrazyl [DPPH] radical scavenging activity, mg TE/g) in 56 perilla leaf varieties (Perilla frutescens L.) from cultivars (cvs), elite lines (Els), and genetic resources (GRs).

FIGURE 3

Distribution of individual phenolic compounds (caffeic acid [CA], rosmarinic acid [RA], luteolin [LT]) in 56 perilla leaf varieties (Perilla frutescens L.) from cultivars (cvs), elite lines (Els), and genetic resources (GRs).

FIGURE 4

Selection of useful resources for perilla leaves (Perilla frutescens L.) through a mass screening system for beneficial effects against fine particulate matter (PM_2.5)‐induced respiratory disease. (A) Cell viability, (B) nitric oxide (NO), and (C) secretion of mucin 5 AC (MUC5AC) in human nasal cells (RPMI2650) exposed to PM_2.5. (D) Cell viability & NO concentration, (E) cell viability & MUC5AC concentration, and (F) three selected kinds of resources.

FIGURE 5

Correlation heat map analysis and principal component analysis (PCA) of the associated antioxidant compounds and activities, individual phenolic compounds, and protective effects against respiratory disease obtained from 56 leaf varieties (Perilla frutescens L.) in different cultivars (cvs), elite lines (Els), and genetic resources (GRs).

FIGURE 6

Respiratory protective effects of selected genetic resources (I286242, YCPL706, and IT242103) in fine particulate matter (PM_2.5)‐induced RPMI2650 cells compared to the control cultivar (Namcheon) and positive control (P.C; thymoquinone 2.5 ppm). Assessment of (A) cell viability, (B) reactive oxygen species (ROS) fluorescence intensity, (C) intracellular ROS levels, (D) lipid peroxidation of malonaldehyde (MDA; nmol/mg protein), and (E) antioxidant enzyme activity of glutathione reductase (GR; μmol/min/mg protein), glutathione peroxidase (GPX; μmol/min/mg protein), catalase (CAT; μmol/min/mg protein), and superoxide dismutase (SOD; unit/mg protein) in RPMI2650 cells treated for 24 h with the sample and 100 μg/mL PM_2.5. Values are the mean ± SD of 3 replicates. Different small letters in the same items indicate a significant difference (p < 0.05) among different perilla resources and concentrations of extracts. ^### p < 0.001 and ***p < 0.001 represents significant difference compared to PM2.5 treated control.

FIGURE 7

Inhibitory effects of selected genetic resources (I286242, YCPL706, and IT242103) on fine particulate matter (PM_2.5)‐induced inflammation, mucus hypersecretion, and fibrosis in RPMI2650 cells compared with the control cultivar (Namcheon) and positive control (P.C; thymoquinone 2.5 ppm). Assessment of (A) nitric oxide (NO), (B) tumor necrosis factor‐alpha (TNF‐α), (C) interleukin (IL)‐6, (D) IL‐1β, (E) mucin 5 AC (MUC5AC), and (F) matrix metalloproteinase‐9 (MMP‐9) levels in RPMI2650 cells treated for 24 h with the sample and 100 μg/mL PM_2.5. Values are the mean ± SD of 3 replicates. Different small letters in the same items indicate a significant difference (p < 0.05) among different perilla resources and concentrations of extracts. ^### p < 0.001 and ***p < 0.001 represents significant difference compared to PM2.5 treated control.

FIGURE 8

Antimicrobial activities of selected genetic resources (IT286242, YCPL706, and IT242103) compared with those of control cultivar (Namcheon) against Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae . (A) Minimum inhibitory concentration (MIC) and (B) disk diffusion method. N.D.: Not detected.