The preparation, dubbed PL-tLB, consists of two bacterial strains, Lactobacillus plantarum VIOAP03 and Lactobacillus fermentum VIMPP04, combined in a one-to-one volume ratio. Both strains were deposited with the Korean Collection for Type Cultures, and one of them was cultured in a medium enriched with P. linteus concentrate before harvesting. The mixture was then subjected to tyndallization, a repeated heating process named after the nineteenth-century physicist John Tyndall that renders bacterial cells nonviable while preserving many of their structural components. The final product was flash-frozen in liquid nitrogen, freeze-dried, and standardized to contain at least one hundred billion nonviable cells per gram. According to the authors, this approach sidesteps a central weakness of live probiotics, which can lose viability during storage and gastrointestinal transit and, in vulnerable patients, carry a small risk of microbial translocation.

Tyndallized bacteria belong to a category of products sometimes called paraprobiotics or postbiotic-related materials. Although dead cells cannot perform metabolic activity, their cell walls, peptidoglycans, and other surface molecules can still interact with immune cells and modulate inflammatory signaling pathways. Previous work with heat-killed Lactobacillus rhamnosus, for example, showed reduced immunoglobulin E levels in a mouse model of atopic dermatitis. The Korean team reasoned that bacteria living in symbiosis with a medicinal mushroom might carry particularly potent immunomodulatory properties, since the mushroom itself is rich in polysaccharides, phenolic compounds, terpenoids, and proteins with documented anti-inflammatory and antioxidant effects.

The first experiments used HaCaT cells, a widely studied line of human keratinocytes, the dominant cell type of the outer epidermis. When keratinocytes are stimulated with the inflammatory signals TNF-alpha and IFN-gamma, they mimic the cytokine milieu of an atopic dermatitis lesion, ramping up production of chemokines such as CCL17/TARC and CCL22/MDC, both recognized biomarkers of the disease, along with the proinflammatory cytokines IL-1beta, IL-6, and IL-8. Treatment with PL-tLB suppressed the expression of all of these mediators in a concentration-dependent manner, measured both at the messenger RNA level by real-time PCR and at the protein level by enzyme-linked immunosorbent assay. At a concentration of thirty micrograms per milliliter, the suppressive effect was comparable to that of cyclosporine A, a potent immunosuppressive drug used in severe eczema.

Not every dose was benign. At sixty and one hundred micrograms per milliliter, PL-tLB reduced HaCaT cell viability to below eighty percent, a signal of cellular stress that the authors attribute, hypothetically, to excessive exposure of the cells to bacterial cell wall components such as peptidoglycans and lipoteichoic acids. Importantly, the researchers did not measure, isolate, or deplete any candidate molecules, so the component responsible for the toxicity, and indeed for the anti-inflammatory benefit, remains unknown. All subsequent cell experiments were therefore conducted at three, ten, and thirty micrograms per milliliter, concentrations that preserved viability while retaining biological activity.

The team then moved to an animal model. Thirty female BALB/c mice were divided into groups and given topical applications of DNCB, 2,4-dinitrochlorobenzene, a chemical sensitizer that reliably induces atopic dermatitis-like lesions on mouse skin. After an initial sensitization week, both ears of each mouse were challenged twice weekly for three weeks, while the animals received daily oral gavage of PL-tLB at three escalating doses, or dexamethasone as a positive control. Four weeks of DNCB exposure produced the expected pathology: swollen ears, thickened epidermis and dermis, and dense infiltration of mast cells, the immune cells whose granules release histamine and drive the itching characteristic of eczema. Mice treated with PL-tLB showed significantly reduced ear thickness, less epidermal and dermal hypertrophy on hematoxylin and eosin staining, and fewer mast cells on toluidine blue staining compared with untreated DNCB animals.

The immunological fingerprints of the disease were also blunted. Atopic dermatitis is driven largely by T helper type 2 cells, which stimulate B cells to secrete immunoglobulin E, the antibody class responsible for allergic hypersensitivity, along with shifts in IgG subclasses. Serum levels of IgE, IgG1, and IgG2a all rose in DNCB-treated mice and fell significantly after PL-tLB administration. Notably, at the highest dose of one hundred billion cell equivalents per kilogram of body weight, the preparation suppressed IgE more effectively than dexamethasone in this experiment. Real-time PCR analysis of ear tissue confirmed the pattern at the transcriptional level, with dose-dependent reductions in the messenger RNA for IL-1beta, IL-4, IL-6, TNF-alpha, CCL17, and CCL22, and effects at the highest dose similar to those of the steroid control.

Perhaps the most intriguing finding concerned the skin barrier itself. DNCB exposure sharply reduced expression of filaggrin, involucrin, and loricrin, three structural proteins essential for the integrity of the stratum corneum, the outermost layer of the epidermis. Filaggrin deficiency in particular is a well-established genetic risk factor for atopic dermatitis, because it compromises the skin’s ability to retain moisture and exclude allergens. PL-tLB treatment produced a concentration-dependent partial recovery of all three genes. The preparation also restored, at least in part, the expression of tight junction components, including claudin-4, occludin, and tight junction protein 1, which seal the gaps between keratinocytes and provide a second, deeper line of defense complementary to the stratum corneum. A treatment that addresses both inflammation and barrier architecture simultaneously would represent a meaningful departure from therapies that suppress symptoms alone.

The authors are careful to frame the work as preclinical. Because the two bacterial strains were tested only as a combined mixture, their individual contributions, and any possible synergy between them, cannot be disentangled from the present data. The in vitro and in vivo experiments used different dosing metrics, micrograms per milliliter in cell cultures versus cell equivalents per kilogram in mice, and no validated conversion between the two was established. The study also did not assess pharmacokinetics, tissue distribution, or long-term safety, and no human efficacy can be inferred from mouse models. Future work, the researchers write, should fractionate the preparation, test each strain alone under matched conditions, and apply formal interaction analyses to determine whether the combined response is synergistic, additive, or driven by a single dominant component.

Even with those caveats, the study offers a compelling proof of concept that bacteria harvested from a medicinal mushroom and killed by heat can retain meaningful anti-inflammatory and barrier-protective activity. If the active molecules can be identified and standardized, tyndallized preparations could offer a shelf-stable, infection-free alternative to live probiotics for managing atopic dermatitis, a disease whose global prevalence continues to climb. For now, the humble Sanghwang mushroom has yielded more than polysaccharides: it has offered up two strains of lactic acid bacteria whose inert remains, in mice at least, quiet the immune storm and begin to rebuild the skin’s broken walls.

Subject of Research: Effects of tyndallized lactic acid bacteria from Phellinus linteus on atopic dermatitis-like inflammation and skin barrier damage

Article Title: Effects of tyndallized lactic acid bacteria separated from Phellinus linteus on inflammation and skin barrier damage induced by DNCB

Article References: Bak, S. G., Cheon, Y. J., Chandimali, N., Lim, H. J., Won, Y.-S., Kwon, H. S., Oh, H., Yun, S.-I., Lee, S. W., Bae, J., Kim, S., & Lee, S.-J. (2026). Effects of tyndallized lactic acid bacteria separated from Phellinus linteus on inflammation and skin barrier damage induced by DNCB. Archives of Dermatological Research, 318(1), Article 450. https://doi.org/10.1007/s00403-026-04963-3

Image Credits: AI Generated

DOI: 10.1007/s00403-026-04963-3

Keywords: atopic dermatitis, Phellinus linteus, tyndallized bacteria, postbiotics, skin barrier, tight junctions, filaggrin, lactic acid bacteria, DNCB, mast cells, immunoglobulin E, keratinocytes

The research team, led by Ruizhi Fan, Zeyuan Li, Meihua Liang, Chunyan Zhao, Xueli Wang and corresponding author Zhibin Zhang of Shanxi University of Traditional Chinese Medicine, systematically searched PubMed, Embase, the Cochrane Library and Web of Science for randomized controlled trials testing plant-based interventions in patients with allergic rhinitis. Their final dataset comprised 27 randomized controlled trials encompassing 1,681 participants, with studies published up to March 2025. Methodological quality was assessed with the Cochrane Risk of Bias Tool, and the statistical analysis, performed in Stata 15.4, employed a Bayesian network meta-analysis framework using Markov Chain Monte Carlo methods to allow both direct and indirect comparisons among interventions.

What distinguishes a network meta-analysis from a conventional pairwise meta-analysis is its ability to rank treatments even when they have never been compared head-to-head in a single trial. The team quantified each intervention’s performance using SUCRA values—the surface under the cumulative ranking curve—where a value approaching 100 percent signals the highest probability of being the most effective option in the network. The interventions ranged from well-known supplements such as spirulina and Pycnogenol to more specialized botanicals including Benifuuki green tea, broccoli sprout extract, fermented red ginseng, Perilla frutescens extract, Nigella sativa oil, stinging nettle root extract and Petasites hybridus leaf extract (Ze 339).

The rankings that emerged are strikingly specific to the outcome measured. For Total Nasal Symptom Scores, the primary clinical metric combining congestion, rhinorrhea, sneezing and itching, tomato extract rose to the top with a SUCRA value of 78.0 percent, suggesting it may offer the most consistent relief of core nasal symptoms. Glycyrrhiza glabra, commonly known as licorice, led the network for reducing Sino-Nasal Outcome Test-22 scores—a validated patient-reported instrument capturing nasal, sleep and emotional domains of sinonasal disease—with a SUCRA of 92.6 percent.

Spirulina, the blue-green cyanobacterium widely consumed as a nutritional supplement, achieved a perfect SUCRA of 100 percent for reducing Visual Analog Scale symptom ratings while simultaneously improving quality of life. Fermented red ginseng dominated the immunological endpoint, reducing serum immunoglobulin E levels with a SUCRA of 99.7 percent—a finding of mechanistic interest because IgE is the antibody class central to the allergic cascade, binding to mast cells and triggering histamine release upon allergen exposure. Flos Magnoliae volatile oil, derived from the flower buds used in traditional Chinese medicine for nasal obstruction, ranked highest at lowering serum eosinophil counts, with a SUCRA of 80.6 percent. Eosinophils are white blood cells recruited to inflamed nasal tissue in allergic disease, and their reduction signals a dampening of the underlying inflammatory process rather than merely masking symptoms.

Perhaps the most complete immunological result came from Phlai, a Thai ginger-family rhizome (Zingiber cassumunar), which achieved a perfect SUCRA of 100 percent for reducing interleukin-5 levels. IL-5 is the key cytokine driving eosinophil maturation, activation and survival, positioning Phlai upstream in the inflammatory hierarchy. Together, these biomarker findings sketch a plausible biological picture: several of the top-performing botanicals appear to act on the T helper 2-skewed immune signaling that underlies allergic rhinitis, modulating cytokines such as IL-4, IL-5 and IL-13, the NF-κB transcriptional pathway, and downstream effectors including eosinophils, leukotrienes and IgE.

The authors conclude that tomato extract, Glycyrrhiza glabra extract, spirulina, fermented red ginseng, Flos Magnoliae volatile oil and Phlai demonstrate more favorable efficacy profiles than the other plant-derived interventions in improving symptoms and quality of life. The study protocol was prospectively registered on PROSPERO (CRD420251052539), and the review’s breadth—spanning 24 substances and multiple laboratory indicators including interleukins, tumor necrosis factor-alpha, interferon-gamma and toll-like receptor signaling markers—makes it a valuable roadmap for prioritizing future trials.

Cautions remain, however. Network meta-analyses inherit the limitations of their component trials, which in this field often involve small samples, heterogeneous dosing, variable extract standardization and short follow-up periods. The certainty of evidence for individual comparisons can vary substantially, and indirect rankings should be read as hypothesis-generating rather than definitive prescriptions. The researchers note no competing interests, and the work was funded by the Department of Traditional Chinese Medicine Otorhinolaryngology of Shanxi University of Traditional Chinese Medicine and the Scientific Research Project of Shanxi Provincial Health Commission.

Even with those caveats, the analysis arrives at a moment of genuine clinical need. Allergic rhinitis prevalence continues to climb globally, and patients increasingly seek adjunctive or alternative options with favorable safety profiles. If larger, well-designed randomized trials confirm the rankings reported here—particularly for tomato extract on nasal symptoms and spirulina on patient-rated outcomes—everyday dietary and herbal compounds could earn a more rigorous, evidence-based place alongside conventional therapy. The study, published open access on 10 September 2026, invites both clinicians and researchers to look more closely at the pharmacological potential hiding in ordinary plants.

Subject of Research: Network meta-analysis of plant-derived active substances for the treatment of allergic rhinitis

Article Title: Active substances of plants in the treatment of allergic rhinitis: a systematic review and network meta-analysis

Article References: Fan, R., Li, Z., Liang, M., Wang, X., Zhao, C., & Zhang, Z. (2026). Active substances of plants in the treatment of allergic rhinitis: a systematic review and network meta-analysis. BMC Complementary Medicine and Therapies. https://doi.org/10.1186/s12906-026-05571-4

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05571-4

Keywords: allergic rhinitis, plant extracts, network meta-analysis, spirulina, tomato extract, fermented red ginseng, Glycyrrhiza glabra, Flos Magnoliae volatile oil, Phlai, immunoglobulin E, interleukin-5, randomized controlled trials