Experimental Anti-Allergic and Immunomodulatory Effects of Vernonia amygdalina-Derived Biomaterials, Vernodalin and Its Leaf Extracts

Abstract

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disorder with a relatively high prevalence in children in developed countries. In this study, we (1) explored the immunomodulatory and (2) compared the anti-allergic effects of Vernodalin isolated from Vernonia amygdalina (VAM) leaf and VAM leaf extracts in NC/Nga mice. In the first experiment, AD-like disease was induced using 2,4,6-trinitrochlorobenzene (TNCB); the hapten was applied on mice rostral and ear’s dorsal areas after disrupting skin barrier with the use of SDS solution. After AD induction, 36 NC/Nga mice that developed moderate to severe skin lesions were divided into 6 pretreatment groups of 6 animals: 1 μg/mL Vernodalin, 10 μg/mL Vernodalin, 100 μg/mL Vernodalin, 1,000 μg/mL VAM extracts, 1,000 μg/mL VAM extracts, and PBS-treated vehicle group. Skin samples were collected after 14 days of treatment; immunofluorescence and qRT-PCR assays were performed to determine changes in filaggrin (FLG) production and FLGmRNA and IL-33mRNA expressions, respectively. In the second experiment, 18 NC/Nga mice with Dermatophagoides pteronyssinus extract (DPE)-induced AD-like disease were divided into 3 treatment groups to test the curative effects of the experimental agents: 100 μg/mL Vernodalin, 10 μg/mL VAM extracts, and PBS-treated vehicle group as control.