Citric acid and enzyme-assisted modification of flavonoids from celery (Apium graveolens) extract and their anti-inflammatory activity in HMC-1.2 cells.

Apium graveolens (celery) of the family Apiaceae contains bioactive compounds including luteolin and apigenin. The purpose of this study was to increase the extraction yield of apigenin and luteolin in celery extract using green technology and to evaluate their biological activities. The results showed that CA and ß-glucosidase-assisted celery extraction transformed apiin in the celery to apigenin with an increase in luteolin concentration. The CA and ß-glucosidase-treated celery extract (CAGE) improved the anti-inflammatory properties of celery extract by inhibiting the expression and production of inflammatory cytokines (IL-6, IL-8, IL-31, and TNF-α) in IL-33-stimulated mast cells (HMC-1.2 cells). Their mechanism of action was tied to the inhibition of ERK, JNK, IKKα, IκBα, and NF-κB activation by CAGE in the stimulated cells. In conclusion, CA and enzyme treatment can be considered as a useful biotechnology tool for the improvement of bioactive compounds in celery and hence improve on their bioactivity. PRACTICAL APPLICATIONS: Apium graveolens commonly called celery is an edible agricultural product cultivated throughout the world and known as a "superfood." Celery contains bioactive compounds including apigenin and luteolin that contribute to their described biological activities. However, extracting celery using normal extraction procedures such as hot water and ethanol methods yields only a small amount of apigenin and luteolin. In the present study, we introduced an eco-friendly method using citric and ß-glucosidase to obtain apigenin and luteolin-rich celery extract with improved anti-inflammatory activities. The present work will spark studies on the conversion of less biologically active compounds in functional food materials to more active compounds using CA and ß-glucosidase, and the development of functional food with specifically enriched bioactive substances at the industrial levels.

Enzyme-treated date plum leave extract ameliorates atopic dermatitis-like skin lesion in hairless mice

Objective: To evaluate the effect of different extracts of Diospyros lotus leaves in atopic dermatitis Methods: Diospyros lotus leaves were extracted in ethanol and treated with or without hydrochloric acid or α-rhamnosidase to obtain three different extracts-ethanol, acid-hydrolyzed, and enzyme-hydrolyzed leaf extracts of date plum. The myricitrin content in all samples was measured using HPLC analysis. In vitro antioxidant and anti-inflammatory activities of the extracts were determined by measuring DPPH radical scavenging activities and nitric oxide production in RAW264.7 cells, respectively. Seven-week-old male hairless mice were used to evaluate the anti-atopic dermatitis effects of three extracts in vivo. Splenocytes and mast cells were used to further determine the anti-atopic dermatitis effects of the major compound in the ethanol leaf extract. Results: Enzyme-hydrolyzed leaf extract showed significant in vitro antioxidant and anti-inflammatory activities, and attenuated atopic dermatitis-like skin symptoms and clinical signs more significantly than ethanol and acid-hydrolyzed leaf extracts in 1-fluoro-2,4-dinitrobenzene and house dust mite antigen-treated hairless mice. Enzyme-hydrolyzed leaf extract also suppressed the serum level of immunoglobulin E, interleukin (IL)-4, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, thymic stromal lymphopoietin, and thymus and activation-regulated chemokine in mice with atopic dermatitis. Furthermore, histological analysis revealed that enzyme-hydrolyzed leaf extract suppressed the increased epidermal thickness, dermal infiltration of inflammatory cells, and infiltration and degranulation of mast cells more markedly than the other two extracts in atopic dermatitis-like skin lesions. In addition, this extract effectively inhibited the production of IFN-γ, IL-4, and thymus and activation-regulated chemokine compared with the other two extracts in concanavalin A-stimulated splenocytes. Myricitrin, a major compound of enzyme-hydrolyzed leaf extract, suppressed atopic dermatitis biomarkers in stimulated mouse splenocytes and HMC-1 human mast cells.Conclusions: These results suggest that enzyme-hydrolyzed leaf extract might be a potential candidate to treat atopic dermatitis.

Apigenin Inhibits IL-31 Cytokine in Human Mast Cell and Mouse Skin Tissues.

IL-31 is a recently discovered cytokine that is produced not only in T-cells but also in mast cells. It is strongly implicated to play a key role in inflammatory diseases and in the pathogenesis of itch in atopic dermatitis. Apigenin, a flavonoid of plant origin has numerous biological applications. In this study, we showed that apigenin modulates IL-31 mRNA, protein expression, and release in stimulated human mast (HMC-1) by inhibiting the phosphorylation activation of MAPK and NF-κB. To determine whether apigenin has similar effects in vivo, using Compound 48/80, we developed an atopic dermatitis itch model in mice and found an increase in IL-31 expression in the skin. We also revealed that apigenin prevents the infiltration and degranulation of mast cells and suppressed mRNA and protein expression of IL-31 in the skin of mice. These results provide a new suggestion of the potential applicability of apigenin for treatment of various inflammatory diseases and itch mediated by IL-31.