An Investigation of Anti-atopic Dermatitis Activity of Oroxylum indicum Extract Incorporated Cream

Abstract

Aims: The search for plant-based treatments against atopic dermatitis (AD), a relapsing dermatological condition with high prevalence in tropical regions, has always been attracting                     special attention. Among many folk remedies for AD, Oroxylum indicum Linn (Bignoniaceae) is a commonly used medicinal plant whose effectiveness has not yet been scientifically reported. This study thus aimed to investigate the anti-AD activity of ethyl acetate extract from the bark of Oroxylum indicum. The plant, known as midnight horror or Indian trumpet flower plant distributed throughout different areas of Southeast Asia. Methodology: Five cream formulations containing Oroxylum indicum ethyl acetate bark extract in different concentrations (0%, 1.25%, 2.5%, 3.75%, and 5%) were topically applied onto the dorsal skin of 2,4-dinitrochlorobenzene-sensitized BALB/C mice once a day during 6 weeks. Phosphate-Buffered Saline (PBS) and Protopic (Tacrolimus 0.1%) were used as negative and positive control, respectively. All mice were subjected to the assessment of AD-like symptoms including the development of eczematous skin lesions, intensity of pruritus and histological alterations. Results: The plant extract at 5% was significantly effective in suppressing the dermatitis scores by 23.26% (n=6, p<0.001) and scratching frequency by 34.86% (n=6, p<0.001) compared to the negative control while markedly reducing the signs of parakeratosis, hyperplasia, spongiosis, acanthosis, as well as the epidermal and dermal thickness in immunized mice. Conclusion: These results confirmed the inhibitory effect of Oroxylum indicum on the advance of AD at 5% when incorporated into a cream formulation and revealed the plant’s therapeutic potential in the approach to disease treatment. However, more studies on the immunosuppressive mechanism of the extract and the interplaying roles of main phytocomponents should ultimately support the utilization of this valuable medicinal plant.