Evaluation of anti-inflammatory and antioxidant properties of Citrus Sinensis peels and Morus Alba extracts in vitro

In recent years, the antioxidant and anti-inflammatory properties of natural compounds have gained significant attention in the field of health and nutrition. When an organism experiences stress, it responds by generating free radicals. In normal conditions, the antioxidant system of the organism will keep free radicals in dynamic equilibrium. However, once the balance is disrupted, the free radicals that have been accumulated in excess will attack the normal cells of the body, resulting in oxidative stress. Oxidative stress has been strongly associated with the process of aging and the development of diverse chronic diseases. Studies have shown that antioxidants can attenuate the harm caused by oxidative stress. Natural, harmless antioxidants have been proven to have good antioxidant effects 1. On the other hand, inflammation commonly occurs as a result of the invasion of infectious microorganisms such as bacteria, viruses, or fungi into the organism. These microorganisms can either reside in specific tissues or circulate within the bloodstream. Additionally, inflammation can be triggered by various processes, including tissue injury, cell death, cancer, ischemia, and degeneration. Numerous inflammatory mediators are synthetized and released during inflammatory responses. Among the various biological activities documented in the literature regarding natural plant products, anti-inflammation is one of the most reported.2. Starting from this, this study aims to evaluate the antioxidant and anti-inflammatory properties of extracts from the peel of three varieties of oranges (Citrus Sinensis), and two types of white mulberry (Morus Alba). Extracts were obtained via Microwave-assisted distillation, a method that uses microwave energy to accelerate the distillation process. A preliminary evaluation of the potential antioxidant activity of volatile and polar fractions of the extracts was made using DPPH and β-carotene bleaching assays 3. The extracts were then tested for their potential anti-inflammatory activity using the NF-kB anti-inflammatory assay and for potential antioxidant activity using CAA (cellular antioxidant activity) assay at the “Masaryk University” Faculty of Pharmacy in Brno (CZ). Each compound was testes in vitro at the concentration of 20 μg/mL, 10 μg/mL and 5 μg/mL, using THP1-Blue™ NF-kB cells purchased from Invivogen. The study revealed that almost none of the tested compounds express a significant anti-inflammatory activity, while some others, like the Citrus varieties at the concentration of 10 μg/mL, showed a minimal activity which can be a good starting point for further investigations. On the other hand, antioxidant activity tested promising for all the compounds, especially the Morus Alba extracts, at all concentrations.