Phytochemical investigation and assessment of antimicrobial, anti-inflammatory and antioxidant activities of Sudanese Citrus paradisi peel extract

The peel of grape fruit is used in traditional medicine for the treatment of several diseases. The objective of this study was to evaluate the antimicrobial, anti-inflammatory and antioxidant activities of peel extract from Citrus paradisi. Qualitative phytochemical screening of peel indicates the presence of alkaloids, flavonoids, sterols, triterpenes, tannins, saponins, coumarins, glycosides, reducing sugars, anthraquinones, lignin and carbohydrates. Extract was assessed for their effectiveness against four bacterial strains including both Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Salmonella typhi) bacteria as well as fungal species (Candida albicans and Aspergillus niger) using disc diffusion method. Antibacterial effects of peel extract showed different degrees of inhibition profiles against tested bacteria with inhibition zone that ranged from 13 to 17 mm. Peel extract showed high antifungal activity against A. niger (24 mm) and C. albicans (22 mm). The C. paradisi peel showed high anti-inflammatory activity with inhibition percentage 77.57%. The antioxidant potential of extract was determined on the basis of their scavenging activity of the 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical stability. The peel extract showed DPPH scavenging activity (55%) and vitamin C content was 23.08 mg/kg by HPLC. The quantitative analysis of chemical composition of the extract was determined by Gas Chromatography–Mass Spectrometry (GC-MS). The results showed high amounts of Naringenin (28.09%). The peel extract of C. paradisi is a natural source of chemical constituents which have medicinal uses in treating many disease. Key words: Citrus paradisi peel, antimicrobial activity, phytochemical screening, vitamin C, Naringenin.