Elachi lemon (Citrus limon) peel and pulp: antioxidant, antimicrobial, anticoagulant activities, bioactive compounds, minerals, and heavy metals

Background: According to a number of previous studies, citrus fruits are rich in phytochemicals, minerals and bioactive compounds.

Objective: The aim of this study was to investigate the antioxidant, antimicrobial and anticoagulant activities, phytonutrients, bioactive compounds, mineral and heavy metals in the peel and pulp of Elachi lemon (Citrus limon).

Methods: Phytochemical screening was performed to estimate the total polyphenol, flavonoid, tan-nin, reducing sugar, total protein and vitamin C contents. High performance liquid chromatography was performed to determine the concentrations of phenolics and ascorbic acid. Antioxidant activities were evaluated by measuring 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging ac-tivity, reducing power assay and ferric reducing antioxidant power (FRAP) assay. Antibacterial activity was evaluated by the disc diffusion method and minimum inhibitory concentration (MIC). Besides estimating heavy metals and minerals, activated partial thromboplastin time (aPTT) and prothrombin time (PT) were observed for detecting anticoagulant activity.

Results: In the case of antioxidant and antimicrobial activities, the pulp was found to be richer. Both the peel and pulp showed similar anticoagulant activities. Among the phytonutrients, protein content was richer in the peel than in the pulp. Catechin, rutin, tannic, gallic and vanillic acids were detected in the peel, whereas in pulp quercetin, tannic and gallic acids were found. Pb, Cr, Cd were present in a negligible amount whereas, Co, Cu and Fe were high in both the peel and the pulp.

Conclusion: This study exhibits that both the peel and the pulp of Citrus limon are a rich source of antioxidant, antimicrobial, anticoagulant, minerals and various bioactive compounds with nutrition-al values.