Phytochemical content and antioxidant potential of leaf extracts of Citrus limon (L.) Osbeck collected in the Eastern Cape Province, South Africa

This study was designed to investigate the phytochemical and the antioxidant activities of the extracts of Citrus limon L Osbeck leaf using ethanol, acetone and distilled water as extraction solvents. The total alkaloids, saponin, phenolic acid and flavonoids were determined spectrophotometrically while antioxidant potentials were evaluated with 2,2’-diphenyl-1-picrylhydrazyl (DPPH), Ferric-reducing/antioxidant power (FRAP) and 2,2’-azino-bis(3ethylbenzothiazoline-6-sulfonic acid) (ABTS) protocols. The phytochemical evaluation of the leaf of C. limon, reveals high contents of alkaloids, (12.23%) and saponin (5.53%). In addition, the aqueous extract shows the highest phenolic acid content of 289.4 ± 5.73 mg/GAE/g followed by ethanol 209.72 ± 6.38 mg/GAE/g and the least was the acetone extracts 207.56 ± 7.03mg/GAE/g. Flavonoids content was also highest in the ethanol extract (1052.58 ± 39.44mg/QE/g) and the aqueous extract (447.41 ± 4.56mg/QE/g). All the extracts showed significant antioxidant activities with ABTS, FRAP and DPPH along a concentration gradient. The high phytochemical content and the antioxidant activity of C. limon leaf extracts observed in this study supports and justifies its use in folk medicine.