Phytochemical screening and antibacterial activity of peel and seed extracts of Citrus limon
Abstract
Rapidly increasing antibiotic resistance is one of the greatest threats to global health. There is
a growing demand today for naturally derived drugs and medicine in place of synthetic drugs
that are more commercially available. This study was undertaken to screen for the
phytochemicals and evaluate antibacterial activity of Citrus limon peel and seed extracts.
Methanolic and aqueous extracts of the C. limon peel and seed were prepared. Qualitative
phytochemical screening of the C. limon seed and peel extracts revealed a composition of
Saponins, tannins, flavonoids and steroids. Glycosides were absent in the peel extracts.
Antibacterial activity of Citrus limon peel and seed extracts was determined using agar disc
diffusion assay. The bacterial isolate used was obtained from an environmental source.
Inhibitory activity was observed for all the extracts except aqueous seed extract. Citrus limon
methanolic seed extracts exhibited the largest zone of inhibition (19.83 ± 1.17) mm against
the test bacterial isolate. Aqueous extract of C. limon seed showed no antibacterial activity
against the test bacteria isolate. None of the inhibitory effects of the Citrus limon seed and
peel extracts exceeded the zone of inhibition (28.50 ± 1.05) mm elicited by the standard
positive control, Ciprofloxacin against test bacterial isolate.
The presence of a zone of inhibition in the cultures inoculated with the C. limon seed and
peel extracts indicated the potent antibacterial activity of these plant extracts. This research
has thus provided scientific evidence confirming the efficacy of C. limon peel and seed
extracts as natural antimicrobial agents. Further detailed studies should focus on
identification, isolation, purification and quantification of the active compound (s) in C.
limon seed and peel extracts that possess antibacterial activity.