Antimicrobial Activity, Toxicity and Phytochemical Screening of Lantana Trifolia Leaf Extracts
Abstract
Medicinal plants have played a significant role all over the world in preventing and
healing a range of diseases. Lantana trifolia is a plant used in the management of
asthma, common cold, cerebral malaria, epilepsy and tonsillitis. However, empirical
data to validate its toxicity profile and safety is lacking. Thus, this study was designed
to investigate the phytochemical composition, antimicrobial activity and the acute and
sub-acute toxicity of extracts from L. trifolia leaves to validate its ethnomedicinal
usage. This study provides information on the safety of the plant.
Acute oral toxicity study of the aqueous leaf extract of L. trifolia was conducted
according to guideline 423 described by the Organization for Economic Co-operation
Development (OECD) whereby a single dose of the extract was given to female rats at
dose levels 300mg/Kg Bwt and 2000mg/Kg Bwt. Thereafter, the rats were observed
individually for the first four hours, then over a period of 24 hours and at least once
daily for 14 days.
Sub-acute oral toxicity of the aqueous leaf extract of L. trifolia was investigated at
three dose levels of 250 mg/Kg Bwt, 500 mg/Kg Bwt, and 1000 mg/Kg Bwt in both
female and male Swiss albino mice based on the OECD guideline number 407 for 28
days. The control group received distilled water. Thereafter, body weight, feed
consumption and water consumption were monitored. Vital parameters of the blood
such as haematological profiles and biochemical profiles were determined at the end
of the experiment. Moreover, histopathological examination of the various harvested
organs was done.
Qualitative phytochemical analysis was performed on both aqueous and organic
extracts to identify compounds of pharmacological value. The extraction yield of the
aqueous and organic extracts was 5.2% and 11.2% respectively. Qualitative
phytochemical screening of the extracts showed the presence of tannins, saponins,
phenolics, terpenoids, flavonoids, alkaloids and reducing sugars in both extracts. In
an acute oral toxicity study, the aqueous leaf extract of L. trifolia demonstrated a
median lethal dose (LD50) of >2000 mg/Kg Bwt, depicting its safety. Following subacute
oral toxicity, the urea levels in female mice which received 1000 mg/Kg Bwt
dose of the aqueous leaf extract of L. trifolia were significantly elevated compared to
those of the control group mice (P<0.05). Moreover, there was no significant
difference in the mean body weight between the treated and control groups(P>0.05).
Treatment groups that received 1000mg/kg body weight of the aqueous extract
demonstrated diffuse tubular epithelium degeneration, indicating nephrotoxicity and a
dose-related hepatocyte degeneration, indicating hepatotoxicity
Staphylococcus aureus (Gram-positive), Bacillus cereus (Gram-positive), Escherichia
coli (Gram-negative) and Candida albicans(fungus) were used to determine the
antimicrobial activities of aqueous and DCM-methanol extracts. The most susceptible
microorganism in the current study was C. albicans. The minimum inhibitory
concentration and minimum bactericidal concentration values of aqueous and organic
leaf extracts of L. trifolia for S. aureus were 200mg/ml and 400mg/ml; 3.12mg/ml and
6.25mg/ml respectively. The MIC and MFC for C. albicans were 100mg/ml and
3.125mg/ml for both aqueous and organic extracts. The aqueous leaf extract of L.
xiv
trifolia may be relatively non-toxic when administered orally for a short period. This
is supported by a higher LD50 which was determined to be >2000mg/kg body weight.
There is need to monitor the liver, kidneys, haematological and biochemical
parameters especially when higher doses are administered for a long time since
deleterious dose-dependent effects can result. Various phytochemical constituents
were present in the L. trifolia leaf extracts hence this could form the basis for the
discovery and development of novel drugs.
Publisher
University of Nairobi
Rights
Attribution-NonCommercial-NoDerivs 3.0 United StatesUsage Rights
http://creativecommons.org/licenses/by-nc-nd/3.0/us/Collections
The following license files are associated with this item: