Evaluation of the Antipyretic Effects of Methanolic Leaf Extract of Chromolaena odorata in Albino Rats

Abstract

This study evaluates the antipyretic activity of methanolic leaf extract of Chromolaena odorata in albino rats. Pyrexia, commonly known as fever, is the medical term for an elevated body temperature. It occurs when the body's temperature rises above the normal range, typically over 38°C (100.4°F), as a response to infection, inflammation, or other stimuli. The experimental setup included five groups of albino rats, with two control groups receiving either normal saline (negative control) or acetaminophen (positive control), and the test groups receiving 200 mg/kg and 400 mg/kg of the leaf extract. Fever (pyrexia) was induced using 0.01 mL/kg of Escherichia coli suspension injected into the rats, after which varying doses of the methanolic leaf extract were administered. The results demonstrated a significant reduction in rectal temperature in the rats treated with the extract, showing a dose-dependent response. The highest antipyretic activity was observed in the group administered 400 mg/kg, where the rectal temperature decreased by 2.5°C within two hours of treatment. This effect was comparable to, and in some cases, exceeded that of acetaminophen, suggesting that the methanolic extract of Chromolaena odorata possesses significant antipyretic properties. The observed antipyretic effect may be attributed to the bioactive constituents of the plant, including flavonoids, terpenoids, and anthraquinones. Further research is recommended to isolate and characterize the active compounds responsible for the observed pharmacological activity.

Full text

Email Addresses: odeyadebe@yahoo.com (Oko), dakafyippp@gmail.com (Akafyi) , mustamina19@nilest.edu.ng
(Umar) , crytals52002@yahoo.co.uk (Buhari) , oyelakinopeyemik@gmail.com (Oyelakin) , sbonire@gmail.com
(Ojeleye) , zubairuhalima968@gmail.com (Zubair) , ishola.sulyman@gmail.com (Yusuf) , shangs4real@gmail.com
(Jakheng) , kigbualbert2@gmail.com (Albert)
Evaluation of the Antipyretic Effects of Methanolic Leaf
Extract of Chromolaena odorata in Albino Rats
Oko, J. O.1,2*, Akafyi, D. E.1, Umar, M.1, Buhari, R. D.4, Oyelakin, O. K.3, Ojeleye, F. S.1,
Zubair, H.1, Yusuf, S. I.1, Jakheng, S. P.E.1, Albert, K. A.1
1.Department of Science Laboratory Technology, Nigerian Institute of Leather and Science Technology, Zaria
2.Department of Pharmaceutics and Pharmaceutical Microbiology, Faculty of Pharmaceutical Sciences,
Ahmadu Bello University, Zaria
3.Department of Leather Technology, Nigerian Institute of Leather and Science Technology, Zaria
4.Water Resources and Environmental Management, National Water Resources Institute, Mando, Kaduna
State
Abstract
This study evaluates the antipyretic activity of methanolic leaf extract of Chromolaena odorata in
albino rats. Pyrexia, commonly known as fever, is the medical term for an elevated body temperature.
It occurs when the body's temperature rises above the normal range, typically over 38°C (100.4°F), as
a response to infection, inflammation, or other stimuli. The experimental setup included five groups
of albino rats, with two control groups receiving either normal saline (negative control) or
acetaminophen (positive control), and the test groups receiving 200 mg/kg and 400 mg/kg of the leaf
extract. Fever (pyrexia) was induced using 0.01 mL/kg of Escherichia coli suspension injected into
the rats, after which varying doses of the methanolic leaf extract were administered. The results
demonstrated a significant reduction in rectal temperature in the rats treated with the extract, showing
a dose-dependent response. The highest antipyretic activity was observed in the group administered
400 mg/kg, where the rectal temperature decreased by 2.5°C within two hours of treatment. This effect
was comparable to, and in some cases, exceeded that of acetaminophen, suggesting that the methanolic
extract of Chromolaena odorata possesses significant antipyretic properties. The observed antipyretic
effect may be attributed to the bioactive constituents of the plant, including flavonoids, terpenoids, and
anthraquinones. Further research is recommended to isolate and characterize the active compounds
responsible for the observed pharmacological activity.
Keywords: Chromolaena odorata, Antipyretic, Methanolic extract, Albino rats, Escherichia coli,
Rectal temperature.
IJEMD-BMCR, 2 (1) (2024), 1 – 18 https://doi.org/10.54938/ijemdbmcr.2024.02.1.362
International Journal of Emerging Multidisciplinaries:
Biomedical and Clinical Research
Research Paper
Journal Homepage: www.ojs.ijemd.com
ISSN (print): 2957-8620 ISSN (online): 2960-0731

2 International Journal of Emerging Multidisciplinaries
INTRODUCTION
Fever, also known as pyrexia and febrile response [4], is defined as having a temperature above the
normal range due to an increase in the body’s temperature set-point [9],[12]. There is not a single
agreed-upon upper limit for normal temperature with sources using values between 37.5 and 38.3°C
(99.5 and 100.9°F) [10]. The increase in set-point triggers increased muscle contraction and cause a
feeling of cold [18]. This results in greater heat production and efforts to conserve heat. When the set-
point temperature returns to normal, a person feels hot, becomes flushed, and may begin to sweat [17].
Rarely a fever may trigger a febrile seizure. This is more common in young children. Fevers do not
typically go higher than 41 to 42°C [8].
A fever can be caused by many medical conditions ranging from non-serious to potentially serious.
This includes viral, bacterial and parasitic infections such as the common cold, urinary tract infections,
meningitis, malaria and appendicitis among others [3]. Non-infectious causes include vasculitis, deep
vein thrombosis, side effects of medication, and cancer among others (Rayamajhi).
Normal body temperature varies depending on many factors, including age, sex, time of day, ambient
temperature, activity level, and more. A raised temperature is not always a fever, for example, the
temperature of a healthy person rises when he or she exercises, but this is not considered a fever, as
the set-point is normal. On the other hand, a “normal” temperature may be a fever, if it is unusually
high for that person. For example, medically frail elderly people have a decreased ability to generate
body heat, so a “normal” temperature of 37.5°C may represent a clinically significant fever [16].
Medicinal plants have been used for centuries as remedies for human diseases because they contain
chemical components of therapeutic value. According to the World Health Organization (WHO), more
than 80% of the world’s population relies on traditional medicines for their primary healthcare needs
[14].
Chromolaena odorata is a perennial semi wood, shrub. In traditional medicine, a decoction of leaf is
used as a cough remedy and as an ingredient with lemon grass and guava leaves for the treatment of
malaria. Other medicinal uses include antidiarrheal, astringent, antiplasmodic, antihypertensive, anti-
inflammatory and diuretic [11]. A decoction of flowers is used as a tonic, antipyretic and heart tonic
[3]. A study was done using another species of Chromoleana and it was found to possess anti-
protozoan activity [19].
The secondary metabolites of plants like other xenobiotics are usually detoxified in the liver. The use
of natural therapy for relieving pyrexia is the next target in the advancement of human medicine. This
is because of less toxicity and adverse effects of plant extracts used for the treatment of various
ailments [5]. Thus, the present study was undertaken to evaluate the antipyretic activity of methanolic
leaf extract of Chromolaena odorata in albino rats.
MATERIALS AND METHODS
Sample Collection and Preparation of Extract
Fresh plant leaves of Chromolaena odorata were collected from Abuja and were taxonomically
identified at the Herbarium section of the Biological Science Department, Ahmadu Bello University,
Zaria. The leaves were thoroughly washed with running water and dried under shade for 4-6 days as
described by [15]. The dried plant was crushed into powder was stored in a sealed sterile reagent bottle
for further use. The plant extract was prepared by the method of [2] with minor modifications. The
extraction of the leaves of Chromolaena odorata was done using methanol. A mass of 50 grams of

Evaluation of the Antipyretic Effects of Methanolic Leaf Extract 3
dried powder was weighed using a weighing balance (Mettle 166(R)) and was extracted by 200 mL of
solvent by using a Soxhlet extractor for 72 hours at a temperature not exceeding the boiling point of
the methanol until the content evaporated completely as adopted by [13]. The extract was collected
and weighed in varying concentrations and kept in an air-tight container at 4°C.
Animal Selection and Ethical Approval
Adult healthy male and female albino rats weighing 60-150 grams were obtained from the Department
of Pharmacology, Faculty of Pharmaceutical Sciences, Ahmadu Bello University, Zaria. All the
animals were housed in a standard animal room (cages) under standard laboratory conditions, 21-22°C,
light (12 hours light/dark cycled humidity (50 ± 10%)). The animals were provided with a standard
pellet diet and water. They were acclimatized (getting used to the environment) for 7 days before
experiments. The experiments were performed according to the guiding principle in the use of animals
in toxicology and approved by the institutional animal ethics committee, Ahmadu Bello University,
Zaria.
Preparation of Escherichia coli Suspension
The pure and identified culture of Escherichia coli was obtained on McConkey agar from
the microbiology laboratory, Nigerian Institute of Leather and Science Technology (NILEST) Zaria
and incubated for 24 hours at 35°C. A colony of the organism was picked and washed in normal saline
spread on an agar plate for re-culture (sub-culture) and incubated for 24 hours. Several washing and
sub-culturing of the organism reduces its virulence. The final inoculum was maintained as pure culture
in nutrient broth and adjusted to the 0.5 McFarland scale from which a tenfold dilution of the suspended
broth culture was prepared with normal saline and a total number of cells in the dilution was
determined.
Experimental Design
The antipyretic activity of the methanolic leaf extract of Chromolaena odorata was screened using
Escherichia coli-induced pyrexia method. Albino rats of both sexes weighing 60-150 grams were
selected and divided into five (5) groups having 5 animals each. They were maintained at a constant
body temperature of 24-25°C for 24 hours. Pyrexia was produced in albino rats by injecting
Escherichia coli suspension in the marginal ear vein of the albino rats at a concentration of 0.01 mL/kg
body weight [6]. Rectal temperature was recorded before and after injection of the inducing agent and
at regular intervals during the period of the experiment. Pyrexia was examined 2 hours after injection
of Escherichia coli suspension before treatment. Groups I and IV were not induced with the
Escherichia coli and not treated with the extract but group I was treated with normal saline.
Treatment of Animal with Plant Extract
The extract of Chromolaena odorata was suspended in normal saline and administered orally. Group
I received 2 mL/kg of normal saline. Group II received 150 mg/kg of paracetamol. This served as
a positive control. Group III and IV received 200 mg/kg and 400 mg/kg respectively of methanolic
extract of Chromolaena odorata and group V animals were not induced and therefore were not treated.
Rectal temperature was noted at 30-minute intervals up to 180 minutes.
RESULTS AND DISCUSSIONS
The results of the Escherichia coli-induced pyrexia in rats is presented in Table 1. The injection of
Escherichia coli suspension elevated the rectal temperature after 2 hours of administration. Treatment

4 International Journal of Emerging Multidisciplinaries
with paracetamol at a dose of 150 mg/kg and extract of Chromolaena odorata at a dose of 200 and
400 mg/kg decreased the rectal temperature of the rats in a dose-dependent manner (Table 2). It was
found that the extract at a dose of 200 and 400 mg/kg caused a significant lowering of rectal
temperature at 3 hours following its administration. It was revealed that the extract showed dose-
dependent antipyretic activity. There was a significant difference (p < 0.05) in the reduction of rectal
temperature between the doses of extract and the positive control, paracetamol.
The antipyretic effect of methanolic leaf extracts was dose-dependent being that the reduction at the
higher dose level was visible than at the lower dose level. The reduction in Escherichia coli-induced
pyrexia was also found to be increasingly progressive with time (Fig. 1). The antipyretic effect of the
extracts agreed with the report of [7] in which the extracts could be acting centrally on the temperature
regulation centre in the brain or peripherally through inhibiting the synthesis of prostaglandin. The
effects produced by the extracts at the doses tested showed a higher antipyretic effect than the positive
control. This is in disagreement with the findings of [7] where the standard showed superiority in
reducing Escherichia coli-induced pyrexia in laboratory animals. The result of this current study
differs from that of [1] who recorded no significant antipyretic effect with the plant studied. The
differences in the activity of the extracts compared to paracetamol may be due to the high quantities
of bioactive constituents like flavonoids, anthraquinones and terpenoids in the methanol extract as
earlier reported by [20].
Table 1: Induction of pyrexia in albino rats
Animals’ groups
RTo(°C)
RT2(°C)
Group I
37.7
-
Group II
37.6
39.8
Group III
37.7
39.2
Group IV
37.8
39.3
Group V
-
-
RTo = Initial Rectal Temperature.
RT2 = Rectal Temperature after 2 H of inducti

Evaluation of the Antipyretic Effects of Methanolic Leaf Extract 5
Table 2: Rate Activity of Antipyretic Effect of Chromolaena odorata of Methanolic Leaf
Extract
Test items
Dose
(mg/kg)
Body
weight
(g)
RTo(°C)
RT2(°C)
Rectal temperature (°C) after treatment with extract
Animal
group
30
minutes
60
minutes
90
minutes
120
minutes
150
minutes
180
minutes
Group I
Normal saline
2 ml
90.0
37.7
-
37.8
38.5
37.6
36.8
37.8
37.9
Group
II
Paracetamol
150
107.2
37.58
39.76
37.24
37.92
37.32
37.02
37.22
37.22
Group
III
Chromolaena
odorata
200
85
37.72
39.2
38.26
38.24
38.0
37.24
37.1
38.26
Group
IV
Chromolaena
odorata
400
121.8
37.78
39.26
38.78
38.62
37.86
37.76
37.94
37.7
Group
V
-
-
119.6
-
-
37.82
39.38
38.68
37.64
37.84
38.84
RTo = Initial Rectal Temperature. RT2 = Rectal Temperature after 2 H of induction

6 International Journal of Emerging Multidisciplinaries
Fig. 1: Antipyretic Effect of Chromolaena odorata of Methanolic Leaf Extract
CONCLUSION
The results of this study showed that the methanolic extract of Chromolaena odorata exhibited
antipyretic activity. The presence of some bioactive phytochemical constituents in the leaves may be
responsible for the observed effect. However, further studies are necessary to isolate and characterize
the active principles of Chromolaena odorata leaf responsible for the antipyretic properties.
Conflict of interest
The authors declared that no conflict of interest exists.
REFERENCES
[1] Abbas, M. Y., Ejiofor, J. I., Yaro, A. H., Yakubu, M. I., & Anuka, J. A. (2017). Anti-inflammatory
and antipyretic activities of the methanol leaf extract of Acacia ataxacantha D.C. (Leguminosae) in
mice and rats. Bayero Journal of Pure and Applied Sciences, 10(1), 1–5.
[2] Alade, P. I., & Irobi, N. O. (1993). Antimicrobial activities of crude leaf extracts of Acalypha
wilkesiana. Journal of Ethnopharmacology, 39, 171–174.
39.3
37.24
37.92
37.32
37.02 37.22 37.22
39.2
38.26 38.24 38
37.24 37.1
38.26
35.5
36
36.5
37
37.5
38
38.5
39
39.5
RT2(°C) 30 60 90 120 150 180
RECTAL TEMPERATURE (°C)
TIME IN MINUTES
Group II Paracetamol 150 Group III Chromolaena odorata 200

Evaluation of the Antipyretic Effects of Methanolic Leaf Extract 7
[3] Al-Edany TY. Medicinal plants of Shatt al-Arab river and adjacent area. Tigris and Euphrates
Rivers: Their Environment from Headwaters to Mouth. 2021:643-61.
[5] Zayed A, Salem MA, Negm WA, Ezzat SM. Validation of anti-pyretic-derived natural products
and their potentials for drug discovery. Revista Brasileira de Farmacognosia. 2023 Aug;33(4):696-
712.
[4] Axelrod, Y. K., & Diringer, M. N. (2008). Temperature management in acute neurologic disorders.
Journal of Neurological and Clinical Science, 26(2), 585–603.
[6] Elmas, M., Yazar, E., Uneyk, & Karabacak, E. A. (2006). Anti-inflammatory effect of petroleum
ether extract of leaves of Litchi chinensis Gaertn (Sapindaceae). Journal of Veterinary Medicine, 53,
410–414.
[7] Flower, R. J., & Vane, J. R. (1972). Inhibition of prostaglandin synthetase in brain explaining
antipyretic activity of paracetamol. Nature, 230, 410–411. https://doi.org/10.1038/240410a0
[8] Gadekar S, Solanki P, Tiwari A, Rai H, Pandey A, Khan MN, Commander SL, Gupta H.
Understanding Fever: A Practical Approach for Clinicians. Professional Publication Services; 2024
Oct 25.
[9] Garmel, S. V., & Mahadevan, M. (2012). An introduction to clinical emergency medicine (2nd
ed.). Cambridge: Cambridge University Press.
[10] Grünebaum A, Chervenak FA, McCullough LB, Dudenhausen JW, Bornstein E, Mackowiak PA.
How fever is defined in COVID-19 publications: a disturbing lack of precision. Journal of Perinatal
Medicine. 2021 Mar 26;49(3):255-61.
[11] Iwu, M., Duncan, A. R., & Okunji, C. O. (1999). New antimicrobials of plant origin perspectives
on new crops and new uses. ASHS Press, Alexandria, VA, 457–462.
[12] Kluge, J. (2005). Fever: Its biology, evolution, and function. Princeton University Press.
[13] Lin, J., Opoku, A. R., Gheeb-Keller, M., Hutchings, A. D., Terblanche, S. E., & Jager, A. K.
(2005). National Institute of Health and Sciences, 25, 23–33.
[14] Nostro, A., Germano, M. P., Dangelo, V., & Cannatelli, M. A. (2000). Extraction method and
bioautography for evaluation of medicinal plant antimicrobial activity. Applied Microbiology, 30, 379–
384.
[15] Onoruvwe, O., & Olorunfumi, P. O. (1998). Antibacterial screening and pharmacological
evaluation of Dichrostachys cinerea root. African Journal of Biological Science, 7, 91–99.
[16] Ravindran SY, Sharma D, Chakravorty I. National MERIT Conference 2024, Manchester, UK:
Scientific Abstracts. The Physician. 2024 Apr 20;9(1):1-41.
[17] Sue, E. (2014). Pathophysiology: The biologic basis for disease in adults and children (7th ed.).
Elsevier Health Sciences.

8 International Journal of Emerging Multidisciplinaries
[18] Sullivan, J. E., & Farrar, H. C. (2011). Fever and antipyretic use in children. Paediatrics, 127(3),
580–587. https://doi.org/10.1542/peds.2010-3852
[19] Taleb-Contini, S. H., Salvador, M. J., Balanco, J. M., Albuquerque, S., & de Oliveira, D. C.
(2004). Antiprotozoal effect of crude extracts and flavonoids isolated from Chromolaena hirsuta
(Asteraceae). Phytotherapy Research, PTR, 18(3), 250–254.
[20] Timothy, S. Y., Wazis, C. H., Bwala, A. Y., Bashir, H. J., & Rhoda, A. S. (2012). Comparative
study on the effects of aqueous and ethanol leaf extracts of Cassia alata Linn on some pathogenic
bacteria and fungi. International Research Journal of Pharmacy, 3(8), 125–127.