Veterinary World, EISSN: 2231-0916 RESEARCH ARTICLE

Available at www.veterinaryworld.org/Vol.12/June-2019/16.pdf Open Access

Evaluation of phytochemical constituents and sedative-hypnotic activity

of the methanol leaf extract of Ficus exasperata in mice
Hudu Garba Mikail1, David Dezi Akumka1, Mohammed Adamu1 and Aishatu Ummi Zaifada2

1. Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Abuja, Abuja, Nigeria;
2. Veterinary Teaching Hospital, University of Abuja, Abuja, Nigeria.
Corresponding author: Hudu Garba Mikail, e-mail: mghudu@yahoo.com
Co-authors: DDA: ddakumka@gmail.com, MA: adamu210@gmail.com, AUZ: aishatu.zaifada@uniabuja.edu.ng
Received: 18-02-2019, Accepted: 30-04-2019, Published online: 17-06-2019

doi: 10.14202/vetworld.2019.830-833 How to cite this article: Mikail HG, Akumka DD, Adamu M, Zaifada AU (2019)
Evaluation of phytochemical constituents and sedative-hypnotic activity of the methanol leaf extract of Ficus exasperata in
mice, Veterinary World, 12(6): 830-833.

Abstract
Background and Aim: Sedative drugs mostly cause dose-dependent depression of the central nervous system which results
in hypnosis and anesthesia possibly; however, these agents are associated with some side effects ranging respiratory, digestive,
immune system dysfunctions, tolerance, cognitive function deterioration, and physical dependence; hence, investigations of
newer and safer agents are, therefore, imperative. The current study was aimed at investigating the sedative-hypnotic (S-H)
effects of the methanol leaf extract of Ficus exasperata in mice.
Materials and Methods: Phytochemical screening of the leaf extract was conducted, and S-H activity of the plant extract
was evaluated. Twenty Swiss Albino mice were randomly divided into four groups of five mice each. The mice in Groups A
and B were injected with the extract intraperitoneally (IP) at the dose rate of 100 and 200 mg/kg, respectively, those in
Group C were injected with xylazine at the dose rate of 10 mg/kg, while Group D mice received distilled water at the dose
rate of 2 ml/kg. All the four experimental groups were injected with ketamine (IP) at the dose rate of 100 mg/kg after 30 min.
Results: Phytochemical analysis of the extract revealed the presence of carbohydrates, cardiac glycosides, reducing sugars,
steroids and triterpenes, saponins, tannins, condensed tannins, and flavonoids, while anthraquinones, anthracene derivatives,
and alkaloids were absent. Results from the S-H evaluation show no significant difference (p≥0.05) on the onset of sleep
time between the four experimental groups; however, statistically significant difference (p≤0.05) was recorded in the sleep
duration time between the groups treated with only ketamine and the other experimental groups pre-treated with either the
extract or xylazine before ketamine administration. The group pre-treated with a high dose of the plant extract (200 mg/kg)
and the treated with ketamine after 30 min exhibited longer sleeping duration time. The plant extract, xylazine and ketamine,
sedated the mice for some period of time after arousal from sleep.
Conclusion: Our finding suggests that methanol leaf extract of F. exasperata possesses S-H potential that may require
further scientific investigations.
Keywords: Ficus exasperata, methanol leaf extract, mice, sedative-hypnotic activity.
Introduction fruits and often recognized by the milky juice, the min-
Anxiolytics or sedative drugs should reduce anxi- ute unisexual flowers often arranged on various shaped
receptacles and the prominent stipule that leaves a scar
ety with little or no effect on mental or motor function.
on falling [4]. Different parts of F. exasperata Vahl.
Most of these agents’ cause dose-dependent depres- (Moraceae) are used in traditional medicine as diuretic,
sion of the central nervous system (CNS), leading to analgesic, antiarthritic, antiparasitic, wound healing,
sleep-inducing effects (hypnosis) and possibly anes- vermifuge, ecbolics, abortifacient, and for treating
thesia [1]. However, these agents are associated with venereal diseases and hemorrhoids. The plant parts are
some side effects ranging from respiratory, digestive, also used as animal fodder [5].
immune system dysfunctions, tolerance, cognitive func- Dissociative anesthetics such as ketamine are
tion deterioration, and physical dependence [2]. Ficus likely the most widely used class of anesthetics in vet-
exasperata is a well-known tree with very rough leaves erinary medicine [1]. These agents are associated with
used widely in the Nigerian ecoregions; industrially, emergence delirium (e.g., anxiousness, vocalization,
sandpaper leaves are used in woods polishing [3]. The and thrashing). Emergence delirium could be danger-
Ficus genus is distinguished by its highly characteristic ous in larger animals like horses but merely unpleas-
ant in smaller animals. Combine administration of
Copyright: Mikail, et al. Open Access. This article is distributed under dissociative anesthetics with sedatives or tranquilizers
the terms of the Creative Commons Attribution 4.0 International
License (http://creativecommons.org/licenses/by/4.0/), which agents such as xylazine, diazepam, and acepromazine
permits unrestricted use, distribution, and reproduction in any can minimize or prevent this unwanted side effect [6].
medium, provided you give appropriate credit to the original
author(s) and the source, provide a link to the Creative Commons Thus, the investigation of newer and safer agents with
license, and indicate if changes were made. The Creative Commons little or no side effects is, therefore, imperative.
Public Domain Dedication waiver (http://creativecommons.org/
publicdomain/zero/1.0/) applies to the data made available in this
Ethnobotanically, the plant F. exasperata has
article, unless otherwise stated. been reported to have diverse medicinal uses in
Veterinary World, EISSN: 2231-0916 830
 Available at www.veterinaryworld.org/Vol.12/June-2019/16.pdf

treating hemorrhoid, cough, high blood pressure, Xylazine hydrochloride (20 mg/ml), XYL-M2 injec-
etc. [3]. Some communities locally use it as a calming tion solution, VMD, Belgium, were used during the
agent (personal communications, 2017). The current experiment.
study was aimed at investigating the sedative-hyp- Drugs reconstitution
notic (S-H) effects of the methanol leaf extract of Xylazine 0.1 ml was diluted with 1.9 ml of dis-
F.  exasperata in mice. tilled water to get a solution of 1 mg/ml. Ketamine
Materials and Methods 0.4 ml was diluted with 1.6 ml of distilled water to get
Ethical approval a solution of 10 mg/ml. Forty and 20 mg of the meth-
This experiment was approved by the University anol leaf extract were dissolved in 4 ml of distilled
of Abuja Ethical Committee on Animal Use water each to get solutions of 10 mg/ml and 5 mg/ml,
(UAECAU/2018/008), Abuja, Nigeria. respectively.
Study area Treatment of experimental groups
The investigation was conducted at the Faculty Twenty Swiss Albino mice were used, the mice
of Veterinary Medicine, University of Abuja, Nigeria. in Groups A and B were injected intraperitoneally
(IP) with the leaf extract at the dose rate of 100 and
Plant material
200 mg/kg, respectively, Group C mice were injected
The freshly collected plant was identified and (IP) with xylazine at the dose rate of 10 mg/kg, while
a voucher specimen numbered 0516 was deposited Group D mice received distilled water at dose rate
at the departmental herbarium. The identification of 2 ml/kg. All the animals in the four experimental
was done by Mr. US Gallah of National Research Groups A-D were injected with ketamine at the dose
Institute of Chemical Technology, Zaria, Kaduna rate of 100 mg/kg (IP) after 30 min.
State, Nigeria.
Assessment of S-H effects
Processing and extraction
Modified methods of S-H activities screen-
Leaf of F. exasperata was under the shade air
ing were employed. Activities such as spontaneous
dried for 2 weeks and mechanically pounded into fine
movement [12] or movement in response to catch,
particles using pestle and mortar. About 500 g of the
rearing (when mouse’s body inclined vertically with
pounded plant materials were weighed and extracted
hind paws on the floor and forepaws on the wall of
by maceration for 72 h in absolute methanol [7]. The
the cage [13] or when the mouse stands on its hind
extracts were then filtered, evaporated to dryness, and
paws stretching the forepaws up), and climbing the
stored in capped bottles inside the refrigerator at 4°C
wire roofing of the cage were used to as an index S-H
until required.
effects of the drugs and/or extract administered. The
Phytochemical analysis activities were measured with some modifications by
The screening of the phytochemical constituents considering only the presence of these activities was
of the leaf extract was conducted according to stan- recorded rather than their durations. Mice in each
dard procedures; the method of Evans [8] was used group were observed at 0, 30, 40, 50, 60, 90, and
for the determination of carbohydrates, reducing sug- 120 min for 3 min for the presence of these activi-
ars, anthraquinones, anthracene derivatives, cardiac ties, onset and duration of sleep for each mouse was
glycosides, saponins, tannins, condensed tannins, and recorded. Response to the drug/extract administration
alkaloids. Flavonoids as described by Silva et al. [9], was graded as follows:
triterpene and steroids as described by Harborne [10] 1. Sleeping: Laterally recumbent and inactive (no
and Sofowora [11]. The phytochemical analysis was movement at all)
conducted at the Faculty of Pharmaceutical Sciences, 2. Awake: Sitting on four paws and inactive (no
Pharmacognosy Laboratory of Ahmadu Bello movement at all)
University, Zaria, Nigeria. 3. Slightly Active: Awake and moving slowly in
Experimental animals response to catch
Swiss Albino mice weighing between 17 and 4. Active: Awake, moving in response to catch and
29 g were used for the experiment; the animals were rearing
divided randomly into four groups (A-D) of five mice 5. Very active: Awake, moving in response to catch,
each totally 20 in number. The mice were marked rearing, and climbing the wired cage roofing.
using picric acid solution on the tail, back, head, and Animals on Grades 2 and 3 were considered
right leg, the fifth mouse was unmarked for easy iden- sedated and slightly sedated, respectively, while those
tification. The animals were kept in cages measuring on Grades 4 and 5 were considered fully awake.
44  cm × 28 × 12.5  cm and were allowed access to Statistical analysis
pelleted feed and tap water ad libitum. One-way analysis of variance was used to get
Drugs a level of significance in the data obtained from the
Ketamine hydrochloride injection USP study which was followed by Tukey post hoc using
(50  mg/  ml), Rotexmedica, Trittau, Germany and SPSS statistical software, version 4.0 (IBM, USA).
Veterinary World, EISSN: 2231-0916 831
 Available at www.veterinaryworld.org/Vol.12/June-2019/16.pdf

Values ≤0.05 were considered statistically significant. Discussion

Results are presented as mean plus/minus standard In the present study, chemical constituents
error of the mean. recorded present in the methanol leaf extract of
Results F.  exasperata agrees with those reported by Adebayo
The result from the phytochemical analysis et al. [14] and are slightly at variance with those
revealed the presence of carbohydrates, cardiac reported by Lawal et al. [3] present on stem bark
glycosides, reducing sugars, steroids and triter- extract of the plant. Flavonoids and saponins have
penes, saponins, tannins condensed tannins, and been shown to have S-H effects [12,15]. The S-H
flavonoids, whereas the absence of anthraquinones, effects of Ficus abutilifolia methanol leaf extract
anthracene derivatives, and alkaloids was recorded found in this study could, therefore, be linked to the
(Table-1). No significant difference (p≥0.05) was presence of phytochemical constituents such as flavo-
recorded in the onset of sleep time between the four noids and saponins.
different experimental groups; however, there was The activities of the mice were affected by either
statistically significant difference (p≤0.05) in the the drug or extract administration, the animals were
sleep duration time between the group treated with very active before receiving any form of treatment;
only ketamine and the other three groups that were however, their activities subsided, i.e., they were
pre-treated treated with low and high doses of the sedated following treatment with either the extract
plant extract and xylazine, respectively, before ket- or xylazine and hypnotized finally due to ketamine
amine administration after 30 min (Table-2). The administration. Movement of any form was not seen
group pre-treated with high dose of the plant extract in the hypnotized mice except that of the abdomi-
(200 mg/kg), then treated with ketamine after 30 min nal muscle indicating evidence of respiration. The
exhibited longer sleeping duration time, followed mice did not resume their very active position up to
by the group pre-treated with low dose of the plant the end of the experiment. These findings are in line
extract, then the xylazine pre-treated group, whereas with the reports of Moniruzzaman et al. [16] and
the group treated with only ketamine exhibited Khan et al.  [17] regarding the S-H activity of natu-
the least sleep duration time (Table-2). The plant ral products of plant origin. Mostly, the S-H effect of
extract, xylazine and ketamine, calmed the mice by drugs is dose-dependent, with sedation initially then
reducing their activities and putting them in sedative followed by hypnosis and possibly anesthesia with
position for some period of time after arousal from increasing doses of the agent in use and visa vis [1].
sleep (Figure-1). Xylazine and leaf extract pre-treatment pro-
Activities grade key long the sleeping time in comparison with ketamine
(1) Sleeping, (2) awake but sedated, (3) awake treatment alone, the prolongation dose-dependent as
but slightly sedated active, (4) awake and active, and the high extract dose produced the longest sleeping
(5) awake and very active. time than the low dose. Similarly, all the administered

6
Table-1: Phytochemical constituents of the methanol leaf
5
extract of Ficus exasperate.
Activities grades

4
Constituents Inference
3
Carbohydrates +
Cardiac glycosides + 2
Reducing sugars +
1
Steroid and triterpenes +
Anthraquinones − 0
Anthracene derivatives − 0 min 30 min 40 min 50 min 60 min 90 min 120 min
Saponins + Time in minutes
Tannins +
Condensed tannins + Group 1 Group 2 Group 3 Group 4
Flavonoids +
Figure-1: Sedative-hypnotic activities of the methanol leaf
Alkaloids −
extract of Ficus exasperata in mice.

Table-2: Effect of the methanol leaf extract of Ficus exasperata on ketamine‑induced sleeping time in mice.

Group Treatment Onset of sleep (min) Duration of sleep (min)

Group 1 100 mg/kg extract+ketamine 100 mg/kg after 30 min 3.400±0.200 45.8000±0.37*
Group 2 200 mg/kg extract+ketamine 100 mg/kg after 30 min 2.800±0.200 71.2000±9.25a*
Group 3 10 mg/kg xylazine+ketamine 100 mg/kg after 30 min 3.000±0.320 35.4000±3.85a*
Group 4 100 m/kg ketamine only after 30 min 3.000±0.320 20.8000±2.98*
*Significant difference (p≤0.05) between Group 4 and Groups 1, 2, and 3, asignificant difference (p≤0.05) between
Groups 2 and 3

Veterinary World, EISSN: 2231-0916 832

 Available at www.veterinaryworld.org/Vol.12/June-2019/16.pdf

agents induced a calming effect on the mice, ­especially 2. Dhawan, K., Dhawan, S. and Chhabra, S. (2003) Attenuation
after arousal from sleep, this effect is otherwise known of benzodiazepine dependence in mice by a tri-substituted
benzoflavone moiety of Passiflora incarnata Linneaus:
as sedation which lasts for some period of time before A non-habit forming anxiolytic. J. Pharm. Pharm. Sci.,
the resumption of normal activities by the treated 6(2): 215-222.
mice. Thus, the leaf extract of F. exasperata possesses 3. Lawal, I.O., Borokini, T.I., Oyeleye, A., Williams, O.A. and
S-H activity. Olayemi, J.O. (2012) Evaluation of extract of Ficus exas-
perata Vahl root bark for antimicrobial activities against
The mechanism by which the plant stem bark some strains of clinical isolates of bacterial and fungi. Int.
extract produced the S-H effect was not investigated; J. Mod. Bot., 2(1): 6-12.
however, most S-H drugs facilitate the actions of 4. Berg, C.C. (1989) Classification and distribution of Ficus.
GABA, a major inhibitory transmitter in the CNS [1]. Experientia, 45(7): 605-611.
5. Ahmed, A., Mueen-Ahmed, K.K., Zainul-Abedin, M.D.,
GABAA receptor activation leads to increased C1 ion Alias, A. and Karim, A.A. (2012) Traditional uses and phar-
influx; GABAB receptor activation causes increased macological potential of Ficus exasperata Vahl. Syst. Rev.
efflux of K+. Both mechanisms result in membrane Pharm., 3(1): 15-23.
hyperpolarization [1]. Dissociative anesthetic drugs 6. Posner, L.P. (2017) Injectable anesthetics. In: Papich, M.G.
prevent the binding of glutamate, the major excit- and Riviere, J.E., editors. Veterinary Pharmacology and
Therapeutics. 10th ed. Wiley-Blackwell, Iowa, USA. p247-280.
atory neurotransmitter in the CNS to the N-methyl- 7. Pandey, A. and Tripathi, S. (2014) Concept of standardiza-
D-aspartate receptor, resulting in depressed activities tion, extraction and pre phytochemical screening strategies
of thalamocortical and limbic system as well as the for herbal drug. J. Pharmacogn. Phytochem., 2(5): 115-119.
activities of the reticular activating systems nuclei [6]. 8. Evans, W.C. (2009) Trease and Evans Pharmacognosy.
16th ed. Saunders Publishers, Elsevier, Edinburgh, UK.
Conclusion p196, 227, 228, 246, 304, 324, 327, 358.
9. Silva, G.L., Lee, I. and Kinghorn, A.D. (1998) Special prob-
Our current finding suggests that methanol leaf lems with the extraction of plants. In: Cannell, R.J.P., editor.
extract of F. exasperata possesses S-H activity that Natural Products Isolate. Human Press, New Jersey, United
may require further investigations scientifically to States. p343-363.
10. Harborne, J.B. (1973) Phytochemical Methods: A Guide to
find out the active ingredient and mechanism of action Modern Techniques of Plant Analysis. Vol. 119. Chapman
contained in the plant extract. and Hall Ltd., London, England. p212-231.
11. Sofowora, A. (1993) Medicinal Plants and Traditional
Authors’ Contributions Medicine in Africa. Spectrum Book Ltd., Ibadan, Nigeria.
HGM: Designed and wrote the manuscript; p150-153.
12. Jiang, J.G., Huang, X.J., Chen, J. and Lin, Q.S. (2007)
HGM, DDA, MA, and AUZ: Conducted the research. Comparison of the sedative and hypnotic effect of flavo-
All authors read and approved the final manuscript. noid, saponins and polysaccharides extracted from Semen
Ziziphus jujube. Nat. Prod. Res., 21(4): 310-320.
Acknowledgment
13. Pitychoutis, P.M., Pallis, E.G., Mikail, H.G. and
The authors wish to thank Dr. J.O. Omamemgbe Papadopoulou-Daifoti, Z. (2011) Individual differences in
novelty-seeking predict differential responses to chronic
of Surgery Department, Faculty of Veterinary antidepressant treatment through sex-and phenotype-depen-
Medicine, University of Abuja, Abuja, Nigeria. The dent neurochemical signatures. Behav. Brain Res., 223(1):
authors did not receive any fund for this study. 154-168.
14. Adebayo, E.A., Ishola, O.R., Taiwo, O.S., Majolagbe, O.N.
Competing Interests and Adekeye, B.T. (2009) Evaluations of the metha-
nol extract of Ficus exasperate stem bark, leaf and root
The authors declare that they have no competing for phytochemical analysis and antimicrobial activities.
interests. Afr. J. Plant Sci., 3(12): 283-287.
15. Aguirre-Hernández, E., González-Trujano, E., Terrazas, T.,
Publisher’s Note
Santoyo, J.H. and Guevara-Fefer, P. (2016) Anxiolytic and
Veterinary World remains neutral with regard sedative-like effects of flavonoids from Tilia americana
to jurisdictional claims in published institutional var. mexicana: GABAergic and serotonergic participation.
Salud Ment., 39(1): 37-46.
affiliation. 16. Moniruzzaman, M., Atikur-Rahman, M. and Ferdous, A.
References (2015) Evaluation of sedative and hypnotic activity of
ethanolic extract of Scoparia dulcis Linn. Evid. Based
1. Kerecsen, L. and Kirishna, B.R. (2019) CNS drugs: Complement. Alternat. Med., March 2015: 1-6.
Sedatives-hypnotics-anxiolytic drugs. In: Davis, C. and 17. Khan, I.N., Sarker, M.I. and Ajrin, M. (2014) Sedative and
Harris, S.R., editors. USMLE step 1 Pharmacology anxiolytic effects of ethanolic extract of Calotropis gigantea
Lecture Notes. Kaplan Medical, a Division of Kaplan, Inc., (Asclepiadaceae) leaves. Asian Pac. J. Trop. Biomed., 4(1):
New York. 400-404.

********

Veterinary World, EISSN: 2231-0916 833