A Review of the Ethnobotany and Pharmacological Importance of Alstonia boonei De Wild (Apocynaceae).
ABSTRACT Alstonia boonei De Wild is a herbal medicinal plant of West African origin, popularly known as God's tree or "Onyame dua". Within West Africa, it is considered as sacred in some forest communities; consequently the plant parts are not eaten. The plant parts have been traditionally used for its antimalarial, aphrodisiac, antidiabetic, antimicrobial, and antipyretic activities, which have also been proved scientifically. The plant parts are rich in various bioactive compounds such as echitamidine, Nα-formylechitamidine, boonein, loganin, lupeol, ursolic acid, and β-amyrin among which the alkaloids and triterpenoids form a major portion. The present paper aims at investigating the main research undertaken on the plant in order to provide sufficient baseline information for future work and for commercial exploitation.
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ABSTRACT: Folkloric use of root-bark extract of Alstonia boonei in the treatment and management of many disease conditions may be associated with free radical scavenging as part of its mechanisms of action. We therefore evaluated the ability of different solvent fractions of the methanol extract, crude precipitate from the extract, and isolated compound from the crude precipitate for scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Phytochemical analysis revealed the presence of useful phytocompounds. Ethyl acetate fraction showed better antioxidant activity with IC50 of 54.25 μ g/mL while acetone and methanol fractions have 121.79 and 141.67 μ g/mL, respectively. The crude precipitate and isolated compound showed IC50 values of 364.39 and 354.94 μ g/mL, respectively. The crude precipitate, fractions, and compound 1 showed antioxidant activity against DPPH radical although lower than that of ascorbic acid.ISRN pharmacology. 01/2014; 2014:741478.
International Scholarly Research Network
Volume 2012, Article ID 587160, 9 pages
AReviewof theEthnobotany andPharmacological Importanceof
Alstoniaboonei DeWild (Apocynaceae)
YawOpoku Boahen,1andFrederickAto Armah2
1Department of Chemistry, School of Physical Sciences, University of Cape Coast, Cape Coast, Ghana
2Department of Environmental Science, School of Biological Sciences, University of Cape Coast, Cape Coast, Ghana
Correspondence should be addressed to John Prosper Kwaku Adotey, email@example.com
Received 15 April 2012; Accepted 17 May 2012
Academic Editors: T. Kumai and M. van den Buuse
Copyright © 2012 John Prosper Kwaku Adotey et al. This is an open access article distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
West Africa, it is considered as sacred in some forest communities; consequently the plant parts are not eaten. The plant parts have
been traditionally used for its antimalarial, aphrodisiac, antidiabetic, antimicrobial, and antipyretic activities, which have also
been proved scientifically. The plant parts are rich in various bioactive compounds such as echitamidine, Nα-formylechitamidine,
boonein, loganin, lupeol, ursolic acid, and β-amyrin among which the alkaloids and triterpenoids form a major portion. The
present paper aims at investigating the main research undertaken on the plant in order to provide sufficient baseline information
for future work and for commercial exploitation.
Many cultures throughout the world still rely on indigenous
medicinal plants for their primary health care needs . To
date, 25% of modern medicines are derived from plants that
have been used by traditional medical practitioners . It
is a fact that traditional systems of medicine have become
a topic of global importance. Although modern medicine
may be available in many developed countries, people
are still turning to alternative or complementary therapies
medicinal herbs have been scientifically evaluated for their
possible medical applications. The safety and efficacy data
are available for even fewer herbs, their extracts and active
ingredients and the preparation containing them. Tropical
and subtropical Africa contains between 40–45,000 species
of plant with a potential for development and out of which
in spite of this huge potential and diversity, the African
continent has only contributed 83 of the 1100 classic drugs
medicine is considered more for its capacity to generate
other medicine than for its own sake. In many cases research
undertakings and the commercial use stemming from that
research have always relied on information provided by
the local communities and, in many instances, have hardly
benefited from the research results . In Africa, traditional
healers and remedies made from plants play an important
role in the health of millions of people. The relative ratios
of traditional practitioners and university-trained doctors in
relation to the whole population in African countries are
revealing. In Ghana,for example, in the Kwahu district, there
nearly 21,000 people for one university-trained doctor .
boonei have focused on the bioactivity of its chemical
constituents, ethnobotany, pharmacology, and taxonomy.
However, a comprehensive or systematic review on the plant
is lacking. Furthermore, in much of the older literature
concerning West Africa, the name Alstonia congensis has
paper synthesizes studies on Alstonia boonei (Figure 1). This
is necessary to recapitulate the findings on the plant and
thereby provide a comprehensive and current repository for
references on the plant.
Figure 1: Plate showing clockwise order from top right, the leaves, stem, branches, and whole plant of Alstonia boonei.
EthnobotanicalUses of Alstonia
2.1. Classification. Alstonia comprises about 40 species and
hasapantropical distribution. Thereareabouttwelvespecies
of the genus Alstonia. Alstonia boonei De Wild belongs to
the family Apocynaceae. The species are scattered all over
the world of which two are indigenous to Africa. The plant
is known locally in Ghana as Onyame dua, Osen-nuru, or
Sinduro in Twi, Onyame dua in Fante, Sinu or Adawura
in Ga-Adangbe, Bakunin, Nyamenlebaka, Emenle, or Emie
in Nzema, and Siaketekre, Nyemi dua, or Asi atoe in Ewe
. Elsewhere, Alstonia is known as Australian fever bush,
Australian quinine, Devil tree, Dita bark, fever bark, or
2.2. Cultivation. Alstonia grows into a giant tree in most of
the evergreen rain forests of tropical West Africa. The plant
thrives very well in damp riverbanks. It is well known to
all the traditional healers practicing along the west coast of
Africa. It occurs in deciduous and fringing forest of Ghana
. Alstonia boonei De Wild is a deciduous tree up to 35
meters high (Figure 1). It buttresses deep-fluted high and
narrow. Its white latexes are copious. The leaves are in whorls
at nodes, oblanceolate, apex rounded to acuminate, lateral
vein prominent almost at right angle to midrib. The flowers
are white with lax terminal cymes. The fruits are paired with
2.3. Ethnobotanical Uses. The bark of Alstonia tree is one of
the effective analgesic  herbs available in nature. All the
parts of the plant are very useful but the thick bark cut from
the matured tree is the part that is most commonly used for
therapeutic purposes.The bark of the tree is highly effective
when it is used in its fresh form; however, the dried one
could equally be used. Therapeutically, the bark has been
found to possess antirheumatic , anti-inflammatory ,
analgesic/pain-killing, antimalaria/antipyretic, antidiabetic
(mild hypoglycaemic), antihelminthic, antimicrobial and
antibiotic properties [8–10]. A decoction could be sweetened
with pure honey and be taken up to 4 times daily as an
effective painkiller for the following conditions.
Painful menstruation (dysmenorrhoea), when associated
with uterine fibroid or ovarian cysts in women; lower
abdominal and pelvic congestion associated with gynaeco-
logical problems such as pelvic inflammatory diseases; to
relieve the painful urethritis common with gonococcus or
other microbial infections in men. Alstonia decoction also
exerts a mild antibacterial effect in this case, relieving the
aches and pains associated with malaria fever. Alstonia is
taken in the form of preparations that exhibits antipyrexia
and anti-malaria effects, to combat rheumatic and arthritic
pains. The decoction of Alstonia bark could be taken alone
as an effective pain-killing agent. A cold infusion made from
the fresh or dried bark of Alstonia taken orally two to three
times daily exerts a mild hypoglycaemic effect on diabetic
patients. The cold infusion is also administered orally for the
purpose of expelling round worms, threadworms , and
other intestinal parasites in children.
The fresh bark of Alstonia could be used in preparing
herbal tinctures; it is particularly useful as an effective
antidote against snake, rat, or scorpion poison. It is also
useful in expelling retained products of conception and
afterbirth when given to women. Asthma can be treated
with a drink prepared from parts of Trema orientalis and
decoction of the bark of Alstonia boonei mixed with the
roots and bark of cola and fruits of Xylopia parviflora with
hard potash . The bark decoction of Alstonia boonei is
used with other preparations in the treatment of fractures
or dislocation , jaundice, and for inducing breast milk. Its
latex is taken as a purgative. The hardened latex is used for
the treatment of yaws. Alstonia boonei De Wild is regarded as
one of few herbs with potential anti-HIV indicators. In some
African countries Alstonia boonei is considered a sacred tree
countries do not eat its parts.
A wide array of chemical compounds has been isolated from
Alstonia boonei. These include alkaloids, tannins, iridoids,
and triterpenoids . Chromatography of bark extracts of
Alstonia boonei on silica gel plates with the solvent system
AcOEt-MeOH-H2O (150:26:19) produced 6 separate spots
with alkaloid reactions and the alkaloids isolated from the
plant include echitamine (1) and echitamidine (Scheme 1),
voacangine and akuammidine, Nα-formylechitamidine, and
Nα-formyl-12-methoxyechitamidine [5, 11–13]. Echitamine
(1), which is also isolated from the bark of Alstonia scholaris,
Echitamine (1) [C22H29N2O4]+Mwt = 385.48
assigned the nomenclature [(3β, 16R)-3,17-Dihydroxy-16-
ammilinium. Its structure is as shown in Scheme 1.
Echitamidine (2), on the other hand, has molecular
formula of C20H22O3N2, with a melting point of 244◦C and
molecular weight of 338g/mol. Its structure is as shown in
These alkaloids, especially echitamine (1), possess a
battery of pharmacological and autonomic activities [14,
15] including anticancer activities [16–23]. Alkaloids and
related compounds isolated from other Alstonia species
include the glycosides of venoterpene , nareline [25, 26],
lagunamine , 19-epischolaricine , butamine, dobu-
tamine [29, 30], alschomine , Nα-methylbutylamine,
imanine , vallesamine , (20S)-19,20 dihydrocondy-
locarpine , scholarine, pseudoakuammigine,
tetrahydroalstonine, akuammicine, picralinal,
rhazine, scorlarine-N(4)- oxide, scholaricine [45, 46],
and flavone glycosides [47, 48].
Iridoids isolated from Alstonia boonei include boonein
and loganin. Loganin (Scheme 4) is a key intermediate in
the biosynthesis of indole alkaloids. It is a crystal of melting
point of 222-223◦C [α]D
in water, less soluble in 96%, alcohol and sparingly soluble in
20−82.1 (water). It is freely soluble
Loganin [C17H22O10] Mwt = 390.39
ligroin, ethyl acetate, and chloroform.
Boonein (5) is a C-9 monoterpenoid α-lactone, isolated
from the bark of A. boonei (Apocynaceae). The structure was
established by chemical and spectroscopic methods and by
X-ray analysis. Its structure is as shown in Scheme 5. It is a
possible precursor in the indole alkaloid biogenesis .
The triterpenoids isolated from Alstonia boonei include
lupeol (6), ursolic acid (7), and β-amyrin (8).
Lupeol is also known as (3β)-Lup-20(29)-en-3-ol, mon-
ogynol B, β-viscol, or fagarasterol. Its structure is as shown
in Scheme 6. It has a melting point of 215◦C and a molecular
weight of 426.73 with a molecular formular of C30H50O.
The percentage composition of the various elements is, C =
84.44, H = 11.81, and O = 3.75. Lupeol forms needlelike
crystals from alcohol or acetone. It is freely soluble in ether,
benzene, pet. ether, and in warm alcohol. It is practically
insoluble in water, dilute acids, and alkalis. Its acetate
C32H52O2 forms needlelike crystals from acetone with
melting point of 218◦C and [α]D
Ursolic acid is also known as urson, prunol micromerol,
or malol. Its systematic name is (3β)-3-hydroxyurs-12-en-
28-oic acid. Its structure is as shown in Scheme 7. Its melting
point range is 285◦C–288◦C. One part dissolves in 88 parts
of methanol, 178 alcohol (35 boiling alcohol), 140 ether,
and 388 chloroform, 1675 carbon disulfide. It is moderately
soluble in acetone and soluble in hot glacial acetic acid and
in 2% alcoholic NaOH. It is insoluble in water and pet. ether
its acetate has a melting point of 289-290◦C. Ursolic acid is
used as an emulsifying agent in pharmaceuticals and foods.
β-amyrin (8) has a molecular formula of C30H50O with
a molecular weight of 426.73. Its structure is as shown in
Scheme 8. Its melting point is 197–197.5◦C. It forms needle-
like crystals from pet. ether or alcohol.
For example, five compounds, which are triterpenes and
sterols, were isolated from the hexane fraction of the alcohol
extract of the leaves of Alstonia scholaris R. Br. The com-
pounds are identified as 4α,14α,24-trimethyl-9β,19-cyclo-
5α-cholest-24(29)-en-3β-ol, stigmasterol, betulin, betulinic
acid, and α-amyrin acetate . The structures of the iso-
lated compounds were principally deduced by physiological
and chromatographic characters as well as by spectroscopic
analyses. The isolated compounds were reported for the first
The flowers of Alstonia scholaris contain n-hexacosane,
lupeol, β-amyrin, palmitic acid, and ursolic acid. The com-
separated by chromatographic methods. Mass spectra and
spectrographic methods were used for identification. The
root and root bark of Alstonia scholaris contain α-amyrin,
α-amyrin acetate, lupeol acetate, stigmasterol, β-sitosterol,
and campesterol and its isomer . The stem bark of
Alstonia scholaris contains α-amyrin acetate, lupeol acetate,
and β-sitosterol [71, 72]. The isolation of α-amyrin acetate
and lupeol acetate was done with 96% ethanol on the air-
dried bark. The concentrated extract was stored for 2 weeks
Ursolic acid (7) [C30H48O3] Mwt = 456.71
and gave a solid, which (on several crystallizations from
EtOH) gave colorless needles of melting point of 160◦C. This
productwaschromatographed througha column of alumina
(4 × 32cm) and eluted with pet. ether (b.p. 40–60◦C).
Rechromatography of the fractions gave 2 products. The
first one forms colourless plates in (EtOH-Et2O) with mpt
of 224–5◦C, [α]29D 80◦(all rotations detected in CHCl3),
with one acetyl group and no active H. The second product
colourless needles in (EtOH-Et2O) with mpt of 215–16◦C,
[α]28D 40◦, containing an acetyl group and no active H.
On hydrolysis of the first product with methanolic KOH, a
substance with mpt of 184◦C, [α]28D 84◦, identical with α-
amyrin was obtained. This on benzoylation gave α-amyrin
benzoate which forms prisms in (C6H6-EtOH) with mpt
of 198◦C, [α]28D 92◦. Similarly, on hydrolysis the second
product gave a substance with mpt 212–13◦C, [α]27D 22.6◦,
identical with lupeol. Benzoylation gave lupeol benzoate
which forms colourless plates in (C6H6-EtOH) with mpt of
259–60◦C, [α]27D 60.4◦.
Triterpene compounds (R1 = H, C ≥ 10 fatty acid acyl)
are useful as anti-inflammatory and antiarthritic agents .
α-Amyrin palmitate (9)
α-Amyrin acetate isolated from petroleum ether extract of
Alstonia boonei root bark was hydrolyzed with NaOH to α-
amyrin followed by esterification with palmitoyl chloride
to obtain α-amyrin palmitate (9). Rats were injected with
150μL of complete Freund’s adjuvant containing 10mg/mL
Mycobacterium tuberculosis in the right hind footpad. Its
structure is as shown in Scheme 9. From days 11–19 rats
were fed orally with 56mg I/kg in 1mL of water. Regression
analysis of the rate of the ankle diameter change from days
11–19, postadjuvant injection showed that the diameter of
the ankle decreased by 31% in treated animals.
In a similar research work, the triterpenes-α-amyrin
acetate, β-amyrin acetate, β-amyrin, and lupeol acetate
isolated from the petroleum ether extract of Alstonia boonei
De Wild, root barks were tested for their anti-inflammatory
effects in CFA-induced arthritic rats . When admin-
istered orally daily from days 11 to 19 after adjuvant,
lupeol acetate and β-amyrin acetate were most effective in
preventing further increases in ankle adjuvant swelling. All
triterpenes abrogated the increases in WBC count, increased
liver and/or kidney weights but only α-amyrin acetate
significantly increased serum GOT levels. In the presence
of β-amyrin, there was significant neutrophil degeneration.
Triterpenes of Astonia boonei root barks were shown to be
the possibility of toxicity in antiarthritic therapy.
In another development, lupeol acetate isolated from the
petroleum ether fraction of Alstonia boonei root barks was
tested for its anti-arthritic effect in CFA-induced arthritic
rats . It was administered orally every 48hrs (66mg/kg
body wt.) from days 32 to 40 after adjuvant and assessed
on day 60. Lupeol acetate was able to return the increase in
spleen weight and the reduction in serum alkyl phosphatase
to nonarthritic control values.
The anti-inflammatory triterpenoids are also inhibitors
of serine proteases . The lupane triterpenoid lupeol,
the ursane triterpenoid alpha-amyrin, and esters of these
compounds present in the bark of roots of Alstonia
boonei (Apocynaceae) have anti-inflammatory properties.
Alpha-Amyrin is a competitive inhibitor of bovine trypsin
Table 1: An overview of research work on pharmacological properties of Alstonia boonei.
Plant part used
Stem bark, leaves
Analgesic, aphrodisiac, trypanocidal
Spasmolytic and hypotensive
Abortifacient, astringent, immunostimulant potentials
Bello et al. ; Ebiloma et al. ; Abel and Busia 
Abel and Busia, ; Oigiangbe et al. 
Osadebe et al. ; Olajide et al. 
Kweifio-Okai et al. ; Asuzu and Anaga 
Gabriel et al. ; Majekodunmi ; Olajide et al. 
Asuzu and Anaga 
Din et al. 
Wesche et al. 
Adomi ; Omoregbe et al. 
Olajide et al. 
Amole and Ilori 
Iwu, ; Forster et al. 
Taiwo et al. 
Elisabetsky and Costa-campos 
and chymotrypsin (Ki values 29microM and 18microM,
resp.). Lupeol linoleate, lupeol palmitate, and alpha-amyrin
linoleate are noncompetitive inhibitors of trypsin (Ki val-
ues 7microM, 10microM, and 16microM, resp.). Alpha-
amyrin linoleate is also a non-competitive inhibitor of
chymotrypsin (Ki value 28microM). Lupeol is a competitive
inhibitor of both trypsin and chymotrypsin (Ki values 22
and 8microM, resp.). Alpha-amyrin palmitate is a potent
non-competitive inhibitor of chymotrypsin (Ki 6microM).
Lupeol, alpha-amyrin, and the palmitic and linoleic acid
esters of these compounds are ineffective or very weak
as inhibitors of porcine pancreatic elastase and of Lucilia
cuprina and Helicoverpa punctigera leucine aminopeptidases.
These hydrophobic triterpenoids represent further examples
of anti-inflammatory triterpenoids that are PKA inhibitors
as well as being selective protease inhibitors.
When the methanol extract of the stem bark of Alstonia
boonei was investigated for anti-inflammatory, analgesic,
and antipyretic properties , it was found out that the
extract caused a significant (P < 0.05) inhibition of the
carrageenan-induced paw oedema, cotton pellet granuloma,
and exhibited an anti-arthritic activity in rats. Vascular
permeability induced by acetic acid in the peritoneum of
mice was also inhibited. The extract also produced marked
analgesic activity by reduction of writhing induced by acetic
acid, as well as the early and late phases of paw licking in
mice. A significant (P < 0.05) reduction in hyperpyrexia
in mice was also produced by the extract. This study
has established anti-inflammatory, analgesic, and antipyretic
activities of the stem bark of Alstonia boonei.
The anti-inflammatory activity of a Ghanaian anti-
arthritic herbal preparation was also investigated . The
herbal preparation is made of a boiling water extract from
a powdered sample containing Alstonia boonei root bark
(90%), Rauvolfia vomitoria root bark (5%), and Elaeis
guineensis nut without pericarp (5%). The herbal prepara-
tion was tested intraperitoneally for its anti-inflammatory
activity by measuring rat hind paw oedema induced by
the subplantar injection of carrageenin in the presence or
absence of arachidonic acid. Arachidonic acid increased
swelling during the early phase of carrageenin oedema. The
extract suppressed the late phase of carrageenin oedema
and both phases in the presence of arachidonic acid. These
preliminary results are consistent with a herbal preparation
The extract was again tested for its anti-inflammatory
activity by measuring over a period of 17 days the changes
in rat ankle diameter caused by subplantar injection of
complete Freund’s adjuvant . The extract fed in drinking
water ad libitum reduced ipsilateral ankle adjuvant swelling
by an average of 16% for the period of +4 to +17 days and
improved weight gain.
Rauvolfia vomitoria, was synthesized and tested on complete
Freund’s adjuvant-induced arthritic rats . Administered
for 5 days from days 32 to 40 (chronic), the drug returned
the increases in serum hyaluronate and blood granulocytes
towards nonarthritic levels and correct the moderate anemia
of adjuvant arthritis. Histological examinations of the prox-
imal interphalangeal foot joints showed reduced synovial
proliferation and invasion of joints and reduced leukocyte
rats. The results suggest that α-amyrin palmitate contributes
to the previously shown antiarthritic effect of the herbal
Odeku  reported the anti-malarial property of the
stem bark of Alstonia boonei, which could be formulated in
tablet form. Odugbemi et al.  studied the anti-malarial
activities of Alstonia boonei. Other important pharmacologi-
cal properties of the plant are shown in Table 1.
5.Toxicology, Contaminants,and SideEffects
Modern synthetic medicines have undergone various levels
of experiments for safety and efficacy unlike some herbal
preparations. Large proportion of public assumes that
herbal remedies or complementary and alternative medicine
(CAM) are inherently safe because it is natural. It is impor-
tant to remember that the majority of powerful chemicals
found in plant, which can be used to treat human diseases,
have evolved to serve different purposes in the plant itself.
For instance, the chemical is being used to protect the plant
from insects. These natural insecticides will soon poison the
bugs. In sufficient high doses, it can harm human too. The
World Health Assembly has highlighted the need to develop
herbal pharmacopoeias and to develop and apply scientific
criteria and methods for proof of safety and efficacy of
medicinal plant products. However, only few countries have
developed national herbal pharmacopoeias; limited plant
species that provide medicinal herbs have been scientifically
evaluated for their possible medical applications; the safety
and efficacy data are available for even fewer herbs. Without
well-documented information on the safety, efficacy, and
phytochemical characteristics of different compounds, it is
difficult for external buyers to assess the likely utility or value
of some new raw materials and extracts of African origin.
In order to address these lacunae, the Association of African
Medicinal Plants Standards is developing an African Herbal
Pharmacopeia with trading standards which provide infor-
mation and technical data on some 50 important medicinal
Notwithstanding the potential pharmacological benefits of
Alstonia boonei in particular and medicinal plants in general,
herbal pharmacopeia are largely lacking. The main problem
facing the use of traditional medicines is the proof require-
ment that the active components contained in medicinal
plants are useful, safe, and effective. This is required to assure
the medical field and the public regarding the use of medic-
inal plants as drug alternatives. The proofs of pharmacology
activity that are available at present are mostly based on
empirical experience. The scientific proof then becomes the
most important thing, in order to eliminate the concern of
using medicinal plants as drugs for alternative treatment.
This study attempted to synthesize work on Alstonia boonei
De Wild, a medicinal plant used in African alternative
medicine for its anti-malarial, aphrodisiac, anti-diabetic,
antimicrobial, and antipyretic activities. This study shows
the potential of the plant that research on dose-dependent
safety, side effects. and toxicological issues regarding the use
situation might limit widespread commercial adoption.
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