Researchers employ star apple to treat diabetes, heart disease, infections

THE season is here again to enjoy local
cherry or rather white star apple. Local
cherry is associated with the dry season
and has been enjoyed over the years by
Nigerians as a fruit. But more studies are
supporting its folklore use for treating
diseases such as diabetes, heart diseases
and drug resistant bacteria.
BOTANICALLY called Chrysophyllum albidum,
white star apple belongs to the Sapotaceae
family. It is distributed throughout the
southern part of Nigeria. In Southwestern
Nigeria, the fruit is called agbalumo and
popularly referred to as udara in
Southeastern Nigeria. Chrysophyllum
albidum is a popular tropical fruit tree and
widely distributed in the low land rain
forest zones and frequently found in
villages.
The fleshy pulp of the fruits is eaten
especially as snack and its fruit has been
found to have higher contents of ascorbic
acid than oranges and guava. It is also
reported as an excellent source of vitamins,
irons, flavours to diets. The seeds are also
used for local games or discarded.
Chrysophyllum albidum fruit is common in
both urban and rural centres especially
during the months of December to April. The
fruits are not usually harvested from the
trees, but left to drop naturally to the
ground where they are picked.
A recent study by researchers at the
Department of Biological Sciences, College of
Science and Technology, Covenant
University Ogun State showed that local
cherry lowered blood sugar and cholesterol,
and could be useful in preventing and
treating heart diseases.
The study titled, “Effects of ethanolic leaf
extract of Chrysophyllum albidum G. on
biochemical and haematological (blood-
related) parameters of albino Wistar rats”
was published in African Journal of
Biotechnology.
Previous studies indicate that the roots,
barks and leaves of Chrysophyllum albidum
have been employed in folk medicine for
the treatment of diseases. The bark is used
for the treatment of yellow fever and
malaria, while the leaf is used as an
emollient and for the treatment of skin
eruption, stomachache and diarrhoea. The
cotyledons from the seeds of
Chrysophyllum albidum are used as
ointments in the treatment of vaginal and
dermatological infections in Western
Nigeria.
The fruit pulp is rich in Vitamin C and iron
and an excellent source of raw material for
industries. Tannins, flavonoids, terpenoids,
proteins, carbohydates and resins are the
phytochemicals that have been reported in
Chrysophyllum albidum. Methanolic extract
of the cotyledons from the seeds of
Chrysophyllum albidum led to the isolation
of eleagnine, tetrahydro- 2 -methylharman
and skatole.
Eleagnine was found to be the main
compound responsible for its antimicrobial
activity. Eleagnine was further shown to
exhibit anti-nociceptive, anti-inflammatory
and antioxidant activities. The seed
cotyledon has been reported to possess
anti-hyperglycemic (lowers high blood
sugar) and hypolipidemic (lower blood
cholesterol) effects.
The researchers investigated the effect of
oral administration of the leaf extract of
Chrysophyllum albidum G. on biochemical
and haematological parameters in albino
rats for 16 days.
The researchers write: “In conclusion, the
study has demonstrated that the leaf
extract of Chrysophyllum albidum may not
cause any adverse effect on the
biochemical and haematological indices of
toxicity.
Moreover, the extract was found to possess
anti-platelet and hypoglycemic (lowers
blood sugar) properties and might be
employed in the management of myocardial
infarction (heart attack) and diabetes
mellitus, respectively. Further investigation
is needed to establish the anti-platelet
property of the extract.”
Another study by researchers at the Forest
Research Institute, Ibadan, Oyo State,
showed that star apple leaves exhibited
strong antibacterial activity against
common bacteria isolates.
The study titled, “Antibacterial activity and
phytochemical screening of Chrysophyllum
albidum leaves ” was published in Asian
Journal of Food and Agro-Industry.
Preliminary phytochemical screening of
Chrysophyllum albidum leaves for
secondary metabolites showed the
presence of tannin, anthraquinone and
cardiac glycosides in the plant samples. The
samples were devoid of saponin, alkaloids
and reducing sugars.
The researchers write: “Biological actions
are primarily due to these components in a
very complicated concert of synergistic or
antagonistic activities. Mixtures of such
chemicals show a broad spectrum of
biological effects and pharmacological
properties.
“The antimicrobial properties of the plant
observed in this study could be attributed
to the presence of tannin, anthraquinone
and cardiac glycosides. The results showed
that the test organisms were susceptible to
the water extracts based on their zones of
inhibition, which ranged from 10 to 27 mm.
Escherichia coli showed the highest
susceptibility of 27. All the organisms were
sensitive at all concentrations except
Escherichia coli, which was not sensitive at
125 µg/mL and 250 µg/mL. The least
activity 10 mm was detected at 125 µg/mL
concentration with.
“The methanolic extract of Chrysopyllum
albidum leaves exhibited some
antimicrobial activity against all the
microorganisms tested as assessed by
zones of inhibition that ranged from (25±0
to 35±0.40mm).
Escherichia coli had the highest
susceptibility at 250 µg/mL concentrations
with zone of inhibition of 35±0.40 mm.
There was increase in the zone of inhibition
for Escherichia coli from 30 (±0.15) mm at
125 µg/mL to 35 (±0.40) mm and 35±0.21
at 250 µg/mg and 500 µg/mL respectively.
Salmonella typhi and Shigella spp had a zone
of inhibition of 35 mm at all concentrations
except at 500 µg/mg where Shigella spp.
which had zone of inhibition of 30 (±0.30)
mm.
“These results suggest that water and
methanolic extracts from the leaves of
Chrysophylum albidum may contain active
agent(s). This provides the basis for their
folkloric use as cure for some human
ailments like skin infection, diarrhoea and
stomachache, which are as a result of
infections and inflammatory reactions. It is
suggested that more research be conducted
to further isolate, identify, characterise and
elucidate the bioactive compounds from
Chrysophylum albidum.
“In conclusion, the result of this study
justifies the traditional uses of the leaves of
Chrysophylum albidum for therapeutic
purposes. The findings could also be of
commercial interest to both pharmaceutical
companies and research institute in the
production of new drugs. ”
Researchers have also studied the
nutritional value and mineral contents of
Chrysophyllum albidum fruit. According to
the study published in Journal of the
Science of Food and Agriculture, fresh fruit
samples, both untreated and treated with
2,4-dichlorophenoxyacetic acid, were
investigated