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CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 2, March 2013
10
AFRICA
Cardioprotective and anti-hypertensive effects of
Prosopis glandulosa
in rat models of pre-diabetes
B HUISAMEN, C GEORGE, D DIETRICH, S GENADE
Abstract
Aim:
Obesity and type 2 diabetes present with two debilitat-
ing complications, namely, hypertension and heart disease.
The dried and ground pods of
Prosopis glandulosa
(common-
ly known as the Honey mesquite tree) which is part of the
Fabaceae (or legume) family are currently marketed in South
Africa as a food supplement with blood glucose-stabilising
and anti-hypertensive properties. We previously determined
its hypoglycaemic effects, and in the current study we deter-
mined the efficacy of
P glandulosa
as anti-hypertensive agent
and its myocardial protective ability.
Methods:
MaleWistar rats were rendered either pre-diabetic
(diet-induced obesity: DIO) or hypertensive (high-fat diet:
HFD). DIO animals were treated with
P
glandulosa
(100
mg/kg/day for the last eight weeks of a 16-week period) and
compared to age-matched controls. Hearts were perfused
ex
vivo
to determine infarct size. Biometric parameters were
determined at the time of sacrifice. Cardiac-specific insulin
receptor knock-out (CIRKO) mice were similarly treated
with
P
glandulosa
and infarct size was determined. HFD
animals were treated with
P glandulosa
from the onset of the
diet or from weeks 12–16, using captopril (50 mg/kg/day) as
the positive control. Blood pressure was monitored weekly.
Results
: DIO rats and CIRKO mice:
P
glandulosa
ingestion
significantly reduced infarct size after ischaemia–reperfu-
sion. Proteins of the PI-3-kinase/PKB/Akt survival pathway
were affected in a manner supporting cardioprotection. HFD
model:
P glandulosa
treatment both prevented and corrected
the development of hypertension, which was also reflected in
alleviation of water retention.
Conclusion:
P
glandulosa
was cardioprotective and infarct
sparing as well as anti-hypertensive without affecting the
body weight or the intra-peritoneal fat depots of the animals.
Changes in the PI-3-kinase/PKB/Akt pathway may be causal
to protection. Results indicated water retention, possibly
coupled to vasoconstriction in the HFD animals, while inges-
tion of
P glandulosa
alleviated both.We concluded that treat-
ment of pre-diabetes, type 2 diabetes or hypertension with
P
glandulosa
poses possible beneficial health effects.
Keywords:
Prosopis glandulosa
, hypertension, cardioprotection,
PKB, insulin resistance
Submitted 7/6/12, accepted 4/10/12
Cardiovasc
J Afr
2013;
24
: 10–16
www.cvja.co.zaDOI: 10.5830/CVJA-2012-069
Obesity and type 2 diabetes present with two debilitating
complications, namely, hypertension and heart disease. The dried
and ground pods of
Prosopis
glandulosa
(commonly known
as the Honey mesquite tree) which is part of the Fabaceae (or
legume) family are currently marketed as a food supplement
with blood glucose stabilising and anti-hypertensive properties
in South Africa. In the past, the pods of this tree were used
as the primary foodstuff for the residents of the south-western
regions of the North American deserts and these trees are still
widely distributed across a large portion of the south-western
United States.
1
The pods are composed of 80% carbohydrate,
13% protein, 25% fibre and 3% fat, and grinding of the plant is
thought to improve its use.
2
Obesity is currently classified as a pandemic and is recognised
as the leading cause in the development of the metabolic
syndrome. The metabolic syndrome is described as a cluster of
pathophysiology outlined by the National Cholesterol Education
Program’s Adult Treatment Panel III (NCEP: ATP III) and the
European Group for the Study of Insulin Resistance, to include
insulin resistance or glucose intolerance (pre-diabetes), type
2 diabetes, hypertension and atherogenic dyslipidaemia.
3,4
In
addition, all of these factors can be considered independent risk
factors for the development of cardiovascular disease.
3
According to the World Health Organisation (WHO),
non-communicable diseases such as heart disease, stroke, cancer,
chronic respiratory diseases and diabetes are currently (updated
June 2011) the leading causes of mortality in the world.
5
This
invisible epidemic is an under-appreciated cause of poverty and
hinders economic development in many countries. The burden
is growing and the number of people, families and communities
afflicted is increasing.
The time-line for development of overt type 2 diabetes is
described as developing over many years. The cardiovascular
consequences of this so-called ‘ticking clock’ hypothesis, starting
from obesity and culminating in type 2 diabetes, is present from
the early pre-diabetic stages.
6
In view of the scarcity and cost of modern oral hypoglycaemic
agents, plant-based therapies for the treatment of diabetes are
gaining considerable prominence.
7
According to these authors
more than 400 plant species have been described as having
hypoglycaemic activity. However, not all of these substances
have been researched scientifically to validate their efficacy.
MRC DDP, Parow, South Africa, Faculty of Health Sciences,
University of Stellenbosch, Tygerberg, South Africa
B HUISAMEN, PhD,
bh3@sun.ac.zaDepartment of Biomedical Sciences, Division of Medical
Physiology, Faculty of Health Sciences, University of
Stellenbosch, Tygerberg, South Africa
B HUISAMEN, PhD
C GEORGE, MSc
S GENADE, MSc
Department of Medical Biosciences, University of Western
Cape, Bellville, South Africa
D DIETRICH, PhD