Antihyperlipidemic And Antioxidant Effects Of Phaseolus Vulgaris

ANTIHYPERLIPIDEMIC AND ANTIOXIDANT EFFECTS OF PHASEOLUS VULGARIS

ABSTRACT
In this study, the antihyperlipidemic and antioxidants activities of the extract and fractions of
Phaseolus vulgaris L. were evaluated. The crude extract (PVE) of dried pulverized plant material
was obtained by maceration in methylene chloride/methanol (1:1) while the solvent fractions
were obtained by successive solvent-solvent partition in separating funnel between the crude
extract suspended in aqueous medium and solvents of increasing polarity to obtain the n-hexane
fraction (PVHF), ethylacetate fraction (PVEF), and butanol fraction (PVBF) in that
order.Antihyperlipidemic effects of the extracts and fractions were investigated using acute, subacute
and chronic models. In all threemodels, treatment with (PVE) caused significantreduction
(P<0.05) in the lipid profile parameters with the most significance seen in the sub acute study
where total cholesterol was decreased by 38.44%. Triglycerides level was significantly decreased
(P<0.05) by 18.18% in the acute study model.Similarly, very low density lipoprotein (VLDLC)
and low density lipoprotein (LDL-C) wasrespectively decreased by 18.18% and 48.73% in the
acute antihyperlipidemia model. In contrast, high density lipoprotein (HDL-C) level was
significantly (P<0.05) increased in the acute phase by 20.85%.In all study protocols involving
the various fraction there were significant increase(P<0.05) in lipid profile. PVEF (400 mg/kg)
produced- the most significant reduction in total cholesterol level in the acute study with
percentage decrease of 22.10% compared to the control treatment. Triglycerides level was
similarly reduced by 21.59% and 15.91% at PVHF (200 mg/kg) and PVEF (200 mg/kg) with the
acute study.The sub-acute protocol showed significant decrease at PVBF 200 mg/kg percentage
decrease of 17.28%. VLDL-C level for the fraction study showed significant decrease (P<0.05)
at PVHF 200 mg/kg and PVEF 200 mg/kg with percentage decrease of 21.59% and 15.91%
during the acute protocol, the sub-acute protocol showed significant decrease at PVBF 200
mg/kg percentage decrease of 17.28. LDL-C level for fraction extract study showed dose
dependent significance decrease (P<0.05) seen at PVHF 100 mg/kg, PVEF100 mg/kg, and 200
mg/kg with percentage decrease of 47.19%, 41.62% and 53.39% respectively during the acute
protocol, Finally in the chronic protocol a significant decrease was seen with PVHF 200mg/kg,
PVEF 100 mg/kg, and PVBF 200 mg/kg with percentage decrease of 26.03%, 24.82% and
20.05% respectively. HDL-C level for extract study showed dose dependent significant increase
(P<0.05) seen at PVHF 100 mg/kg, PVEF 100 mg/kg and 200 mg/kg with percentage increase
of 30.44%, 28.88% and 30.86%. DPPH reduction and nitric oxide scavenging assays were used
in the investigation of the extract and fractions for the in vitro antioxidant activities study, the
antioxidant activities of the extract and fractions were further determined in vivo in rats.
Antioxidant enzymes and factors such as catalase, glutathione peroxidase, and lipid peroxidation
activities were measured in carbon tetrachloride-treated rats treated with or without the extract
and fractions studies. The highest percentage reduction of DPPH was 80.61% seen with PVEF
and PVBF fraction at 400 mg/kg. The highest percentage reduction of nitric oxide was 75.86%
seen with PVHF at 200 mg/kg. The in vitro study showed significant increased (P<0.05)
scavenging activity with the PVHF and PVEF having scavenging activity comparable with
ascorbic acid. In in-vivo antioxidant assay showed that the Lipid peroxidation levels estimated by
thiobarbituric acid reaction showed no significant (P>0.05) increase or decrease in the serum
MDA of both the treated and untreated group, while in catalase activity estimation showed
significant (P<0.05) increase was seen with PVE 100 mg/kg of 71.05%, Glutathione peroxidise
activity showed the most significant percentage (P<0.05) increase of 76.19% for PVBF 100
mg/kg.The results of the study showed that the extracts and fractions of Phaseolus vulgaris
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posses anti-hyperlipidemic and antioxidant with the PVEF showing better and more consistent
effects with all protocols used in the investigation.

CHAPTER ONE
1.0. INTRODUCTION
A large volume of scientific research suggests that in situations of oxidative stress, reactive
oxygen species (ROS) are generated and a homeostatic environment between anti-oxidant and
oxidation is created, which are known to be an important concept for maintaining a healthy
biological system (Davies, 2000). Reactive oxygen species (ROS) such as superoxide anions (O2
-
), nitric oxide (NO) and hydroxyl radical (OH-) aids in the inactivation of enzymes and this result
in damage to important cellular components which leads to complication such as coronary heart
diseases (Gessin et al., 1990).
Disease of coronary origins such as stroke, atherosclerosis, etc., continues to be a leading cause
of death in most countries of the world (Davey, 1993).One of the greatest risk factors in the
severity and prevalence of coronary heart diseases is disorders of lipid metabolism known as
hyperlipidemia (Grundy, 1986). According to reports by the World Health Organization
approximately 56% of coronary heart diseases are as a result of hyperlipidemia and this result in
about 4.4million deaths each year worldwide (World Health Organization, 2002).
Hyperlipidemia is a disorder of lipoprotein metabolism, including lipoprotein overproduction or
deficiency and manifested by elevation of the serum total cholesterol, low-density lipoprotein
(LDL) cholesterol and triglyceride concentrations with a decrease in the high-density lipoprotein
(HDL) cholesterol concentration (Adam, 2005).
Man as always looked for a way to fight and control diseased state with inspiration and aid from
his immediate natural environment; this guidance’s have been used for centuries as remedies for
human diseases because they contain components of therapeutic value (Nostro et al., 2000). The
use of medicinal plants in the management of diseases is common around the world (Aliyu et al.,
2007). Herbal medicine, the study and use of medicinal properties of plants, is an aspect of
2
modern medicine (World Health Organization, 2008).The use of traditional medicine is
recognized as the most viable method of identifying of new medicinal plants species
(Farnsworth, 1966; Ajanahoun et al., 1991).
Medicinal plants are used for their beneficial antioxidant and lipid lowering effects thus reducing
the risk of cardiovascular diseases in many countries. HMG-CoA reductase inhibitor that is the
statins is the most recent lipid lowering drugs. They are very effective in lowering total and
LDL- cholesterol and have been shown to reduce coronary events and mortality. They have very
few side effects and are now usually the drugs of first choice (Neal, 2002). Also, ascorbic acid
and tocopherols are widely used anti-oxidants. In recent times antioxidants derived from natural
sources mainly plants have been intensively used to prevent oxidative damage because of its
advantage over synthetic ones; as they are easily obtained, economical and have slight or
negligible effects (Onay-ucar et al., 2006). Although the adverse effect of statins is relatively
low, one rare effect called rhabdomyolysis can be very serious (Miller, 2001). Statins and
fibrates both used in elevated cholesterol, especially in combination; cerivastatin (Baycol) was
withdrawn in 2001 after numerous incidence of rhabdomyolysis (Armitage, 2007). Hence, there
is an urgent need to research natural products that would have minimal or no lipid lowering side
effects.
Phaseolus vulgaris (family: Fabaceae) is a plant whose leaf, bark, roots and seeds are used for
medicinal purposes. It is commonly known as kidney bean, various parts of the plant have been
used extensively for the treatment of diabetes mellitus traditionally (Chopra et al., 1958).
Previous studies have reported the hypolipidemic activities of the aqueous extract (Roman-
Ramos et al., 1995), as well as, the anti-inflammatory, antimutagenic, antioxidant, antimicrobial
and antioxidant activities of the extract (Jorgeet al.,2013). The present study aims to establish the
anti-hyperlipidemic and antioxidants effects of various fractions of Phaseolus vulgaris L. fruit
and determine the most active of the fractions