Cloning & Transgenesis
Volume 2 • Issue 3 • 1000112
Clon Transgen
ISSN: 2168-9849 CTG, an open access journal
Open Access Research Article
Adepoju-Bello et al., Clon Transgen 2013, 2:3
DOI: 10.4172/2168-9849.1000112
Determination of the Concentration of Selected Heavy Metals in
Indigenous Plant: Telfairia occidentalis
Adepoju-Bello AA
1
, Okeke CP
1
, Bamgbade I
1
and Oguntibeju OO
2
*
1
Pharmaceutical Chemistry Department, Faculty of Pharmacy, University of Lagos, Southern Nigeria
2
Department of Biomedical Sciences, Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, Bellville Campus, 7535, South Africa
Abstract
Telfairia occidentalis Hook. F. is an edible vegetable, rich in essential diet components and contains protein,
vitamins, iron, calcium and other nutrients, which are not adequately supplied in our diet. However, Telfairia occidentalis
is believed to contain heavy metals over a range of concentrations which could pose potential health risk to the
consumers. The objective of this study was to determine whether the concentration of selected heavy metals present
in Telfairia occidentalis cultivated in twenty Local Government areas of Lagos State, Nigeria, are within the acceptable
range for human consumption. Telfairia occidentalis leaf samples were collected from twenty local government areas
in Lagos State, washed thrice with water and air-dried prior to grounding into fne powder and sieved. The samples
were digested with concentrated HNO
3
and the concentrations of the metals were determined using the Buck 205
Atomic Absorption Spectrophotometer. The British Pharmacopoeia calibration plot method was adopted. All the
Telfairia occidentalis samples (100%) from the 20 Local Governments in Lagos State contained arsenic and mercury
below the USP oral component limit while 100% contained cadmium above the oral component limit. Twenty percent
(20%) contained iron above the USP oral component limit. These metals could bio-accumulate in the biological system
of people consuming this vegetable, thus posing potential health risk to consumers especially if consumed over a
long period. We therefore suggest regular assessing of these metals in vegetables grown in these localities and that
government should monitor and ensure proper disposal of waste within the environment in order to reduce the level
of contamination of vegetables by heavy metals which are mainly resulting from industrial wastes and other sources
of environmental pollution.
*Corresponding author: Oluwafemi Oguntibeju, Department of Biomedical
Sciences, Faculty of Health and Wellness Sciences, Cape Peninsula University
of Technology, Bellville Campus, 7535, South Africa, Tel: +27219538495; Fax:
+27219538490; E-mail: oguntibejuo@cput.ac.za, bejufemi@yahoo.co.uk
Received July 05, 2013; Accepted August 16, 2013; Published August 19, 2013
Citation: Adepoju-Bello AA, Okeke CP, Bamgbade I, Oguntibeju OO (2013)
Determination of the Concentration of Selected Heavy Metals in Indigenous Plant:
Telfairia occidentalis. Clon Transgen 2: 112. doi:10.4172/2168-9849.1000112
Copyright: © 2013 Adepoju-Bello AA, et al. This is an open-access article
distributed under the terms of the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided
the original author and source are credited.
Keywords: Vegetable; Contamination; Heavy metals; Health hazards
Introduction
Telfaira occidentalis Hook generally known as futed pumpkin
occurs in the forest zone of West and Central Africa, mostly in Benin,
Nigeria and Cameroon. It is a popular vegetable all over Nigeria. It is
rare in Uganda and absent in the rest of East Africa. It is believed that
it originated in south-east Nigeria and was distributed by the Igbos
who had cultivated it for centuries. Te plant produces luxuriant edible
green leaves which are rich in iron and vitamins. Stems of the plants
have branching, long twisting tendrils and the leaves are divided into
three to fve leafets with the terminal leafets measuring 15 cm in
length and the male plant is grown mainly for leaves and seeds and
form important soup ingredients in Nigeria [1-4].
Recent studies have shown that Telfairia occidentalis leaf is rich in
minerals such as iron, potassium, sodium, phosphorus, calcium and
magnesium and antioxidant vitamins such as thiamine, ribofavin and
ascorbic acid and phytochemicals such as phenols [5-8]. Te young
leaves sliced and mixed with coconut water and salt are stored in a
bottle and used for the treatment of convulsion in ethno medicine [4].
Te leaf extract is used in the management of cholesterolemia, liver
problems and impaired immune system. It has been reported that its
amino acid contents compared favourably with those of important
legumes. Te study of Emeka and Obidoa [9] reveals that long-term
feeding of T. occidentalis-supplemented diet caused a signifcant
increase in weight of the animals which may be attributed to its rich
nutritional contents. An anecdotal report has it that T. occidentalis
leaf is a key ingredient in most Nigerian soups and the high vegetable
content provides high dietary fbre, good for sound bowel function and
ideal in a weight control diet [4,10,11].
Various vegetables abound in Nigeria which is utilized either as
condiments or spices in human diets and these vegetables could be
harvested at all stages in the process of growth and could be used either
in the fresh, processed or semi-processed form. However, the presence
of inherent toxic metals has been implicated as one of the variables
afecting the nutritional values of food. Although a lot of information
could be available about the nutrient and antinutrient contents of
these commonly consumed green leafy vegetables in Nigeria, there is
a dearth of information with regard to their safety. It is known that
vegetables take up metals by absorbing them from contaminated soils,
as well as from deposits on diferent parts of the vegetables exposed to
the air from polluted environments [6,12]. It has been reported that
nearly half of the means of ingestion of lead, cadmium and mercury
through food is due to plant origin (fruit, vegetables and cereals).
Moreover, some population groups seem to be more exposed, especially
vegetarians, since they absorb more frequently ‘tolerable daily doses’.
Food contamination by heavy metals depends both on their mobility
in the soil and their bioavailability [3,13].
Iron is one of the elements present in T. occidentalis and iron is
very important for blood building but when in excess it becomes toxic
and causes iron overload disease known as haemochromatosis. Large
amounts of ingested iron can cause excessive levels of iron in the
blood. High blood levels of free ferrous iron react with peroxides to
produce free radicals, which are highly reactive and can damage DNA,
proteins, lipids, and other cellular components. Tus, iron toxicity
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ISSN: 2168-9849