Vol.2, No.1, 26-32 (2010) Natural Science
Copyright © 2010 SciRes. OPEN ACCESS
Study of some Indian medicinal plants by application of
INAA and AAS techniques
Ram Lokhande1, Pravin Singare2*, Mahadeo Andhele1, Raghunath Acharya3
1Department of Chemistry, University of Mumbai, Mumbai, India
2Department of Chemistry, Bhavan’s College, Mumbai, India; pravinsingare@vsnl.net
3Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai, India
Received 15 September 2009; revised 18 October 2009; accepted 20 October 2009.
Instrumental neutron activation analysis (INAA)
and atomic absorption spectroscopy (AAS)
techniques were used to analyze 18 elements
(K, Mn, Na, Fe, Zn, Cu, Co, Br, Sm, Cl, La, Al,
Cr, Ca Cd, Ni, Pb and Hg) in different medici-
nal plants often used in Indian Ayurvedic
system. The samples were irradiated with
thermal neutrons in a nuclear reactor and the
induced activities were counted by γ-ray
spectrometry using efficiency calibrated high
resolution High Purity Germanium (HPGe)
detector. Most of the medicinal plants were
found to be rich in one or more of the ele-
ments under study. The elemental concentra-
tion in different part of medicinal plants and
their biological effects on human beings are
Keywords: Instrumental Neutron Activation
Analyses; Atomic Absorption Spectroscopy;
Medicinal Plants; Trace Elemental Analysis;
Inter-Elemental Correlations
There are many references to the curative properties of
several herbs in the ancient Indian literature, Rigveda,
though a more detailed account is found in the Athar-
vaveda from where Ayurveda, the Indian traditional
health care system (ayus=life, veda=knowledge, mean-
ing science of life) originated. Fairly comprehensive
information about herbs has been recorded in two trea-
tises Charak Samhita and Shusruta Samhita-a base for
Ayurvedic system of medicine [1,2]. These herbs are
now being increasingly used in cosmetics, food as well
as alternative medicine [3]. Some of the ingredients of
allopathic and most of the Ayurvedic and Homeopathy
medicines are derived from plants. Traditional Indian
medical herbs used for strengthening the body immune
system are known to have many essential and nutritional
elements. Their excess or deficiency may disturb normal
biochemical functions of the body [4]. Some western
scholars have pursued the analysis of various Indian
plants and herbs for their medicinal properties [5]. Most
studies on such medicinal plants pertain to their organic
contents, viz. essential oils, glycosides, vitamins, alka-
loids and other active components and their pharmacol-
ogical/therapeutic effects. Besides, several organic com-
pounds, it is now well established that many trace ele-
ments play a vital role in general well-being as well as in
the cure of diseases [6,7]. Several studies have reported
elemental contents in plant extracts, which are consumed
by us either as an herbal health drink or medicine [8-10].
These elements are presented at varying concentrations
in different parts of the plants, especially in roots, seeds
and leaves which are used as a dietary item as well as
ingredient in the Ayurvedic medicinal preparation. The
leaves of the plants are still used in some countries, as
for instance, in Malaysia [11], Greece [12] and India [13]
particularly for their therapeutic effects. Since these
trace elements constitute a minute fraction in different
parts of the medicinal plants, a sensitive and reliable
analytical technique is a prerequisite for obtaining pre-
cise and accurate data.
Considering the importance of trace elements in vari-
ous human metabolic processes and also considering
their curative properties, in the present investigation we
have applied one of the sensitive analytical techniques
like INAA to study the essential elemental content in
different parts of Indian medicinal plants and herbs. The
overall impact of these essential trace elements on hu-
man health is also discussed. Due to increasing indus-
trialization and environmental pollution, the study was
also extended to estimate the level of toxic elements
present in these medicinal plant samples. Even though
the direct link between the essential elemental content
and their curative capacity is not yet established, the
experimental data of the present work will be of im-
R. Lokhande et al. / Natural Science 2 (2010) 26-32
Copyright © 2010 SciRes. OPEN ACCESS
mense importance in the synthesis of new Ayurvedic
formulations. Also, it will help in deciding the propor-
tion of various active constituents and managing dose of
a particular formulation.
2.1. Sampling
The various medicinal plants (Table 1) in the form of
leaves and roots were collected from and around the
Keshav Shrushti, Bhayander and Narsing K. Dube Col-
lege, Nalasopara, Maharashtra, India. Surface contami-
nants of the plant samples were removed by washing
with deionized water twice and then with deionized
double distilled water. The leaves were air dried in a
clean drying chamber and then dried at 80oC for over-
night in an oven. The samples were powdered in agate
mortar and passed through 100-mesh sieve. Sampling
was done from this powder.
2.2. Irradiation and Counting
About 50-80 mg of each sample was sealed in a poly-
ethylene cover. Samples, reference standard and control
sample were packed together and irradiated in the E8
position of the Apsara reactor, BARC. Irradiation time
was varied between 30 min and 7 h depending on the
half lives of the activation products. The sub-cadmium
neutron flux in this position is in the order of 1x1012cm-2
s-1. The samples were also irradiated at Dhruva reactor
for 1 d in order to determine the elemental concentration
of the long-lived radionuclides, such as Fe. The short
irradiation and counting were conducted at the reactor
site followed by spectra unfolding at the Radiochemistry
Division of BARC, Mumbai. The radionuclides used for
the analysis and their γ energies are given in Table 2. All
the samples and SRMs were counted at a calibrated
sample-detector distance from a HPGe detector (Ortec)
with 25% relative efficiency and 2.1 keV resolution at
1332.5 keV of 60Co line, which was connected, to an
IBM PC XT computer system. Most of the short lived
isotopes contributing to the dead time belong to the ele-
ments present in major Ca and minor Al levels. The
presence of different elements analyzed in various me-
dicinal plants was confirmed by measuring their charac-
teristic γ-ray energy as well as half lives which are in
Table 1. Medicinal plant samples selected for the study.
Sample Number Local NameBotanical Name Parts of plants: Medicinal use
1 Karranj Beej Pongamia pinnata
Seed: Cough, skin diseases, flatulence, diarrhoea, cough, arthritis,
ulcers, wounds, diabetes, inflammation, low back pain, fever, hem-
orrhoids, and anemia. Seed oil is also used as insecticidal, nemati-
cidal and bactericidal
2 Kutaja
Seed: Constipation, Piles, acidity, diarrhoea, dysentery, hemorrhage,
hemorrhoids, amoebiasis, hepatitis and skin diseases.
3 Jaiphal Myristica fragrans
Seed: Constipation, in treating dehydration caused by vomiting and
diarrhoea, particularly in cholera. It is used as an excellent sex tonic.
It is used in treatment of insomnia, irritability, depression, skin dis-
eases like ringworm and eczema.
It is aromatic, carminative, digestive, anti-inflammatory, diuretic,
lactagogue, aphrodisiac, hypnotic, hallucinogenic, antispasmodic
and stimulant agent. Helps relieving flatulency, useful in nausea,
stomachache, vomiting, diarrhoea associated with cholera. Also
useful in diseases of the liver, spleen, headaches, palsy and eye trou-
Nutmeg oil stimulates the heart and circulation, activates the mind
and relives people from fainting spells. The oil has good
anti-inflammatory action, and is also successful in relieving pain,
especially muscular aches and pain, as well as rheumatism.
4 Krishna
Carum bulbocas-
Seed: Appetizer, in dyspeptic problems, such as mild, sapstic condi-
tions of the gastrointestinal tract, The Ayurvedic Pharmacopoeia of
India recommended the seed in chronic fevers. Seed oil shows mod-
erate antibacterial and antifungal activity against several bacteria and
fungi. Mixed with alcohol and castor oil, it is used for scabies.
5 Babbul Acacia arabica
Fruit: Epilepsy, Insomnia, Diarrhoea, teeth disorders, eczema, tonsil-
litis, conjunctivitis, epiphora, leucorrhoea, used in toothpastes and
R. Lokhande et al. / Natural Science 2 (2010) 26-32
Copyright © 2010 SciRes. OPEN ACCESS
Table 2. Radionuclides used for the analysis and their γ-en-
Nuclide γ- ray energy in keV
42K 1524.0
56Mn 847.0
24Na 1368.0
59Fe 1099.0
65Zn 1115.0
64Cu 1040.0
60Co 1332.0
82Br 776.0
153Sm, 103.0
38Cl 1642.0
140La 1596.0
28Al 1779.0
Thermal neutron flux: 1012-1013 n cm-2 s-1.
good agreement with the literature values. Radioactivity
measuring times were chosen not to exceed 0.2 times the
half lives of the radionuclide of interest. Long irradiated
samples were brought to Radiochemistry Laboratory at
Mumbai University and γ-activity was measured.
Counting was followed for 1, 2, 6 and 12 h at different
intervals up to 3m. Care was taken to obtain maximum
elemental information from more than one counting and
the reproducibility of data was checked. Elemental con-
centrations of various Ayurvedic medicinal plants were
calculated by relative method using control and refer-
ence multielemental standard as comparators.
2.3. Atomic Absorption Spectrometer (AAS)
The samples in the powdered form were accurately
weighed and digested in (5:1) mixture of nitric acid and
perchloric acid [14]. After digestion few drops of con-
centrated HCl was added. The solution was heated gently
and then filtered. The residue was again subjected to di-
gestion and filtrate was collected. The entire filtrate was
diluted suitably with distilled deionized water. The dilute
filtrate solution was used for analysis of elements of in-
terest (Cr, Ca, Cd, Ni, Pb and Hg) by AAS (Perkin Elmer
3100 model) using suitable hollow cathode lamps. The
elements were analyzed by AAS technique by measuring
the absorbance of the species at its resonance wavelength.
The concentration of various elements was determined by
relative method using A.R. grade solutions of elements of
interest. The standard conditions for atomic absorption
measurement are represented in Table 3.
2.4. Quality Control
To provide quality control biological reference material,
namely, Polish CRM Virginia Tobacco Leaves (CTA-
VTL-2) was used. The concentrations of all the elements
investigated in this study are well certified in the refer-
ence material. The SRMs of biological origin were ana-
Table 3. Standard conditions for atomic absorption measure-
Element Wavelength
Slit width
check ppm
Lamp current
Cr 357.9 0.2 4.0 7.0
Ca 422.9 0.5 4.0 10.0
Cd 228.8 0.5 1.5 4.0
Ni 232.0 0.5 7.0 4.0
Pb 283.6 0.5 20.0 5.0
Hg 253.7 0.5 200.0 4.0
lyzed for quality control and method validation. It was
observed that most elemental contents are within±10%
of the certified values. Standard deviations were also
relatively small. The values listed in Table 4 (which are
averages of three independent measurements) are having
the precision of ~ ± 2 to 10%.
An examination of the data from Table 4 shows that
different medicinal plants contain elements like K,Mn,
Na,Fe,Zn,Cu,Co,Br,Sm,Cl,La,Al,Cr,Ca,Cd,Ni,Pb and Hg
in various proportions. The variation in elemental con-
centration is mainly attributed to the differences in bo-
tanical structure, as well as in the mineral composition of
the soil in which the plants are cultivated. Other factors
responsible for a variation in elemental content are pref-
erential absorbability of the plant, use of fertilizers, irri-
gation water and climatological conditions [15].
An examination of the data from Table 4 indicates
that fruits of Babbul contain high K (8.79 mg/g), and
low Na (0.08 mg/g) concentration. The K content is low
in seeds of Kutaja (1.06mg/g), while Na content is to the
maximum of 0.90 mg/g in seeds of Jaiphal. It is impor-
tant here to note that the regulation of potassium is inti-
mately involved with that of sodium and the two are
largely interdependent. Potassium is accumulated within
human cells by the action of the Na+, K+-ATPase (so-
dium pump) and it is an activator of some enzymes; in
particular co-enzyme for normal growth and muscle
function [16].
The calcium content in various medicinal plants
analyzed varies from 1.58 mg/g in Karranj Beej to 15.1
mg/g in Kutaja. Calcium is essential for healthy bones,
teeth and blood [17,18]. The health of the muscles and
nerves depends on calcium. It is required for the ab-
sorption of dietary vitamin B, for the synthesis of the
neurotransmitter acetylcholine, for the activation of
enzymes such as the pancreatic lypase. The recom-
mended daily dietary allowance of Ca for children is
between 500 and 1000 mg, and 800 mg for adults. The
appreciable high Ca content in fruits of Babbul sug-
gests its possible use in toothpastes and gargles to
overcome deficiency of Ca.
R. Lokhande et al. / Natural Science 2 (2010) 26-32
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Table 4. Elemental analysis of some medicinal plants by NAA and AAS techniques.
Name of
the me-
Parts used
(±0.07) ND
(±0.01) ND 0.77
(±0.03)ND 2.77
(±0.08) ND
(±0.28) ND 1.22
Elements detected by AAS technique; (±) Standard deviation; [ ] Certified values; { } Measured values; ND=Not detected.
The elements like Zn, Fe and Cr are essential trace
elements (micro nutrients) for living organisms. Zinc is
relatively non-toxic [19]. Zinc deficiency is character-
ized by recurrent infections, lack of immunity and poor
growth. Growth retardation, male hypogonadism, skin
changes, poor appetite and mental lethargy are some of
the manifestations of chronically zinc-deficient human
subjects [19]. Zinc is necessary for the growth and mul-
tiplication of cells (enzymes responsible for DNA and
RNA synthesis), for skin integrity, bone metabolism and
functioning of taste and eyesight [20]. From the results
obtained, it is observed that the concentration of Zn
ranges from 95.0 µg/g in Jaiphal to 40.2 µg/g in Krishna
Jirak. The high concentration of zinc in seeds of Jaiphal
suggests its possible use in sex tonic, treatment of worms,
skin disease, and eye trouble. The appreciable high Zn
content in Karranj beej and Babbul may also be helpful
in treatment of skin disease. Iron occupies a unique role
in the metabolic process. The role of iron in the body is
clearly associated with hemoglobin and the transfer of
oxygen from lungs to the tissue cells [21]. Iron defi-
ciency is the most prevalent nutritional deficiency in
humans [22] and is commonly caused by insufficient
dietary intake, excessive menstrual flow or multiple
births. In this case, it results especially an anemia. In
various medicinal plants samples analyzed, the Fe con-
tent was observed maximum in seeds of Karranj beej
(601µg/g) and minimum in seeds of Jaiphal and Babbul
(261µg/g). Hence the use of Karranj beej seeds in gen-
eral tonic preparation may be advised to compensate for
treatment of anemia. Chromium plays an important role
in diabetes treatment. It is an important element required
for the maintenance of normal glucose metabolism. The
function of chromium is directly related to the function
of insulin, which plays a very important role in diabetes.
Chromium is found in the pancreas, which produces
insulin. One usable form of chromium is the Glucose
Tolerance Factor (GTF) [23], an inorganic compound
containing glutamic acid, cysteine and niacin. The ab-
sorption of the trivalent chromium in GTF is about 10 to
25%. It enhances the removal of glucose from the blood.
The important constituent of GTF is Cr which helps in
the potentiating of insulin [24]. Chromium also acts as
an activator of several enzymes. Deficiency of chro-
mium decreases the efficiency of insulin and increases
sugar and cholesterol in the blood. Chromium deficiency
can cause an insulin resistance, impair in glucose toler-
ance and may be a risk factor in artherosclerotic disease
[25]. From the results obtained, it is observed that Cr
content is high in fruits of Babbul (2.71 µg/g) and seeds
R. Lokhande et al. / Natural Science 2 (2010) 26-32
Copyright © 2010 SciRes. OPEN ACCESS
of Karranj beej (2.11 µg/g). Hence the use of this me-
dicinal plant may be advised for the treatment and con-
trol of diabetics.
In experiments conducted by Anke et al. [26] with
growing, gravid and lactating goats, a poor Br-nutrition
(<1 mg/g dry matter) led to a significantly reduced
growth, a worse conception rate, reduced milk fat pro-
duction and decreased hemoglobin content. The high
concentration of Br along with Fe in Karranj beej,
Jaiphal, Babbul and Krishna jiraka suggests there possi-
ble use in preparation of drugs for curing natural diuretic,
phlegm eliminating and stomach invigorating diseases
[27] and purifying breast milk. However, further inves-
tigations regarding possible essentiality of Br are neces-
sary due to the fact that Br accumulates well in plants
due to the application of agricultural chemicals such as
methyl bromide as fumigant.
The higher Mn content was observed in seeds of
Krishna jiraka (188.1 µg/g). It is important here to note
that Mn is an essential element required for various bio-
chemical processes [28]. Mn is also important for sev-
eral enzymatic processes. It helps in eliminating fatigue
and reduces nervous irritability [7,29,30]. Hence use of
Krishna jiraka seeds in medicinal preparations may help
to supplement Mn for various body functions.
The Co content was observed to be high in Karranj
beej (83.0 µg/g). Cobalt is an essential element for the
plants having the capability to fix nitrogen in the root
tubercles. Animals are able to synthesize vitamin B12,
which is the main source of Co in animal foods. Never-
theless, only a part of Co in food derived from animals is
present in the form of cobalamines. The recommended
daily intake of vitamin B12 for adults is 3 mg (0.13 mg
Co), taking into account that only 50% is absorbed in the
intestine [20]. In humans, deficiency of vitamin B12
leads to a megaloblastic anemia. Cobalt also plays an
important role in thyroid metabolism in humans. The
higher Co and Fe content in Karranj beej suggests there
use in medicinal preparation for treatment of anemia.
The elements like Hg, Pd, Cd and Ni are supposed to
be toxic in nature and their presence in trace amount in
various medicinal plant sample analyzed is due to the
pollution arising from automobile and industrial activi-
3.1. Inter-Elemental Correlations
Several literature reports suggest interrelationship of
essential elements like K, Na, Fe, Co and Zn [6,10,14].
The regulation of metal ion flows, especially of K+ and
Na+, is crucial to life and is most clearly exemplified by
the ionic movements that occur in nerve cells during
excitation and transmission of the action potential. The
regulation of potassium is intimately involved with that
of sodium and the two are largely interdependent. From
the experimental data, it is observed that K/Na ratio var-
ies between minimum of 1.4 in Jaiphal to maximum of
109.9 in Babbul. The result indicates that potassium
content is 1.4 times of sodium in Jaiphal, and 110 times
in Babbul. The variation of K/Na ratio for different plant
samples is graphically represented in Figure 1. The
transition elements Fe, Zn and Co are well known for
their role in biochemical processes [10]. Iron deficiency
is common in uremic patients, it causes substantial blood
losses. Some reports indicate that dysgeusia, poor food
intake, and impaired sexual function, which are common
problems of uremic patients, may be improved by zinc
supplements [31]. In blood, about 85% of the zinc com-
bines with protein for transport after its absorption, and
its turnover is rapid in the pancreas. Deficiency of zinc
causes diabetic hyposima, hypogeusia or coma [15]. The
availability of Zn in the range of 14.8-8.4 μg/g may be
beneficial for diabetic patients as its deficiency has been
correlated with acute and chronic mal absorption states
[30,32]. Similarly Fe is important because it eliminates
phlegm and strengthens the function of stomach. Iron is
found in body tissue enzymes and helps with energy
metabolism. It facilitates the oxidation of carbohydrates,
protein and fat to control body weight, which is very
important in diabetes [15]. The requirement of Fe for an
adult is 20 mg/day and for a child is 10 mg/day. From
the result of medicinal plants analyzed, Fe/Zn ratio var-
ies from 2.7 in Jaiphal to 8.1 in Kutaja (Figure 2). Co-
balt in the form of Vitamin B-12 is in its physiologically
active form. It is very essential to provide 3 µg per day
in the form of Vitamin B-12 for a diabetic individual. A
plot of Fe versus Co shows linear relationship (Figure 3)
with r=0.907, which represents somewhat poor relation-
ship. It is possible due to the fact that all parts of the
medicinal plants are different i.e. seeds and fruits as re-
ported by Razic et al. [33]. In general, it may be men-
tioned that interrelationship of several elements in me-
dicinal herbs suggest synergistic or antagonistic effects,
thus providing various elements to the body in bio-avail-
able form in a balanced manner with almost no harmful
effects except some environmental contaminants. These,
however, should be avoided by collecting herbs grown in
a clean and well controlled environment [10].
Although there appears to be little knowledge of the pre-
cise molecular mechanisms, many Ayurvedic prepara-
tions nevertheless appear to demonstrate significant
success in treatment of complex diseases. Presumably
Ayurvedic medicines contain trace elements in a
bio-available form and their impact on the overall phar-
macological action cannot be ruled out. Although the
direct link between elemental content and curative capa-
bility is yet to be established, such studies are vital to
understanding the pharmacological action of herbs. The
R. Lokhande et al. / Natural Science 2 (2010) 26-32
Copyright © 2010 SciRes. OPEN ACCESS
2.1 2.5 1.4 6.3
Karranj BeejKutajaJaiphalKrishna JirakaBabbul
Medicinal Plants
K/Na ratio
Figure 1. Variation of K/Na ratio in different medicinal plant samples.
8.0 8.1
KutajaJaiphal Krishna
Medicinal Plants
Fe/Zn ratio
Figure 2. Variation of Fe/Zn ratio in different medicinal plant samples.
0200400 600800
Concentration of Fe
Concentration of Co
Figure 3. Correlation between Fe and Co concentrations in different medicinal
plant samples. Correlation coefficient (r)=0.907.
R. Lokhande et al. / Natural Science 2 (2010) 26-32
Copyright © 2010 SciRes. OPEN ACCESS
data obtained in the present work will be helpful in the
synthesis of new Ayurvedic drugs which can be used for
the control and cure of various diseases. In order to de-
velop a stronger basis for appreciating the curative ef-
fects of medicinal plants, there is a need to investigate,
their elemental composition. It has been demonstrated
that INAA, with multi-elemental characterization over a
wide range of concentration, its blank free-nature and
minimum sample preparation is ideal for such studies.
[1] Parchure, S.N. (1983) Charak Samhita, Sagar Publica-
tions, Pune, 1-3.
[2] Sharma, P.V. (1993) Dravya Guna Vigyan, Chaukhamba
Bharati Academy, Varanasi.
[3] Bakhru, H.K. (1998) Herbs that heal natural remedies for
good health. Orient Paperbacks, Division of Vision Book
Pvt. Ltd, New Delhi.
[4] Lyengar, G.V. (1989) Elemental Analysis of Biological
Systems: Biomedical Environmental, Compositional and
Methodological Aspects of Trace Elements, Boca Raton,
CRC Press, Florida, 1, pp. 242.
[5] Ambasta, S.P. Ed. (1986) The Useful Plants of India,
CSIR, New Delhi, pp. 918.
[6] Underwood, E.J. (1977) Trace Elements in Human and
Animal Nutrition, 4th Ed, Academic Press, New York, pp.
[7] Prasad, A.S. (1993) Essential and Toxic Elements in
Human Health and Disease: An Update, Wiley-Liss,
New York.
[8] Powel, J.J., Burden, T.J. and Thompson, R.P.H. (1998) In
vitro mineral availability from digested tea: A rich die-
tary source of manganese. Analyst, 123, pp. 1721.
[9] Abou Arab A.A.K. and Donia, M.A.A. (2000) Heavy
metals in Egyptian spices and medicinal plants and the
effect of processing on their levels. J. Agri. Food Chem.,
48, pp. 2300.
[10] Kumar, A., Nair, A.G.C., Reddy, A.V.R. and Garg, A.N.
(2005) Analysis of essential elements in Pragya-peya-a
herbal drink and its constituents by neutron activation. J.
Pharma. Biomed. Anal., 37, pp. 631.
[11] Majid, A.A.B., Sarmani, S., Yusoe, N.I., Wie, Y.K. and
Hamzah, F. (1995) Trace elements in Malaysian medici-
nal plants. J. Radioanal. Nucl. Chem., 195, pp. 173.
[12] Kanias, G.D., Kilikoglou, V., Tsitsa, E. and Loukis, A.
(1993) Determination and statistical analysis of trace
element and active constituent concentrations in the me-
dicinal plant Eucalyptus Camaldulensis Dehnh (E. Ros-
tratus schlecht). J. Radioanal. Nucl.Chem., 169, pp. 483.
[13] Patel, N.G. (1986) India’s traditional medicine: Ayurveda.
In: Steiner, R.P. Ed., Folk Medicine: The Art and the
Science, American Chemical Society, Washington D.C.
[14] Herber, R.F.M. and Stoeppler, M. Eds. (1994) Trace Element
Analysis in Biological Specimens, Elsevier, New York.
[15] Rajurkar, N.S. and Pardeshi, B.M. (1997) Analysis of
some herbal plants from India used in the control of dia-
betes mellitus by NAA and AAS techniques. Appl. Ra-
diat. Isot., 48, pp. 1059.
[16] Birch, N.J. and. Padgham, C (1994) Potassium. In: Seiler,
H. G., Sigel, A. and Sigel, H. Eds., Handbook on Metals
in Clinical and Analytical Chemistry, Marcel Dekker,
New York.
[17] Charles, P. (1992) Calcium absorption and calcium bio-
availability. J. Int. Med., 231, pp. 161.
[18] Hughes, M.N. (1972) The Inorganic Chemistry of Bio-
logical Processes, Wiley, London.
[19] Prasad, A.S. (1982) Clinical and biochemical spectrum of
zinc deficiency in human subjects. In: Prasad, A.S. Ed.,
Clinical, Biochemical and Nutritional Aspects of Trace
Elements, Alan R. Liss, Inc, New York.
[20] Thunus, L. and Lejeune, R. (1994) Cobalt, Zinc. In:
Seiler, H.G., Sigel, A. and Sigel, H. Eds., Handbook on
Metals in Clinical and Analytical Chemistry, Marcel
Dekker, New York.
[21] Sigel, H. Ed. (1978) Iron in model and natural com-
pounds. Metals in Biological Systems, Marcel Dekker,
New York, 7.
[22] Reddy, M.B., Chidambaram, M.V. and Bates, G.W. (1987)
In: Winkelmann, G., Helm, Van der D. and Neilands, J.B.
Eds., Iron Transport in Microbes, Plants and Animals,
VCH, New York.
[23] Zetic, V.G. Tomas, V.S. Grba, S. Lutilsky, L. and Kozlek,
D. (2001) Chromium uptake by Saccharomyces cere-
visiae and isolation of glucose tolerance factor from
yeast biomass. J. Biosci., 26, pp. 217.
[24] Anderson, R.A. (1989) Essentiality of chromium to hu-
mans. Sci. Total Environ., 86, pp. 75.
[25] Mertz, W. (1982.) Clinical and public health significance
of chromium. In: Prasad, A.S. Ed., Clinical, Biochemical
and Nutritional Aspects of Trace Elements, Alan R. Liss,
Inc, New York.
[26] Anke, M., Groppel, B., Arnhold W., and Larger, M.
(1988) Essentiality of the trace element Bromine. In:
Briitter, P. and Schramel, P. Eds., Trace Element Ana-
lytical Chemistry in Medicine and Biology, Walter de
Gruyter, Berlin, New York, 5.
[27] Chen, K.S., Tseng, C.L. and Lin, T.H. (1993) Trace ele-
ments in natural drugs determined by INAA. J. Radio-
anal. Nucl. Chem., 170, pp. 265.
[28] Guenther, W. and Konieczynski, P. (2003) Speciation of
Mg, Mn, and Zn in extracts of medicinal plants. Anal.
Bioanal. Chem., 375, pp. 1067.
[29] Hamilton, E.M.N., Whitney, E.N. and Sizer, F.S. (1994)
Nutrition: Concepts and Controversies, 4th Ed., St. Paul,
West Publishing Co, MN, USA.
[30] O’Dell, B.L. and Sunde, R.A. Eds. (1997) Handbook of
Nutritionally Essential Mineral Elements, Marcell Dek-
ker Inc, New York.
[31] Shils, M.E. and Young, V.R. (1988) Modern Nutrition in
Health and Diseases, 7th Ed, K. M. Verghese Co.
[32] Garg, A.N., Kumar, A., Maheshwari, G. and Sharma, S.
(2005) Isotope dilution analysis for the determination of
Zinc in blood samples of diabetic patients. J. Radioanal.
Nucl.Chem., 263, pp. 39.
[33] Razic, S., Onjia, A. and Potkonjak, B. (2003) Trace ele-
ments analysis of Echinacea purpurea-herbal medicinal. J.
Pharm. Biomed. Anal., 33, pp. 845.