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Ethnobotanical Leaflets 14: 856-63.
2010. Analysis of Heavy Metal and Inorganic
Element Content in Barringtonia
acutangula Leaf R. Vijaya Bharathi*, A. Jerad
Suresh, M. Thirumal, B. Kumudhaveni Department
of Pharmacognosy, College of Pharmacy, Madras Medical College, Chennai-03, Tamil
Nadu, India *Email: rvbharathi2003 @ yahoo.com Issued August 1, 2010 Abstract The estimation of heavy
metals and inorganic elements in Barringtonia acutangula leaves were carried
out, using Atomic absorption Spectrophotometry (AAS), Colorimetric, Cold
Vapour Atomic Absorption, Argentometric, Turbidimetric and sodium 2-
(parasulfophenylazo)- 1 ,8-dihydroxy-3,6-naphthalene di sulphonate (SPADNS)
colorimetric method. The heavy metals determined were Arsenic, Cadmium, Lead,
Mercury and Copper. The inorganic elements present, Fluoride, Chloride and
Sulphate were Quantitatively estimated. The results obtained revealed that heavy
metals level in Barringtonia acutangula
leaves were within the permissible limit and hence seem to be a safe herbal medicine to health. Key words: Barringtonia acutangula, Heavy metals, Inorganic elements. Introduction Medicinal plants have been
in use since for many years to cure a great variety of diseases. Recently
with the emphasis of the World Health Organization, the use of traditional
herbal medicine has spread not only in the developing countries but also in
the industrialized ones, as a complementary way to treat and to prevent
illnesses (World Health Organisation, 2003). Heavy metals, such as zinc, lead, copper, mercury, cadmium,
arsenic are extremely toxic in very small amounts. When one or more of these
elements are present in the environment at high concentrations, living
organisms are subjected to strong natural selection for tolerance.
Environmental contamination by metals exerts physiological pressures that are
clearly too severe for survival of most species by means of phenotypic
plasticity or physiological acclimation, rather than genetic adaptation
(Tonguc, 1998). The pharmacological
properties of the medicinal plants have been attributed to the presence of
active constituents which are responsible for important physiological
function in living organisms. It has been reported that trace elements play
an important role in the reactions which will lead to the formation of these
active constituents (Serfor-Armah et al.,
2001). However, a correlation between elemental composition of medicinal
plants and their curative properties have not been established yet. Besides,
element concentrations present in medicinal plants are of great importance to
understand their pharmacological actions (Serfor-Armah et al., 2002). Materials
and Methods Fresh
leaves of Barringtonia acutangula
(L.) Gaertn. (Lecythidaceae) were collected from Madras Medical College
premises, Chennai, Tamilnadu. The
plant was identified, and authenticated by botanist Dr. P. Jayaraman, Plant
Anatomical Research Centre, Tambaram, Chennai. Estimation of heavy
metals Estimation of Arsenic Arsenic was estimated by
using Modified Arsenic estimation apparatus. Take sample in an arsine
generator. Add 3 gm of Zinc and 2 ml potassium iodide solution to the
generator. Impregnate the glass wool in the scrubber with lead acetate
solution. Take 4 ml silver diethyl dithiocarmate reagent in the absorber
tube. Take 5 ml conc. Hydrochloric acid and 1 ml Stannous chloride reagent in
a measuring cylinder. Connect the generator scrubber absorber assembly and
make sure that all connections are tightly fitted. Remove the stopper of
arsine generator and immediately close the generator by the stopper. Allow 30
minutes for complete evolution of arsine. Pour the solution from the absorber
directly in to 1 cm cell and measure the absorbance of the solution at 535 nm
spectrophotometrically. Prepare standard curve by using the standard
solution. Estimation of Mercury Adjust all control knobs present in the instrument. Remove the
stopper and take a suitable aliquot of the blank, standard or sample solution
in the reaction vessel. Add 10 % Nitric acid to maintain a volume of 100 ml.
add 2 ml of Stannouschloride and replace the stopper immediately. Switch on
the magnetic stirrer and stir vigorously for about 5 mnts. Adjust ‘0’ and 100
% T. Leave the filter rod in the position. Switch to ‘HOLD’ mode of
operation. Start the pump and allow air to purge through the reaction vessel.
Note the absorbance as early as possible with in a min and switch back to
‘NORMAL MODE’. The meter indication should be back to 100 % T. switch off the
pump and the magnetic stirrer. Adjust 0 % and 100 % just before each
measurement. Repeat the measurements for standard. Plot Absorbance vs.
Concentration of Mercury Estimation of Lead,
Copper and Cadmium The instrument
used for analysis was Perkin Elmer Analyser 300. After calibrating the
instrument, aspirate a blank consisting of deionized water containing the
same concentration of acid in standard and sample. Zero the instrument.
Aspirate a standard solution and adjust aspiration rate of the nebulizer to
obtain maximum sensitivity. Adjust burner both vertically and horizontally to
obtain maximum response. Aspirate blank again and re-zero the instrument.
Repeat the same for sample and determine its absorbance (Clesceri et al., 1998). The metal concentration was estimated on dry weight basis by
using the following equation Metal concentration, mg/kg
(dry weight basis) = A x
B x 100
g
of Sample D Where: A-
concentration of
metal in digested solution, mg/l B-
final volume of
digested solution, ml D-
total solids, % Qualitative and
quantitative estimation of inorganic elements Qualitative analysis of Inorganic elements Prepare ash of drug material. Add 50 % v/v Hydrochloric acid.
Keep for 1 hour or longer. Filter. With filtrate perform the following tests
(Khandelwal 2006). Calcium: To 10 ml filtrate, add 1
drop dil. ammonium hydroxide and saturated ammonium oxalate solution. White precipitate
of calcium oxalate forms. Precipitate is soluble in Hydrochloric acid but
insoluble in acetic acid. Magnesium: Filter and separate white
calcium oxalate precipitate obtained above. Heat and cool the filtrate which
with solution of sodium phosphate in dilute ammonia solution gives white
crystalline precipitate. Sodium: To 2 ml test solution,
add little uranyl magnesium acetate reagent. Shake well and keep for few
minutes. Yellow crystalline precipitate of sodium magnesium uranyl acetate
observed. Potassium: To 2-3 ml test solution,
add few drops sodium cobalt nitrite solution. Yellow precipitate of potassium
cobalt nitrite observed. Iron: To 5 ml test solution add
few drops of 2% potassium ferrocyanide. Dark blue coloration is observed. Sulphate: With lead acetate reagent
gives white precipitate soluble in sodium hydroxide. Phosphate: To 5 ml test solution
prepared in Nitric acid add few drops ammonium molybdate solution. Heat 10
min. Cool. Yellow crystalline precipitate of ammonium molybdate is observed. Chloride: To about 5 to 7 ml
filtrate, add 3 to 5 ml lead acetate solution. White precipitate soluble in
hot water is observed. Carbonate: With dilute acid liberate
carbon dioxide. Nitrates: With solution of ferrous
sulphate yield no brown colour but if sulphuric acid is added (slow from the
side of the test tube), a brown colour is produced at the junction of two
liquids. Quantitative estimation of Inorganic elements Sulphate: Sulphate ion is
precipitated in an acetic acid medium with barium chloride so as to form
barium sulfate crystals of uniform size. Light absorbance of the barium
sulphate suspension is measured by a photometer and the sulphate
concentration is determined by comparison of the reading with a standard
curve. Estimation: Sulphate
was estimated by Turbidimetric method. Absorbance was measured using Chemito
2100 scanning spectrometer. A suitable portion of sample made up to 100 ml
taken into 250 ml Erlenmeyer flask. Add 20 ml buffer solution and mix in
stirring apparatus. While stirring, add a spoonful of Barium chloride
crystals and begin timing immediately. Stir for 60 + 2 s at constant speed.
After stirring period has ended, pour solution into absorption cell of
spectrophotometer and measure turbidity at 420 nm. Estimate Sulphate (SO42-)
conc. in sample by comparing turbidity reading with a calibration curve
prepared by carrying SO42- standards. Fluoride: Fluoride was estimated by
sodium 2-(parasulfophenylazo)- 1 ,8-dihydroxy-3,6-naphthalene disulphonate
(SPADNS) colorimetric method and it is based on the reaction between fluoride
and a zirconium-dye lake. Fluoride reacts
with the dye lake, dissociating a portion of it into a colourless complex ion
(ZrF62-); and the dye. As the amount of fluoride
increase, the colour produced becomes progressively lighter. Absorbance was
measured using Chemito 2100 scanning spectrometer. Estimation: Prepare
fluoride standards in the range of 0 to 1.40 mg F-/L by diluting
appropriate quantities of standard fluoride solution to 50 ml with distilled
water. Pipette 5 ml each of SPADNS solution and zirconyl-acid reagent or 10
ml mixed acid-zirconyl-SPADNS reagent, to each standard and mix well. Avoid
contamination. Set photometer to zero absorbance with the reference solution
and obtain absorbance readings of standards. If the sample contains residual
chlorine, remove it by adding 1 drop (0.05 ml) NaAsO2 solution/
0.1 mg residual chlorine and mix. A portion of sample is diluted to 50 ml
with distilled water. Adjust sample temperature to that used for the standard
curve. Add 5 ml each of SPADNS solution and zirconyl-acid reagent, or 10 ml
acid-zirconyl-SPADNS reagent; mix well and read absorbance at 570 nm. Chloride: In a neutral or slightly
alkaline solution, potassium chromate can indicate the end point of the
silver nitrate titration of chloride. Silver chloride is precipitated
quantitatively before red silver chromate is formed. Estimation: Chloride
was estimated by Argentometric method. A suitable portion of sample was
diluted to 100 ml. If the sample is highly colored, add 3 ml Aluminiumhydroxide
suspension, mix, let settle and filter. Directly titrate samples in the pH
range 7 to 10. Adjust sample pH to 7 to 10 with Sulphuricacid or Sodiumhydroxide
if it is not in this range. Add 1 ml Potassium chromate indicator solution.
Titrate with standard Silvernitrate titrant to a pinkish yellow end point. Result
and Discussion The crude powder was ashed
and acid digested were analysed for the presence of Heavy metals like
Arsenic, Lead, Mercury, Cadmium and Copper were found to be within the
permissible limit (Table 1). The presence of essential element copper in the
leaves confirms the potentiality of the drug in various ailments. The
Qualitative and quantitative estimation reveals the presence of inorganic
elements like Chloride, Fluoride and Sulphate (Table 2). The estimation of
heavy metals and inorganic elements content in this medicinal plant
represents one of the factors for the evaluation of their quality. The present
study provides valuable information for authentication of this medicinally
useful plant. The results obtained revealed that heavy metals level in Barringtonia acutangula leaves were
within the permissible limit and hence seem to be a safe herbal medicine to health. Table 1. Quantitative estimation of Heavy Metals
WB- wet basis and DB-
Dry basis Table 2. Qualitative and Quantitative analysis of
the leaf powder.
(+) Present, (-) Absent, WB- wet basis References Clesceri LS, Green berg AE, Eaton AD. 1998. Standard methods for the Examination of water and waste water. 20th
edn, American Public Health Association, Washington. Khandelwal
KR. 2006. Practical Pharmacognosy.
16th edn, Nirali Prakashan, Pune. Serfor-Armah
Y, Nyarko BJB, Akaho EHK, Kyere AWK, Osae S, Oppong-Boachie K, Osae EKJ.2001.
Activation analysis of some essential elements in five medicinal plants used
in Ghana. J. Radioanal. Nucl. Chem., 250
(1): 173–176. Serfor-Armah Y, Nyarko BJB, Akaho EHK, Kyere AWK, Osae S,
Oppong-Boachie K.2002. Multielemental analysis of some traditional plant
medicines used in Ghana. J. Trace
Microprobe Tech., 20 (3): 419–427. Tonguc O.1998. Determination of Heavy metal levels in some moss
species Around Thermic power Stations. Turkey
Journal of Biology (28): 171-80. World
Health Organization. Traditional Medicine, Fact sheet No. 134, May 2003.
Available at:
owww.who.int/mediacentre/factsheets/2003/fs134/en4 Access in:
07/08/2003. |