Studies on Tea Quality Grown Through Conventional and Organic Management Practices: Its Impact on Antioxidant and Antidiarrhoeal Activity

Abstract

Quality tea production is in demand for its better palatability and beneficial effects on human health, including controlling several diseases with its high antioxidant properties. So far, few studies have been made on the impact of fertilizer input on tea quality. To address the issue, tea was grown under conventional and organic practices to compare the production of biochemical compounds like crude fiber, starch, total phenolics, (-)-epigallocatechin gallate [(-)-EGCG], (-)-gallocatechin gallate [(-)-GCG], and (-)-epicatechin gallate [(-)-ECG], as well as the antioxidant and antidiarrhoeal properties of the tea leaves. Organically grown tea lowered the content of crude fiber and starch as compared to the no‐fertilizer treatment (control). However, the content was further lowered by the inorganic fertilizer treatment. Organic fertilization produced higher polyphenol than inorganic fertilization, which has shown greater antioxidant properties when analyzed through the methods of dot‐blot and DPPH staining, DPPH radical assay, and hydroxyl radical scavenging activities by electron paramagnetic resonance spectrometry. Animal experiments conducted using green tea extracts on rodents revealed better diarrhoea control with organically tea than with inorganically grown tea. This study reveals the importance of organic agricultural practices in tea for quality improvement and sustainability of the food chain system.

Full text

Transactions of the ASABE
Vol. 51(6): 2227-2238 E 2008 American Society of Agricultural and Biological Engineers ISSN 0001-2351 2227
STUDIES ON TEA QUALITY GROWN THROUGH CONVENTIONAL
AND ORGANIC MANAGEMENT PRACTICES:
ITS IMPACT ON ANTIOXIDANT AND ANTIDIARRHOEAL ACTIVITY
S. Palit, B. C. Ghosh, S. Dutta Gupta, D. K. Swain
ABSTRACT. Quality tea production is in demand for its better palatability and beneficial effects on human health, including
controlling several diseases with its high antioxidant properties. So far, few studies have been made on the impact of fertilizer
input on tea quality. To address the issue, tea was grown under conventional and organic practices to compare the production
of biochemical compounds like crude fiber, starch, total phenolics, (-)-epigallocatechin gallate [(-)-EGCG],
(-)-gallocatechin gallate [(-)-GCG], and (-)-epicatechin gallate [(-)-ECG], as well as the antioxidant and antidiarrhoeal
properties of the tea leaves. Organically grown tea lowered the content of crude fiber and starch as compared to the
no‐fertilizer treatment (control). However, the content was further lowered by the inorganic fertilizer treatment. Organic
fertilization produced higher polyphenol than inorganic fertilization, which has shown greater antioxidant properties when
analyzed through the methods of dot‐blot and DPPH staining, DPPH radical assay, and hydroxyl radical scavenging
activities by electron paramagnetic resonance spectrometry. Animal experiments conducted using green tea extracts on
rodents revealed better diarrhoea control with organically tea than with inorganically grown tea. This study reveals the
importance of organic agricultural practices in tea for quality improvement and sustainability of the food chain system.
Keywords. Antidiarrhoeal activity, Antioxidant activity, Biochemical compounds, Inorganic fertilizer, Organic fertilizer.
ea is a widely consumed beverage worldwide. It is
a long‐duration (around 70 years) crop grown as
monoculture (Ghosh Hajra, 2001). Tea production
quality influences its palatability and marketabil‐
ity. In conventional tea farming, application of chemical fer‐
tilizer and pesticides is in vogue, which deteriorates soil
health and reduces the product quality in terms of biochemi‐
cal constituents and residual toxicants in the product (Ghosh
Hajra, 2001). Recently, organic agricultural practices for tea
have been gaining popularity, as compared to conventional
farming, due to their effect on sustainability in tea production
and improved product quality (Barbora, 1995). In organic tea
farming, traditional conservation farming methods are com‐
bined with modern techniques while eliminating synthetic
inputs such as fertilizers and pesticides. The latter are re‐
placed with biological nutrient sources like compost, animal
waste, and green manures, which are used to build up soil fer‐
tility, improve physical properties of the soil, and facilitate
slow and steady release of nutrients during tea cultivation.
Fertilization is the most important and controllable factor
that affects the quality of tea (Owuor et al., 1990). The fertil‐
Submitted for review in August 2007 as manuscript number BE 7162;
approved for publication by the Biological Engineering Division of
ASABE in October 2008.
The authors are Soumen Palit, Senior Research Fellow, Bijoy
Chandra Ghosh, Professor, Snehasis Dutta Gupta, Associate Professor,
and Dillip Kumar Swain, Assistant Professor, Department of Agricultural
and Food Engineering, Indian Institute of Technology, Kharagpur, India.
Corresponding author: Bijoy Chandra Ghosh, Agricultural and Food
Engineering, Indian Institute of Technology, Kharagpur 721302 India;
phone: +91‐3222‐283120; fax: +91‐3222‐255303; e‐mail: bcg@agfe.
iitkgp.ernet.in.
izer source affects the release patterns of nutrients and their
resulting availability to the crop. It also indirectly influences
crop physiology and biochemical composition (Weston and
Barth, 1997; Sams, 1999). Organic fertilizers typically used
in organic farming are time‐tested materials for improving
fertility and productivity of the soil (Ghosh Hazra, 2006). Or‐
ganic fertilizers also have a corrective effect on adverse soil
conditions caused by the continuous and excessive use of in‐
organic fertilizers. In addition, organic manures cause favor‐
able changes in soil reaction, enrich the nutrient status of the
soil, and nourish soil microorganisms for better mineraliza‐
tion processes (Brady and Weil, 2002). Humus, a stabilized
decomposed organic manure, has chelating properties as well
as nutrient buffering capacity. By virtue of these properties,
humus increases the availability of both the added and native
nutrients. Well‐established organic systems have also shown
low incidence and severity of plant diseases caused by soil‐
borne pathogens compared to conventional systems (Work‐
neh and van Bruggen, 1994; van Bruggen and Termors-
huizen, 2003).
In addition to improving the physical, chemical, and bio‐
logical properties of soil, use of organic fertilizer affects the
quality of the produce. Phytonutrients with known beneficial
(often antioxidant) effects on human health are found to be
higher in organic produce, which has been confirmed for ly‐
copene in tomatoes (Pither and Hall, 1990; Carbonaro et al.,
2002), polyphenols in potatoes (Hamouz et al., 1999), flava‐
nols in apples (Weibel et al., 2000), and resveratrol in red
wine (Levite et al., 2000). Organic produce tends to contain
10% to 50% higher phytonutrients than non‐organic produce
(Brandt and Molgaard, 2001). There is a growing concern
that the levels of some phenolics may be lower than optimal
for human health in foods grown using conventional agricul‐
T

2228 TRANSACTIONS OF THE ASABE
tural practices (Brandt and Molgaard, 2001; Woese et al.,
1997). This concern arises because conventional agricultural
practices utilize levels of pesticides and fertilizers that can re‐
sult in a disruption of the natural production of phenolic me‐
tabolites in the plant (Macheix et al., 1990). There is
anecdotal evidence indicating that organic crops mostly con‐
tain higher levels of phenolic metabolites than conventional‐
ly grown crops, and very few studies have directly addressed
this issue (Woese et al., 1997), particularly for tea crops.
The economic plant part of tea consists of two leaves and
a bud, which has a complex chemistry responsible for a “good
cup.” The major biochemical components of tea shoots differ
considerably with the species of tea plant, age of the crop, soil
nutrient status, and method of tea processing. These signifi‐
cantly affect the flavor and taste of tea infusion (Ninomiya et
al., 1997). Some important chemical constituents of tea
shoots are polyphenol (25% to 30%), flavonols and flavonol
glycosides (3% to 4%), caffeine (3% to 4%), theobromine
(0.2%), theophylline (0.5%), amino acids (4% to 5%), cellu‐
lose and hemicellulose (4% to 7%), chlorophylls and other
pigments (0.5% to 0.6%), and volatiles (0.01% to 0.02%). In
processed tea, the biochemical compounds responsible for
tea liquor, color, and taste are theaflavins, thearubigins, fla‐
vonol glycosides, pheophorbide, pheophytin, polyphenol,
amino acids, and caffeine.
The major beneficial physiological effect of tea consump‐
tion is associated with the presence of eight naturally occur‐
ring tea catechins: (+)-catechin, (-)-epicatechin, (-)
gallocatechin, (-)-epigallocatechin, (-)-catechin gallate,
(-)-gallocatechin gallate, (-)-epicatechin gallate, and
(-)-epigallocatechin gallate. Tea catechins are effective
scavengers of free radicals (Salah et al., 1995), with more ef‐
fective catechins having a galloyl moiety at C3 (Rice‐Evans
and Miller, 1996) and a trihydroxy structure in the B ring
(Nanjo et al., 1996). These natural products also have numer‐
ous potentially beneficial medicinal properties, including in‐
hibition of carcinogenesis, tumorigenesis, and mutagenesis.
Additionally, they have antibacterial, antiviral, antiarterio‐
sclerotic, hypocholesterolaemic, antidiarrhoeal, and antial‐
lergic properties and have been demonstrated to induce
apoptosis and inhibit platelate aggregation (Yamamoto,
1997).
So far, very little work has been conducted to assess the
quality of tea leaves produced under organic farming. In our
work, we have created a tea garden on fallow land, which is
now four years old. Conventional and organic agricultural
practices are followed in this plot for a comparative quality
assessment of tea leaves with respect to synthesis of
biochemical compounds, antioxidant properties, and diar‐
rhoea control.
Table 1. Agricultural conditions, soil type,
and irrigation source for tea crop.
Agricultural
Practice Soil Type
Crop
Age
(years)
Previous
Crop
Irrigation
Source
Conventional Acid laterite 4 Fallow Deep
(type Haplustalf) land tubewell
sandy‐loam
texture
Organic Acid laterite 4 Fallow Deep
(type Haplustalf) land tubewell
sandy‐loam
texture
MATERIALS AND METHODS
CHEMICALS
Ethanol, HPLC‐grade methanol, perchloric acid, an‐
throne reagent, petroleum ether, sulfuric acid, sodium hy‐
droxide, sodium carbonate, trifluroacetic acid, ferrous
ammonium sulfate, sodium chloride, and gum acacia were
obtained from Merck (Mumbai, India). Folin‐Ciocalteu's
phenol reagent, gallic acid monohydrate, (-)-epigallocate‐
chin gallate [(-)-EGCG], (-)-gallocatechin gallate
[(-)-GCG], (-)-epicatechin gallate [(-)-ECG], 2,2-diphe‐
nyl-1-picrylhydrazyl (DPPH), eugenol, and dime‐
thyl-1-pyrroline-N-oxide (DMPO) were obtained from
Sigma‐Aldrich (New Delhi, India). Loperamide was ob‐
tained from Central Drugs Laboratory (Kolkata, India), cas‐
tor oil was obtained from New India Pharmaceutical
(Kolkata, India), and charcoal was obtained from Ranbaxy
(Mumbai, India). Deionized water for all the experiments
was obtained from a Diamond‐Nanopure water purification
system (Barnstead/Thermolyne, Dubuque, Iowa).
AGRICULTURAL CONDITION AND SOIL CHARACTERIST ICS
A field experiment was conducted on fallow land that had
not been cultivated for more than 50 years. The soil at the ex‐
perimental site was acid laterite (type Haplustalf, pH 5.4),
sandy‐loam in texture, which is low in organic carbon (2.8 g
kg-1) and available N (73 mg kg-1), P (4 mg kg-1), and K
(16mg kg-1) (table 1). The land was deep ploughed, leveled,
and a pit of 45 cm diameter and 60 cm depth was prepared at
a spacing 100 × 75 cm for the transplantation of the tea seed‐
lings. Two organic fertilizations, i.e., vermicompost (V) and
vermicompost + vermiwash (V+Vw), one inorganic fertiliza‐
tion (IF), and one control treatment were used for two culti‐
vars of tea (TV1 and TV25) in the experimentation. The
experiment was laid in a split‐plot design with four replica‐
tions, where cultivar was allocated to the main plot and fertil‐
izer source to the subplot of the design. The dimensions of the
subplot were 25 × 25 m. The treatments receiving organic
and inorganic sources of fertilization were added yearly with
nutrients as follows: N, P2O5, and K2O at 200:60:120 kg ha-1
(table 2). Each treatment was separated from the others by in-
Table 2. Fertilizer usage records for tea crop.
Agricultural
Practice Fertilizer Description Rate Timing
Conventional Standard commercial chemical fertilizers: urea,
single super phosphate, and muriate of potash
N, P2O5, and K2O200:60:120 kg ha-1 4 splits in a year
Organic Vermicompost 11.1 t ha-1 4 splits in a year
Vermiwash 650 L ha-1 4 splits in a year

2229Vol. 51(6): 2227-2238
serting plastic sheets to a depth of 4 m inside the soil and
0.5m above the surface soil to prevent leaching and contami‐
nation between the treatments.
Tea seedlings of eight months age were planted in the year
2002 in the prepared pits. In the plantation year, the total re‐
quired fertilizer was applied in 45 days prior to the trans‐
plantation of the seedlings. The fertilizer was well mixed.
The inorganic fertilizers were applied through urea, single
super phosphate (SSP), and muriate of potash (MOP). The
calculation of vermicompost dose to supply 200 kg N ha-1
was based on its N equivalent basis considering its N content
of 1.8%. In the V+Vw treatment, in addition to vermicompost
application, vermiwash was used at 650 L ha-1, which sup‐
plied 0.0325 kg N ha-1 considering its N content of 0.005%.
Nutrient compositions of the vermicompost and vermiwash
used in the experiment are presented in table 3. In the follow‐
ing years, the total required fertilizers were applied in four
equal sub‐applications and were well‐mixed with the top soil.
The inorganic fertilizers applied to the pits in each sub‐
application were 8.33 g urea, 7.03 g SSP, and 3.6 g MOP. The
vermicompost was applied at 833 g pit-1 in each sub‐
application for the V and V+Vw treatments. For the V+Vw
treatment, the total volume of vermiwash was sprayed equal‐
ly in four sub‐applications on the crop canopy. The control
plot received no fertilizer; however, the soil preparation and
pit filling were similar to those of the fertilized treatments.
DETERMINATION OF TEA QUALITY PARAMETERS
The quality parameters such as crude fiber, starch, and
polyphenol content as well as the antioxidant and antidiarr‐
hoeal activities of the tea leaves were analyzed.
Determination of Crude Fiber
Ground leaf samples of 2 g (dry weight basis) were ex‐
tracted with petroleum ether by boiling at 52°C for 1 h. The
sample was again mixed with 200 mL 0.255 N H2SO4 and
boiled for 30 min. The boiled sample was filtered through
muslin cloth and washed thoroughly with boiling water. The
collected residue was again boiled with 200 mL 0.313 N
NaOH for 30 min, again filtered through muslin cloth, and
washed with 25 mL H2SO4 followed by 150 mL water and by
25 mL alcohol. The residue obtained after the final filtration
was weighed, incinerated at 550°C, cooled, and weighed
again. The loss in weight was equal to the crude fiber content
(Maynard, 1970).
Determination of Starch
Starch was determined from finely ground leaf samples.
About 0.2 g (dry weight basis) of the leaf sample was mixed
Table 3. Composition of vermicompost and vermiwash.
Parameters Vermicompost Vermiwash
pH 6.9 6.9
Organic carbon (g kg‐1) 141 ‐‐
N (g kg‐1) 18 0.05
P ( g kg‐1) 9.8 0.025
K ( g kg‐1) 11 0.63
Ca (mg kg‐1) 2760 786
Mg (mg kg‐1) 4100 328
S ( mg kg‐1) 0.6 ‐‐
Cu ( mg kg‐1) 38 0.117
Zn ( mg kg‐1) 180 0.132
Fe ( mg kg‐1) 11200 0.151
Mn ( mg kg‐1) 1290 213
with 20 mL of 80% hot alcohol. The tube was shaken for 5
to 10 min and centrifuged (REMI, India) at 5000g for 10 min.
The supernatant was decanted. About 6.5 mL of 52% perch‐
loric acid was added to the residue and allowed to stand for
15 min at 4°C. The supernatant was collected by centrifuging
(5000g) at 4°C. The volume of the supernatant was made up
to 100 mL with 52% perchloric acid. About 5 mL of this ex‐
tract was placed in a tube and mixed with 10 mL freshly pre‐
pared anthrone reagent (anthrone reagent was prepared by
dissolving 1 g anthrone in 500 mL of 72% sulfuric acid). The
mixture was incubated in a boiling water bath for 7.5 min.
The tubes were cooled under running tap water. The absor‐
bance value of these solutions was read at 630 nm using a
spectrophotometer. The obtained value was multiplied by 0.9
for the conversion of glucose to that of starch (Hodge and Ho‐
freiter, 1962).
Total Phenolic Estimation
Fresh tea leaves from each treatment were collected from
the field and used for extraction through grinding with a mor‐
tar and pestle in the presence of deionized water. The extract
was centrifuged at 7000g for 20 min. The supernatant was
collected, lyophilized, and stored at -20°C for phenolic es‐
timations and for determination of antioxidant capacity.
The amount of total phenolic content in the tea leaf ex‐
tracts was determined using Folin‐Ciocalteu's phenol re‐
agent (FCR) at 765 nm (Singleton and Rossi, 1965). Phenols
react with the oxidizing agent phosphomolybdate present in
FCR in alkaline conditions and result in the formation of a
blue‐colored complex. A calibration curve was prepared by
mixing 1 mL aliquots of methanolic gallic acid solutions of
concentrations ranging from 5 to 75 mg mL-1 with 2.5 mL
FCR reagent (diluted ten‐fold) and 2 mL (75 g L-1) sodium
carbonate. The absorption was read after 5 min at 50°C at
765nm, and the calibration curve was established. One mL
leaf extract (1 mg mL-1) was mixed with the same reagents
as described above and allowed to stand for 5 min. The ab‐
sorption was measured for determination of the leaf phenol‐
ics. All determinations were performed in triplicate, and the
mean value was presented. Total content of phenolic com‐
pounds in tea leaf extracts was expressed in gallic acid equiv‐
alent (GAE) and was calculated as follows (eq. 1):
C = c·V/m (1)
where
C= total content of phenolic compounds (mg g-1 plant
extract expressed in GAE)
c= concentration of gallic acid established from the
calibration curve (mg mL-1)
V= volume of extract (mL)
m= weight of pure plant extract (g).
Catechins Determination
Fresh tea leaves (0.5 g) were crushed and extracted with
100 mL of 70% methanol in a Soxhlet apparatus for 45 min.
Methanol was removed by rotary vacuum evaporator. The
residue was redissolved in 1 mL of 70% methanol. Catechin
standards selected for this study were (-)-epigallocatechin
gallate [(-)-EGCG], (-)-gallocatechin gallate [(-)-GCG],
and (-)-epicatechin gallate [(-)-ECG]. Standard solutions
were prepared by dissolving 2 mg of each catechin in 2 mL
of 70% methanol. Six different calibration levels were used
to prepare the standard calibration plot of each catechin stan‐
dard. Calibration standards in the concentration range of 10

2230 TRANSACTIONS OF THE ASABE
to 300 mg mL-1 were prepared by diluting the stock solution
of the respective catechins with aqueous methanol (50:50,
v/v). Each calibration solution was injected into HPLC in
triplicate. The calibration curve was drawn by plotting the
peak area against the concentration of the compound. The
calibration curves, characterized by slope and intercept, were
used to determine the concentration of respective catechins
in the sample.
Chromatography was performed on a Waters HPLC sys‐
tem (Waters Corp., Milford, Mass.), which consists of a 1500
series HPLC pump, 2487 dual‐wavelength absorbance detec‐
tor, and Breeze software (ver. 3.2) for instrument control and
data processing. A C18 reverse‐phase HPLC column (Synergi
Hydro‐RP, Phenomenex, Torrance, Cal.) was used for the
study. The column has an internal particle size of 5 mm with
250 mm length and 4.6 mm internal diameter (Sachan et al.,
2004). A linear isocratic solvent system consisting of
aqueous trifluoroacetic acid (1 mM) and methanol (17:8) at
a flow rate of 1.0 mL min-1 for 20 min at room temperature
was used to elute the tea catechins. The identification of each
phenolic compound was confirmed by comparing retention
time and UV spectra with external standards procured from
Sigma Aldrich.
ANTIOXIDANT ACTIVITY
Antioxidant activity of tea leaves was determined by three
different methods as follows:
Rapid Screening of Antioxidant by Dot‐Blot and DPPH
Staining
For screening of antioxidant property by dot‐blot and
DPPH staining, an aliquot of each dilution (50, 100, 200, and
300 mg mL-1) of lyophilized tea leaf extracts of different
treatments, eugenol, and epigallocatechin gallate (5, 10, 20,
and 40 mg mL-1) were loaded on a 10 × 20 cm silica gel
(Weston and Barth, 1997) TLC plate (Merck, Germany) and
allowed to dry. Drops of each sample were loaded in order of
decreasing concentrations along the column. The plate bear‐
ing the dry spots was stained upside down for 10 s in 0.4 mM
DPPH solution in methanol (Soler‐Rivas and Espin,
2000).The intensity of the yellow color was proportional to
the amount and nature of the radical scavenger present in the
sample.
2,2-Diphenyl-1-Picrylhydrazyl (DPPH) Radical Assay
The antioxidant activity of tea leaf extracts was measured
in terms of hydrogen donating or radical scavenging ability
using the stable radical DPPH (Brand‐Williams et al., 1995).
Stock solutions of the tea leaf extracts obtained from different
treatments were prepared by dissolving 1 mg of lyophilized
extract in 1 mL of 60% methanol. A fresh solution of DPPH
in methanol (6 × 10-5 M) was prepared before the
measurements. A methanolic solution (0.1 mL) of sample of
various concentrations (50, 100, 150, 200, and 300 mg mL-1
prepared from the stock solution) was placed in a cuvette, and
2.9 mL of DPPH was added. The mixture was shaken
vigorously, and absorbance measurements were recorded
immediately. The decrease in absorbance at 515 nm was
observed continuously at 5 min intervals until the reaction
reached a plateau. Methanol was used as blank. Radical
scavenging activity was calculated as shown in equation 2
(Yen and Duh, 1994):
Percent inhibition = [(AB - AA)/AB] × 100 (2)
where
AB = absorption of blank sample (t = 0)
AA = absorption of tested extract solution (t = T).
Scavenging Activities against Hydroxyl Radical by
Electron Paramagnetic Resonance (EPR) Spectrometry
The hydroxyl radical was generated by Fenton reaction
according to the method of Kohno and Yamada (1991). For
each reaction mixture, 200 mL mixture was prepared by
mixing the different lyophilized tea samples (1 mg mL-1),
300 mM DMPO (dimethyl-1-pyrroline-N-oxide), 20 mM
ferrous ammonium sulfate, and 20 mM H2O2 in equal ratio.
Phosphate‐buffered saline of 0.05 M, pH 7.4, was used as the
control. Samples were transferred to a quartz capillary and
fitted into the cavity of the EPR spectrometer. The EPR
spectra were recorded at ambient temperature (298 K) on an
EMX‐10 X‐band EPR spectrometer (Bruker Corp., Billerica,
Mass.) under the following run conditions: modulation
frequency of 50 KHz, modulation amplitude of 0.50 G,
receiver gain of 8.93 × 104, time constant of 655.360 ms,
conversion time of 163.840 ms, sweep time of 167.772 s,
center field of 3482 G, sweep width of 100 G, microwave
frequency of 9.768 GHz, and microwave power of 0.642 mW.
The scavenging activity (SA) of the tea extracts was
calculated as: SA (%) = 100 × (ho - hx)/ho, where ho and hx
are the height of the second peak in the EPR spectrum of
DMPO-OH spin adduct of the blank and the sample,
respectively (Ćetković et al., 2004).
ANTIDIARRHOEAL ACTIVITY OF TEA EXTRACTS
Antidiarrhoeal activity of tea extracts obtained from
different treatments was tested on conventional rodent
models of diarrhoea through the following steps:
Experimental Animal
Two experiments were carried out with male albino rats
(Sprague Dawley strain), each weighing 150 to 200 g, and
male ICR mice (25 to 30 g each) bred in the Indian Institute
of Chemical Biology, Kolkata. The animals were housed
under conditions of 22°C ±2°C, 50% ±10% humidity, and
12 h light/dark cycle. During maintenance, the animals
received a diet of food pellets (fortified with minerals and
vitamins) and water ad libitum. Before drug administration,
the animals were subjected to fasting overnight (18 h).
Preparation of Hot Water Extract of Tea
Green tea samples (10 g) from each treatment were soaked
separately in 100 mL boiling water for 2 min and filtered.
Accordingly, 24 different green tea extracts (8 treatments ×
3 seasons) were prepared for the experiment.
Gastrointestinal Transit (GIT) in Mice
GIT was measured using the charcoal meal test in male
ICR mice (Izzo et al., 1992). Twenty‐four different green tea
extracts (1 mL 100 g-1 mice) and one 0.9% saline (0.2 mL
mouse-1, as control) were administered orally (Besra et al.,
2003); loperamide (1 mg kg-1 mice), a reference
antidiarrhoeal agent, was administered intraperitoneally
(Besra et al., 2002) to 18 h fasted mice. After 30 min, a
charcoal suspension (12 g charcoal and 2 g gum acacia
ground in a mortar and suspended in 130 mL distilled water;
Ghosh, 1971) was administered orally to each mouse at
0.1mL per 10 g of body weight. Six mice were used per each
treatment. The mice were killed by cervical dislocation after

2231Vol. 51(6): 2227-2238
30 min of the charcoal administration. Their abdomen was
cut open, and the small intestine from the pylorus up to the
caecum was carefully removed, gently stretched, and its total
length and the distance reached by the charcoal were
measured. The gastrointestinal transit was expressed as a
percentage of the length traversed by the charcoal marker to
the total length of the small intestine (Besra et al., 2003). A
lower distance traveled by the charcoal marker indicates
better gastric transit delaying action.
Intraluminal Fluid Accumulation in Rat
Intraluminal fluid accumulation in male albino Sprague
Dawley rats was determined by enteropooling (Robert et al.,
1976). Castor oil was used as a cathartic agent for initiation
of diarrhoea in rats. Twenty‐four different green tea extracts
(1 mL 100 g-1 rat) and one 0.9% saline (0.2 mL rat-1, as
control) were administered orally (Besra et al., 2003);
loperamide (1 mg kg-1 rat), a reference antidiarrhoeal agent,
was administered intraperitoneally (Besra et al., 2002) to
18h fasted rats. After 30 min, castor oil (2 mL rat-1) was
administered orally. The rats were killed by exsanguination
after 30 min of the castor oil administration. The pyloric and
caecal ends of the small intestine were tied, and the intestine
was removed. The intestinal content was collected in a
volumetric tube (centrifuge tube), and the volume of
intraluminal fluid was measured.
STATISTICAL ANALYSIS
The recorded data were treated for analysis of variance
using MSTAT‐C following standard statistical procedures
(Gomez and Gomez, 1984). Differences among the
treatments were tested at 5% level of significance.
Data for antidiarrhoeal activity of tea extracts were
presented as arithmetic mean ±SEm (SEm = standard error
of the mean) for the two experiments (GIT and intraluminal
fluid accumulation). Student's t‐test was used for treatment
comparison. Correlation coefficients (r) among tea quality
parameters was determined from 24 samples (8 treatments ×
3 replications), and significance was tested at p = 0.05.
RESULTS AND DISCUSSION
Crude fiber is one the most important quality evaluation
parameters, which influences the sensory properties,
appearance, and thereby marketability of tea (Śmiechowska
and Dmowski, 2006). In this work, the crude fiber content of
fresh tea leaves was assessed under different fertilizer
treatments. Crude fiber content was high in the control
treatment, which decreased with application of nutrient
(fig.1). The decrease followed the order: V, V+Vw, and IF
treatments. A decreasing crude fiber content of tea leaves
with increasing fertilizer level has been previously reported
(Venkatesan et al., 2005). Decrease in crude fiber content was
also reported for other crops such as amaranthus (Sams,
1999) and cabbage (Weston and Barth, 1997), where
increased levels of nitrogen fertilizer decreased the fiber
content. Fiber content increases with crop age since younger
cells have a thinner cellular wall, which becomes thicker as
the plant grows (Strasburger, 1962). We observed no
significant difference among the treatments for the crude
fiber content at the early growth stages of the plants, but at
later stages the content in the control was significantly higher
6
7
8
9
10
11
12
13
14
2002 2003 2004 2005
Year
Crude Fiber Content (%)
C
IF
V
V+Vw
Figure 1. Crude fiber content (%) in tea leaf as influenced by fertilizer
sources (C = control, IF = inorganic fertilizer, V = vermicompost, V+Vw=
vermicompost + vermiwash). Vertical lines indicate standard errors.
1
1.5
2
2.5
3
3.5
4
2002 2003 2004 2005
Year
Strach Content (%)
C
IF
V
V+Vw
Figure 2. Starch content (%) in tea leaf as influenced by fertilizer sources
(C = control, IF = inorganic fertilizer, V = vermicompost, V+Vw =
vermicompost + vermiwash). Vertical lines indicate standard errors.
0
40
80
120
160
200
240
280
320
C IF V V+Vw
Treatments
Total Phenolics Content (mg g-1 in GAE)
Figure 3. Total phenol content (mg g-1 plant extract expressed in GAE) in
tea leaf as influenced by fertilizer sources (C = control, IF = inorganic
fertilizer, V = vermicompost, V+Vw = vermicompost + vermiwash).
Vertical lines indicate standard errors.

2232 TRANSACTIONS OF THE ASABE
Table 4. Catechins content (mg g-1) in tea leaf as influenced by fertilizer sources.
Variety Treatment[a]
Concentration of Catechins
(mg g‐1 tea leaves) Total Content
of Catechins
(mg g‐1 tea leaves)
Percentage of Increase/
Decrease of Catechins Content
over Control Treatment
EGCG GCG ECG
TV25 C 7.65 3.83 3.31 14.79 ‐‐
IF 2.41 3.30 1.61 7.32 50.5 (‐)
V 9.04 4.26 3.07 16.37 10.7 (+)
V+Vw 8.20 6.94 3.55 18.69 26.4 (+)
TV1 C 6.35 3.13 3.13 12.61 ‐‐
IF 1.76 2.15 1.03 4.94 60.82 (‐)
V 7.96 4.37 3.61 15.94 26.4 (+)
V+Vw 8.55 4.71 3.22 16.48 30.7 (+)
[a] C = control, IF = chemical fertilizer, V = vermicompost, V+Vw = vermicompost + vermiwash.
Descending order of concentration
TV1 (C)
Eugenol
[(-)-EGCG]
TV25 (V+Vw)
TV25 (V)
TV25 (IF)
TV25 (C)
TV1 (V+Vw)
TV1 (V)
TV1 (IF)
Figure 4. Dot blot assay of tea extracts grown under different fertilizer
treatments on a silica sheet stained with a DPPH solution in methanol:
TV25 and TV1 = variety, C = control, IF = inorganic fertilizer, V =
vermicompost, V+Vw = vermicompost + vermiwash, and [(-)-EGCG] =
(-)-epigallocatechin gallate; [(-)-EGCG] and Eugenol represent two
standards arranged in descending order of concentration (i.e., 40, 20, 10,
and 5 mg mL-1); and varieties TV25 and TV1 with treatments C, IF, V, and
V+Vw represent eight different samples arranged in descending order of
concentration (i.e., 300, 200, 100, and 50 mg mL-1).
than that of the fertilized treatments. Crude fiber is composed
of polysaccharides like cellulose, hemicellulose, and
hydrocarbon like wood‐wool (Śmiechowska and Dmowski,
2006). Figure 2 shows that starch, which is also a component
of polysaccharide, was higher in the control. Lower fiber
Table 5. Scavenging effect for DPPH radical (percent inhibition)
of tea leaf extracts as influenced by fertilizer sources.[a]
Concentration of Tea Extract (μg mL‐1)
50 100 200 300
Variety
TV25 22.3 36.3 58.6 58.4
TV1 23.7 36.9 60.7 60.5
LSD (5%) NS NS NS NS
Fertilizer
C 22.1 34.6 57.4 57.5
IF 20.2 31.5 47.6 47.7
V 23.7 38.4 67.1 67.0
V+Vw 25.9 42.1 74.1 74.4
LSD (5%) 2.1 2.5 4.1 4.3
[a] C = control, IF = inorganic fertilizer, V = vermicompost, V+Vw =
vermicompost + vermiwash, LSD = least significant difference, NS =
not significant.3
content indicates a higher tea quality (Śmiechowska and
Dmowski, 2006; Chu and Juneja, 1997). Hence, application
of fertilizer either through organic or inorganic sources is
expected to result in better quality tea. Comparing the
sources of fertilizer, IF was found to be superior to the V or
V+Vw treatments in lowering the crude fiber content.
Polyphenols are biochemical constituents that affect tea
quality. The effect of organic and inorganic sources of
fertilizers on synthesis of phenolic antioxidants in tea plants
is shown in figure 3 and table 4. Significantly lower total
phenolics content was observed in leaves of tea plant grown
with the IF treatment (197.45 mg g-1 in GAE) as compared
to the organic treatments, i.e., V (279.05 mg g-1 in GAE),
V+Vw (288.26 mg g-1 in GAE), and C (251.65 mg g-1 in
GAE). A similar result was also reported for other crops like
peach and pear, where organically grown crops had higher
levels of total phenolics than those grown under conventional
agricultural practices (Carbonaro et al., 2002). It was
observed that the total contents of [(-)-EGCG], [(-)-GCG],
and [(-)-ECG] were higher in V and V+Vw than in IF.
Increase in polyphenol content of organically grown field
crops has also been confirmed in previous studies (Daniel et
al., 1999; Lea and Beech, 1978; Nicolas et al., 1994).
Tea catechins are potent antioxidants, which modulate
key biological pathways in vivo in mammals (Lunder, 1992).
In order to determine the radical scavenging/antioxidant
activity of tea, a rapid antioxidant activity screening was
done by qualitative dot‐blot and DPPH staining method
(Soler‐Rivas and Espin, 2000), where DPPH turns from
violet to pale yellow, depending on the radical scavenging
capacity of the antioxidant (Molyneux, 2004). As shown in

2233Vol. 51(6): 2227-2238
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-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
(a)
Magnetic Field (G)
Intensity (x 103)
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-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
8(b)
Magnetic Field (G)
Intensity (x 103)
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-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
(c)
Magnetic Field (G)
Intensity (x 103)
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-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
(d)
Magnetic Field (G)
Intensity (x 103)
Figure 5. EPR spectra of DMPO-OH spin adducts: (a) in the absence of tea extracts (blank), (b) in the presence of 0.25 mg mL-1 of water extract of
tea, (c) in the presence of 0.50 mg mL-1 of water extract of tea, and (d) in the presence of 1 mg mL-1 of water extract of tea obtained from variety TV1
grown under the IF treatment.
figure 4, the appearance of yellow spots of different
intensities was an indirect evaluation of the antioxidant
activity of the tea extracts. The spots of high intensity were
observed in the extracts of the V+Vw and V treatments,
which gradually decreased in the C and IF treatments for both
varieties TV25 and TV1.
The second approach for estimating antioxidant activity
of the different tea extracts was using the DPPH assay (Yen
and Chen, 1995). The assay is based on the measurement of
the scavenging ability of antioxidants of a free radical,
2,2-diphenyl-1-picrylhydrazyl (DPPH), transforming it to
the corresponding hydrazine when it reacts with hydrogen
donors (Contreras-Guzmán and Strong, 1982). From a
methodological point of view, the DPPH method is
recommended as easy and accurate with regard to measuring
the antioxidant activity of fruit, vegetable juices, and plant
extracts (Sanchez-Moreno, 2002). The results are highly
reproducible and comparable to other free radical scavenging
methods (Gil et al., 2000). The radical scavenging ability of
lyophilized tea extracts at various concentrations (50, 100,
200, and 300 mg mL-1) is presented in table 5. A higher
radical scavenging activity in tea leaf extracts of the V+Vw
treatment was noted, followed by V, C, and IF for both
varieties. Radical scavenging capacity of the tea extracts was
increased up to the concentration of 200 mg mL-1.
The antioxidant property of extracts of tea leaves was also
evaluated on hydroxyl radical using the EPR spin trapping
method. EPR spectroscopy was successfully applied for
determination of radical scavenging activity of catechins and
their epimers in previous studies (Guo et al., 1999; Unno et
al., 2002). The EPR spin trapping method involves trapping
of reactive short‐lived free radicals by a diamagnetic EPR
silent compound (spin trap) via addition to a spin trap double
bond to produce a more stable free radical product (spin
adduct) (Polovka et al., 2003). To test the reaction of
hydroxyl radical (·OH) with tea extracts, Fenton's reagent
was used as a source of hydroxyl radical, which was trapped
by a spin trapping agent DMPO, i.e., 5,5-dimethyl-1-
pyrroline-1-oxide (Yen and Chen, 1995) (eqs. 3 and 4):
Fe2+ + H2O2 → Fe3+ + OH- + ·OH (3)
DMPO + ·OH → DMPO-OH (4)
Nitrone spin traps like DMPO scavenge free radical
species via addition to a carbon located in a position relative
to the nitrogen (Li et al., 1988). The reaction of Fe2+ and H2O2
in the presence of spin trapping agent DMPO generated a
1:2:2:1 quartet of lines in the EPR spectrum (fig. 5a) with the
hyperfine coupling parameters (aN and aH = 14.9 G). The
signal intensities of DMPO-OH spin adduct obtained from
EPR spectrometry were used to evaluate the hydroxyl radical
scavenging activity of tea extracts. Figures 5b, 5c, and 5d
show that the addition of tea extract obtained from variety
TV1 grown under the IF treatment at varying concentrations

2234 TRANSACTIONS OF THE ASABE
3420 3440 3460 3480 3500 3520 3540
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0 TV25 (C)
Magnetic Field (G)
Intensity (x 103)
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-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5 TV25 (IF)
Magnetic Field (G)
Intensity (x 103)
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-1.6
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2 TV25 (V)
Magnetic Field (G)
Intensity (x 103)
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-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6 TV25 (V+Vw)
Magnetic Field (G)
Intensity (x 103)
Figure 6. EPR spectra of DMPO-OH spin adducts in the presence of water extracts of tea leaves (1 mg mL-1) obtained from variety TV25 as influenced
by fertilizer source (C = control, IF = inorganic fertilizer, V = vermicompost, and V+Vw = vermicompost + vermiwash).
(0.25, 0.5, and 1 mg mL-1) to the reaction system resulted in
a dose‐dependent inhibition on the EPR signal intensity of
DMPO-OH adducts. This confirms that signal intensities
were reduced with an increase in tea concentration (i.e., the
lower the signal intensity, the higher the radical scavenging
activity). A similar observation was also reported by others
(Yen and Chen, 1995).
Further analysis (figs. 6 and 7) showed that addition of tea
extracts obtained from variety TV25 and TV1 grown under
different fertilizer treatments at 1 mg mL-1 concentration to
the reaction system resulted in variation in the signal
intensity of DMPO-OH adducts.It was observed that tea
extracts of both varieties had the lowest signal intensity of
DMPO-OH adduct in the V+Vw treatment, showing the
highest antioxidant capacity, followed by the V, C and IF
treatments. This was confirmed by the strongest scavenging
activity (SA) of tea extracts shown in the V+Vw treatment,
followed by C and IF treatments of both varieties (fig. 8).
Higher SA values for OH radical assay than for DPPH
radicals for the tea extracts can be explained by the fact that
some natural compounds are iron chelators. Flavonoid
compounds (with o-diphenolic groups in the 3,4-dihydroxy
position in ring B and the ketol structure, 4-oxo, 3-OH or
4-oxo, 5-OH, in the C ring of the flavanols) and phenolic
acids (with o-dihydroxyl groups) might be exerting their
protective effects through chelation of metal ions in the
course of the Fenton reaction, or by altering the iron redox
chemistry (Morel et al., 1994; Ruiz‐Larrea et al., 1995). In
our experiment, higher content of total phenolics, flavanols
([(-)-EGCG], [(-)-GCG], and [(-)-ECG]) and antioxidative
status in tea plants could be explained by slow and steady
supply of nutrients through organic fertilization (tables 4 and
5; fig. 3). Increase in the concentration of phenolic
antioxidants and antioxidative status in plants with slow
nutrient availability was also reported by others (Sander and
Heitefuss, 1998; Stout et al., 1998; Wilkens et al., 1996).
Some researchers reported that organically grown spinach
contained 120% higher antioxidant activity, while Welsh
onion, Chinese cabbage, and qing‐gen‐cai contained 20% to
50% higher antioxidant activity compared to their
conventionally grown counterparts (Ren et al., 2001). We
also found significant positive correlations for total phenolics
and catechin content in leaves with the radical scavenging
capacity of tea extract (table 8).
Tea polyphenol has diverse pharmacological effects
(Mukhtar et al., 1992). Green tea extract has also shown

2235Vol. 51(6): 2227-2238
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-1.5
-1.2
-0.9
-0.6
-0.3
0.0
0.3
0.6
0.9
1.2
1.5
1.8
2.1
2.4 TV1 (C)
Magnetic Field (G)
Intensity (x 103)
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-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0 TV1 (IF)
Magnetic Field (G)
Intensity (x 103)
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-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0 TV1 (V)
Magnetic Field (G)
Intensity (x 103)
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-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4 TV1 (V+Vw)
Magnetic Field (G)
Intensity (x 103)
Figure 7. EPR spectra of DMPO-OH spin adducts in the presence of water extracts of tea leaves (1 mg mL-1 obtained from variety TV1 as influenced
by fertilizer source (C = control, IF = inorganic fertilizer, V = vermicompost, and V+Vw = vermicompost + vermiwash).
0
10
20
30
40
50
60
70
0.25 0.5 1
SA (%)
(a)
Concentration of Tea Extracts (mg mL)
0
10
20
30
40
50
60
70
80
90
C IF V V+Vw
SA (%)
TV25
TV1
(b)
Fertilizer Source
Figure 8. (a) Scavenging activity (SA) of different concentrations (0.25, 0.5, and 1 mg mL-1) of water extracts of tea obtained from variety TV1 grown
under the IF treatment on hydroxyl radical, and (b) the SA of water extract of tea leaves (1 mg mL-1) on hydroxyl radical of varieties TV25 and TV1
as influenced by fertilizer source (C = control, IF = inorganic fertilizer, V = vermicompost, and V+Vw = vermicompost + vermiwash).
antidiarrhoeal activity (Ishihara et al., 1996). In the present
investigation, we attempted to evaluate the effect of tea
extracts collected from different fertilizer treatments on
antidiarrhoeal activity using conventional rodent models of
diarrhoea. Green tea extract prepared from plant grown under
different fertilizer treatments exhibited differential anti-
diarrhoeal activity. The green tea extract appears to act by
reducing gastrointestinal transit and intraluminal fluid
accumulation in rodents. As shown in table 6, green tea
extracts from the V+Vw and V treatments have better gastric

2236 TRANSACTIONS OF THE ASABE
Table 6. Gastrointestinal transit of a charcoal
meal in mice as influenced by fertilizer sources.
Treatment[a] Dose
Transit
(% ±SEm)[b]
1. Saline (control) 0.2 mL (orally) 76.8 ±3.2
2. Loperamide 1 mg kg‐1 (intraperitoneally) 19 ±2.2*
11. TV1 (C) 1 mL 100 g‐1 (orally) 54.3 ±2.8*
12. TV1 (IF) ” 59.4 ±3.3*
13. TV1 (V) ” 46.5 ±2.2*
14. TV1 (V+Vw) ” 43.2 ±1.9*
15. TV25 (C) ” 58.2 ±2.3*
16. TV25 (IF) ” 62.3 ±2.9*
17. TV25 (V) ” 54.4 ±1.1*
18. TV25 (V+Vw) ” 51.5 ±1.6*
[a] C = control, IF = inorganic fertilizer, V = vermicompost, V+Vw =
vermicompost + vermiwash.
[b] SEm = standard error of mean; * = significant reduction as compared to
saline control (p < 0.05).
Table 7. Castor oil induced fluid accumulation
in rat as influenced by fertilizer sources.
Treatment[a]
Intestinal Fluid Volume
(mL) (% ±SEm)[b]
Percent Decrease over
Saline Control
Saline (control) 3.4 ±1.4 ‐‐
Loperamide 0.68 ±0.1* 80
TV25 C 1.4 ±0.3* 59
IF 1.8 ±0.16* 47
V 0.95 ±0.14* 72
V+Vw 0.80 ±0.2* 77
TV1 C 1.20 ±0.21* 65
IF 2.0 ±0.19* 41
V 0.74 ±0.11* 78
V+Vw 0.71 ±0.10* 79
[a] C = control, IF = inorganic fertilizer, V = vermicompost, V+Vw =
vermicompost + vermiwash.
[b] SEm = standard error of mean; * = significant reduction as compared to
saline control (p < 0.05).
Table 8. Linear correlation coefficient (r)
among various tea quality parameters.
Parameter r‐value[a]
Total phenolics ~ Scavenging of DPPH radical 0.97*
Total phenolics ~ Scavenging activity (SA) 0.93*
Total catechin ~ Scavenging of DPPH radical 0.98*
Total catechin ~ Scavenging activity (SA) 0.87*
Total phenolics ~ Gastrointestinal transit ‐0.84*
Total phenolics ~ Intestinal fluid volume ‐0.95*
Total catechin ~ Gastrointestinal transit ‐0.87*
Total catechin ~ Intestinal fluid volume ‐0.92*
[a] * = significant at p = 0.05.
transit delaying action than extract from the IF treatment.
Even green tea extract from the C treatment shows better
transit delaying action than that of the IF treatment.
In the other method of antidiarrhoeal study, it can be
observed that organic fertilizer treatments show better
performance in reduction of castor oil induced fluid
accumulation than the IF treatment (table 7). The volumes of
fluid recorded were 0.71 and 0.74 mL in the V+Vw and V
treatments against 1.20 and 2.00 mL in the C and IF treatments
for variety TV1. A similar trend was observed for variety TV25.
This shows that green tea extract obtained from organic
fertilizer treatments have effective control of diarrhoea, which
is comparable to loperamide where the fluid volume was
0.68mL. It has been reported that castor oil and other contact
cathartics produce permeability changes in the intestinal
mucosal membranes to water and electrolytes (Gaginella and
Phillips, 1975), effects associated with the release of
endogenous substances such as prostaglandins (Awouters et al.,
1978), vasoactive intestinal polypeptide (Krejs et al., 1980), and
other substances (Dharmasatha-phorn, 1986; Pinto et al., 1989).
Prostaglandins contribute to the pathophysiological functions in
the gastrointestinal tracts (Sanders, 1984). The release of
prostaglandin is also a major cause of arachidonic acid induced
diarrhoea (Luderer et al., 1980; Doherty, 1981). Tea extracts
appear to act on all parts of the gastrointestinal tract (Besra et
al., 2003). Thus feeding green tea extract reduced intraluminal
fluid accumulation and decreased peristaltic activity, which
delayed gastric transit in rodents. Therefore, the antidiarrhoeal
action of green tea extract may be due to the inhibition of
prostaglandin synthesis and release or its actions at the target
sites.
The results of the present investigation as stated above
showed that organic tea has better therapeutic potential as an
antidiarrhoeal agent with higher content of total phenolics,
flavanols, and radical scavenging capacity as compared to tea
grown conventionally. A negative correlation was observed
for total phenolics content with gastrointestinal transit and
intestinal fluid volume. Total catechin content of tea leaves
also showed negative correlation with gastrointestinal transit
and intestinal fluid volume in rodents (table 8).
Antidiarrhoeal activity of tea infusion is probably related to
the presence of tannins (Besra et al., 2003). It is apparent that
the magnitude of diarrhoea control varies with tea extracts
collected from different fertilizer treatments, organic source
being the most effective.
CONCLUSION
Tea grown organically has shown improvement in quality
parameters such as crude fiber, starch, and polyphenol
content. Organic tea has shown higher antioxidant properties
because of high content of polyphenol. Pharmacological
study on diarrhoea control using green tea extract obtained
from organic fertilizer management practices proved to be
more effective than that grown with inorganic fertilizer.
Therefore, organic tea has promise for higher antioxidant
properties and is thereby healthier for consumption.
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