GLOBAL JOURNAL OF PURE AND APPLIED SCIENCES VOL 15, NO. 3, 2009: 365-368
COPYRIGHT© BACHUDO SCIENCE CO. LTD PRINTED IN NIGERIA. ISSN 1118-057
ANTIBACTERIAL ACTIVITY AND MEDICINAL PROPERTIES OF
GINGER (zingiber officinale)
S. P. MALU, G. O. OBOCHI, E. N. TAWO AND B. E. NYONG
(Received 20, June 2008; Revision Accepted 6, November 2008)
The antibacterial activity and medicinal properties of ginger extracts were studied. Ginger extracts were
obtained using solvents, n-hexane, ethyl acetate, ethanolic soxhlet and water. The extracts were assayed for
antibacterial activity and bacterial growth inhibition activity. The results showed that all the extracts except the water
extract have antibacterial activity and that the inhibition of bacterial growth was dose dependent. The results also
showed that ginger extracts possesses antibacterial properties and could be used for the treatment of bacterial
KEY WORDS: Ginger, Antibacterial activity, inhibition of bacterial growth, medicinal properties and bacterial
Ginger (zingiber officinale), Roscoe belonging to
the Family Zingiberaceae, is a perennial herb with thick
tuberous rhizomes. The erect leafy aerial stem grows up
to approximately 1 meter in height and has purple
flowers (fig.1). Its roots are used as spice in cooking
throughout the world. The ginger plant has a long history
of cultivation known to originate in China and then
spread to India, South East Asia, W est Africa and the
Caribbean (Weiss, 1997; McGee, 2004). Ginger
contains up to 3% of an essential oil that causes the
fragrance of the spice (O’Hara et al,1998). The main
constituents are sesquiterpenoids with (-)-
zingiberene as the main component. Other components
include β-sesquiphellandrene bisabolene and farnesene
which are also sesquiterpenoids,( β-sesquiphellandrene,
cineol and citral )( Opdyke,1974 ;O’Hara et al,1998).
The pungent taste of ginger is due to non-
volatile phenylpropanoid – derived compounds,
gingerols and shogaols. The shogaols are formed from
gingerols when ginger is dried or cooked. Zingerone is
Figure1: An erect stem of ginger zingiber
Figure 2: A thick tuberous rhizome of
S. P. Malu,
Department of chemistry / Biochemistry, Cross River University of Technology, Calabar.
G. O. Obochi, Department of chemistry / Biochemistry, Cross River University of Technology, Calabar.
E. N. Tawo, Department of chemistry / Biochemistry, Cross River University of Technology, Calabar.
B. E. Nyong, Department of chemistry / Biochemistry, Cross River University of Technology, Calabar.
also produced from gingerols during this process, and it
is less pungent and has a sweet aroma (O’Harold,
2004). Ginger is a minor chemical irritant, and has a
sialagogue action, stimulating the production of saliva
(O’Hara et al, 1998). Mature ginger roots are fibrous and
nearly dry. They can be cooked as an ingredient in
many dishes. They can be stewed in boiling water to
make ginger tea, to which honey is often added as a
sweetener; sliced orange or lemon fruit may also be
added. The juice of ginger roots is extremely potent and
is often used as spice to flavour dishes such as seafood,
mutton, snacks or stew. Powdered dry ginger roots
(ginger powder) are typically used to add spiciness to
ginger bread and other recipes. Ginger is also made into
candy and used as flavoring for cookies, crackers and
cakes as well as flavour in ginger ale-a sweet,
carbonated, non-alcoholic beverage. ginger bread,
ginger snaps, ginger cake and ginger biscuits
Medically ginger is used as a stimulant and
carminative, and is used frequently for drypepsia and
colic (O’Hara et al, 1998). It has a sialaggogue action,
stimulating the production of saliva. It is also used to
disguise the taste of medicines. Ginger promotes the
release of bile from the gall bladder (Opdyke, 1974; Kato
et al, 1993; O’Hara et al, 1998). Ginger may also
decrease joint pain from arthritis, may have blood
thinning and cholesterol lowering properties and may be
useful for the treatment of heart diseases and lungs
diseases (Opdyke, 1974; Kato et al, 1993; O’Hara et al,
1998; Kuschener and Stark, 2003). The characteristic
odour and flavour of ginger root is caused by a mixture
of gingerone, shoagoles and gingerols, volatile oils that
make up about 1-3% of the weight fresh ginger.
The gingerols increase the motility of the
gastrointestinal tract and have analgesic, sedative and
antibacterial properties (O’Hara et al, 1998). Ginger has
been found effective by multiple studies for treating
nausea caused by seasickness, morning sickness and
chemotherapy (Ernst and Phittler, 2000). Ginger has
been reported to be effective for the treatment of
inflammation, rheumatism, cold, heat cramps, and
diabetes (Al-Amin, 2006; Afshari, 2007).
Allergic reactions to ginger include heartburn, bloating,
gas, belching and nausea (particularly if taken in
powdered form). Unchewed fresh ginger may result in
intestinal blockage, and individuals who have had
ulcers, inflammatory bowel diseases or blocked
intestines may react badly to large quantities of fresh
ginger (Opdyke, 1974; O’Hara et al, 1998). Ginger can
also adversely affect individuals with gallstones, and
may affect blood pressure, clotting, and heart rhythms
(O’Hara et al, 1998).
The aim and objective of the present study was
to investigate the antibacterial activity and bacterial
growth inhibition of ginger extracts.
MATERIAL AND METHODS
Collection and treatment of sample
The ginger roots were obtained at the Marian
Market (Calabar, Nigeria). The roots were sun dried for
seven days and ground into fine powder using an
electric grinder. Then 100g of the powdered mass
obtained was stored in clean sterile bottles at room
temperature and used for the extractions.
The soxhlet ethanolic extracts was obtained by
soxhlet extraction of 20g of ginger powder in 100ml of
95% ethanol at 78
C using soxhlet apparatus. The
extract was then concentrated to 20ml on a water bath
and dried at room temperature.
The n-hexane extract was obtained by
dissolving 20g of the powdered ginger in 100ml of n-
hexane in a conical flask. The mixture was stirred,
covered, and allowed to stand for 24hrs, and filtered
using sterile Whitman No.1 filter paper. The filtrate was
concentrated to 20ml on a water bath and evaporated to
dryness at room temperature.
The ethyl acetate and water extracts were
obtained by repeating the above procedure for n-
hexane. The various extracts were used for the analysis
of antibacterial activities and bacterial inhibition assay.
The antibacterial activity was determined by the
diffusion method of Kirby Bauer described by Duguid et
al, (1989). This method determines the antibacterial
activity of the extracts.
Preparation of the nutrient medium
Nutrient agar medium was prepared by
dissolving 2.8g of nutrient agar in 100ml distilled water.
The solution was sterilized in an autoclave at 121
(1.1N pressure) for 15 min. The suspension was cooled
and poured into sterile Petri-dishes to solidify. The agar
depth of the medium was 4.0mm.
Preparation of cultures and innoculation
Pure cultures of coli form bacillus,
staphylococcus epidermidis and streptococcus viridans
obtained from the Microbiology Laboratory in the
Department of Microbiology, Cross River University of
Technology, Calabar, Nigeria, were separately used to
inoculate the Petri-dishes. This was done by streaking
the surface of the plates in a zigzag manner until the
entire surface was then covered. The inoculated plates
were then incubated at room temperature for 24hours.
Assay of antibacterial activity
The extracts were serially diluted to obtain
1.0%, 0.5%, 0.25%, and 0.125% solutions in sterile test
tubes. Sterilized 9mm filter paper disc soaked in the
diluted extracts were placed on the plates and incubated
for 24hours at room temperature.
The plates were examined for clear zones of inhibition.
Presence of zones of inhibition indicated activity. The
zones were measured.
Table 1 presents the results of antibacterial
activity of the ginger extracts. The results showed that
the extracts except the water extract have antibacterial
activity. The results that ginger roots extracts, viz.n-
hexane, ethyl acetate and soxhlet extracts have
antibacterial activities on colliform bacillus,
staphylococcus epidermidis and streptococcus viridians
while the water extract did not have antibacterial activity
on these bacterial. The results may suggest that n-
hexane; ethyl acetate and soxhlet extract of ginger root
could be potent against bacterial infections while the
water extract of ginger roots could be ineffective.
S. P. MALU, G. O. OBOCHI, E. N. TAWO AND B. E. NYONG
Table 2 presents the results of inhibition of
bacterial growth by the extracts. The results showed that
n-hexane, ethyl acetate and soxhlet extracts showed
inhibition of bacterial growth of coliform bacillus,
strapylococcus epidermidis and streptococcus viridans.
However, there was no bacterial growth inhibition with
the water extract of the ginger roots. futhermore, the
inhibition of bacterial growth appeared to be dose
dependent since no activiy was observed at low
concentrations. Since no activity was observed at very
Table 1.The antibacterial activity of the ginger roots extracts
Test organism n-hexane
Soxhlet extract Water extract
+ + + -
+ + + -
+ + + -
+ = Active
- = Not active
Table 2. Inhibition of bacterial growth by the ginger extracts
Zone of inhibition (mm)
n-hexane Ethyl acetate Soxhlet Water
Test organism Dilution
1.00 4.0 5.0 5.5 _
0.50 1.5 2.5 3.0 _
1.00 4.5 5.0 6.5 _
0.50 2.5 3.5 4.0 _
0.25 1.0 2.5 _
0.125 _ _ _
1.00 5.0 5.6 7.0 _
0.50 3.0 4.0 4.5 _
The results for the antibacterial screening have
shown that the entire extracts except the water extracts
have antibacterial activity. The results of the inhibition of
bacterial growth have shown that the extracts are active
at high concentration and inactive at very low
concentrations. Thus the study may suggest that the
inhibition of bacterial growth activity of the extracts is
dose dependent. The soxhlet appears to be most active
and can be beneficial in the treatment of bacterial
The antibacterial activity and inhibition activity of ginger
extracts could be attributed to the chemical properties of
ginger. The main constituents of ginger are
sesquiterpenoids with zingiberene as the main
component. Other components include β-
sesquiphellandrene, bisabolene and farnesene, which
are sesquiterpenoids, and trace monoterpenoid
fraction,( β-sesquiphellandrene, cineol and citral
)(O’Hara et al,1998).
The terpenoids are of important in pharmacy
due to their relationship with such compounds as vitamin
A and could be of immense medical applications.
Terpenoids are reactive compounds (Ekam and Ebong,
2007). Ginger has a sialagogue action, which stimulate
the production of saliva, and can be used to disguise the
taste of medicines (O’Hara et al,1998). The gingerols
could make ginger available for treatment of stomach
acidity and may have analgesic and sedative properties
(O’Hara et al, 1998).
In conclusion, this study has shown that ginger
extracts possess medicinal properties, antibacterial
activity and that the inhibition of bacterial growth was
The results of this may suggest that the n-
hexane, ethyl acetate and soxhlet extracts of the ginger
roots could be used for treating bacterial infections,
drypepsia and colic. these extracts may also be used for
treating common cold, digestive disorders,
hypercholesterolemia, heart diseases, lung diseases
and could also be used as analgesic, particularly, in
relieving pains from arthritis.
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neuropathy, plasma antioxidant capacity and
lipid peroxidation in rats. Food Chemistry,
Al-Amin, Z. M., 2006. Antidiabetic and hypolipidaemic
properties of zingiber (zingiber officinale) in
MEDICINAL PROPERTIES OF GINGER
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S. P. MALU, G. O. OBOCHI, E. N. TAWO
AND B. E.