PHARMACOGNOSTIC AND ANTIBACTERIAL STUDIES OF THE LEAVES OF CHROMOLAENA ODORATA (L.) KING & ROBINSON (ASTERACEAE
PHARMACOGNOSTIC AND ANTIBACTERIAL STUDIES OF THE LEAVES OF CHROMOLAENA ODORATA (L.) KING & ROBINSON (ASTERACEAE
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Date
2011-08
Authors
OHANELE, CHUKWUMA CYRINUS
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Abstract
The plant, Chromolaena odorata (L.) King & Robinson is a member of the
Asteraceae family. It grows abundantly in Southern Nigeria where its leaves are
used as traditional herbal treatment for wounds and fevers. The plant, C. odorata
was therefore investigated for antibacterial activities. The leaves of C. odorata
were collected from plants growing in their natural habitat in Kaduna State.
Standard pharmacognostic methods were used to conduct macroscopic and
microscopic studies of the leaf. Physical constants of the leaf were also
determined. Furthermore, phytochemical and biological evaluations of the leaf
extracts and fractions were conducted. The matured, fresh leaf of C. odorata is
green in colour, mildly hairy and deltoid to ovate-lanceolate in shape. The leaf
margin is dentate. The leaf measures between 6 – 8 cm in width and 8 – 10 cm in
length. The leaf is amphistomatic with anomocytic stomata and non-glandular,
uniseriate and multicellular trichomes. The stomata were more in the abaxial
surface than in the adaxial with means of 9 ± 1.35 and 3 ± 0.45, respectively. The
abaxial surface equally had higher stomatal index of 24.6 % ± 3.69 compared
to 7.4 % ± 1.05 for the adaxial surface. Vein islet number and vein termination
number were 5.8 ± 0.87 and 4.8 ± 0.72, respectively. The palisade ratio has a
mean value of 6.5 ± 0.98. The powdered drug has a moisture content
of 9.78 % ± 1.5. The ash value and the acid insoluble ash value
were 12.13 % ± 1.82 and 4.11 % ± 0.62 respectively. The alcohol extractive value
was 4.87 % ± 0.73, while water extractive value was 3.47 % ± 0.52. The
phytochemical study demonstrated the presence of flavonoids, triterpenes,
tannins, saponins and anthraquinones in the ethanolic leaf extract. The ethanol
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extract was further partitioned into aqueous, I-butanol and chloroform fractions.
Flavonoids and triterpenes were present in all the fractions while tannins were
found only in the aqueous and butanol fractions. The chromatographic resolution
of ethanolic extract with the solvent system Benzene: Methanol (9:1) showed
over 10 spots visible in the daylight. Phytochemical tests indicated that most of the
bands represented flavonoids. The ethanol extract and the chloroform, butanol
and aqueous fractions showed various degrees of antibacterial activities against
Staphylococcus aureus, Streptococcus pyogenes, Salmonella typi and Escherichia
coli. The chloroform fraction however, had the most antibacterial activity with the
highest zones of inhibition (S. aureus (31 mm), S. pyogene (30 mm), S. typhi (29
mm) and E. coli (29 mm)), lowest minimum inhibitory concentration (MIC) (S.
aureus (2.5 mg/ml), S. pyogene (2.5 mg/ml), S. typhi (5 mg/ml) and E. coli (5
mg/ml)) and minimum bactericidal concentration (MBC) (S. aureus (5 mg/ml), S.
pyogene (10 mg/ml), S. typhi (20 mg/ml) and E. coli (10 mg/ml)). This study
therefore showed that the leaf extract of C. odorata has broad-spectrum
antibacterial properties against the common bacteria that infect wounds. This
result suggests the scientific reason for the traditional use of the leaf of the plant
for wound treatment. Thus, the plant can be an effective and easily accessible
herbal drug for the treatment of wounds.
Description
DEPARTMENT OF PHARMACOGNOSY AND DRUG DEVELOPMENT
FACULTY OF PHARMACEUTICAL SCIENCES
AHMADU BELLO UNIVERSITY ZARIA
AUGUST 2011
Keywords
PHARMACOGNOSTIC,, ANTIBACTERIAL STUDIES,, LEAVES,, CHROMOLAENA ODORATA (L.) KING,, ROBINSON,, (ASTERACEAE).