Anti-bacterial Properties and GC-MS Analysis of Extracts and ,Essential Oils of Selected Plant Products
Loading...
Date
2013-10-17
Authors
Nyaitondi, Ombuna Dinah
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Bacteria, as common microorganisms found in air, food, water and soil remain a major
problem in developing countries where disease. outbreaks frequently occur in congested
areas. Antibiotics are used to treat common bacterial diseases such as respiratory, ear,
gastrointestinal and skin infections but bacteria develop resistance to most of the drugs.
The drugs also have serious side effects and the cost of medication is high. Plants are
traditionally used for treatment of bacterial infections though they are not clinically
regulated due to lack of awareness and enough data to support the reported therapeutic
claims. Some plants used as food and vegetables are hardly considered in such studies.
The aim of this study was to investigate the antibacterial properties associated with garlic,
ginger, lemon, turmeric and onion. The bioactivities of juices, methanol extracts and
essential oils of these materials were tested, individually and as blends, against
Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi.
Bioassay data obtained from the active extracts and oils were subjected to analysis of
variance (ANOV A). Treatment means showing significant difference (p :s 0.05) were
separated using Student-Newman-Keuls test (SNK). Identification of suspected
antibacterial compounds was done by comparison of retention indices and the mass
spectra with those in National Institute of Standards and Technology (NIST) libraries
using GC-MS analysis. Garlicjuice was bactericidal against Salmonella typhi (17.7±2.5),
Staphylococcus aureus (14.7±2.5), Pseudomonas aeruginosa (10.O±O.O)and Escherichia
coli (11. 7±O.6). Lemon/garlic juice exhibited significantly higher activity against
Escherichia coli (15.O±O.O) and Salmonella typhi (12.O±O.O). Turmeric/lemon/garlic
methanol extracts blend was most active against S. aureus (I2.O±I.0). Preliminary
screening of the essential oils indicated significant antibacterial activity of lemon/garlic
essential oil blend (10.O±O.O) against Pseudomonas aeruginosa. Garlic recorded timecourse
increasing activity against pseudomonas aeruginosa, Staphylococcus aureus and.
Escherichia coli from day 1 to day.S, ·GC-MS analysis of the active samples confirmed
the presence of compounds containing -OOH, -OH, -N, -CI, -F, -NH2 and -S groups
which are associated with bacterial inhibition in conventional antibiotics. The 10 major
constituents obtained from samples suspected to contain antibacterial activity include
limonene (85.08%);)-vinyl-l,2-dithiacyclohex-4-ene (21.43%); u-zingiberene (33.75%);
diallyl disulphide (10.84%); 2-butanone,4-(-hydroxy-3-methoxyphenyl)- (14.14%); 3-
chlorothiophene (8.93%); methanehydrazonic acid,N-[3-(methylthio)-I,-2,4-thiadiazol-5- .
yl]-,ethyl ester (8.87%); n-hexadecanoic acid (8_01%); 'Y-sitosterol (8.00) and
propanamide,2-amino-3-phenyl (6.71%). Since juices of garlic, lemon and lemon/garlic
blend were found to be active against one or more of the bacteria tested unlike methanol
extracts and essential oils, they should be used in raw form as heating and drying is likely
to render them inactive. Further studies on methanol extract and fresh juice of
lemon/garlic blend need to be undertaken in order to elucidate the active principles in
these extracts. These may provide novel antimicrobial agents and/or models for new
generation of synthetic antibiotics.
Description
Department of Chemistry, 116p. The QR 97 .A58O4 2013
Keywords
Antibacterials, Plants --Antibacterial properties, Plant products (extracts and essential oils) --Analysis