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Study of phytoconstituents, antioxidant and antibacterial activities of Citrus karna fruit peels

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Title Study of phytoconstituents, antioxidant and antibacterial activities of Citrus karna fruit peels
 
Creator Dar, Muhammad Sikander
 
Contributor Lawrence, Dr. (Mrs) Reena S.
 
Subject vegetative propagation, planting, rice, genes, genotypes, tolerance, yields, selection, land resources, biological development
phytoconstituents, Citrus karna, Peel extracts, Flavonoids, Polyphenols, Essential oil, Antioxidant, Antibacterial.
 
Description A Thesis on "Study of phytoconstituents, antioxidant and antibacterial activities of Citrus karna fruit peels"
Submitted in partial fulfillment of the requirement for the award of the degree of Doctor of Philosophy in Chemistry by Muhammad Sikander DAR.
The most effective way to eliminate free radicals which cause the oxidative stress is with the
help of antioxidants. The main drawback of using synthetic antioxidants is their potentials of
causing health hazards. Even though pharmacological industries have produced a number of new
antibiotics in the last three decades, resistance to these drugs by microorganisms has increased.
Thus, safer and natural alternatives of antioxidative compounds and antibiotics are desirable.
Bioactive flavonoids present in Citrus essential oils and peel extracts have various functional
properties such as attractive aroma and insect repellant, antimicrobial, antioxidant, anti-ulcer,
anti-inflammatory, anti-viral, anti-aggregatory, anti-mutagenic, and antitumor effects. The
present work was designed to determine the different bioactive compounds present in Citrus
karna fruit peel extracts and essential oil and also evaluate the antioxidant and antimicrobial
activities of different peel extracts and essential oil. Seven different compounds were isolated
from three (hexane, chloroform and methanol) fruit peel extracts by using column
chromatography. The isolated compounds were first analyzed by physical methods (visible
observation, ignition tests and solubility in different solvents) and later characterized by IR, mass
and 1H-NMR spectroscopic techniques. The isolated compounds were identified as β-carotene
and naringin from hexane extract, naringenin and chlorogenic acid from chloroform extract and
hesperidin, caffeic acid and ascorbic acid from methanol extract respectively. The essential oil
from the peels of Citrus karna fruit was isolated by hydro-distillation with the help of Clevenger
type apparatus and later analyzed by GC/MS. Nine compounds were identified from essential oil
of Citrus karna and the major compounds were limonene (93.50%), β-pinene (2.97%), α-pinene
(0.78%) and β-phellandrene (0.54%). The peel extracts and essential oil reduced the
concentration of DPPH free radical with an efficacy near to that of standard antioxidant gallic
acid but less than BHT. The IC50 value of methonal extract was 0.67 mg/ml, chloroform extract
= 0.71 mg/ml, hexane extract = 1.02mg/ml, essential oil = 0.94 mg/ml was compared to IC50 of
Gallic acid = 0.61 mg/ ml and BHT = 0.41 mg/ml. The nitric oxide activity was also close to
gallic acid but less than standard antioxidant BHT. The IC50 value was calculated and it was
found that the IC50 of methanolic extract = 0.64mg/ml, chloroform extract = 0.703mg/ml, hexane
extract = 0.73mg/ml and of essential oil = 0.72mg/ml. In the reducing power assay, the
antioxidant activity of Citrus karna fruit peel extracts and essential oil was more than the
standard antioxidant gallic acid but less than BHT. The antioxidant activity was increasing with
increase in concentration of sample. In case of β-carotene bleaching method, methanol extract in
the first 20 minutes showed 83.02% bleaching followed by chloroform extract (81.50%),
essential oil (76.70%) and hexane extract (73.28%) as compared to 93.77% bleaching shown by
the BHT. The methanol extract of fruit peels of Citrus karna had highest percent of β-carotene
bleaching activity than other samples but less than that of standard (BHT). The antibacterial
activity of Citrus karna fruit peel extracts and essential oil was screened by agar well diffusion
method using ampicillin as a standard antibiotic and DMSO as control. The methanolic extract
showed the highest zone of inhibition (20mm) against P. aeruginosa which is same as shown by
ampicillin against the same bacteria. The results of antibacterial activity showed that Citrus
karna fruit peels are highly active against both Gram positive and Gram negative bacteria. The
MIC values of methanol, chloroform and hexane extracts and essential oil of Citrus karna fruit
peels against different pathogenic bacteria are in range from 37 to 111 μg/ml for methanol
extract, 37 to 333 μg/ml for chloroform extract, 111 to 333 μg/ml for hexane extract and 111 to
333 μg/ml for essential oil respectively.
 
Date 2016-12-14T11:27:11Z
2016-12-14T11:27:11Z
2016
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/90083
 
Language en
 
Format application/pdf
 
Publisher Sam Higginbottom Institute of Agriculture, Technology & Sciences (SHIATS)