2015 Seminar, Institute of Food Science & Biotechnology, NCHU
Title:
Chemical Composition, Antioxidant, and Antimicrobial Activities of Essential Oil from Pine Needle (Cedrus deodara)
Authors:
Wei-Cai Zeng, Zeng Zhang, Hong Gao, Li-Rong Jia, and Qiang He
Source: Journal of Food Science _ Vol. 77, Nr. 7, 2012
Impact Factor:1.791
Date: 2015/06/14
Speaker: 柯彥如
Advisor: Dr.溫曉薇
Abstract:
The chemical composition of essential oil from pine needles (Cedrus deodara) whose antioxidant and antimicrobial
activities were evaluated was determined. Twenty-three components were identified by gas chromatography mass spectrometry.
Pine needle essential oil showed remarkable antioxidant activity in scavenging free radicals, in lipid peroxidation, and in
reducing power assays. Moreover, the essential oil revealed strong antimicrobial activity against typical food-borne
microorganisms, with 0.2 to 1.56μg/mL of MIC and 0.39 to 6.25μg/mL of MBC.
TEM observation displayed that the bactericidal mechanism of pine needle essential oil may be the induction of cytoplasmic
outflow and plasmolysis. The results show that the essential oil from pine needles has potential to be used as a natural antioxidant
and antimicrobial agent in food processing.
Introduction:
Oxidation is a common biochemical reaction occurring in food processing and storage, which may shorten product shelf life
and lead to the deterioration in flavor, texture, and color of food. Microbial contamination is another factor promoting food
deterioration and contributing to food-borne disease incidence.
Many synthetic antioxidants and preservatives’ safety and potential impact on health are receiving growing attention,
although they have been widely used in food industry. That’s why many recent studies are directed toward finding natural
alternatives. They are mainly composed of terpenes, terpenoids, and some other aromatic and aliphatic constituents, which usually
have strong smell and low molecular weight.
Cedrus deodara belongs to the family of Pinaceae has been widely utilized in Chinese drink and herbal medicine due to its
nutritional and pharmaceutical effects. Besides, reports have also shown that C. deodara possess diverse biological activities such
as antibrowning and antimicrobial effects.
The main objectives of this study were to characterize the chemical compositions of pine needle essential oils, and
determine its antioxidant and bacterial static and bactericidal properties.
Material and Methods:
Results:
Chemical composition of pine needle essential oil
Pine needle essential oil is a complex mixture, but it is mainly composed of 2 groups: terpenoids (78.66%) and aromatic
compounds(16.13%). It can be deduced that the possible biological and antimicrobial activities of pine needle essential oil may be
attributed to the 2 groups of compounds.
Antioxidant activities
Pine needle essential oil showed remarkable free radical scavenging and reducing properties which are concentration-dependent. It
also showed much higher superoxide and hydroxyl radical scavenging activity than Vc.
Pine needle essential oil was observed to significantly inhibit peroxidation of egg yolk homogenate. The reducing property of pine
needle essential oil was expressed stronger reducing activity which increased with increasing concentration, and pine needle
essential oil exhibited greater activity than Vc.
Antimicrobial activity
Although pine needle essential oil developed smaller inhibition zones than gentamicin, it showed significant inhibition against
tested bacteria, yeast, and fungi. The yeast and fungi were more sensitive to pine needle essential oil than bacteria.
The inhibition zones of yeast and fungi showed that the yeast and fungi were more sensitive to pine needle essential oil than
bacteria.
From MIC and MBC values, we could see R. oryzae was the most susceptible microorganism tested and B. subtilis was the most
susceptible of all tested bacteria to pine needle essential oil.
TEM of B. subtilis cell treated by pine needle essential oil
B. subtilis cells were claviform and elliptical in shape, and white spots observed in cells were spores. The cells treated by pine
needle essential oil looked more translucent with less electron density in TEM images, a condition attributable to the outflow of
cytoplasm. In addition, some localized separation between cell membrane and wall can be discerned.
Conclusions:
Twenty-three components, which can be classified as terpenoids and aromatic compounds, were identified in pine needle (C.
deodara) essential oil. The essential oil showed significant inhibitory and sterilizing activity against typicald food-borne
microorganisms, as a result of cytoplasmic outflow an plasmolysis. The results indicate that pine needle essential oil has the
potential to be used as a natural antioxidant and antimicrobial agent in food industry.
References:
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