Abstract

Peppermint oil (PO) and Green Tea oil (GTO) are two essential oils (EOs) were encapsulated in chitosan nanoparticles (CS NPs) via two-steps method (emulsification followed by ionic gelation). Encapsulation of GTO and PO in CS NPs were investigated through different characterization techniques such as; Fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD). Both NPs (CS/PO NPs and CS/GTO NPs) showed a spherical shape with 20-90 nm size range as detected by Transmission electron microscopy (TEM). Thermogravimetric analysis (TGA) was used to study the thermal stability of both bulk and encapsulated EOs that showed an enhancement in the thermal stability of both encapsulated EOs by about 2.18 and 1.75 folds for PO and GTO, respectively. Through UV-vis spectroscopy, both encapsulation efficiency (EE%), loading capacity (LC%) and in-vitro release were estimated. EE% of CS/PO NPs and CS/GTO NPs were about 82-78% and 22-81%, respectively, when the initial EO amount was 0.25–1 w/w CS. Whereas, the loading capacity (LC%) of CS/PO NPs and CS/GTO NPs were about 8-22% and 2.2-23%, respectively for the initial EO amount was 0.25–1 w/w CS. The in-vitro release studies of both EOs showed an initial rapid release profile followed by a slow release at two different pH conditions: acidic pH (acetate buffer) and neutral pH (phosphate buffer saline). Furthermore, the stability of the total phenolic contents (TPC) of both EOs in CS NPs was studied using Folin–Ciocalteu reagent. The antioxidant activity of both pure and encapsulated PO and GTO was evaluated by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The antioxidant activities of CS/PO NPs and CS/GTO NPs were improved by about 2 and 2.4 folds, respectively. Finally, agar dilution and colony counting method were used to study the antibacterial activity of pure and encapsulated PO and GTO against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) bacteria. In case of Gram positive bacteria, encapsulated PO showed an enhanced antibacterial activity by about 39.63%, while encapsulated GTO showed an improvement in antibacterial activity by about 57.5% on the other hand, against Gram negative bacteria, encapsulated PO showed an enhanced antibacterial activity by about 3%, while encapsulated GTO showed an improvement in antibacterial activity by about 1.8%.

Department

Nanotechnology Program

Degree Name

MS in Nanotechnology

Graduation Date

2-1-2017

Submission Date

November 2017

First Advisor

Mamdouh, Wael

Committee Member 1

Elsayyed, Mayyada

Committee Member 2

El-Meshad, Aliaa

Extent

130 p.

Document Type

Master's Thesis

Rights

The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy.

Institutional Review Board (IRB) Approval

Not necessary for this item

Comments

AUC research grant

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