Citation
Lim, Sheo Kun
(2006)
Enzymatic Synthesis of Palm-Based Ferulate Ester as Sunscreen Agent.
Masters thesis, Universiti Putra Malaysia.
Abstract
The invention of modifying palm oils to produce sunscreen agent, ferulate
ester (RBD-FE) had been investigated through transesterification reaction of
RBD palm olein with ferulic acid (4-hydroxy-3-methoxy-cinnamate, FA) by
enzymatic synthesis. Ferulic acid is a natural substance which has free
radical scavenging effects and helps to prevent damage to our cells caused
by UV light. However, incorporation of ferulic acid into cosmetic compositions
is problematic due to its instability in aqueous solution and limited solubility in
water in oil emulsions. Besides, currently used sunscreen agent in 90 percent
of all sunscreen products throughout the world; octyl methoxycinnamate
(OMC) is reported could be toxic to human skin.
This process has been studied as one approach in order to overcome these
problems to provide a natural cosmetic ingredient with enhanced efficiency
and stability. It combines the ultraviolet-absorbing properties of a cinnamate
(ferulic acid) with the water-insoluble properties of a lipid (RBDPO) resulting
in ultraviolet-absorbing lipids (RBD-FE) made from all natural ingredients
under mild, solvent-free conditions to ensure a safe, clean and cosmetically
acceptable product.
Enzyme screening revealed Novozym 435 to be the most efficient biocatalyst
for the reaction and was chosen for optimization studies. The important
parameters that may affect the synthesis of RBD-FE had been investigated.
The corresponding optimal conditions for the transesterification reaction was
time, 96 h; temperature, 40 °C; mole ratio of ferulic acid: RBDPO, 1:3; and
amount of enzyme used, 0.10 g resulting in highest percentage of conversion
(24.51%) to ultraviolet-absorbing lipids (RBD-FE) that works as a sunscreen
agent.
Identities of product were verified using TLC, gas chromatography (GC),
Fourier transform infrared spectroscopy (FT-IR), High Performance Liquid
Chromatography (HPLC), GC-Mass Spectroscopy (GC-MS) and Nuclear
Magnetic Resonance (NMR) Spectroscopy analyses. Thermal and oxidative
stability of the RBD-FE were also evaluated. Later, palm-based ferulate ester
was also formulated into cosmetic formulations to evaluate it as sunscreen
agent followed by Sun Protection Factor (SPF) analysi RBD-FE showed higher thermal stability and better oxidative stability.
Besides, it became an active ingredient in sunscreen formulation which acted
as a broadband sunscreen agent which covers both UVA and UVB rays. It
showed a wider light absorption peak between 290 and 400nm.s
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