ORCID Profile
0000-0003-0495-3303
Current Organisation
Monash University Malaysia
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Publisher: Wiley
Date: 20-06-2018
Abstract: Dilute acid polymerizes degassed, aqueous acrylamide with concomitant gelation, without the need for added free radical initiator or cross-linking agent. This reaction is accelerated by sonication or UV irradiation, but inhibited by adventitious oxygen or the addition of a free radical inhibitor, suggesting an acid-accelerated free radical process. The resulting hydrogels are thixotropic in nature and partially disrupted by the addition of chaotropic agents, indicating the importance of hydrogen bonding to the 3D network. This discovery was made while trying to prepare pectin-polyacrylamide hydrogels. We observed that pectin initiated the gelation of acrylamide, but only if the aqueous pectin s les had a pH lower than ca. 5.
Publisher: Elsevier BV
Date: 07-2017
Publisher: Wiley
Date: 15-12-2015
DOI: 10.1111/IJFS.12999
Publisher: American Chemical Society (ACS)
Date: 06-02-2023
Publisher: Informa UK Limited
Date: 02-01-2016
Publisher: Wiley
Date: 10-08-2020
DOI: 10.1002/AOCS.12404
Publisher: Springer Science and Business Media LLC
Date: 03-11-2016
DOI: 10.1007/S10529-016-2246-5
Abstract: To investigate the lipase-catalyzed acylation of quercetin with oleic acid using Candida antarctica lipase B. Three acylated analogues were produced: quercetin 4'-oleate (C Quercetin oleate esters with enhanced lipophilicity can be produced via lipase-catalyzed reaction using C. antarctica lipase B to be used in topical applications.
Publisher: American Chemical Society (ACS)
Date: 03-07-2023
Publisher: Elsevier BV
Date: 04-2017
DOI: 10.1016/J.CARBPOL.2016.12.033
Abstract: Pectins are a erse family of biopolymers with an anionic polysaccharide backbone of α-1,4-linked d-galacturonic acids in common. They have been widely used as emulsifiers, gelling agents, glazing agents, stabilizers, and/or thickeners in food, pharmaceutical, personal care and polymer products. Commercial pectin is classified as high methoxy pectin (HMP) with a degree of methylation (DM) >50% and low methoxy pectin (LMP) with a DM <50%. Amidated low methoxy pectins (ALMP) can be obtained through aminolysis of HMP. Gelation of HMP occurs by cross-linking through hydrogen bonds and hydrophobic forces between the methyl groups, assisted by a high co-solute concentration and low pH. In contrast, gelation of LMP occurs by the formation of ionic linkages via calcium bridges between two carboxyl groups from two different chains in close proximity, known as the 'egg-box' model. Pectin gels exhibit Newtonian behaviour at low shear rates and shear-thinning behaviour when the shear rate is increased. An overview of pectin from its origin to its physicochemical properties is presented in this review.
Publisher: The Royal Society of Chemistry
Date: 28-07-2016
DOI: 10.1039/9781782623984-00205
Abstract: Pectins (also known by the singular pectin) are a erse family of biopolymers with a complex range of structures. Their common feature is a polysaccharide backbone of 1,4-linked α-d-galacturonic acids. Pectins are derived from dicotyledonous and some monocotyledonous plants and make up one third of the cell wall materials. Pectin has been widely used as a gelling and stabilizing agent in food, as an incipient ingredient in pharmaceuticals, in personal care products and in other polymer products. It is recognized as safe (GRAS) by the United States Food and Drug Administration (FDA). Commercial pectin is extracted using acids from by-products of the food industry such as citrus peel, apple pomace and sugar beet pulp. There are two types of pectin: high methoxyl (HM) pectin with a degree of methylation (DM) & 50% and low methoxyl (LM) pectin. LM pectins are usually manufactured from HM pectins by de-esterification. HM pectins gel by cross-linking homogalacturonan residues through hydrogen bonds and hydrophobic forces between the methoxyl groups, assisted by a high sugar concentration and low pH. In contrast, LM pectins gel by forming ionic linkages via calcium bridges between two carboxyl groups from two different chains in close proximity, known as the ‘egg-box’ model. The viscoelastic behavior of both gels depends on intrinsic and extrinsic factors. Chemical modifications of pectin such as alkylation, amidation and thiolation have been used to manipulate hydrophilicity, hydrophobicity and adhesion.
Publisher: MDPI AG
Date: 18-11-2016
DOI: 10.3390/POLYM8110404
Publisher: Oxford University Press (OUP)
Date: 14-12-2022
Abstract: Cannabis is a plant notorious for its psychoactive effect, but when used correctly, it provides a plethora of medicinal benefits. With more than 400 active compounds that have therapeutic properties, cannabis has been accepted widely as a medical treatment and for recreational purposes in several countries. The compounds exhibit various clinical benefits, which include, but are not limited to, anticancer, antimicrobial, and antioxidant properties. Among the vast range of compounds, multiple research papers have shown that cannabinoids, such as cannabidiol and delta-9-tetrahydrocannabinol, have antiviral effects. Recently, scientists found that both compounds can reduce severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) viral infection by downregulating ACE2 transcript levels and by exerting anti-inflammatory properties. These compounds also act as the SARS-CoV-2 main protease inhibitors that block viral replication. Apart from cannabinoids, terpenes in cannabis plants have also been widely explored for their antiviral properties. With particular emphasis on four different viruses, SARS-CoV-2, human immunodeficiency virus, hepatitis C virus, and herpes simplex virus-1, this review discussed the role of cannabis compounds in combating viral infections and the potential of both cannabinoids and terpenes as novel antiviral therapeutics.
No related grants have been discovered for Wee Sim Choo.