The synthesis, properties, and applications of ascorbyl esters

Karmee, Sanjib Kumar

doi:10.1002/lite.201100146

Cited by 18 publications

(10 citation statements)

References 6 publications

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“…Secara umum, Karmee (2011) menyatakan bahwa laju esterifikasitransesterifikasi paling cepat pada penggunaan alkohol primer, karena mempunyai reaktivitas yang paling tinggi pada reaksi esterifikasi-transesterifikasi, sehingga alkohol primer tersebut yang menyerang karbon positif dari suatu ester. Selanjutnya pada reaksi tersebut akan mengalami eliminasi ROH dan akan membentuk suatu ester baru yang dituju, yaitu ester-C (ascorbyl ester).Hubungan antara uji stabilitas enzim secara berulang dengan persentase konsentrasi ester-C disajikan pada Gambar 3.…”

Section: Gambar 2 Reaksi Transesterifikasi Dalam Sintesis Ester-cunclassified

Sintesis Ester-C Sebagai Senyawa Antioksidan Menggunakan Biokatalis Enzim Lipase/Zeolit Alam

Wijayati

Rohmah

Supartono

2016

JKR

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AbstrakImobilisasi enzim lipase merupakan metode yang digunakan untuk meningkatan daya tahan enzim terhadap perubahan lingkungan dan penggunaan secara berulang. Penelitian mengenai imobilisasi enzim lipase dari jamur tiram putih (Pleurotus ostreatus) telah dilakukan dengan metode entrapment (penjebakan, penjeratan) menggunakan zeolit alam teraktivasi dan larutan gel NaF. Waktu pengadukan optimum yang diperoleh dalam imobilisasi enzim lipase ialah selama 3 jam dengan nilai aktivitas lipase sebesar 4,24 U/mL dan enzim loading sebesar 63,07%. Enzim lipase terimobilisasi yang diperoleh diaplikasikan dalam uji stabilitas berulang pada sintesis ester-C. Hasil sintesis dianalisis menggunakan instrument FT-IR dan HPLC. Kata kunci: enzim, lipase, imobilisasi, ester-C AbstractImmobilized lipase enzyme is the method used to improve the durability of enzymes to changes in the environment and use repeatedly. Research on the lipase enzyme immobilization of white oyster mushroom (Pleurotus ostreatus) has been done by the entrapment method using activated natural zeolites and NaF gel solution. The optimum stirring time obtained in immobilized lipase is for 3 hours with a value of lipase activity of 4.24 U/mL and enzyme loading of 63.07%. Immobilized lipase enzyme obtained in the stability tests repeatedly applied to the synthesis of ester-C. Synthesis results were analyzed using FT-IR instrument and HPLC.

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Section: Gambar 2 Reaksi Transesterifikasi Dalam Sintesis Ester-cunclassified

Sintesis Ester-C Sebagai Senyawa Antioksidan Menggunakan Biokatalis Enzim Lipase/Zeolit Alam

Wijayati

Rohmah

Supartono

2016

JKR

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“…However, vitamin C ester undergoes oxidation, degradation and rearrangement under the chemo-catalyzed reaction (Karmee 2011). Owing to a number of important applications of ascorbic acid or its derivatives, the aim of the present work was to synthesize ascorbyl palmitate in an organic medium using Celite-bound immobilized commercial lipase (Lipolase 100L).…”

Section: Introductionmentioning

confidence: 99%

Ascorbyl palmitate synthesis in an organic solvent system using a Celite-immobilized commercial lipase (Lipolase 100L)

2016

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Ascorbyl palmitate was synthesized using a Celite-immobilized commercial lipase (Lipolase 100L) in dimethylsulfoxide (DMSO) as an organic solvent system. Lipase immobilized by surface adsorption onto Celite 545 matrix and subsequently exposed to 1 % glutaraldehyde showed 75 % binding of protein. The Celite-bound lipase was optimally active at 75 °C and pH 8.5 under shaking and showed maximum hydrolytic activity toward p-NPP as a substrate. The bound lipase was found to be stimulated only in the presence of Al3+ and EDTA. All surfactants (Tween-20, Tween-80 and Triton X-100) had an inhibitory effect on lipase activity. The optimization of various reaction conditions of ascorbyl palmitate was achieved considering one factor at a time. The esterification of ascorbic acid and palmitic acid was carried out with 1 M ascorbic acid and 2.5 M palmitic acid in DMSO at 75 °C for 18 h under shaking (120 rpm). Molecular sieves had an important effect on the ester synthesis resulting in an enhanced yield. The by-product (H2O) produced in the reaction was scavenged by the molecular sieves (20 mg/ml) added in the reaction mixture which enhanced the ester yield to 80 %. The characterization of synthesized ester was done through FTIR spectroscopy.

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“…. In addition, because of their amphiphilic structure, these esters are potential biosurfactants and components for drug nanoparticles formulations . At this moment, ascorbyl palmitate is being commercially produced in the process catalyzed by chemical means, in spite of disadvantages such as low yields and the absence of regioselectivity .…”

Section: Introductionmentioning

confidence: 99%

Influence of fatty acid on lipase‐catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity

Stojanović

Carević

Mihailović

et al. 2015

Biotech and App Biochem

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Fatty acid (FA) ascorbyl esters are recently emerging food, cosmetic, and pharmaceutical additives, which can be prepared in an eco-friendly way by using lipases as catalysts. Because they are amphiphilic molecules, which possess high free radical scavenging capacity, they can be applied as liposoluble antioxidants as well as emulsifiers and biosurfactants. In this study, the influence of a wide range of acyl donors on ester yield in lipase-catalyzed synthesis and ester antioxidant activity was examined. Among saturated acyl donors, higher yields and antioxidant activities of esters were achieved when short-chain FAs were used. Oleic acid gave the highest yield overall and its ester exhibited a high antioxidant activity. Optimization of experimental factors showed that the highest conversion (60.5%) in acetone was achieved with 5 g L(-1) of lipase, 50 mM of vitamin C, 10-fold molar excess of oleic acid, and 0.7 mL L(-1) of initial water. Obtained results showed that even short- and medium-chain ascorbyl esters could be synthesized with high yields and retained (or even exceeded) free radical scavenging capacity of l-ascorbic acid, indicating prospects of broadening their application in emulsions and liposomes.

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The synthesis, properties, and applications of ascorbyl esters

Cited by 18 publications

References 6 publications

Sintesis Ester-C Sebagai Senyawa Antioksidan Menggunakan Biokatalis Enzim Lipase/Zeolit Alam

Sintesis Ester-C Sebagai Senyawa Antioksidan Menggunakan Biokatalis Enzim Lipase/Zeolit Alam

Ascorbyl palmitate synthesis in an organic solvent system using a Celite-immobilized commercial lipase (Lipolase 100L)

Influence of fatty acid on lipase‐catalyzed synthesis of ascorbyl esters and their free radical scavenging capacity

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