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All Journal Indonesian Journal of Chemistry
Roswanira Abdul Wahab
Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia
Chemical Engineering, Chemistry & Bioengineering Chemistry

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Statistical Modelling of Ultrasonic-Aided Extraction of Elaeis guineensis Leaves for Better-Quality Yield and Total Phenolic Content Nissha Bharrathi Romes; Mariani Abdul Hamid; Siti Ernieyanti Hashim; Roswanira Abdul Wahab
Indonesian Journal of Chemistry Vol 19, No 3 (2019)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (15.927 KB) | DOI: 10.22146/ijc.41603

Abstract

The present study highlighted the statistical modeling of an ultrasonic-aided extraction (UAE) of Elaeis guineensis leaves extract for maximal extraction yield (EY) and total phenolic content (TPC). A Box-Behnken design investigated the effects of ethanol concentration (X1: 0−100%), extraction time (X2: 5−55 min), the solvent-to-solid ratio (X3: 15:1−35:1 mL/g) and sonification amplitude (X4: 20−100 %). Under optimized conditions, the highest EY of 14.38% was attained using 50% (v/v) ethanol:water ratio, 55 min, 35 mL/g solvent-to-solid ratio, 60% sonication amplitude, whereas maximum TPC was 209.70 mg gallic acid equivalent (GAE)/g [50% (v/v) ethanol:water ratio, 30 min, 25 mL/g solvent-to-solid ratio, 60% sonication amplitude]. Second-order polynomial models of EY and TPC showed the R2 value corresponding to 0.9303 and 0.9500, respectively, indicating their significance (p < 0.05) to predict the responses. HPLC chromatograms revealed gallic acid and catechin were present in the UAE extracts. UAE technique afforded better EY (14.38%) and TPC (209.70 mg GAE/g) than maceration (3.73%, 85.23 mg GAE/g) and Soxhlet (6.86%, 102.13 mg GAE/g) extractions, as based on scanning electron micrographs of untreated, UAE, macerated and Soxhlet treated samples. Cell walls of ultrasonic-treated E. guineensis leaves were visibly disrupted to facilitate the higher release of bioactive plant materials, thus justifying the higher EY and TPC. The application of ultrasound appeared to remarkably increase the extraction efficiency of E. guineensis leaves to extract as compared to the conventional methods.
Formulation and Characterization of a Kinetically Stable Topical Nanoemulsion Containing the Whitening Agent Kojic Acid Gan Yi Yun; Nur Azzanizawaty Yahya; Roswanira Abdul Wahab; Mariani Abdul Hamid
Indonesian Journal of Chemistry Vol 21, No 2 (2021)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.56587

Abstract

The research was carried out to synthesize a stable kojic acid (KA) encapsulated nanoemulsion as a whitening agent for topical skin usage. In this study, the oil-in-water (O/W) KA nanoemulsion was formulated using integrated low and high energy methods that combined ultrasonic and hot temperature inversion methods. Several different combinations of parameters were screened, viz. xanthan gum amount (1.0 to 2.0 g), kojic acid (KA) amount (0.5 to 1.5 g), and surfactant-to-water ratio (1:10.75 to 1:4.875), to prepare a stable KA nanoemulsion. The identified best parameters to design the O/W KA nanoemulsion were then subjected to different stability tests: storage and pH stability (freeze-thaw and centrifugal tests). Results revealed that the Trial 6 formulation, with the highest ratio of Tween 80 to water (1:4.875 v/v), yielded the best polydispersity index at 0.255 ± 0.006 with an average particle size of 90.57 ± 1.401 nm. The formulation retained the recommended pH range (pH 4.95–5.18) for topical skin applications within six-week storage under room condition. The nanoemulsions were also kinetically stable as proven by the absence of phase separation after the centrifugation, freeze-thaw cycle, and storage temperature (2 and 25 °C) tests, except at the 37 °C three-week extended storage. The results collectively showed that the formulated O/W KA nanoemulsion is suitable for topical application on human skin.
Co-Authors Gan Yi Yun Mariani Abdul Hamid Mariani Abdul Hamid Nissha Bharrathi Romes Nur Azzanizawaty Yahya Siti Ernieyanti Hashim