Immobilization of Candida Rugosa Lipase onto N-Vinyl-2-Pyyrolidone-Co-Styrene Hydrogel for Use in Enantioselective Esterification

Lipase from Candida rugosa was immobilized onto N-vinyl-2- pyyrolidone-co-styrene hydrogel (VP-co-ST) The crosslinker and the initiator used were EDMA and AIBN respectively Three different compositions of monomer were used, namely, (VP.ST)% , 1090, 5050 and 70 30 The VP-co ST hydrogel immobilized lipases were used in the enantioselective esterification of (R,S)-2-(4-chlorophenoxy) propanoic acid with n-tetradecanol The optimum reaction time was 24h for native and all immobilized lipases StudIes on the effect of percentages composition of monomers of the VP-co-ST hydrogel immobilized lipases showed that lipase immobilized onto hydrogel (VP ST)%, 1090 exhibited the highest percentages of enantiomeric excess at approximately 24% Generally, increasing the temperature of the enantioselective esterification increases the percentage of ester conversion for all VP-co-ST hydrogel immobilized lipases However, the percentages of enantiomeric excess increases up to 40°C and subsequently decreases At 40°C, the highest percentage of enantiomeric excess was shown by VP-co-ST hydrogel with compositlOn of monomer (VP ST)%, 1090 at 45% In the solvent effect studies, the percentage of ester conversion was higher in relative more polar organic solvents with log P value ranging from 20 to 30 for all immobilized lipases and native lipase The organic solvents such as toluene, chloroform and carbon tetrachloride showed higher percentage of ester conversion as compared with other solvents Immobilized lipases exhibited higher percentage of enantiomeric excess compared to the native lipase Higher percentage of enantiomeric excess were obtained when using chloroform and carbon tetrachloride at approximately 50% and 46% for VP-co-ST (VP ST)%, 5050 and (VP ST)%, 1090 respectively In the water activity studies, at optimum a, all immobilized lipases showed higher percentage of ester conversion compared to the native lipase at approximately 23%, 16% and 22% for VP-co-ST hydrogel with composition of monomer (VP ST)%, 1090, 5050 and 7030 respectively At optimum all, VPco- ST hydrogel immobilized lipase with composition of monomer (VP ST)%, 1090, 5050 and 7030 exhibited higher percentage of enantiomeric excess at approximately 40%, 21% and 28% respectively compared to the native lipase

Relationship between the microstructure and property of Al-0.21wt% Mg-0.41wt% Si alloy

In this study, the relationships between microstructure and property have been investigated for Al­ 0.21wt%Mg-0.41wt%Si alloy. JMatPro calculations was used to predict the phase relationships as a function of temperature. The effects of solution treatment (ST) and artificial ageing (AA) as well as natural ageing at room temperature (NA) were studied. A comparison of the alloy ageing response was made at different ageing temperatures using Vickers hardness test. Tensile test was carried out to evaluate the strength and ductility of the alloy. The microstructures of as received and solution treated alloys were observed by polarized light optical microscopy. The morphology of the precipitates formed was monitored using transmission electron microscopy (TEM). Results indicate that needle-shaped precipitates are responsible for hardening the alloy. The higher density of precipitates in the alloy enhanced the precipitates strengthening. It was found that the tensile strength results for the alloy that aged at room temperature and 185°C followed the hardness graphs trends. The most possible particles observed in the solution treated alloy were suspected to be a or 13-A1FeSi and a-AlMnSi. The results of TEM-EDX analysis were verified by JMatPro calculations

In vitro study of antifungal activity of Entada spiralis Ridl. crude extract against dermatophytes of superficial skin disease

The antifungal activity of crude extracts from the stem bark of Entada spiralis was evaluated in vitro against human dermatophytes by disc diffusion method. Three types of human dermatophytes, known as Trichophyton mentagrophytes, Microsporum gypseum, Trichophyton tonsurans and one non-dermatophyteCandida glabrata, were tested against petroleum ether, ethyl acetate and methanol crude extracts of the E. spiralis. Results revealed that all dermatophytes were susceptible towards all tested crude extracts, whereas, the non-dermatophyte showed resistance to all the extracts. M. gypseum was found to be most susceptible towards petroleum ether extract (400mg/ml), with a zone of inhibition of 16 mm. The ethyl acetate and methanol crude extracts (400mg/ml each) exhibited highest activity against T. tonsurans with inhibition zones of 12.7 mm and 11.5 mm, respectively. Nystatin was used as the standard antifungal drug in all experiments and served as the positive control. All these results suggested that the petroleum ether crude extract was the most active extract against all tested dermatophytes except for C. glabrata. Based on these current findings, it can be concluded that the stem bark extracts of E. spiralis have promising antifungal activities and can be used as a potent antifungal drug against certain dermatophytes

Two isolated crystalline solids from the stem of Entada spiralis Ridl.(akar Sintok) = Pemencilan dua jenis pepejal kristal dari batang pokok Entada spiralis (Akar Sintok)

Entada spiralis Ridl. (Leguminosae) is a woody climber which locally known as ‘akar sintok’. The isolation and structure determination of two crystalline solids from active methanol fraction of E. spiralis stem bark had been examined. The structure identification of both solids was based on spectroscopic data (1 H and 13C NMR, HMQC, HMBC, DEPT135 and MS) along with comparison with literature data. The results revealed that these two crystalline solid sugars isolated from the most active fraction were known as penta-2-acetoxy-β-D-digitoxopyranosyl-(1→2)-fructofuranosyl-(6→4)-β-D-glucopyranosyl-(1→4)- glucopyranosyl-(1→2)-β-D fructofuranosyl-(6→1)-β-D-glucopyranosyl-(4→1)-acetylglucosamine (1) and β,D-glucopyranosyl(1→2)-β,D-glucopyranosyl)-(1→3)-β,D-xylopyranosyl(1→4)-α,L-rhamnopyranosyl)-(1→3)-β,D- glucopyranosyl(1→3)- β,D-glucopyranoside (2) Thus, this finding can be utilized as a scientific baseline information for further skin disease studies, since both constituents were isolated from moderate antidermatophytic active fraction. Pemencilan dan penentuan struktur dua komponen bersifat kristal dari batang pokok E. spiralis yang juga dikenali sebagai akar sintok telah dijalankan. Eksperimen penentuan struktur berdasarkan data – data spektroskopi menggunakan 1 H, 13C NMR, HMQC, HMBC, DEPT135 dan spektrometer jisim dan juga perbandingan dengan kajian terdahulu. Hasil analisa spektroskopi yang terperinci menunjukkan kedua – dua kristal tersebut dikenali sebagai penta-2-asetoksi-β-D-digitoxopiranosil-(1→2)- fruktofuranosil-(6→4)-β-D-glukopiranosil-(1→4)-glukopiranosil-(1→2)-β-D fruktofuranosil-(6→1)-β-D-glukopiranosil-(4→1)- acetilglukosamina (1) and β,D-glukopiranosil(1→2)-β,D-glukpiranosil)-(1→3)-β,D-xilopiranosil(1→4)-α,L-rhamnopiranosil)- (1→3)-β,D-glukopiranosil(1→3)-β,D-glukopiranosid (2). Penemuan ini boleh dijadikan maklumat asas untuk kajian penyakit kulit kerana kedua-dua komponen ini dipencilkan dari fraksi metanol yang bersifat antiderma

Bioactive compounds from sterm bark of Entada Spiralis RIDL

Introduction: Entada spiralis Ridl. (Leguminoceae) which is locally known as beluru or sintok is a liana or woody climber that grows wildly in Malaysia. The isolation and characterisation of the major chemical constituents from the bioactive extract of the stem bark of E. spiralis has been carried out. Our previous study revealed that the methanol extract was active against dermatophytes that causes skin infections. Strains of dermatophytes, Trichophyton mentagrophytes ATCC 9533, Trichophyton tonsurans ATCC 28942 and Microsporum gypseum ATCC 24102 were used

Understanding Customer Intention to Use E-Payment for Online Shopping

The emergence of e-commerce has sparked a huge change in consumer behavior, transforming how individuals purchase and conduct transactions. E-payment has become a pillar of this digital transition. However, some customers are still hesitant to adopt e-payment despite its advantages. This paper aims to unravel the factors influencing customer intentions to use e-payment for online shopping. Based on a review of existing literature on the Technology Acceptance Model (TAM Model) and additional external factors, a proposed model was developed to test consumer's intention to use e-payment for online shopping. The result of this study would be useful to understand consumers’ behaviors in employing electronic transactions when making payments for online purchases. This paper also provides valuable insights for e-payment service providers and online retailers on how to promote sustainable online shopping in the future

In-vitro antidermatophytic activity of methanolic fraction from entada spiralis ridl. stem bark and its bioautographic profile

This study was performed to evaluate the antifungal activities of the methanolic fractions from the stem bark of Entada spiralis Ridl. against human dermatophytes and yeast-like fungus in in vitro. Three types of human dermatophytes and one yeast-like fungus namely Trichophyton mentagrophytes ATCC 9533, Microsporum gypseum ATCC 24102, Trichophyton tonsurans ATCC 28942, and Candida glabrata ATCC 66032 were tested against the methanolic fractions labelled as FA1, FA4 and FA5. First, the activities of antifungal were studied by disc diffusion method and broth micro dilution method. Second, we used an agar overlay bioautography assay to reveal antidermatophytic compounds of methanolic fractions. T.mentagrophytes, T.tonsuran and M.gypseum were susceptible towards all tested fractions in a concentration-dependent manner whereas C.glabrata was resistant. Fraction FA1 at a concentration of 400 mg/mL was found to exhibit highest antifungal activity with inhibition zone diameter of 22mm (T.mentagrophytes). FA1 showed MIC at 0.097 mg/mL while the MIC value for FA4 and FA5 were 3.12 mg/ml and 1.56 mg/ml respectively. Nystatin was used as standard antifungal drug and served as positive control. A garoverlay bioautography assay results showed that most of the bioactive compounds were 3 found in FA1. Based on these findings, it can be concluded that the stem bark extracts of E. spiralis can be a future source of potent natural antimicrobial drugs for superficial skin diseases

Bioassay guided isolation of an antidermatophytic active constituents from the stembarks of entada spiralis ridl

Entada spiralis ridl (lenguminoceae) is a liana or woody climber that grows in the wild in Malaysia and is known locally as "Beluru" or "Sintok". The isolation and characterization of the chemical constituent from an active fraction of E. spiralis stem bark has been carried out. Our previous study revealed that methanol extract of E. spiralis stem bark exhibited promising antifungal activity against three dermatophyte strains, namely Trichophyton mentagrophytes ATCC 9533, Trichophyton tonsurans ATCC 28942 and Microsporum Gypseum ATCC 24102 that cause skin infection. This study was performed to elucidate the structure of active constituent known as ester saponin from the active fraction of E. spiralis stem bark. The factions were prepared using fractionation process and repeated antifungel test was conducted to identify the most active fraction. The structure elucidation of this compound was based on spectroscopis data (1H, 13C NMR, HMQC, HMBC and DEPT135) and comparison with literature. on the basis of spectroscopis analysis, the compound was identified as 28-α,L-rhamnopyranosyl-18,21,22-trihydroxy-12-en-29-(2-acetylamino-β-Dglucopyranosyl)triterpene ester. The current study provides important baseline information for the use of E. spiralis for the treatment of skin infection caused by the microorganism investigated in this study

Antioxidative constituents from twig and leaves of jasminum sambac / Nurul Fatin Fakhira Mohd Padli ... [et. al.]

This study aimed to investigate new antioxidative constituents from twig and leaves of Jasminium sambac (Oleaceae family) as potent antioxidant sources. The antioxidant behaviour of each extract from twig and leaves of J. sambac was assessed qualitatively by spraying the thin layer chromatography (TLC) of extracts with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and quantitatively by DPPH radical scavenging method. The collection of antioxidative constituents was carried out using centrifugal chromatography. The chemical structures of all constituents were identified from Gas Chromatography Mass Spectrometer (GCMS). The qualitative Thin Layer Chromatography (TLC) screening of antioxidants showed that all types of extracts from J. sambac leaves demonstrated moderate antioxidant behaviour as well as the extracts from twig parts. The quantitative DPPH radical scavenging activity of leaves and twig extracts revealed dichloromethane (DCM) extract scavenged DPPH free radicals more effective at IC50of 6.24 ppm and 5.22 ppm respectively compared to petroleum ether extract and methanol extract where both extracts exhibited IC50more than 100 ppm. The antioxidative constituents isolated from DCM extract of twig of J. sambac were recognized as isoamyl nitrite and benzophenone whereby benzophenone was also found in DCM extract of J.sambac leaves. Thus, J. sambaccan be considered as a promising source of bioactive compounds with potent antioxidant properties which can be utilized as baseline information to overcome health disorders