ABSTRACT:Lipase from Candida rugosa was immobilized by entrapment while polymerizing a poly(N-vinyl-2-pyrrolidone-co-styrene) [poly(VP-co-ST)] hydrogel using ethylene dimethacrylate (EDMA) as the crosslinking agent. The immobilized enzymes were used in the esterification reaction of oleic acid and butanol in hexane. The activities of the immobilized enzymes and the leaching ability of the enzyme from the support with respect to the different compositions of the hydrogels were investigated. The thermal, solvent, and storage stability of the immobilized lipases were also determined. The activities were relatively higher when the percent compositions of VP (
Lipase from Candida rugosa was immobilized on poly(N-vinyl-2-pyrrolidone-co-styrene) hydrogel (poly-(VP-co-ST)) with ethylene dimethacrylate and ␣,␣'-azoisobutyronitrile, which act as crosslinker and initiator, respectively. Three different compositions of monomers were used, namely VP(%):ST(%), 10:90, 50:50, and 70:30 (wt(%)/wt(%)). The immobilized lipases were used in the enantioselective esterification of (R,S)-2-(4-chlorophenoxy)-propanoic acid with n-tetradecanol. The optimum reaction condition of the enantioselective esterification for the native lipase and the poly(VP-co-ST) hydrogel immobilized lipases was determined with respect to temperature, solvents, and initial water activity (a w ). The optimum temperature obtained was 40°C, with the poly(VP-co-ST) hydrogel immobilized lipase VP(%)/ST(%):10:90 showing the highest enantiomeric excess. In the solvent effect studies, the best solvents for high enantioselectivity were chloroform and carbon tetrachloride. In the a w studies, optimum ␣ w for NL, VP(%):ST(%), 10:90, and 50:50 was 0.328, while for VP(%): ST(%), 70:30, it was 0.55.
In this paper, we investigate the potency of Leea indica locally known as Memali plant from Tasik Chini, Pahang as a potent antioxidant and antimicrobial agent. Antibacterial activity of root, stem and leaf extracts of L. indica was evaluated against skin disease caused-microb Staphylococcus aureus and Staphylococcus epidermidis. Antioxidant activity was assessed by 2,2 diphenyl-1-picrylhydrazyl ( DPPH) thin layer chromatography (TLC) and dot blot assay method. The dichloromethane (DCM) extracts of all three parts displayed obvious antibacterial effect compared to other extracts and DCM extracts from leaves was the most effective in inhibiting the growth of S. epidermis with inhibition zone (IZ) of 18 mm. The methanol extracts from stem scavenged DPPH radicals more effective than root and leaf extracts at a concentration as low as 0.19 mg/ml. The antibacterial and antioxidant properties of leaves and stem might be attributed to the high content of terpenoid and phenolic. Thus, Memali appears to be a promising source of bioactive ingredients with antioxidant and antimicrobial activity. Keywords: Leea indica, antimicrobial, antioxidant, phytochemicals, secondary metabolitesAbstrak Kertas kerja ini meliputi penyelidikan ke atas potensi pokok Leea indica dari Tasik Chini, Pahang yang juga dipanggil Memali sebagai agen antioksidan dan antimikrob. Bahagian akar, batang dan daun dipilih untuk kajian aktiviti antibakteria dan antioksidan di mana ujian antibakteria menggunakan bakteria penyakit kulit seperti Staphylococcus aureus and Staphylococcus epidermidis. Ujian antioksidan menggunakan kaedah kromatografi lapisan nipis 2,2 diphenyl-1-picrylhydrazyl (DPPH) dan ujian dot blot. Didapati ekstrak dari diklorometana (DCM) menunjukkan aktiviti antimikrob yang lebih tinggi berbanding dengan ekstrak lain dan ekstrak dari daun mempunyai aktiviti yang paling tinggi dengan zon perencatan 18 mm. Ujian antioksidan menunujukkan ekstrak metanol bahagian batang lebih efektif memerangkap radikal DPPH pada kepekatan serendah 0.19 mg/ml. Sifat antioksidan dan antimikrob ini berkemungkinan akibat daripada adanya kandungan bahan seperti terpen dan fenolik yang tinggi. Maka pokok Memali dilihat sebagai punca asas bahan bioaktif yang bersifat antimikrob dan antioksidan.
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 13 C 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-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.
This study investigated the molluscicidal effect of the stem extracts of Tinospora crispa in controlling the golden apple snail Pomacea canaliculata. Extracts were prepared in four solvents, i.e., hexane, chloroform, methanol, and distilled water at three concentrations (1,000, 5,000, and 10,000 ppm) per solvent. The phytochemical contents of the extracts were qualitatively identified, and the lethal concentration (LC50) of the extracts for mollusicicidal potential was determined using the probit analysis. The effect of T. crispa extracts on the snail was monitored for three days and the snail mortality was recorded every 24 h. The stem extract prepared in methanol at 10,000 ppm showed the highest molluscicidal effect with a mortality of 80% at 72 h. Phytochemicals identified in the stem extracts included alkaloids, flavonoids, saponin, tannin, and terpenoids. Based on the probit analysis, stem extracts of T. crispa prepared in methanol showed the lowest LC50 value of 3,428 ppm for mollusicicidal potential and followed by extracts prepared in chloroform, hexane, and distilled water at 5,888, 14,771, and 14,993 ppm, respectively.
The present study was designed to compare the antibacterial effect between stem and leaves of Entada spiralis against soft rot bacteria Erwinia chrysanthemi and its antioxidant properties which could benefit to indigenous people. E. spiralis which locally knows as ‘sintok’ is a liana and it grows wildly in Malaysia. Indigenous people are utilizing this plant as natural washing agent and shampoo as well as ethnomedicine to cure diseases since they have little access to modern medicines. E. chrysanthemi is bacteria which commonly cause soft-rot disease of vegetables. The antibacterial activity of stem and leaves of E. spiralis against E. chrysanthemi were evaluated from disc diffusion method. The DPPH radical scavenging method and dot blot assay were utilized to see the potential of stem and leaves of E. spiralis as an antioxidant agent. The results indicated that the leaves part was more antioxidative than stem of E. spiralis with IC50 of 10.5 μg/mL. Ethyl acetate extract from stem part at concentration of 200 mg/mL was found to be the most active extract against E. chrysanthemi with the highest inhibition zone of 16.3mm. The investigation is hoped to provide basic information for the development of potent natural pesticides and natural remedy which is safer and eco-friendly.
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