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Kar Lin Nyam - One of the best experts on this subject based on the ideXlab platform.

  • effect of various solvents on the pulsed ultrasonic assisted extraction of phenolic compounds from Hibiscus cannabinus l leaves
    Industrial Crops and Products, 2019
    Co-Authors: Yan Yi Sim, Wei Ting Jess Ong, Kar Lin Nyam
    Abstract:

    Abstract This work aimed to assess the effect of different extraction solvents (water, methanol, ethanol, and acetone) on the pulsed ultrasonic assisted extraction of Hibiscus cannabinus L. (kenaf) leaves extract (KLE), including extraction yield, antioxidation evaluation, antimicrobial analysis, tyrosinase inhibitory, Fourier transform infrared spectroscopy (FTIR) and ultra high performances liquid chromatography (UPLC) study. Results showed that the ethanol extracted KLE exhibited the highest content of total phenolic content (98.17 mg/g KLE). The ethanol extracted KLE also presented a good performances on 2,2-diphenyl-1- picrylhydrazyl (DPPH) radical scavenging capacity assay, 2,2′- azino- bis (3- ethylbenzo thiazoline- 6-sulphonic acid) (ABTS) radical scavenging assay, ferric reducing antioxidant power (FRAP) assay, and antimicrobial activity. Good correlation was obtained between the antioxidant activities analysis and total phenolic contents. Additionally, the ethanol extracted KLE showed the strong tyrosinase inhibitory (70.42%), although it was lower than the water extracted KLE (77.50%). Three phenolic compounds (caffeic acid, catechin hydrate, and tannic acid) were identified in the ethanol extracted KLE by UPLC. These findings clearly indicate that ethanol was the most effective solvent for extraction of phenolic and flavonoid compounds from kenaf leaves. The results suggest that the kenaf leaves can be a promising source of natural antioxidant, antimicrobial, and antityrosinase constituent for application in the food, cosmetic and pharmaceutical industries.

  • In vitro Simulated Digestion on the Biostability of Hibiscus cannabinus L. Seed Extract
    Czech Journal of Food Sciences, 2018
    Co-Authors: Yu Hua Wong, Chin Ping Tan, Kamariah Long, Kar Lin Nyam
    Abstract:

    Wong Y.-H., Tan Ch.-P., Long K., Nyam K.-L. (2014): In vitro simulated digestion on the biostability of Hibiscus cannabinus L. seed extract. Czech J. Food Sci., 32: 177–181. We investigate the biostability of phenolic acids from a kenaf ( Hibiscus cannabinus L.) seed extract using an in vitro model simulating the physicochemical (pH, temperature and bile salts) and biological (gastric and pancreatic enzymes) gastrointestinal conditions. Some of the antioxidants in the kenaf seed extract were not relatively stable in the intestinal phase of the gastrointestinal tracts. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity and total phenolic content (TPC) assays displayed similar trends as the biostability of phenolic acids, which decreased during the digestion process. The overall percentage loss of selected phenolic acids was 8.4–49.4% in the intestinal phase. For the overall in vitro digestion system, significant correlations between phenolic acids, total phenolic content (TPC) and antioxidant activity (DPPH) were obtained in all digestion phases with the exception of the gastric phase.

  • kenaf Hibiscus cannabinus l seed oil in water pickering nanoemulsions stabilised by mixture of sodium caseinate tween 20 and β cyclodextrin
    Food Hydrocolloids, 2016
    Co-Authors: Ai Mun Cheong, Chin Ping Tan, Khang Wei Tan, Kar Lin Nyam
    Abstract:

    The limit application of functional kenaf (Hibiscus cannabinus L.) seed oil in food and pharmaceutical industry owing to the poor water solubility and low storage stability can be overcome by the development of kenaf seed oil-in-water Pickering nanoemulsions. In this study, oil-in-water Pickering nanoemulsions were produced to investigate its stability by optimising emulsifier mixtures, namely sodium caseinate (SC), Tween 20 (T20) and β-cyclodextrin (β-CD). The interaction effects of SC and T20 on the formation of Pickering nanoemulsions with β-CD was studied and found synergistic effect among them that enhanced the stability of Pickering nanoemulsions. The optimum proportion of emulsifier mixtures obtained by employing simplex centroid mixture design was found to be 57.9% (w/w) SC, 27.6% (w/w) T20, and 14.5% (w/w) β-CD, which produced Pickering nanoemulsion with mean particle size of 155.53 nm, PDI of 0.07 and zeta-potential of −46.67 mV. These experimental values were in accordance with the predicted value, indicating the adequacy of the fitted models. The mixture design was found to be a valuable tool to optimise and study the interaction effects of different components for the development of stable Pickering nanoemulsions.

  • Cytotoxic activity of kenaf (Hibiscus cannabinus L.) seed extract and oil against human cancer cell lines.
    Asian pacific Journal of Tropical Biomedicine, 2014
    Co-Authors: Yu Hua Wong, Chin Ping Tan, Kamariah Long, Wai Yan Tan, Kar Lin Nyam
    Abstract:

    Objective To examine the cytotoxic properties of both the kenaf (Hibiscus cannabinus L.) seed extract and kenaf seed oil on human cervical cancer, human breast cancer, human colon cancer and human lung cancer cell lines.

  • binary solvent extraction system and extraction time effects on phenolic antioxidants from kenaf seeds Hibiscus cannabinus l extracted by a pulsed ultrasonic assisted extraction
    The Scientific World Journal, 2014
    Co-Authors: Yu Hua Wong, Chin Ping Tan, Kamariah Long, Hwee Wen Lau, Kar Lin Nyam
    Abstract:

    The aim of this study was to determine the best parameter for extracting phenolic-enriched kenaf (Hibiscus cannabinus L.) seeds by a pulsed ultrasonic-assisted extraction. The antioxidant activities of ultrasonic-assisted kenaf seed extracts (KSE) were determined by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay, β-carotene bleaching inhibition assay, and ferric reducing antioxidant power (FRAP) assay. Total phenolic content (TPC) and total flavonoid content (TFC) evaluations were carried out to determine the phenolic and flavonoid contents in KSE. The KSE from the best extraction parameter was then subjected to high performance liquid chromatography (HPLC) to quantify the phenolic compounds. The optimised extraction condition employed 80% ethanol for 15 min, with the highest values determined for the DPPH, ABTS, and FRAP assay. KSE contained mainly tannic acid (2302.20 mg/100 g extract) and sinapic acid (1198.22 mg/100 g extract), which can be used as alternative antioxidants in the food industry.

Don Koo Lee - One of the best experts on this subject based on the ideXlab platform.

  • assessment of pb uptake translocation and immobilization in kenaf Hibiscus cannabinus l for phytoremediation of sand tailings
    Journal of Environmental Sciences-china, 2008
    Co-Authors: Lai Hoe Ang, Don Koo Lee
    Abstract:

    The potential of kenaf (Hibiscus cannabinus L.) for phytoremediation of lead (Pb) on sand tailings was investigated. A pot experiment employing factorial design with two main effects of fertilizer and lead was conducted in a nursery using sand tailings from an ex-tin mine as the growing medium. Results showed that Pb was found in the root, stem, and seed capsule of kenaf but not in the leaf. Application of organic fertilizer promoted greater biomass yield as well as higher accumulation capacity of Pb. In Pb-spiked treatments, roots accumulated more than 85% of total plant Pb which implies that kenaf root can be an important sink for bioavailable Pb. Scanning transmission electron microscope (STEM) X-ray microanalysis confirmed that electron-dense deposits located along cell walls of kenaf roots were Pb precipitates. The ability of kenaf to tolerate Pb and avoid phytotoxicity could be attributed to the immobilization of Pb in the roots and hence the restriction of upward movement (translocation factor < 1). With the application of fertilizer, kenaf was also found to have higher biomass and subsequently higher bioaccumulation capacity, indicating its suitability for phytoremediation of Pb-contaminated site.

Wai Mun Ho - One of the best experts on this subject based on the ideXlab platform.

  • assessment of pb uptake translocation and immobilization in kenaf Hibiscus cannabinus l for phytoremediation of sand tailings
    Journal of Environmental Sciences-china, 2008
    Co-Authors: Wai Mun Ho
    Abstract:

    Abstract The potential of kenaf ( Hibiscus cannabinus L.) for phytoremediation of lead (Pb) on sand tailings was investigated. A pot experiment employing factorial design with two main effects of fertilizer and lead was conducted in a nursery using sand tailings from an ex-tin mine as the growing medium. Results showed that Pb was found in the root, stem, and seed capsule of kenaf but not in the leaf. Application of organic fertilizer promoted greater biomass yield as well as higher accumulation capacity of Pb. In Pb-spiked treatments, roots accumulated more than 85% of total plant Pb which implies that kenaf root can be an important sink for bioavailable Pb. Scanning transmission electron microscope (STEM) X-ray microanalysis confirmed that electron-dense deposits located along cell walls of kenaf roots were Pb precipitates. The ability of kenaf to tolerate Pb and avoid phytotoxicity could be attributed to the immobilization of Pb in the roots and hence the restriction of upward movement (translocation factor

Maznah Ismail - One of the best experts on this subject based on the ideXlab platform.

  • phenolic content and antioxidant activity of Hibiscus cannabinus l seed extracts after sequential solvent extraction
    Molecules, 2012
    Co-Authors: Noordin Mohd Yusri, Kim Wei Chan, Shahid Iqbal, Maznah Ismail
    Abstract:

    A sequential solvent extraction scheme was employed for the extraction of antioxidant compounds from kenaf (Hibiscus cannabinus L.) seeds. Yield of extracts varied widely among the solvents and was the highest for hexane extract (16.6% based on dry weight basis), while water extract exhibited the highest total phenolic content (18.78 mg GAE/g extract), total flavonoid content (2.49 mg RE/g extract), and antioxidant activities (p < 0.05). DPPH and hydroxyl radical scavenging, β-carotene bleaching, metal chelating activity, ferric thiocyanate and thiobarbituric acid reactive substances assays were employed to comprehensively assess the antioxidant potential of different solvent extracts prepared sequentially. Besides water, methanolic extract also exhibited high retardation towards the formation of hydroperoxides and thiobarbituric acid reactive substances in the total antioxidant activity tests (p < 0.05). As conclusion, water and methanol extracts of kenaf seed may potentially serve as new sources of antioxidants for food and nutraceutical applications.

  • supercritical carbon dioxide fluid extraction of Hibiscus cannabinus l seed oil a potential solvent free and high antioxidative edible oil
    Food Chemistry, 2009
    Co-Authors: Kim Wei Chan, Maznah Ismail
    Abstract:

    The supercritical fluid extraction (SFE) trends and antioxidant activities of Hibiscus cannabinus seed oils were studied. SFE results indicate that extraction pressure is the major factor determining the oil yield. In comparison, classic Soxhlet extraction (SOX/L) yielded higher oil content than SFE (P 0.05). Antioxidant activities of H. cannabinus seed oils were compared with 7 types of commercial edible oils. DPPH scavenging activity test indicated that H. cannabinus seed oil extracted by SFE at 200 bars/80 °C possessed the highest antiradical activity whereas beta-carotene bleaching (BCB) assay revealed that all H. cannabinus seed oils (except for SFE at 400 bars/80 °C and 600 bars/80 °C) exhibited higher antioxidant activity than all commercial edible oils (P < 0.05). Thus, SFE - H. cannabinus seed oil may serve as an excellent source of solvent-free edible oil with high antioxidant properties.

M. Umadevi - One of the best experts on this subject based on the ideXlab platform.

  • Antibacterial activities of Hibiscus cannabinus stem-assisted silver and gold nanoparticles
    Materials Letters, 2014
    Co-Authors: M.r. Bindhu, P. Vijaya Rekha, T. Umamaheswari, M. Umadevi
    Abstract:

    Abstract The synthesis of silver (Ag) and gold (Au) nanoparticles (NPs) using Hibiscus cannabinus stem extract was studied. The synthesized NPs were characterized using UV–visible spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Energy Dispersive X-ray analysis (EDX). The surface plasmon resonance (SPR) peak of synthesized NPs was observed at 444 nm and 547 nm corresponding to AgNPs and AuNPs respectively. The prepared AgNPs and AuNPs were almost spherical in shape with the average particle size of 10 nm and 13 nm respectively. The FTIR study reveals that the carboxylic acid present in H. cannabinus stem extract has been used as reducing agent. The observed antibacterial properties, suggest the possible utilization of prepared NPs in water purification.

  • synthesis of monodispersed silver nanoparticles using Hibiscus cannabinus leaf extract and its antimicrobial activity
    Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013
    Co-Authors: M.r. Bindhu, M. Umadevi
    Abstract:

    Synthesis of silver nanoparticles using leaf extract of Hibiscus cannabinus has been investigated. The influences of different concentration of H. cannabinus leaf extract, different metal ion concentration and different reaction time on the above cases on the synthesis of nanoparticles were evaluated. The synthesized nanoparticles were characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The prepared silver nanoparticles were monodispersed, spherical in shape with the average particle size of 9 nm and shows surface plasmon peak at 446 nm. The study also reveals that the ascorbic acid present in H. cannabinus leaf extract has been used as reducing agent. The prepared silver nanoparticle shows good antimicrobial activity against Escherichia coli, Proteus mirabilis and Shigella flexneri.