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Author: search.filters.author.Laosinwattana, ChamroonSubject: search.filters.subject.antioxidant

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    Formulation and evaluation of nanoemulsions from Jasminum officinale essential oil for controlling postharvest browning and maintaining quality in jasmine (Jasminum sambac) flowers
    (2025-01-01)
    Yeamsuriyotai, Kittiya
    ;
    Pradabkun, Natthamon
    ;
    Manichart, Nutcha
    ;
    Yonsawad, Nipaporn
    ;
    Khamchatra, Na Monrug
    The jasmine (Jasminum sambac (L.) Aiton) flower has delicate petals, resulting in rapid browning after harvest. The aim of this study was to search for an innovative postharvest treatment for delaying browning of jasmine petals using plant essential oils. J. officinale L. f. var. grandiflorum (L.) essential oil was found to reduce peroxidase activity in jasmine flower by 44.21% in the in vitro condition. The antioxidant activities and chemical composition of J. officinale essential oil were subsequently characterized. The essential oil exhibited the ability to scavenge 2,2-diphenyl-1-picrylhydrazil (DPPH) radicals with a 50% inhibition (EC<inf>50</inf>) value of 6.72 ± 0.89 mg/mL, a chelating effect with EC<inf>50</inf> value of 7.42 ± 1.59 mg/mL, and reducing power with EC<inf>0.5</inf> value of 14.89 ± 0.73 mg/mL. GC-MS analysis detected 29 compounds in the oil, with benzyl alcohol (20.68%) and benzyl acetate (19.87%) predominating. As plant essential oils have restricted water solubility, an oil-in-water emulsion was formulated using a spontaneous emulsification method. The resulting J. officinale essential oil naonoemulsion (JEN) had an oil droplet size of 70.2 ± 0.39 nm and a narrow polydispersity index. In vivo testing confirmed the inhibitory effects of JEN on jasmine flower browning and relevant enzyme activities. Jasmine flowers were soaked in various concentrations of JEN for 5 min, packed in polyethylene plastic bags, and stored in a refrigerator at 10 ± 3°C with relative humidity 66 ± 5%. Flowers treated with 1 and 2 mg/mL JEN showed effective delay of petal browning and maintained good quality with minimum flower opening index, high freshness score, and high color retention index. JEN treatment also reduced phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD) activities, indicating postponement of the browning process. In addition, scanning electron microscopy micrographs of treated flower epidermis cells revealed delayed cell wall collapse, indicating retention of intact cells. Taken together, these results support JEN as a potential preventative of enzymatic browning and hence petal browning in jasmine flower.
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    Antioxidant and Antibacterial Activities of Jasminum officinale L. f. var. grandiflorum (L.) Kob. Leaf Extracts
    (2024-05-01)
    Charoenying, Patchanee
    ;
    Laosinwattana, Chamroon
    ;
    Chotsaeng, Nawasit
    The investigation of phytochemicals and their effects on plants is currently receiving significant attention due to the well-known fact that plants contain secondary metabolites that have high levels of usefulness in various applications. These applications include food additives, biopesticides, and pharmaceuticals. In a recent study, we thoroughly examined the total phenolic content (TPC), and the antioxidant, and antibacterial properties of Jasminum officinale L.f. var. grandiflorum (L.) Kob. (also known as Spanish jasmine) leaf extracts, providing valuable insights into its potential benefits. Our study performed a crude methanol (ME) extraction of Spanish jasmine leaves with acid-base solvent partitioning, resulting in an acidic fraction (AE), a neutral fraction (NE), and an aqueous fraction (AQ). The Folin-Ciocalteu method was used to determine the TPC of the extracts. The AE fraction displayed the highest TPC (79.8±0.61 mgGAE/g dry weight), followed by the NE and AQ fractions. The extracts were further evaluated for their antioxidant activity using the DPPH assay. The AE fraction had the highest antioxidant activity with an EC<inf>50</inf> value of 4.6±0.40 µg/mL. The main active compound, oleuropein, was isolated and determined using spectral data. The isolated compound displayed excellent antioxidant activity with an EC<inf>50</inf> value of 13.0±0.06 µg/mL. Moreover, the antibacterial activity of the Spanish jasmine leaf extracts was calculated using the disc diffusion method based on the minimum inhibitory concentration. The AE fraction exhibited activity against the Gram-negative bacteria, Vibrio parahaemolyticus, with a MIC value of 0.78 µg/mL. The AE fraction also displayed the highest degree of activity against Staphylococcus strains, including drug-resistant strains (MRSA and VRSA), with a MIC range of 0.39-12.5 µg/mL. It is important to highlight that the AE fraction demonstrated the highest level of activity against all VRSA strains tested despite their resistance to vancomycin and oxacillin. These findings strongly indicate that Spanish jasmine leaves possess potent natural antioxidant and antibacterial properties, positioning them as a highly promising plant source.