Sikhao, Potjana
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Preferred name
Sikhao, Potjana
Alternative Name
Sikhao, P.
Main Affiliation
Email
potjana.si@kmitl.ac.th
4 results
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Item type:Publication, Siamese neem tree as a natural preservative: Chemical profile, antioxidant properties, and antibacterial efficacy against foodborne pathogens and spoilage bacteria(2025-03-01); ; ; The objective of the present study was to investigate the effect of various ethanol in water solvent systems (0, 25, 50, 75 and 100 % v/v) on the extraction crude yield, total phenolic content, total flavonoid content, and chemical profile of Azadirachta indica (Siamese neem tree) leaf extracts. In addition, the antioxidant and antimicrobial properties were investigated using in vitro assays. Crude yield was highest for the water extract (5.78 g/100 g DW) and decreased with increased ethanol. Total phenolic and flavonoid contents were highest in the 75 % ethanol extract (26.95 mg GAE/g crude and 23.73 mg QE/g crude, respectively). GC-MS analysis of the 75 % ethanol extract revealed 33 bioactive compounds, accounting for 96.33 % of the total area. Significant components included benzene, 1,4-bis(phenylmethyl)- (15.05 %), and naphthalene, 1,6-dimethyl- (10.98 %); also present were sterols, fatty acids, hydrocarbons, aromatic, and heterocyclic compounds, indicating a complex chemical profile. In antioxidant assays, the 75 % ethanol extract revealed the highest DPPH radical scavenging activity (IC<inf>50</inf>: 143.03 mg/L), reducing power (IC<inf>50</inf>: 378.69 mg/L), and lipid peroxidation (IC<inf>50</inf>: 526.25 mg/L). However, the absolute ethanol extract exhibited both the highest metal chelating activity (IC<inf>50</inf>: 382.60 mg/L) and the strongest antimicrobial activity, inhibiting all 11 tested foodborne pathogenic and spoilage bacteria. The lowest minimum inhibitory concentration (MIC) of 25 mg/mL was observed for Staphylococcus aureus, Aeromonas hydrophila, Pseudomonas fluorescens, Latilactobacillus sakei, Streptococcus sp., and Lactococcus cremoris, with inhibition zone diameters of 27.21, 28.79, 28.19, 17.60, 15.09 and 11.20 mm, respectively. Similarly, the lowest minimum bactericidal concentration (MBC) of 25 mg/mL was obtained for S. aureus and L. sakei, indicating potent antibacterial effects against these species. Future studies should include direct comparative analyses of neem extracts and synthetic preservatives to evaluate further their relative efficacy and applicability in real-world food systems. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, High-Energy Emulsified Clove Essential Oil Nanoemulsion as a Natural Herbicidal Product: Germination Suppression and Seed Structure Alteration in Echinochloa crus-galli(2026-03-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Development of a Melia azedarach L. based natural herbicide: formulation and efficacy studies(2025-08-01); ; This study evaluated the phytotoxic activity of Melia azedarach L. leaf extract against Echinochloa crus-galli and Phaseolus lathyroides. Crude extracts were obtained using sequential solvent separation, of which the dichloromethane fraction exhibited the highest phytotoxicity for both weed species. However, P. lathyroides appeared more sensitive to the extracts compared to E. crus-galli. GC-MS analysis of the dichloromethane crude extract identified phytol (29.14 %), linolenic acid (21.74 %), and palmitic acid (7.20 %) as the main chemical components. Three formulations, a soluble liquid (SL), pellet, and wettable powder, were developed and evaluated for their effects on seed germination and seedling growth. The SL formulation showed the highest efficacy in inhibiting germination (p < 0.05). Further testing of its pre-emergence utility via soil application in greenhouse conditions confirmed the herbicidal efficacy, effectively suppressing P. lathyroides emergence (36.8 % over control) and reducing growth parameters. Mechanistic assays showed the SL product to affect seed imbibition, α-amylase activity, and cell division in a dose-dependent manner, suggesting these as potential mechanisms of action. This study highlights the potential of a M. azedarach-based SL product as an alternative to synthetic herbicides, potentially leading to the development of a new botanical herbicide. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Herbicidal Activity of the Invasive Weed Malachra capitata L.: Growth Stage Dependence, Bioassay-Guided Fractionation, and Physiological Effects on Seed Germination(2026-03-01)