Anthocyanin Profile,Antioxidant, Anti-Inflammatory,and Antimicrobial against Foodborne Pathogens Activities of Purple Rice Cultivars in Northern Thailand

Five glutinous purple rice cultivars and non-glutinous purple rice cultivated in different altitudes in the north of Thailand were collected. The samples were extracted using ethanol and determined for anthocyanins using HPLC. The total phenolic content (TPC), total flavonoid content (TFC), and the antioxidant, anti-inflammatory, and antimicrobial activities against foodborne pathogens were investigated. The highland glutinous cultivar named Khao’ Gam Luem-Phua (KGLP) extract had significantly high levels of cyanidin 3-O-glucoside, peonidin 3-O-glucoside, delphinidin 3-O-glucoside, TPC, and TFC, as well as exerting a potent antioxidant activity through ABTS assay (524.26 ± 4.63 VCEAC, mg l-ascorbic-ascorbic/g extract), lipid peroxidation (IC₅₀ = 19.70 ± 0.31 µg/mL), superoxide anions (IC₅₀ = 11.20 ± 0.25 µg/mL), nitric oxide (IC₅₀ = 17.12 ± 0.56 µg/mL), a suppression effect on nitric oxide (IC₅₀ = 18.32 ± 0.82 µg/mL), and an inducible nitric oxide synthase production (IC₅₀ = 23.43 ± 1.21 µg/mL) in combined lipopolysaccharide-interferon-γ-activated RAW 264.7 murine macrophage cells. Additionally, KGLP also exhibited antimicrobial activity against foodborne pathogens, Staphylococcus aureus, Escherichia coli, Salmonella Enteritidis, and Vibrio parahaemolyticus. These results indicate that Thai glutinous purple rice cultivated on the highland could be a potent natural source of antioxidants, anti-inflammatories, and antimicrobial agents for use as a natural active pharmaceutical ingredient in functional food and nutraceutical products.     

Sustainable Downscaled Catalytic Colorimetric Determination of Manganese in Freshwater Using Smartphone-Based Monitoring Oxidation of 3,3′,5,5′-Tetramethylbenzidine by Periodate

A sustainable downscaled procedure using smartphone-based colorimetric determination of manganese (Mn(II)) was developed. This novel Mn(II) determination procedure is proposed using a simple, available microwell-plate platform and a smartphone as a detector. This approach is based on the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by periodate using Mn(II) as a catalyst. The catalytic kinetics of Mn(II) under different conditions was investigated to determine the optimum condition where the different catalytic activities of various concentrations of Mn(II) evince. Under the optimum condition, the bluish-green product of oxidized TMB, proportioned to the concentration of Mn(II), was monitored using a smartphone camera, and the color signals were processed using ImageJ Software. The developed procedure showed great selectivity and sensitivity as linearity ranged from 1.8 × 10⁻⁶ to 4.6 × 10⁻⁵ M (0.1 to 2.5 μg/mL). The limits of detection and quantitation were 3.6 × 10⁻⁶ and 1.1 × 10⁻⁵ M (0.2 and 0.6 μg/mL), respectively. The determination of Mn(II) in freshwater samples was demonstrated to assess environmental water quality as an initial model to more easily promote water management according to the United Nations Sustainable Development Goals (UN-SDGs). The intensity of the red could be successfully applied to evaluate Mn(II) in canals and river water with no significant differences compared with the reference method of Inductively Coupled Plasma Optical Emission Spectrometry at a confidence level of 95%.