Phytochemical Study and Evaluation of the Antioxidant Activity of Extracts of the Roots of Chrysopogon nigritanus

In this work, we were interested in a medicinal plant named Chrysopogon nigritanus, belonging to the Poaceae family. In order to carry out this study, we were interested first in the phytochemical screening test, after having carried out the extraction with two solvents (water and isopropanol), to characterize the different families of metabolites present in the extracts. Then, the assays of polyphenols and flavonoids were carried out in order to quantify the contents of these two compounds in each extract. Finally, the antioxidant activity of the extracts was evaluated by three methods: the CUPRAC method, the trapping of the 2,2-diphenyl-1-picryl-hydrazyl radical (DPPH•) and the trapping of the ABTS•+ radical-cation (2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid)). The best antioxidant activities were obtained with the ABTS•+ radical scavenging with IC50 of 0.13 mg/mL for the aqueous extract and 0.19 mg/mL for the isopropanol extract. Based on these first results, an in-depth study is underway for various biological tests and the isolation of bioactive molecules.

Purified novel and new diferuloyl glycerate related phenolic acid from Pandanus odoratissimus flowers shows antioxidant, invertase inhibition and control against diabetic foot ulcer (DFU) causing bacterial pathogens - An in vitro study to establish an effective regulation over type 2 diabetes mellitus

Abstract Chronic type 2 diabetes mellitus (T2DM) and its associated diseases are major concern among human population and also responsible for significant mortality rate. Hence, the present study aims to evaluate and correlate the invertase inhibition, antioxidant activity and control against DFU causing bacterial pathogens by Pandanus odoratissimus flowers. Two dimensional preparative thin layer chromatography (2D PTLC) was adopted to purify the phenolic acid component and LC-MS2 was done to predict the phenolic acid structures. Standard spectrophotometry methods were adopted to investigate the in vitro invertase inhibitory and antioxidant (CUPRAC and ABTS) activities. Agar well diffusion and broth dilution assays were used to record the antibacterial property against DFU causing pathogens isolated from clinical samples. Statistical analyses were used to validate the experiments. A new and novel diferuloyl glycerate related phenolic acid (m/z 442) purified from PTLC eluate has recorded satisfactory cupric ion reducing power (ED50= 441.4±2.5 µg), moderate ABTS radical scavenging activity (IC50= 450.3±10 µg; 32.5±1.5%), and a near moderate, in vitro, invertase mixed type inhibition (24.5±4.5%; Ki: 400 µg). Similarly, bacterial growth inhibitory kinetics has showed a significant inhibition against E. coli and S. aureus.

Potential antioxidant effect of fruit peels for human use from northern Peru, compared by 5 different methods / Potencial efecto antioxidante de las cáscaras de frutas para uso humano del norte de Perú, comparado por 5 métodos diferentes

The objective of the work was to determine the antioxidant potential in vitro of freeze-dried peel extracts of 20 fruits from the northern region of Peru through five tests (Folin-Ciocalteu, DPPH., ABTS+., FRAP and CUPRAC). According to multivariate statistical analyzes, five groups were found: (i.) peel extracts with the highest values of antioxidant capacity (AC) from custard apple, and star fruit; (ii.) rind extracts with high AC values from quince, sweet granadilla, guava, and black grape; (iii.) husk extracts with middle values of AC from passion fruit, and red mombin; (iv.) shell extracts with low AC values from tangerine, mandarine, and bitter orange; and, (v.) coating extracts with the lowest AC values from pawpaw, red pawpaw, muskmelon, dragon fruit, yellow and red indian figs, pear, apple, and green grape. To conclude, the fruit lyophilized-husk extracts of custard apple, star fruit, quince, sweet granadilla, guava, and black grape obtained the best AC.

El objetivo del trabajo fue determinar el potencial antioxidante in vitro de extractos de cáscara liofilizada de 20 frutos de la región norte del Perú mediante cinco pruebas (Folin-Ciocalteu, DPPH., ABTS+., FRAP y CUPRAC). Según análisis estadísticos multivariados, se encontraron cinco grupos: (i.) Extractos de piel con los valores más altos de capacidad antioxidante (CA) de chirimoya y carambola; (ii.) extractos de cáscara con altos valores de CA de membrillo, granadilla dulce, guayaba y uva negra; (iii.) extractos de cáscara con valores medios de CA de maracuyá y mombina roja; (iv.) extractos de cáscara con valores bajos de CA de mandarina, mandarina y naranja amarga; y (v.) recubrir extractos con los valores de CA más bajos de papaya, papaya roja, melón, fruta del dragón, higos indios amarillos y rojos, pera, manzana y uva verde. Para concluir, los extractos de cáscara liofilizada de chirimoya, carambola, membrillo, granadilla dulce, guayaba y uva negra obtuvieron el mejor CA.

Changes in Phenolic Content and Antioxidant Activity between Twinings English breakfast Tea Bags and Opened Tea Bags

Tea is one of the most widely consumed beverages in the world and is recognized as having numerous beneficialhealth effects due to its phenolic content. The current study aimed to evaluate and compare the phenolic andflavonoid content of two forms of Twining English Breakfast Tea: tea bags (TBs) and opened tea bags (OTBs).The antioxidant activity was also assessed using DPPH, FRAP, and CUPRAC assays. The results obtainedrevealed that the OTB infusion exhibited significantly higher phenolic and flavonoid content than the TB infusionat 5 and 10 minutes. The OTB infusion also significantly showed higher iron and cupper reducing powers thanthe TB infusion at the same time points. However, both samples demonstrated the same scavenging activity acrossall infusion times. These results suggest that the tea bags used with Twinings English Breakfast Tea may affectthe phenolic and flavonoid content released by the tea and subsequently influence the antioxidant ability of thetea as a reducing agent.