Measurement, correlation, and thermodynamic properties for solubilities of bioactive compound (−)-epicatechin in different pure solvents at 298.15 K to 338.15 K

Polysaccharides, Total Phenolic, and Flavonoid Content from Different Kenaf (Hibiscus cannabinus L.) Genotypes and Their Antioxidants and Antibacterial Properties

Kenaf (Hibiscus cannabinus L.) is a valuable plant with a potential health benefit because of its extensive bioactive compounds. Leaf extracts of 33 kenaf genotypes were investigated for their polysaccharide, total phenolic, and flavonoid content. The antioxidant properties were evaluated by 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric reducing antioxidant potential (FRAP) assays. Antimicrobial capacity was also assessed against Staphylococcus aureus and Escherichia coli using a disc diffusion assay. The polysaccharide content varied from 6.45-16.12 mg glucose per g DW. Total phenolic and flavonoid content ranged from 6.03-21.15 mg GAE/g DW and 1.55-9.24 mg RE/g DW, respectively. Similarly, varied values in the range 20.55-79.99% of inhibition by DPPH, 56.28-88.30% of inhibition by ABTS and 1.26-5.08 mmol Fe²⁺/g DW by FRAP assays were obtained for antioxidants of the genotype extracts. Extracts from CS4 and CS2 genotypes had the highest antioxidant activities. Kenaf leaves exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli. Strong correlation was found between antioxidant activity with polysaccharide (DPPH, r = 0.893; ABTS, r = 0.819; FRAP, r = 0.864) and total phenolic content (DPPH, r = 0.850; ABTS, r = 0.959; FRAP, r = 0.953). The results suggested that the kenaf leaves could be used as a natural antioxidants and antimicrobial in food industries.

Extraction of Carotenoids from Pumpkin Peel and Pulp: Comparison between Innovative Green Extraction Technologies (Ultrasonic and Microwave-Assisted Extractions Using Corn Oil)

Natural pigments improve aesthetic value as well as antioxidant potential of a food product. This study was designed to determine the effects of green extraction techniques on carotenoids, polyphenols and antioxidant activities of pulp and peel of two varieties of pumpkin (Cucurbita maxima). Innovative green extractions (IGE; Ultrasound and Microwave-Assisted Extractions) synergised with corn oil (used as green solvent) were compared with conventional extraction (CE; hexane/isopropyl alcohol; 60:40, v/v). Results showed total carotenoids to be almost double on employing IGE (PM2-UAE-peel = 38.03 ± 4.21; PM4-UAE-peel = 33.78 ± 1.76 µg/g) when compared to conventional extraction (PM2-CE-peel = 19.21 ± 4.39; PM4-CE-peel = 16.21 ± 2.52 µg/g). Polyphenolic contents ranged between 510.69 ± 5.50 and 588.68 ± 7.26 mg GAE/100 g of extract in IGE, compared with conventional extracts (269.50 ± 2.17 to 318.46 ± 6.60 mg GAE/100 g) and percent inhibition of 2,2-Diphenyl-1-picrylhydrazyl (DPPH) ranging between 88.32 ± 1.51 and 93.53 ± 0.30% in IGE when compared with conventional extraction (50.61 ± 1.44 to 57.79 ± 2.09%). Further, oxidative stability of carotenoids extracts from IGE (protection factor = 1.59 ± 0.01 to 1.81 ± 0.05) were found to be significantly higher (p < 0.05) than conventional extracts. Based on results, this study supports the use of innovative green extraction techniques to obtain bioactive pigments like carotenoids. It is anticipated that results generated will find potential applications in food, pharmaceutical and cosmetic industries.

In vitro antioxidant activity of Kyoho grape extracts in DPPH and ABTS assays: Estimation methods for EC50 using advanced statistical programs

The antioxidant capacities of Kyoho skin, seed, and flesh extracts were determined using DPPH and ABTS assays and a suitable statistical program was tested for the prediction of EC₅₀ values of Kyoho skin, seed, and flesh extracts obtained by DPPH and ABTS assays. Statistical programs: OriginPro® version 8, GraphPad Prism® version 7, GraphPad Prism® version 7 five-parameter (5P) logistic model, SigmaPlot® version 14.0, Microsoft Excel® version 2016, interpolation log, and direct interpolation methods were employed to estimate the EC₅₀ values. Linear regression and direct interpolation results showed deviations for non-linear models in the prediction of EC₅₀ values of grape extracts. The correlation results of grape flesh extracts demonstrated a positive correlation (r = ≥ 0.95) between EC₅₀ values of antioxidant assays. Therefore, non-linear methods were appropriate for EC₅₀ calculations. These findings have significant implications for selecting an efficient statistical tool to calculate EC₅₀ values for DPPH and ABTS assays.