Plants possessing various bioactive compounds and antioxidant components have gained enormous attention because of their efficacy in enhancing human health and nutrition. Peppers (Capsicum annuum L.), because of their color, flavor, and nutritional value, are considered as one of the most popular vegetables around the world. In the present investigation, the effect of different solvents extractions (methanol, ethanol, and water) and oven drying on the antioxidant and antimicrobial properties was studied of red, yellow, and green peppers. The green pepper water extract showed the highest total polyphenol content (30.15mg GAE/g DW) followed by red pepper water extract (28.73mg GAE/g DW) and yellow pepper water extract (27.68mg GAE/g DW), respectively. The methanol extracts of all the pepper samples showed higher TPC as compared to the ethanol extract. A similar trend was observed with the total flavonoid content (TFC). The antioxidant assays (DPPH scavenging and reducing power) echoed the findings of TPC and TFC. In both antioxidant assays, the highest antioxidant activity was shown by the water extract of green pepper, which was followed by the water extract of red pepper and yellow pepper. Furthermore, all extracts were assessed for their potential antimicrobial activity against bacterial and fungal pathogens. Aqueous extracts of all three pepper samples exhibited slightly higher inhibition zones as compared to their corresponding ethanolic and methanolic extract. Minimum inhibitory concentration (MIC) values ranged from 0.5 to 8.0mg/ml. The lowest MIC values ranging from 0.5 to 2.0mg/ml concentration were recorded for aqueous extracts of green pepper. High-performance liquid chromatography (HPLC) analysis revealed tannic acid as the major phenolic compound in all three pepper samples. Thus, it is envisaged that the microwave drying/heating technique can improve the antioxidant and antimicrobial activity of the pepper.

Beetroot is a widely consumed crop all over the world and contains plenty of bioactive compounds. In this study, we analyzed the bioactive as well as the antimicrobial properties of the oven-dried beetroot (pulp and peel) using different solvents. The 50% methanolic extract yielded the highest content of total polyphenols and total flavonoids as well as the reducing power of the beetroot. The beetroot peel exhibited a higher content of total polyphenols, total flavonoids, and reducing power activity under all the extraction solvents. Mixture of methanol and water (50% v/v) extracted the highest chlorogenic acid (78.24 mg/100 g) of the dried beetroot peel, while 1,2-dihydroxybenzene was the most noteworthy phenolic compound (42.52 mg/100 g) in beetroot peel methanolic extract. The 50% methanolic extract of both peel and pulp demonstrated the highest antibacterial and anticandidal potential. These results can be helpful for beetroot consumption.

The eggplant is an important vegetable that is used all over the world and it contains valuable bioactive properties. Cooking methods affect the nutritional value as well as the functional characteristics of vegetables. This study investigated the effect of air-frying at different temperatures and the extraction solvents on the bioactive properties of eggplant. The eggplant air-fried for 25 min and extracted with 50% ethanol exhibited the highest total flavonoid content (35.10 mg catechin equivalent per gram dry weight), while its total polyphenol content was found as 87.81 mg gallic acid equivalent per gram dry weight. The uncooked sample exhibited the lowest DPPH scavenging (IC₅₀: 422.12 mg/mL reducing power: 0.914), while the highest DPPH scavenging activity (IC₅₀: 2.87 mg/mL; reducing power: 0.936) was recorded for the sample air-fried for 25 min and extracted with 50% ethanol. The highest amount of tannic acid was found in medium-cooked eggplant, while chlorogenic acid was the highest in the high-cooked sample. These results might be helpful for functional food processors.

Background: Polyphenols and flavonoid-rich foods help in arresting reactive oxygen species development and protecting DNA from oxidative damage. Coffee peel (CP) preparations are consumed as beverages, and their total polyphenol or flavonoid content and their effect on oxidative stress–induced human mesenchymal stem cells (hMSCs) are poorly understood.Method: We prepared hot water extracts of CP (CPE) and quantified the amount of total polyphenol and flavonoid using HPLC analysis. In addition, CPE have been studied for their α-amylase inhibitory effect and beneficial effects in oxidative stress–induced hMSCs.Results: The obtained results show that the availability of chlorogenic acid, vanillin, and salicylic acid levels in CPE is more favorable for enhancing cell growth, nuclear integrity, and mitochondrial efficiency which is confirmed by propidium iodide staining and JC-1 staining. CPE treatment to hMSCs for 48 h reduced oxidative stress by decreasing mRNA expression levels of LPO and NOX-4 and in increasing antioxidant CYP1A, GSH, GSK-3β, and GPX mRNA expressions. Decreased pro-inflammatory (TNF-α, NF-κβ, IL-1β, TLR-4) and increased tumor suppressor genes (except Bcl-2) such as Cdkn2A, p53 expressions have been observed.Conclusions: The availability of CGA in CPs effectively reduced mitochondrial oxidative stress, reduced pro-inflammatory cytokines, and increased tumor suppressor genes.

Rosemary (Rosmarinus officinalis) and basil (Ocimum sanctum Linn) are mostly used as herbal teas, made by steeping whole or ground herbs in boiling water. Hence, it is important to know the effect of boiling time on the bioactivity of these herbs. The effect of different boiling times (5, 10, and 15 min) on the antioxidant and antimicrobial properties, and some selected phenolic compounds of these herbs was examined in this study. Experimental results revealed that basil displayed the highest total polyphenol content (TPC), total flavonoid content (TFC), and antioxidant activity when it was boiled for 5 min, and the lowest TPC was obtained when it was boiled for 15 min. On the other hand, rosemary had the highest TPC, TFC, and antioxidant potential after being boiled for 15 min, while it had the lowest after being boiled for 5 min. There was no growth inhibition of rosemary extracts against gram-negative bacteria, whereas higher growth inhibition was observed against gram-positive bacteria. The MIC and MBC of rosemary ethanolic extract against Listeria monocytogenes were 5 and 5 mg/mL and against B. subtilis were 10 and 10 mg/mL, respectively. While MIC and MBC of methanolic extract against L. monocytogenes were 5 and 5 mg/mL and against Bacillus subtilis were and 5 and 5 mg/mL, respectively. Salicylic acid was the most abundant (324.7 mg/100 g dry weight (dw)) phenolic compound in the rosemary sample boiled for 5 min, and acetyl salicylic acid was the most abundant (122.61 mg/10 g dw) phenolic compound in the basil sample boiled for 15 min.