The scavenging behavior of a series of phenolic and anilines compounds toward H2O2 and DPPH was examined. The efficient concentration (EC50) was calculated for all compounds under investigation by using H2O2-scavenging activity assay. The antiradical efficiency (AE) and EC50 were calculated for all investigated compounds by applying DPPH scavenging activity assay. Wide differences among compounds in each series and between the two series were observed. In H2O2-scavenging activity assay, the anilines series were more active than the phenolic series due to the reduction properties of the anilines compounds. While in the DPPH scavenging activity, the phenolic compounds were more active than the anilines compounds due to the lower bond dissociation energies (BDE) of O–H than that of N–H. So, the phenolic compounds were comparatively easier to lose H atom than anilines. The antioxidant activity related to the compound structure was found to be dependable on the number of the included active group (OH or NH2). The more active compound is the more included active groups. The position of the active groups also plays an important role of structure–antioxidant relationship activity. The ortho position was found to be the more active one, due to its ability to form intramolecular hydrogen bonding (iHB), followed by para position and then meta position of compounds

One-third of all food produced for human use is discarded as waste, resulting in environmental pollution and impaired food security. Fruit peels have bioactive compounds that may be used as antimicrobials and antioxidants, and the use of fruit peels is considered an alternative way to reduce environmental problems and agro-industrial waste. The aim of this study was to evaluate the phytochemical, mineral, extraction yield, total phenolic, total flavonoids, antioxidant, and antibacterial activity of several peel fruits, including Citrus sinensis (orange) and Punica granatum (pomegranate). The results revealed that pomegranate peel powder contains the highest amounts of ash, fiber, total carbohydrates, Ca, Fe, Mg, and Cu, while orange peel contains the highest amounts of moisture, protein, crude fat, P, and K. Furthermore, the aqueous and methanolic pomegranate peel extracts yielded higher total phenolic and total flavonoids than the orange peel extract. The identification and quantification of polyphenol compounds belonging to different classes, such as tannins, phenolic acids, and flavonoids in pomegranate peel and flavonoid compounds in orange peel were performed using UPLC-MS/MS. In addition, GC-MS analysis of orange peel essential oil discovered that the predominant compound is D-Limonene (95.7%). The aqueous and methanolic extracts of pomegranate peel were proven to be efficient against both gram-positive and gram-negative bacteria linked to human infections. Sponge cake substituting wheat flour with 3% pomegranate peel and 10% orange peel powder had the highest total phenolic, flavonoid compounds, and antioxidant activity as compared to the control cake. Our results concluded that pomegranate and orange peel flour can be used in cake preparation and natural food preservers.

Crops around the world are facing a diversity of environmental problems, of which high temperatures are proving to be the most serious threat to crops. Polyamine putrescine (Put) acts as a master growth regulator that contributes to optimal plant growth and development and increased stress tolerance. Here, the current study aimed to elucidate how Put functions in regulating chlorophyll (Chl) metabolism, oxidative stress, and antioxidant defense, as well as to characterize the expression of genes related to heat stress in tomato seedlings under such stress. The results revealed that Put treatment significantly attenuates heat-induced damage by promoting biomass production, increasing photosynthetic efficiency, and inhibiting excessive production of oxidative stress markers. Heat stress markedly decreased the Chl content in the tomato leaf and accelerated the leaf yellowing process. However, Put-treated tomato seedlings showed a higher Chl content, which could be associated with the functions of Put in elevating PBGD activity (Chl biosynthesis enzyme) and suppressing the activity of the Chl catabolic enzyme (Chlase and MDCase). Under high-temperature stress, the expression levels of the gene encoding factors involved in Chl biosynthesis and Chl catabolism were significantly down- and upregulated, respectively, and this trend was reversed in Put-treated heat-stressed seedlings. In addition, exogenous application of Put boosted the activity of antioxidant enzymes, along with the levels of expression of their encoding genes, only in plants that were heat stressed. Furthermore, the expression levels of heat-shock-related genes (HSP90, HSP70, and HsfA1) were elevated in Put-treated, high-temperature-stressed tomato seedlings. Taken together, our results indicate that Put treatment significantly increases the heat tolerance of tomato seedlings, by elevating Chl concentrations and suppressing Chl catabolic enzyme activity, modulating endogenous free PA content, increasing antioxidant defense efficiency, and upregulating the expression of heat-shock-related genes.

Numerous plant metabolites, especially amino acids, are accumulated as a result of stress. These amino acids are crucial for plant metabolism and development and have historically been viewed as the building blocks of proteins. Several studies suggested that there is a link between proline buildup and exposure plants to stress. Proline performs important functions under stress in addition to be a great osmolyte, antioxidant enzyme, acts as an antioxidant defense and signaling molecules. Two field trials were during two successive winter seasons (2020/2021 and 2021/2022). The effects of proline foliar application (0, 100, 200, 300 and 400 mg L−1) and irrigation water levels (irrigation by 100, 80 and 60% of crop water requirements, CWR, CWR100, CWR80 and CWR60, respectively) on plant pigments, antioxidants activity, yield traits and nutrient contents of wheat were assessed. The experiment was designed in a split-plot involving 4 replicates. Drought stress (CWR80 and CWR60) led to reductions in photosynthetic pigments, and yield components. Under severe water stress (CWR60), proline 200 and 300 mg L−1 recorded the highest values of chlorophyll a, chlorophyll b, and total pigments. Application of proline 300 mg L−1 was the potent practice for enhancing the antioxidant activity% (DPPH radical scavenging) and phenols content under CWR100 and CWR80. Indole acetic acid (IAA) possessed the maximum values with proline 200 mg L−1 under all irrigation patterns. Under severe deficit water (CWR60), without proline spraying (for super oxide dismutase), 200, 300 or 400 mg L−1 proline (for peroxidase) and 200 or 400 mg L−1 proline (for polyphenol oxidase) recorded the highest values. Spraying proline 300 mg L−1 achieved the highest values of grain number spike−1, weight of 1000 grains and grain yield ha−1 under different irrigation regimes. In conclusion, proline is considered a good mitigator for drought stress, due to it increased wheat plant tolerance to water deficiency throughout improving plant physiology and consequently yields quantity and quality. The most efficient concentrations of proline for coping the adverse impact of drought were 200 and 300 mg L−1.

This study aims to predict the behavior of different tomato rootstocks under drought stress conditions. SCoT and CDDP analyses were employed to characterize the genetic relatedness among a commercial drought-sensitive tomato hybrid (cv. Bark) and four wild tomato accessions (LA2711, LA1995, LA3845, and LA4285) known for their tolerance to adverse conditions. The Bark plants were grafted onto the aforementioned wild accessions and self-grafted as control, and then the behavior of all graft unions was followed under normal and drought stress conditions. Our results showed a general genotype-dependent better growth and yield of heterografts than autografts under all growth conditions. Furthermore, clustering analysis based on growth, yield quantity and quality traits, and the leaf content of minerals, ABA, GA3, and proline, in addition to the activity of APX, POD, and DHAR reflected the same grouping pattern of the studied rootstocks exhibited by SCoT and CDDP. The identical grouping pattern supports the utilization of SCoT and CDDP as a robust screening tool helpful to predict the physiological and agronomical behavior of grafting on different tomato rootstocks. Furthermore, grafting could be a cost-efficient alternative method to improve drought tolerance in sensitive tomato genotypes.

The objective of the present study is to determine the antioxidant and anticancer activities of Nostoc linckia extracts cultivated under heavy metal stress conditions (0.44, 0.88, and 1.76 mg/L for zinc and 0.158, 0.316, 0.632 mg/L for copper). Phycobiliprotein, phenolic compounds, flavonoids, and tannins were measured. Active ingredients of extracts were evaluated by GC-mass spectroscopy. The obtained results revealed that higher zinc and copper concentrations showed growth inhibition while 0.22 mg/L (Zn) and 0.079 mg/L (Cu) enhanced growth, reaching its maximum on the 25th day. Increases in catalase, lipids peroxidation, and antioxidants, as well as tannins and flavonoids, have been induced by integration of 0.88 mg/L (Zn) and 0.316 mg/L (Cu). Elevation of Zn concentration induced augmentation of antioxidant activity of crude extract (DPPH or ABTS), with superior activity at 0.44 mg/L zinc concentration (81.22%). The anticancer activity of Nostoc linckia extract (0.44 mg/L Zn) tested against four cancer cell lines: A549, Hela, HCT 116, and MCF-7. The extract at 500 µg/mL appeared the lowest cell viability of tested cell lines. The promising extract (0.44 mg/L Zn) recorded the lowest cell viability of 25.57% in cervical cell line, 29.74% in breast cell line, 33.10% in lung cell line and 34.53% in the colon cell line. The antioxidant active extract showed significant stability against pH with attributed increase in antioxidant activity in the range between 8–12. The extract can be used effectively as a natural antioxidant and anticancer after progressive testing.