Mohamed Mahmoud Aboul Fotouh

Tomatoes are regarded as the most important crop in the world due to their high nutrient content and flavour. Nevertheless, their limited storability, postharvest losses, rapid deterioration, and senescence limit their marketability. This study investigated the postharvest efficacy of three treatments of kojic acid (0, 2.5, and 5 mM) on maintaining the quality and delaying the senescence of ‘Rosalina’ tomato fruits. The fruits were cold-stored at 8±1 °C with 90–95% relative humidity for a storage duration of 35 days. The results showed that treatment with 5 mM KA preserved acidity and vitamin C. In addition, senescence was delayed through the enhanced activities of antioxidant enzymes specifically catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and phenylalanine ammonia-lyase (PAL), which contributed to the reduction of reactive oxygen species. Consequently, H₂O₂ and malondialdehyde (MDA) accumulation was reduced. Additionally, kojic acid treatment limited cell wall disassembly and browning by significantly inhibiting pectin methyl esterase and polyphenol oxidase activities. Overall, kojic acid was shown to increase the storability of tomatoes and enhance their antioxidant properties postharvest.

In a pot experiment, the dry seeds of the Sweet Marjoram plant ( Origanum majorana L.) were exposed to ultraviolet UV-C (254 nm) light for 30 and 60 min. They were subjected to salinity conditions (4 and 6 dS/m). Plants were evaluated, determining total chlorophyll (SPAD), oil content, and active components in the vegetative phenotypes. The results showed that plants grown under UV for 60 min increased plant height by 67.5% and fresh weight (FW) by 45.5% compared to the corresponding control under non-saline conditions. Similarly, exposing seeds to UV-C for 60 min increased the total chlorophyll group by 52% at 6 dS/m. They were less affected by salt stress, while treating them for 30 min improved the number of branches and leaves under non-saline conditions. Additionally, it helped plants protect themselves by shielding them from osmotic shock. Also, Ultraviolet rays led to a reduction in lipid peroxidation malondialdehyde (MDA) levels and increased the total phenols concentration under UV for 60 min, despite their growth being better than that of the control group. However, treating seeds with UV light for 60 min enhanced the biosynthesis of essential oils in plants. Also, GC–MS analysis detected a total of 30 compounds. Nevertheless, the major components were trans-Sabinene hydrate, terpinen-4-ol, γ-terpinene, α-terpineol, terpinolene, and β-myrcene. In general, it can be concluded that treating marjoram seeds with UV-C light stimulated the plant's ability to tolerate salt stress by activating the antioxidant system.

Dried grapes or raisins are usually treated with sulfur dioxide in high concentrations to prevent enzymatic and non-enzymatic browning reactions and keep golden yellow color of these dried fruits. Sulfur dioxide and sulfite salts are good food preservatives but have high risk on human health especially when using in high concentrations. Thus, this work was achieved to remove sulfur dioxide and sulfite salts from over sulfite raisins before handling in different food industries into lower concentrations by soaking of raisins in water, H2O2 (1%), citric acid (5%) and acetic acid (5%) at 30 and 50oC for 15 and 30 minutes. These treatments led to removing high amounts of sulfur dioxide and sulfite salts from raisins especially with treatment by citric acid (5%) at 50oC for 15 min. Comparatively, soaking of raisins in citric acid (5%) was the best treatment followed by acetic acid (5%) and H2O2 (1%) then water. This work also aimed to desulfurization of raisins with minimal effects on their constituents e.g. total phenols, tannins, flavonoids and color features. The loss rates of these constituents from raisins obtained by the soaking treatments in water were lower than those obtained by citric acid (5%) then acetic acid (5%) while the maximum loss rates of these constituents from raisins were obtained by H2O2 because it is oxidizing and bleaching agent. Therefore this work was achieved to overcome this problem by using citric acid or acetic acid instead of H2O2.

Ephedra is the most widely and largest widespread genus in the Gnetopsida, a subgroup of the gymnosperms. This research was done to find out how gamma radiation affected the in vitro growth of callus and suspension cultures. In addition, the effect of gamma rays (γ-rays) on the ephedrine and pseudoephedrine concentrations was evaluated through HPLC analysis. The callus and cell suspension cultures were established on Murashige and Skoog's basal medium (MS) supplemented with 3 mg/l of 2, 4-dichlorophenoxy acetic acid (2,4-D), and 0.5 mg/l kinetin (Kn) and exposed to variable gamma radiation doses (0, 5, 10, 15, 20 and 25 Gray). Highly significant differences in both fresh and dry callus weights were recorded due to the effect of gamma rays (γ-rays). The results showed that the maximum fresh and dry weights were obtained by 15 Gray as compared to the control in the cell suspension and callus cultures. Similarly, the highest concentrations of ephedrine and pseudoephedrine were found in suspension and callus cultures compared to control at 15 Gray.

Over the past few years, research studies on the therapeutic benefits of medicinal plants with potent antioxidant activity and few side effects have grown significantly. This has sparked interest in determining whether naturally occurring antioxidants could take the place of synthetic antioxidants, which are currently being constricted because of their toxic and carcinogenic properties. The identification and quantification of phytochemicals in the methanolic extract of Kigelia pinnata fruits was measured using gas chromatography–mass spectrometry (GC-MS) and ultra-high-performance liquid chromatography–mass spectrometry (UPLC-MS/MS) techniques. Additionally, the methanolic extract of fruits was used to determine antioxidant activity. Free radical-scavenging (DPPH) and ferric ion-reducing antioxidant power were measured using spectrophotometry, and total antioxidant capacity (TAC) was compared with two common antioxidants, vitamin C and α-tocopherol. Moreover, mature fruits have high DDPH, ferric ion-reducing antioxidant power and total antioxidant capacity. Furthermore, mature fruits have high levels of total phenolic, flavonoid, and tannin content; these compounds are thought to be the sources of the antioxidant activity. The major constituents of the methanolic extracts from the mature fruits of K. pinnata were found to be larixinic acid, 3,5-Dihydroxy-6-methyl-2,3-dihydro-4H-pyran-4-one (DMDP), and 5-Hydrxoymethylfurfural. We performed the elemental analysis of the whole fruit. Huh-7 (liver cancer), PANC-1 (pancreatic cancer), Colo-205 (colorectal cancer), HT-29 (colorectal cancer), SNU-16 (gastric carcinoma), SW620 (colorectal adenocarcinoma) and HCT116 (colon carcinoma) were tested in vitro for anticancer activity. Both methanolic and ethyl acetate extracts of mature fruits had a positive effect on all cancer cell lines as compared to the doxorubicin drug. In addition, the methanolic extracts of mature fruits showed more potent cytotoxic effects than the ethyl acetate extracts. Moreover, the most pronounced cytotoxic effects of the methanolic extract were detected in SW620 (colorectal adenocarcinoma), with an IC₅₀ value of 6.79 μg/mL, SNU-16 (gastric carcinoma), with and IC₅₀ value of 8.69 μg/ ml, and in PANC-1 (pancreatic cancer) with an IC₅₀ value of 10.34 μg/mL. Moreover, the results show that the water, ethyl acetate and methanolic extracts of mature fruits have antioxidant capacity, ferric ion-reducing antioxidant power, DPPH scavenging activity and also anticancer activity. Therefore, the present study suggests that the phytochemical profiles of mature fruits of K. pinnata may be used as potential natural antioxidants and anti-cancer cell lines.

The present study was conducted to evaluate the ability of different extracts of cinnamon and black cumin seeds to inhibit the growth of the phytopathogenic fungus Rhizoctonia solani and its extracellular cell wall degrading enzymes. The results clearly demonstrated that concentrations of 300 or 450 ppm of methylene chloride or hexane extracts of cinnamon completely inhibited the growth of R. solani after 72hours of incubation at 25±1°C in vitro. Methylene chloride or hexane extracts of black cumin seeds at 4000 ppm inhibited the growth of R. solani by 37% and 39% after72 hours of incubation respectively. Moreover, black cumin seeds hexane extract at 2000 ppm inhibited 55% and 38% of the activity of pectin lyase (PL) and polygalacturonase (PG) respectively. In addition, the methanolic extract of black cumin seeds at 2000 ppm exhibited a significant reduction of exo-protease activity (74.8%). GC- MS analysis results showed that linoleic acid is the main component of the fixed oil fraction of black cumin seeds hexane extract while (E)-cinnamaldehyde is the main component in both hexane and methylene chloride extracts of cinnamon. HPLC-MS analysis of black cumin seeds methanolic extract showed that amentoflavone, was the main component.

Rhizoctonia solani is considered one of the most harmful pathogens affecting green bean productivity. Phaseolus vulgaris, L. cv. paulista seeds were subjected to UV-C for 60 min. and/or immersed in glycine betaine (GB, 5 mM) for 24 hours to stimulate plant biochemical defenses against R. solani. After treatments, seeds were sown in soil infested with R. solani, then seedling samples were collected after two weeks to evaluate plant resistance and some antioxidant enzymes activities. The results clearly demonstrated that disease index (DI) was highly reduced by GB (54.7%) followed by UV+GB (38.3%) and UV (35.6%). Seed treatment with UV-C for 60 min or GB (5 mM) for 24 h alone or together enhanced plant rooting in infected seedlings comparing with control. Also, there was a high correlation between the levels of lipid peroxidation and Rhizoctonia root rot disease index. Seed treated with UV-C, GB or both mitigated the effect of infection on the lipid peroxidation (Malondialdehyde levels) with percentages of 26.8, 40.2 and 29.3% respectively in comparison with the infected control. Regarding to the plant defensive enzymes, GB was the only treatment that triggered a significant increment in the superoxide dismutase (SOD) activity in roots of both infected and non-infected seedlings as compared to the control. On the other hand, guaiacol peroxidase (G-POD) and polyphenol oxidase (PPO) activities were elevated by all treatments in infected plant roots in comparison with control. The maximum activity for G-POD was attained with UV treatment (9042.5 U.mg-1 protein) followed by GB+UV, GB and infected control with values of 7776.5, 7152.4 and 6508.8 U.mg-1 protein, respectively. Similarly, PPO exhibited higher activities with significant differences in all treatments over the infected control with percentages of 54, 59.4 and 48.7% for UV, GB and UV+GB respectively. Finally, it can be concluded that treatment of green bean seeds with UV-C and GB enhanced green bean seedlings tolerance to R. solani by activation of the antioxidant enzymes and activation of defense-related enzymes like polyphenol oxidase. The results of combination of UV-C and GB treatments indicated the absence of synergetic effects in induction of plant tolerance.