Actinidia arguta Leaf as a Donor of Potentially Healthful Bioactive Compounds: Implications of Cultivar, Time of Sampling and Soil N Level

Bioactive compounds from Actinidia arguta fruit as a new strategy to fight glioblastoma

In recent years, there has been a significant demand for natural products as a mean of disease prevention or as an alternative to conventional medications. The driving force for this change is the growing recognition of the abundant presence of valuable bioactive compounds in natural products. On recent years Actinia arguta fruit, also known as kiwiberry, has attracted a lot of attention from scientific community due to its richness in bioactive compounds, including phenolic compounds, organic acids, vitamins, carotenoids and fiber. These bioactive compounds contribute to the fruit's diverse outstanding biological activities such as antioxidant, anti-inflammatory, neuroprotective, immunomodulatory, and anti-cancer properties. Due to these properties, the fruit may have the potential to be used in the treatment/prevention of various types of cancer, including glioblastoma. Glioblastoma is the most aggressive form of brain cancer, displaying 90 % of recurrence rate within a span of 2 years. Despite the employment of an aggressive approach, the prognosis remains unfavorable, emphasizing the urgent requirement for the development of new effective treatments. The preclinical evidence suggests that kiwiberry has potential impact on glioblastoma by reducing the cancer self-renewal, modulating the signaling pathways involved in the regulation of the cell phenotype and metabolism, and influencing the consolidation of the tumor microenvironment. Even though, challenges such as the imprecise composition and concentration of bioactive compounds, and its low bioavailability after oral administration may be drawbacks to the development of kiwiberry-based treatments, being urgent to ensure the safety and efficacy of kiwiberry for the prevention and treatment of glioblastoma. This review aims to highlight the potential impact of A. arguta bioactive compounds on glioblastoma, providing novel insights into their applicability as complementary or alternative therapies.

Nitrogen application alleviates salt stress by enhancing osmotic balance, ROS scavenging, and photosynthesis of rapeseed seedlings (Brassica napus)

Nitrogen application could alleviate salt stress on crops, but the specific physiological mechanism is still unclear. Therefore, in this study, a pot experiment was conducted to explore the effects of different application rates of nitrogen (0, 0.15, 0.30, and 0.45 g·kg^-1) on the growth parameters, osmotic adjustment, reactive oxygen species scavenging, and photosynthesis of rapeseed seedlings planted in the soils with different concentrations of sodium chloride (1.5, 3.5, 5.5, and 7.5 g·kg^-1). The results showed that nitrogen could alleviate the inhibition of salt on rapeseed growth, and improve the antioxidant enzyme activities and the contents of non-enzymatic substances, K⁺, soluble protein (SP), soluble sugar (SS), and proline. Besides, there was a significant correlation between the indexes of active oxygen scavenging system, osmoregulation system, and photosynthesis. Therefore, applying appropriate amount of nitrogen can promote the growth and development of rapeseed seedlings under salt stress, accelerate the scavenging of reactive oxygen species, maintain osmotic balance, and promote photosynthesis. This study will improve our understanding on the mechanism by which nitrogen application alleviates salt stress to crops.

Growing Season, Cultivar, and Nitrogen Supply Affect Leaf and Fruit Micronutrient Status of Field-Grown Kiwiberry Vines

The N uptake can affect kiwiberry yield and quality; however, the relationship between an increasing N dose and micronutrient accumulation in leaves and fruit is still to be elucidated. Interrelationships between essential nutrients are one of the most important issues in terms of effectiveness in plant mineral nutrition. A pattern in leaf nutrient accumulation throughout the growing period is required to indicate a suitable sampling time for the purpose of nutrient diagnostics and controlled plant feeding. The experiment was conducted on two commercially available cultivars of kiwiberry, 'Weiki' and 'Geneva', during the 2015-2016 growing seasons with an increasing soil N fertility (30-50-80 mg N kg^-1 soil DW) to test the relationship between soil N level and leaf/fruit micronutrient concentration. The leaf Zn, Cu, Fe, and Mn concentrations significantly increased with a higher N supply in 'Geneva', while in 'Weiki' only Mn increased. Leaf B, Fe, and Mn gradually increased throughout the growing season, while Cu decreased. Between mid-July and the beginning of August, the lowest fluctuations in the micronutrient contents were recorded. The effect of the growing season on leaf micronutrient accumulation was highly significant; except for Fe, significantly higher micronutrient levels were revealed in 2016. Compared to the leaves, the growing season effect was smaller in the case of fruit micronutrient concentrations. Irrespective of cultivar, the increase in N fertilization resulted in a higher fruit Mn concentration and was insignificant in the case of other micronutrients. The results indicate that the N dose may affect the accumulation of micronutrients within a certain range depending on the tissue type and the genotype.