Assessment of the phytochemical profile and antioxidant activities of eight kiwi berry (Actinidia arguta (Siebold & Zuccarini) Miquel) varieties in China

Dietary Polyphenols: Review on Chemistry/Sources, Bioavailability/Metabolism, Antioxidant Effects, and Their Role in Disease Management

Polyphenols, as secondary metabolites ubiquitous in plant sources, have emerged as pivotal bioactive compounds with far-reaching implications for human health. Plant polyphenols exhibit direct or indirect associations with biomolecules capable of modulating diverse physiological pathways. Due to their inherent abundance and structural diversity, polyphenols have garnered substantial attention from both the scientific and clinical communities. The review begins by providing an in-depth analysis of the chemical intricacies of polyphenols, shedding light on their structural diversity and the implications of such diversity on their biological activities. Subsequently, an exploration of the dietary origins of polyphenols elucidates the natural plant-based sources that contribute to their global availability. The discussion extends to the bioavailability and metabolism of polyphenols within the human body, unraveling the complex journey from ingestion to systemic effects. A central focus of the review is dedicated to unravelling the antioxidant effects of polyphenols, highlighting their role in combating oxidative stress and associated health conditions. The comprehensive analysis encompasses their impact on diverse health concerns such as hypertension, allergies, aging, and chronic diseases like heart stroke and diabetes. Insights into the global beneficial effects of polyphenols further underscore their potential as preventive and therapeutic agents. This review article critically examines the multifaceted aspects of dietary polyphenols, encompassing their chemistry, dietary origins, bioavailability/metabolism dynamics, and profound antioxidant effects. The synthesis of information presented herein aims to provide a valuable resource for researchers, clinicians, and health enthusiasts, fostering a deeper understanding of the intricate relationship between polyphenols and human health.

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.

Actinidia arguta (Sieb. et Zucc.) Planch. ex Miq.: A Review of Phytochemistry and Pharmacology

Actinidia arguta (Siebold & Zucc.) Planch ex Miq. (A. arguta) is a highly valued vine plant belonging to the Actinidia lindl genus. It is extensively utilized for its edible and medicinal properties. The various parts of A. arguta serve diverse purposes. The fruit is rich in vitamins, amino acids, and vitamin C, making it a nutritious and flavorful raw material for producing jam, canned food, and wine. The flowers yield volatile oils suitable for essential oil extraction. The leaves contain phenolic compounds and can be used for tea production. Additionally, the roots, stems, and leaves of A. arguta possess significant medicinal value, as they contain a wide array of active ingredients that exert multiple pharmacological and therapeutic effects. These effects include quenching thirst, relieving heat, stopping bleeding, promoting blood circulation, reducing swelling, dispelling wind, and alleviating dampness. Comprehensive information on A. arguta was collected from scientific databases covering the period from 1970 to 2023. The databases used for this review included Web of Science, PubMed, ProQuest, and CNKI. The objective of this review was to provide a detailed explanation of A. arguta from multiple perspectives, such as phytochemistry and pharmacological effects. By doing so, it aimed to establish a solid foundation and propose new research ideas for further exploration of the plant's potential applications and industrial development. To date, a total of 539 compounds have been isolated and identified from A. arguta. These compounds include terpenoids, flavonoids, phenolics, phenylpropanoids, lignin, organic acids, volatile components, alkanes, coumarins, anthraquinones, alkaloids, polysaccharides, and inorganic elements. Flavonoids, phenolics, alkaloids, and polysaccharides are the key bioactive constituents of A. arguta. Moreover, phenolics and flavonoids in A. arguta exhibit remarkable antioxidant, anti-inflammatory, and anti-tumor properties. Additionally, they show promising potential in improving glucose metabolism, combating aging, reducing fatigue, and regulating the immune system. While some fundamental studies on A. arguta have been conducted, further research is necessary to enhance our understanding of its mechanism of action, quality evaluation, and compatibility mechanisms. A more comprehensive investigation is highly warranted to explore the mechanism of action and expand the range of drug resources associated with A. arguta. This will contribute to the current hot topics of anti-aging and anti-tumor drug research and development, thereby promoting its further development and utilization.

Comparative changes of health-promoting phytochemicals and sugar metabolism of two hardy kiwifruit (Actinidia arguta) cultivars during fruit development and maturity

INTRODUCTION

Hardy kiwifruit (Actinidia arguta) has an extensive range of nutritional and bioactive compounds and has been valued as a great resource for kiwifruit breeding. A better understanding of the dynamic changes of the composition and accumulation of nutritional compounds during fruit development and ripening is required before genetic or cultural improvements can be targeted.

METHODS

In the present study, the phytochemical analysis of two A. arguta cultivars 'Yilv' and 'Lvmi-1' showed that they comprised different morphology, with a higher fruit diameter while a lower vertical fruit diameter of 'Lvmi-1' compared with 'Yilv'. The antioxidant capacity of both cultivars decreased during the maturity time and showed no significant difference between them. Furthermore, although glucose gradually increased during the maturity time, the predominant sugar composition was speculated to be fructose in 'Lvmi-1' fruit while sucrose in 'Yilv' fruit at the early fruit developmental stages. Moreover, the predominant acids in 'Yilv' and 'Lvmi-1' were citric acid followed by quinic acid, malic acid, and oxalic acid. The expression of sugar- and starch-related genes encoding the crucial enzymes suggested different changes in 'Yilv' and 'Lvmi-1'. Notably, a subsequent correlation analysis showed a significant positive correlation between sucrose phosphate synthase (SPS) expression and glucose in 'Yilv', fructokinase (FK) expression, and starch content in 'Lvmi-1', implying their vital roles in sugar and starch accumulation. By contrast, a significant negative correlation between FK expression and fructose in 'Lvmi-1' fruit was observed.

RESULTS AND DISCUSSION

In summary, our results provide supplementary information for the dynamic changes of nutritional compounds and antioxidant capacity during hardy kiwifruit maturity time and give a clue for exploring the mechanism of sugar and starch accumulation in hardy kiwifruit.

Dwarf Kiwi (Actinidia arguta Miq.), a Source of Antioxidants for a Healthy and Sustainable Diet

The feasibility of using dwarf kiwi fruits (Actinia arguta Miq.) as a healthy and sustainable food, compared to other types of commercial kiwi fruits, was evaluated in the present study. The overall antioxidant capacity of these fruits was assessed by either extraction-dependent methods (ABTS, ORAC) or the direct method called Quick, Easy, New, CHEap, Reproducible (QUENCHER) (DPPH, FRAP, Folin–Ciocalteu), applied for the first time to analyze kiwi fruits. With this methodology, all the molecules with antioxidant capacity are measured together in a single step, even those with high molecular weight or poor solubility in aqueous extraction systems, such as antioxidant dietary fiber. The effect of kiwi extracts on physiological and induced intracellular reactive oxygen species (ROS) production on IEC-6 cells was also analyzed, as well as total phenolic content (TPC) by Fast Blue BB, flavonols, hydroxycinnamic acids, and hydroxybenzoic acids. A. arguta fruits showed the highest values in all the antioxidant assays, being remarkably higher than the other kiwi species for Q-FRAP and Q-DPPH. Dwarf kiwi showed the highest potential in reducing physiological ROS and the highest values of TPC (54.57 mgGAE/g), being hydroxybenzoic acids the main phenolic family found (2.40 mgGAE/g). Therefore, dwarf kiwi fruits are a natural source of antioxidants compared to conventional kiwi fruits, being a sustainable and healthy alternative to diversify fruits in the diet.

Sensitivity Testing of Natural Antifungal Agents on Fusarium fujikuroi to Investigate the Potential for Sustainable Control of Kiwifruit Leaf Spot Disease

Kiwifruit is a nutritious and economically important fruit that is widely cultivated in China. In 2021, leaf spot disease of kiwifruit was discovered in the main kiwifruit-producing area of Xifeng County, Guizhou Province, China. Leaf spot disease weakens plant photosynthesis and reduces nutrient synthesis, thereby affecting plant growth. We studied the morphological characteristics and performed a combined analysis of EF-1α, RPB2, and TUB2 genes of Fusarium fujikuroi, a fungus associated with leaf spot disease. The pathogenicity of F. fujikuroi followed Koch’s hypothesis, confirming that this fungus is the cause of kiwifruit leaf spot disease. The sensitivity of seven natural antifungal agents against F. fujikuroi was measured using the mycelial growth rate method. Honokiol, cinnamaldehyde, and osthol showed good antifungal effects against F. fujikuroi, with EC50 values of 18.50, 64.60, and 64.86 μg/mL, respectively. The regression coefficient of cinnamaldehyde was the largest at 2.23, while that of honokiol was the smallest at 0.408. Fusarium fujikuroi was the most sensitive to cinnamaldehyde.

Phytochemical profiles, antioxidant and antimicrobial activity of Actinidia polygama and A. arguta fruits and leaves

Plants of two species of Actinidia genus grown in an adverse steppe climate were examined in terms of secondary metabolites’ accumulation, antioxidant potential, and antimicrobial ability. The aim of the work was to reveal whether the introduced plants A. arguta and A. polygama retain their well-known health benefits. Total content of polyphenols (549.2 and 428.1 mg GAE/100 g FW, respectively), flavonoids, and phenolic acids as well as total antioxidant activity and reducing power of the fruit isopropanol extracts were found to be equal or even higher than the reported data on kiwifruit varieties cultivated in China and other regions. Antioxidant potential and phenolic compounds’ content in the fruit peel of both species were higher when compared to pulp, while corresponding indices of leaves exceeded those of the fruit. Disc-diffusion assays showed low to moderate antibacterial activity of A. arguta and A. polygama fruit and leaf extracts against collection Gram-negative and Gram-positive strains. Clinical strains of P. aeruginosa and E. coli resistant to the action of ofloxacin were notably inhibited by A. arguta and A. polygama fruit and leaf crude extracts. Inhibiting effects of plant extracts on clinical strains of K. pneumoniae and A. baumannii were comparable with the effect of ofloxacin. GC-MS assays identified 23 and 36 chemical constituents, respectively in A. arguta and A. polygama fruit isopropanol extracts. The main compounds in both extracts were 2-propenoic acid, pentadecyl ester followed by squalene, 7,9-di-tert-butyl-1-oxaspiro(4,5)deca-6,9-dien-2,8-dione, octadecanoic acid, 2-oxo-methyl ester, ethyl-isoallocholate, and phytol having known bioactivities. Our findings confirmed the preservation of useful properties by the introduced plants and also indicated the rich health-promoting abilities and expedience of cultivating A. arguta and A. polygama in a steppe climate.