Raluca Alexandra

Extreme climatic conditions often intensify abiotic stress factors (such as drought, salinity, heat stress, ultraviolet radiation, and soil degradation), and are increasingly limiting crop productivity and threatening global food security. Secondary metabolites (SMs), traditionally viewed as defense compounds, are now recognized as key regulators of plant adaptation to environmental stress. This review synthesizes recent advances in understanding the role of SMs as biochemical targets for improving crop resilience to climate extremes. By integrating evidence from multi-omics studies, artificial-intelligence-driven analyses, and functional genomics, we examine how stress-specific metabolic signatures and regulatory networks can be exploited for crop improvement. We further discuss the application of genome editing, synthetic biology, and metabolomics-assisted breeding to modulate the SM pathways to enhance stress tolerance. Selected case studies highlight the contribution of flavonoids, alkaloids, and terpenoids to stress adaptation in major and underutilized crops grown under salinity, drought, and low-temperature conditions. Despite significant progress, challenges remain, including metabolic trade-offs between stress tolerance and yield, regulatory constraints, and public acceptance of genetically engineered crops. By linking molecular mechanisms with applied strategies, this review provides a conceptual framework for leveraging secondary metabolism in climate-resilient agriculture and identifies key gaps to guide future research and innovation.

Phoradendron nervosum (hemiparasitic plant) exhibits remarkable metabolic plasticity, with significant variations in bioactive compound content, metabolite profiles, and antioxidant capacity depending on the host species (Laurus nobilis L., Hibiscus rosa-sinensis L., Populus alba L.) and organ type (leaves vs. fruits). A multi-method approach combining spectrophotometry, complementary antioxidant assays (ABTS, DPPH, FRAP), and complete metabolomic profiling by LC–MS was used to elucidate the biochemical interactions between P. nervosum and its hosts. The results obtained showed a differential distribution of total phenolic and flavonoid compounds, with leaves characterized by higher flavonoid concentrations (e.g., up to 0.286 mg QE/g DW). At the same time, fruits exhibited host-mediated modulations, especially in the species L. nobilis (e.g., the highest TPC at 2.723 mg GAE/g DW). Antioxidant activity was consistently higher in leaves (e.g., up to 41.26 µmol Trolox/g DW in DPPH assay), correlating with their enriched presence of phenolic acids and glycosylated flavonoids. The host species played a determining role in antioxidant capacity, as H. rosa-sinensis-associated plants exhibited the highest levels (e.g., 14.53 µmol Trolox/g DW in ABTS, 24.06 µmol Fe²⁺/g DW in FRAP). Correlation analysis suggested complex biochemical trade-offs influencing metabolic allocations. A diversity of bioactive compounds was identified by LC–MS, highlighting the synergistic interaction between metabolites in defining the physiological response of P. nervosum. Our results highlight its adaptive versatility and ecological significance, but also potential pharmacological applications, given that related mistletoe species from Europe are already used in antitumor treatments.

In the context of natural beverages used for human nutrition, our study explored the potential of Myrcianthes hallii leaves (rich in bioactive compounds) as a raw material for the production of non-traditional craft beer. We hypothesized that the phenological stage affects essential oil yield and bioactivity, which in turn influences the functional properties of fortified beer. In our case, M. hallii leaves collected during the flowering stage yielded the highest amount of essential oil (0.5 v/m/%) and exhibited the greatest concentrations of total phenolics (7.7149 ± 0.02143 mg GAE/mL) and flavonoids (1.6531 ± 0.03355 mg QE/mL), correlating with increased antioxidant capacity. These findings suggest this stage as the most suitable period for harvesting M. hallii leaves for nutraceutical and pharmaceutical applications. This non-traditional beer demonstrated notable antioxidant activity, and sensory analysis revealed high acceptance regarding aroma, taste, and color, supporting its potential as a functional beverage.

Gongolaria barbata (Stackhouse) Kuntze (syn. Cystoseira barbata (Stackhouse) C. Agardh), a species of brown macroalgae (seaweed), plays a crucial role in the coastal marine ecosystems. Its ability to form complex three‐dimensional structures is fundamental for supporting rich biodiversity and diverse habitats, making a significant contribution to primary production and carbon sequestration, highlighting its vital importance in maintaining the health and balance of these coastal marine environments. It is a bioindicator species for water quality and environmental conditions. Recently, a concerning decline in the species population has been reported, attributed to pollution, eutrophication, climate change, human activities and the introduction of invasive species. In this context, the conservation and restoration of these environments are crucial for maintaining their ecological integrity. Our research required the development of an in vitro protocol for multiplication, based on both direct and indirect regeneration. Seven different protocols for explant sterilisation and 21 media variants were used for in vitro induction of the multiplication protocol. The satisfactory results of this study indicate that natural seawater supplemented with 0.5 mg L⁻¹ BAP and 1 mg L⁻¹ GA₃ induced direct regeneration by forming buds, and PES medium added with 0.5 mg L⁻¹ BAP and 1 mg L⁻¹ 2,4‐D induced callus mass. Our study is unique in Romania and in the western part of the Black Sea. It represents a starting point for improving protocols for the multiplication of this species with the aim of its conservation purposes.

This study investigates the impact of volcanic ash from Cotopaxi Volcano on the nutritional quality and biological traits of potato tubers (Solanum tuberosum L.) cultivated in the Cotopaxi region. Methods: Samples collected from exposed and unexposed areas were used to characterize the volcanic ash influence on the metabolic aspects of the potato crop. The colorimetric method; DPPH, ABTS, and FRAP assays; and ICP-OES were used to better understand potatoes’ reaction to the stress. Results: Antioxidant activity was significantly higher (4.80 ± 2.38 µmol Trolox g⁻¹ DW-DPPH assay; 11.05 ± 2.57 µmol Trolox g⁻¹ DW-ABTS assay; and 11.96 ± 4.57 µmol Fe²⁺ g⁻¹ DW-FRAP assay) in ash-exposed samples, suggesting enhanced stress responses. The bioactive compounds studied followed a comparable trend, with high content in the exposed tubers. Also, significant changes in elemental composition were registered: Potassium levels decreased in unexposed samples, while magnesium and iron levels increased. Metallic elements (zinc; lithium; boron; manganese; barium; lead; nickel; chromium; indium) were in concentrations <0.01 mg/kg. Conclusion: These findings demonstrate that volcanic ash alters the metabolic and antioxidant profiles of potato tubers, enhancing nutraceutical properties while posing food safety risks due to heavy metals. This dual impact highlights the challenges and opportunities for agriculture in volcanic regions like Cotopaxi.

Background: This research evaluated the metabolic and antioxidant activity in red, white, and yellow corn varieties cultivated in the Cotopaxi region. Methods: Colorimetric methods were used for the total phenolic content and total flavonoids, while the LC-MS method was used for the metabolic profile. Also, assays like ABTS, FRAP, and DPPH were used to determine their ability to neutralize free radicals and reduce oxidants. Results: Red corn contains a significantly higher level of natural bioactive compounds compared to other varieties. Phenolics and flavonoids are crucial in antioxidant capacity, contributing significantly to scavenging free radicals and reducing oxidants. Comparative analysis of the biological properties and bioactive compounds in these maize varieties provides treasured insights into the fitness ability advantages of consuming red corn, emphasizing the importance of phenolics and flavonoids in its antioxidant activity. Conclusions: Our findings suggest that red corn could offer greater health benefits compared to white and yellow corn, underscoring the importance of ongoing studies of the biological properties and bioactive compounds in different maize varieties.

Background: Tabebuia chrysantha (Jacq.) Nichols, commonly known as Guayacan, is a prominent species within the Bignoniaceae family known for its medicinal value and ecological significance. This study aimed to characterize the antioxidant capacity and secondary metabolite composition of Guayacan leaves and flowers grown in Ecuador, a region where its chemical profile remains unexplored. Methods: Comprehensive analyses were conducted to determine the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity using ABTS, DPPH, FRAP assays, and LC-MS. Results: The results revealed remarkable differences between mature leaves and flowers. Leaves exhibited consistently higher flavonoid levels (e.g., 0.280 ± 0.005 mg QE/g DW) and superior antioxidant capacity across all assays (e.g., 10.84 ± 0.51 µmol Trolox g⁻¹ DW in ABTS) compared to flowers, which showed greater variability but lower overall activity. These findings highlight a functional specialization, with leaves synthesizing more flavonoids to mitigate oxidative stress from environmental factors such as UV radiation. LC-MS analysis unveiled various bioactive compounds, including phenolic acids, flavonoids, and terpenoids. Unique metabolites like α-lipoamide in leaves and oleanolic acid in flowers suggest distinct adaptive roles, potentially linked to stress tolerance and reproductive functions. Additionally, strong correlations among antioxidant assays (e.g., FRAP vs. DPPH, r = 0.993, p < 0.001) emphasize the pivotal role of phenolics and flavonoids in free radical scavenging and reduction mechanisms. Conclusions: The findings of this study demonstrate the superior antioxidant capacity of leaves, driven by their higher accumulation of flavonoids and phenolic compounds. This research represents a foundational step toward uncovering the therapeutic potential of Ecuadorian Guayacan as a source of natural antioxidants and bioactive compounds, supporting its future applications in phytotherapy and drug development.

This study investigates the consequences of volcanic ash on the antioxidant properties, nutrient composition, heavy metal levels, and secondary metabolites in Phaseolus vulgaris L. (common bean) and Zea mays L. (yellow corn), two crucial crops in Ecuador. The objective is to determine how volcanic ash exposure affects these crops, focusing on antioxidant properties and potential heavy metal accumulation. Field experiments were conducted in Cotopaxi Province, where both crops were cultivated under varying volcanic ash conditions. Secondary metabolites, particularly total phenols and flavonoids, were quantified using spectrophotometric methods, while heavy metal content was assessed via atomic absorption spectroscopy. Results showed a notable increase in the synthesis of secondary metabolites, especially phenols and flavonoids, in crops exposed to volcanic ash, enhancing their antioxidant capacity. Importantly, no significant heavy metal accumulation was detected, indicating that the benefits of volcanic ash application can be harnessed without associated toxicity risks. This research highlights the potential of volcanic ash to boost beneficial metabolites in yellow corn and common bean, advocating for careful agricultural practices in volcanic regions to optimize health benefits while mitigating toxicity risks.

Background: This research article delves into Babaco fruit’s—an Ecuadorian product with immense nutraceutical potential phytochemical composition and biological activity—in different maturation fruit stages. Bridging the gap between food and medicine, nutraceuticals offer health benefits beyond basic nutrition. Methods: Specifically, this study investigates Babaco’s antioxidant and its phenolic and flavonoid content across different ripening stages: physiological maturity, organoleptic quality immaturity, and commercial maturity. Results: This last stage of maturity exhibits the highest antioxidant activity, making it the optimal phase for marketing Babaco as a nutraceutical product. Further LC-MS analysis reveals the specific secondary metabolites responsible for this potent antioxidant capacity. Conclusions: By introducing Babaco as a nutraceutical fruit, Ecuador can showcase its unique phytochemical profile, which is rich in phenolic compounds and flavonoids. Consumers stand to gain from Babaco’s antioxidant properties, supporting overall health and well-being. Recognizing Babaco’s antioxidant potential aligns perfectly with Ecuador’s diverse biodiversity and offers a promising avenue for health-conscious choices.

The Colentina River is a tributary of the Dâmbovița River in Romania, flowing through the city of Bucharest before joining the main river. It has been significantly altered by human activities, including river course fragmentation, shoreline modification, and exposure to various pollutants from local sources. Macrophytes, which are crucial biotic components, are significantly influenced by human activities. They play several important roles in lakes, such as enhancing water transparency, absorbing nutrients and carbon dioxide, and providing habitats for diverse species. This study aims to assess the structural aspects of two primary producer components (macrophytes and phytoplankton) in different sections of the Colentina River. A specific methodology was employed to evaluate macrophytes and phytoplankton, considering three habitat variables: rural, peri-urban, and urban. The principal findings indicated that anthropogenic pressures have shaped the taxonomic structure. The spatial distribution of macrophytes was found to be correlated with both the geomorphology and water quality of the ecosystems. Peri-urban and rural areas, closer to natural conditions, support greater macrophyte diversity compared to urban areas. Extended periods of eutrophication have resulted in significant growth of Chlorophyceae and Cyanobacteria, negatively impacting the ecological conditions that support macrophytes. Despite these adverse interactions, certain plants, such as Phragmites australis and Typha angustifolia, have demonstrated adaptability and resilience, occupying niches even in hypereutrophic waterbodies. The varying levels of urbanization along the Colentina River have led to ecological degradation, characterized by a decline in macrophyte and phytoplankton diversity and an increase in pollution-resistant species. This highlights the urgent need for sustainable management strategies to mitigate human impacts and preserve ecosystem health.