Elderberries—A Source of Bioactive Compounds with Antiviral Action

Are the Effects of Bioactive Components on Human Health a Myth?: Black Elderberry (Sambucus nigra L.) from Exotic Fruits

PURPOSE OF REVIEW

Black elderberry has come to the fore in recent years due to its health benefits. Black elderberry fruit (Sambucus nigra L.), collected from natural sources, has a rich content of protein, vitamins, antioxidants, unsaturated fatty acids, and minerals as it contains conjugated and free forms of amino acids.

RECENT FINDINGS

Black elderberry can prevent oxidative stress and reduce blood pressure and prevent cardiovascular diseases, diabetes mellitus, neurodegenerative diseases thanks to the polyphenols it contains. It can prevent diseases, stimulate the immune system, show an antitumor effect, and be effective in the course of disease processes by rising the activity of antioxidant enzymes, including glutathione. Since black elderberry is a promising food in terms of bioactive components, it is considered as promising to treat and prevent many diseases. However, it is not correct to prove its beneficial effects on the prevention of chronic diseases and to make generalisations. Therefore, there is a need of more comprehensive evidence-based clinical studies and data. This review examined current evidence and discussions about the health-related effects of black elderberry, which contains many biologically active components such as polyphenols, phenolic acids, flavonols, proanthocyanidins and anthocyanins, as well as terpenes and lectins, and offered some suggestions on its use in the future.

Immunostimulatory activity of the aqueous extract from the leaves of Sambucus racemosa subsp. pendula through TLR4‑dependent JNK activation in RAW264.7 cells

Sambucus racemosa subsp. pendula (SRP) is an endemic plant of Korea, exclusively found on Ulleungdo Island. SRP is widely used as both a traditional medicine and food source. However, there is a lack of research on the pharmacological activities of SRP. Therefore, the present study aimed to explore the potential use of SRP leaves (SRPL) as a natural immunostimulant by analyzing its macrophage activation properties and the underlying mechanisms of action. Among the various extraction conditions, SRPL (AE20-SRPL) extracted with 100% distilled water at 20˚C induced the highest nitric oxide (NO) production in RAW264.7 cells. Thus, the further studies were performed using AE20-SRPL. AE20-SRPL increased the production of immunostimulatory factors such as NO, prostaglandin E2, inducible nitric oxide synthase, cyclooxygenase-2, IL-1β and TNF-α and phagocytosis in a dose-dependent manner in RAW264.7 cells without exhibiting cytotoxicity. Among Toll-like receptor (TLR)2 and TLR4, inhibition of TLR4 significantly reduced AE20-SRPL-mediated increases in the production of immunostimulatory factors and phagocytosis in RAW264.7 cells. Furthermore, in RAW264.7 cells, inhibition of JNK, one of the components of MAPK signaling along with ERK1/2 and p38, attenuated the AE20-SRPL-mediated increases in the production of immunostimulatory factors and phagocytosis. Additionally, AE20-SRPL induced the phosphorylation of JNK and inhibition of TLR4 reduced AE20-SRPL-mediated JNK phosphorylation. These results suggested that AE20-SRPL may enhance the production of immunostimulatory factors and phagocytosis through TLR4-dependent activation of JNK in macrophages. Although the present study is limited to in vitro research using a cell model, AE20-SRPL demonstrated potential as a natural material capable of inducing macrophage activation for immune enhancement.

Unlocking insights: Navigating COVID-19 challenges and Emulating future pandemic Resilience strategies with strengthening natural immunity

The original COVID-19 vaccines, developed against SARS-CoV-2, initially mitigated hospitalizations. Bivalent vaccine boosters were used widely during 2022-23, but the outbreaks persisted. Despite this, hospitalizations, mortality, and outbreaks involving dominant mutants like Alpha and Delta increased during winters when the population's vitamin D levels were at their lowest. Notably, 75 % of human immune cell/system functions, including post-vaccination adaptive immunity, rely on adequate circulatory vitamin D levels. Consequently, hypovitaminosis compromises innate and adaptive immune responses, heightening susceptibility to infections and complications. COVID-19 vaccines primarily target SARS-CoV-2 Spike proteins, thus offering only a limited protection through antibodies. mRNA vaccines, such as those for COVID-19, fail to generate secretory/mucosal immunity-like IgG responses, rendering them ineffective in halting viral spread. Additionally, mutations in the SARS-CoV-2 binding domain reduce immune recognition by vaccine-derived antibodies, leading to immune evasion by mutant viruses like Omicron variants. Meanwhile, the repeated administration of bivalent boosters intended to enhance efficacy resulted in the immunoparesis of recipients. As a result, relying solely on vaccines for outbreak prevention, it became less effective. Dominant variants exhibit increased affinity to angiotensin-converting enzyme receptor-2, enhancing infectivity but reducing virulence. Meanwhile, spike protein-related viral mutations do not impact the potency of widely available, repurposed early therapies, like vitamin D and ivermectin. With the re-emergence of COVID-19 and impending coronaviral pandemics, regulators and health organizations should proactively consider approval and strategic use of cost-effective adjunct therapies mentioned above to counter the loss of vaccine efficacy against emerging variants and novel coronaviruses and eliminate vaccine- and anti-viral agents-related serious adverse effects. Timely implementation of these strategies could reduce morbidity, mortality, and healthcare costs and provide a rational approach to address future epidemics and pandemics. This perspective critically reviews relevant literature, providing insights, justifications, and viewpoints into how the scientific community and health authorities can leverage this knowledge cost-effectively.

Development of Potential Therapeutic Agents from Black Elderberries (the Fruits of Sambucus nigra L.)

Elderberry (Sambucus nigra L.) is a widespread deciduous shrub, of which the fruits (elderberries) are used in the food industry to produce different types of dietary supplement products. These berries have been found to show multiple bioactivities, including antidiabetic, anti-infective, antineoplastic, anti-obesity, and antioxidant activities. An elderberry extract product, Sambucol®, has also been used clinically for the treatment of viral respiratory infections. As the major components, phenolic compounds, such as simple phenolic acids, anthocyanins and other flavonoids, and tannins, show promising pharmacological effects that could account for the bioactivities observed for elderberries. Based on these components, salicylic acid and its acetate derivative, aspirin, have long been used for the treatment of different disorders. Dapagliflozin, an FDA-approved antidiabetic drug, has been developed based on the conclusions obtained from a structure-activity relationship study for a simple hydrolyzable tannin, β-pentagalloylglucoside (β-PGG). Thus, the present review focuses on the development of therapeutic agents from elderberries and their small-molecule secondary metabolites. It is hoped that this contribution will support future investigations on elderberries.

VOLKSMED Database: A Source for Forgotten Wound Healing Plants in Austrian Folk Medicine

The global increase in the incidence of wounds is concerning and fuels the search for new treatment options. The use of traditional medicinal plants in wound healing represents an appreciated available therapeutic possibility. This work introduces the VOLKSMED database, which contains plants and other materials used in Austrian folk medicine, either as monographs or mixtures. This work focuses on the monographs of the database. Concerning wound healing, Hypericum sp., Arnica montana, Calendula officinalis, Plantago sp., and Malva sp. are the most commonly used plants. The focus of this paper is set on selected lesser-known plants (Abies alba, Anthyllis vulneraria, Brassica sp., Gentiana sp., Larix decidua, Picea abies, Sambucus sp., Sanicula europaea) and their status quo in literature concerning wound healing. A systematic search using the databases SciFinder, SCOPUS, and PubMed yielded substantial evidence for the wound healing potential of Brassica sp., Gentiana sp., the Pinaceae A. abies, L. decidua, and P. abies, as well as Sambucus nigra. In vivo and clinical studies substantiate their use in Austrian folk medicine. According to the literature, especially A. vulneraria, Sambucus racemosa, and S. europaea would be worth investigating in-depth since data concerning their wound healing effects - even though scarce - are convincing. In conclusion, the VOLKSMED database contains promising opportunities for further treatment options in the field of wound healing. Future research should consider the listed plants to support their traditional use in Austrian folk medicine and possibly promote the implementation of old knowledge in modern medicine.

Novel Betanucleorhabdoviruses Infecting Elderberry (Sambucus nigra L.): Genome Characterization and Genetic Variability

The genus Betanucleorhabdovirus includes plant viruses with negative sense, non-segmented, single-stranded RNA genomes. Here, we characterized putative novel betanucleorhabdoviruses infecting a medically important plant, elderberry. Total RNA was purified from the leaves of several plants, ribodepleted and sequenced using the Illumina platform. Sequence data analysis led to the identification of thirteen contigs of approximately 13.5 kb, showing a genome structure (3'-N-P-P3-M-G-L-5') typical of plant rhabdoviruses. The detected isolates showed 69.4 to 98.9% pairwise nucleotide identity and had the highest identity among known viruses (64.7-65.9%) with tomato betanucleorhabdovirus 2. A detailed similarity analysis and a phylogenetic analysis allowed us to discriminate the elderberry isolates into five groups, each meeting the sequence-based ICTV demarcation criterion in the Betanucleorhabdovirus genus (lower than 75% identity for the complete genome). Hence, the detected viruses appear to represent five novel, closely related betanucleorhabdoviruses, tentatively named Sambucus betanucleorhabdovirus 1 to 5.

Walnut By-Products and Elderberry Extracts-Sustainable Alternatives for Human and Plant Health

A current alternative for sustainable development through green chemistry is the replacement of synthetic compounds with natural ones through the superior capitalization of natural resources, with numerous applications in different fields. The benefits of walnuts (Juglans regia L.) and elderberries (Sambucus nigra L.) have been known since ancient times, due to the presence of phytochemicals such as flavonoids, polyphenols, carotenoids, alkaloids, nitrogen-containing compounds, tannins, steroids, anthocyanins, etc. These active compounds have multiple biological activities for human health, including benefits that are antibacterial, antioxidant, anti-inflammatory, antidiabetic, hepatoprotective, antihypertensive, neuroprotective, etc. Like other medicinal plants, the walnut and the elderberry possess important phytosanitary properties (antibacterial, antifungal, and insecticidal) and their extracts can also be used as environmentally safe biopesticides, with the result that they constitute a viable and cheap alternative to environmentally harmful synthetic products. During recent years, walnut by-products and elderberries have attracted the attention of researchers, and investigations have focused on the species' valuable constituents and active properties. Comparing the information from the literature regarding the phytochemical profile and biological activities, it is highlighted that, apart from the predominant specific compounds, the walnut and the elderberry have common bioactive compounds, which come from six classes (phenols and derivatives, flavonoids, hydroxycinnamic acids, tannins, triterpenoids, and phytosteroids), and act on the same microorganisms. From this perspective, the aim of this review is to provide an overview of the bioactive compounds present in the different constitutive parts of walnut by-products and elderberries, which present a specific or common activity related to human health and the protection of agricultural crops in the context of sustainable development.

The Phenolic Composition, Antioxidant Activity and Microflora of Wild Elderberry in Asturias (Northern Spain): An Untapped Resource of Great Interest

The objective of this study is the characterization of the phenolic profile and antioxidant activity of elderberries (Sambucus nigra L.) from a collection of 79 wild specimens in northern Spain to assess variations in the species at the local level and evaluate its interest as a source of biocompounds. Also, a first study was carried out on the microflora present in this fruit, providing information relevant to its commercial exploitation. Moreover, the phenolic composition, antioxidant capacity and microbial composition in overripe fruits were determined, seeking a better use for this currently wasted resource. A wide variability in levels of phenolics was detected. Elderberries showed high antioxidant activity related to a high cyanidin derivative content, making them of interest to industry. Microflorae were present in very variable concentration ranges, so their levels should be monitored in those applications that require strict control. Overripe fruits are of interest as a source of anthocyanidins, since their concentration and antioxidant capacity remain after the optimal ripening period, promoting sustainability and a better use of natural resources. The database generated is of particular interest for further breeding trials based on the phenolic profile and antioxidant activity of the samples.

Enhanced Elderberry Snack Bars: A Sensory, Nutritional, and Rheological Evaluation

Interest in functional foods is continuously increasing, having the potential to be an ally in reducing cardiometabolic risk factors. This study focuses on developing and evaluating oat- and millet-based snack bars enriched with freeze-dried elderberry powder (FDEBP), aiming to combine great taste with enhanced nutritional value, antioxidant properties, and prebiotic potential. The research encompassed a sensory evaluation, nutritional assessment, and rheological analysis of the snack bars. A hedonic test was conducted to gauge consumer preferences and overall liking, providing insights into taste, texture, and acceptance. Sensory evaluation revealed positive feedback from participants, and acceptance rating scores ranged from 7 to 8.04, the best score recorded by one of the enhanced bars with 1% FDEBP. The rheological analysis determined the bars' dynamic storage modulus (G') and loss modulus (G″), assessing the material's elasticity and mechanical properties. Results showed that the incorporation of 0.5% and 1% FDEBP in the oat and millet snack bars significantly impacted their rheological properties, enhancing structural strength. Nutritional analysis demonstrated that the snack bars provided a complete mix of macronutrients required in a daily diet. The study sheds light on the potential of functional snack bars enriched with FDEBP, offering a delectable way to access essential nutrients and bioactive compounds in a minimally processed form, without the addition of sweeteners or additives, friendly to the gut microbiota.

Comparative Amino Acid Profile and Antioxidant Activity in Sixteen Plant Extracts from Transylvania, Romania

In addition to the naturopathic medicines based on the antiseptic, anti-inflammatory, anticancer, or antioxidant properties of plant extracts that have been capitalized upon through the pharmaceutical industry, the increasing interest of the food industry in this area requires potent new materials capable of supporting this market. This study aimed to evaluate the in vitro amino acid contents and antioxidant activities of ethanolic extracts from sixteen plants. Our results show high accumulated amino acid contents, mainly of proline, glutamic, and aspartic acid. The most consistent values of essential amino acids were isolated from T. officinale, U. dioica, C. majus, A. annua, and M. spicata. The results of the 2,2-diphenyl-1-pycrylhydrazyl (DPPH) radical scavenging assay indicate that R. officinalis was the most potent antioxidant, followed by four other extracts (in decreasing order): T. serpyllum, C. monogyna, S. officinalis, and M. koenigii. The network and principal component analyses found four natural groupings between samples based on DPPH free radical scavenging activity content. Each plant extracts' antioxidant action was discussed based on similar results found in the literature, and a lower capacity was observed for most species. An overall ranking of the analyzed plant species can be accomplished due to the range of experimental methods. The literature review revealed that these natural antioxidants represent the best side-effect-free alternatives to synthetic additives, especially in the food processing industry.

Elderberry Extracts: Characterization of the Polyphenolic Chemical Composition, Quality Consistency, Safety, Adulteration, and Attenuation of Oxidative Stress- and Inflammation-Induced Health Disorders

Elderberry is highly reputed for its health-improving effects. Multiple pieces of evidence indicate that the consumption of berries is linked to enhancing human health and preventing or delaying the onset of chronic medical conditions. Compared with other fruit, elderberry is a very rich source of anthocyanins (approximately 80% of the polyphenol content). These polyphenols are the principals that essentially contribute to the high antioxidant and anti-inflammatory capacities and the health benefits of elderberry fruit extract. These health effects include attenuation of cardiovascular, neurodegenerative, and inflammatory disorders, as well as anti-diabetic, anticancer, antiviral, and immuno-stimulatory effects. Sales of elderberry supplements skyrocketed to $320 million over the year 2020, according to an American Botanical Council (ABC) report, which is attributable to the purported immune-enhancing effects of elderberry. In the current review, the chemical composition of the polyphenolic content of the European elderberry (Sambucus nigra) and the American elderberry (Sambucus canadensis), as well as the analytical techniques employed to analyze, characterize, and ascertain the chemical consistency will be addressed. Further, the factors that influence the consistency of the polyphenolic chemical composition, and hence, the consistency of the health benefits of elderberry extracts will be presented. Additionally, adulteration and safety as factors contributing to consistency will be covered. The role of elderberry in enhancing human health alone with the pharmacological basis, the cellular pathways, and the molecular mechanisms underlying the observed health benefits of elderberry fruit extracts will be also reviewed.

Bioactive Potential of Elderberry (Sambucus nigra L.): Antioxidant, Antimicrobial Activity, Bioaccessibility and Prebiotic Potential

Due to its abundance of physiologically active ingredients, one of the oldest medicinal herbs, elderberry (EB) Sambucus nigra L., is beneficial for both therapeutic and dietary purposes. This study determined the bioaccessibility of the phenolic compounds and the prebiotic potential of the polyphenols from freeze-dried EB powder (FDEBP), along with the antioxidant and antimicrobial activities of this extract. The most significant phenolic compounds in black EB are represented by anthocyanins (41.8%), predominating cyanidin-sambubiosides and cyanidin-glucosides (90.1% of the identified anthocyanins). The FRAP assay obtained the highest antioxidant activity value (185 ± 0.18 μmol Fe2+/g DW). The most sensitive to the antimicrobial activity of the extract was proven to be Staphylococcus aureus, and Pseudomonas aeruginosa had the lowest minimum inhibitory concentration of 1.95 mg/mL. To determine the prebiotic potential of the polyphenols, the cell growth of five probiotic strains (Lactobacillus plantarum, L. casei, L. rhamnosus, L. fermentum and Saccharomyces boulardii) was tested. The influence on cell growth was positive for all five probiotic strains used. Overall, the most significant increase (p < 0.05) was recorded at 1.5% FDEBP, on S. boulardii with a growth index (GI) of 141.02%, very closely followed by GI at 0.5% and 1% concentrations. The stability of the total phenolic compounds through simulated gastronitestinal digestion was increased (93%), and the bioaccessibility was also elevated (75%).

Catching the Green—Diversity of Ruderal Spring Plants Traditionally Consumed in Bulgaria and Their Potential Benefit for Human Health

The global climate and societal challenges in the recent years urge us to strengthen food security; thus, the rediscovery of wild foods and foraging practices is also part of the sustainability agenda. Utilization of underappreciated sources such as ruderal plants could be a valuable option, especially for vulnerable parts of the society. We present data on traditional knowledge on spring edible ruderal plant taxa preserved in rural regions of Bulgaria, combining field studies in the period 2017–2022 that were compared to the available recent and historical ethnographic and (ethno)botanical literature. Semi-structured interviews were performed with representatives of 94 households in North and South Bulgaria, focusing on collection practices, used parts, and preparation methods. We list 65 edible ruderals, belonging to 22 plant families, of which 19 appeared only in the literature sources. Unlike in the Mediterranean tradition, edible ruderal plants in Bulgaria were regarded unfavorably, as poverty food. Amaranthaceae and Asteraceae were the most represented families, with 10 taxa each. About half of the taxa were collected for their leaves or whole young herbage that is used as pastry fillings, in stewed, and in cooked dishes. Taxa used in raw salads were mostly from the literature sources. The most diverse utilization was recorded in the southern-most regions of Bulgaria, where immediate tasting of the gathered plants was reported by the participants as the way to collect food plants. The bitter ones or those with an unappealing smell were considered non-edible and were avoided. References about biologically active compounds and potential benefits were collected, classified, and discussed in regard to their potential benefits for human health.

The Effect of the Plant Stabilisation Method on the Composition and Antioxidant Properties of Elderflower (Sambucus nigra L.) Extract

Elderflower extracts are known to be a source of valuable substances that show a wide spectrum of biological activity, including antibacterial and antiviral properties, which demonstrate a degree of effectiveness against SARS CoV-2. In this work, the influence of fresh inflorescence stabilisation methods (freezing, air drying, and lyophilisation) and extraction parameters on the composition and antioxidant properties of the extracts were studied. Wild elderflower plants growing in the Małopolska Region of Poland were studied. Antioxidant activities were evaluated by 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging ability and ferric-reducing antioxidant power assays. The total phenolic content was determined using the Folin-Ciocalteu method and the phytochemical profile of the extracts was analysed using HPLC. The obtained results showed that the best method for the stabilisation of elderflower was lyophilisation, and the determined optimal maceration parameters were 60% methanol as a solvent and a process time of 1-2 days.

Comparison of the Formulation, Stability and Biological Effects of Hydrophilic Extracts from Black Elder Flowers (Sambucus nigra L.)

Elderflower preparations have long been used to treat colds and flu, but their use is undeservedly reduced, and only dried flower teas, less often ethanolic extracts, can be purchased in pharmacies. In the case of homemade teas, the medicinal plant material is extracted with hot water for a relatively short time, thus only a small part of the active substances is extracted. The industrially produced ethanolic extract is rich in active substances, but its use is limited since ethanol in many countries is undesirable and unsuitable for children and geriatric patients. Therefore, the aim of this work was to produce extracts from elder flowers using water as extractant and a mixture of water + polyethylene glycol (PEG) 20%, to compare their chemical composition and stability, and to study the ability to neutralize reactive oxygen species (ROS) and to sustain the viability of C6 glial cells under oxidative stress conditions. The ethanolic extract was used as a standard. Thus, the extract with PEG contained more than two times higher amount of total phenolics (PC) than the aqueous one, and the stability at 6-8 °C was comparable to the stability of ethanolic extract. All three extracts showed an antioxidant effect in a concentration-dependent manner in vitro. However, only the PEG containing extract (at 20-40 µg/mL PC) was the most effective in reducing the intracellular level of ROS and sustaining the viability of glial cells. The results suggest that the co-solvent PEG increases the yield of phenolics in the extract, prolongs the stability, and enhances positive biological effects.