The plant itself has been revered by many cultures, with a story about the “Elder Mother” living within the plant would protect those near the plant. It was even expected to ask the Elder Mother for the berries or flowers before taking them; without permission, she may seek revenge. The leaves, branches, flowers, and berries were believed to have protective powers for a home and the leaves were also used during burial rituals by some Celtic people. The personification and deep reverence for the elderberry show the importance of the plant through generations. Hippocrates and Pliny the Elder both wrote about elderberry and its medicinal properties. Tribes indigenous to North America used flowers and fruit for medicinal and beverages. Berries were also used as a natural dye for baskets and branches were used to make musical instruments.Elderberry is a perennial, deciduous plant native to many regions of the northern hemisphere. Elderberry plants are neither tree nor bush, as the plant sends new canes up each season, large round pot which without pruning, can lead to a large, shrub-like plant that can be several meters tall and wide. They prefer to grow in sunny, riparian climates with moist, well-drained soil, though subspecies in North America can be drought-tolerant.
While pruning even down to the ground level of the elderberry can improve yield and accessibility for harvesting, there is a limitation on pruning of the blue elderberry in the Central Valley of California. Due to the threatened status of the Valley Elderberry Longhorn Beetle , which lives only in the elderberry, branches larger than one inch in protected areas should not be pruned or removed from a growing site. Elderberry shrubs typically produce small white flowers with five petals in the spring, though the elderflowers of the blue elderberry are a creamy yellow color. Small, dark blue-purple berries ripen in the summer in large clusters called umbels or cymes, though there are examples of subspecies that have some variation to these morphologies, such as the blue elderberry that has a white bloom on the berries, causing the berries to look blue, and S. racemosa, which are red. Variation can also occur within a subspecies due to growing conditions, such as soil type, precipitation, and temperatures, as well as a key differentiation tool: cultivars or genotypes. There are established cultivars or genotypes of the European subspecies , such as Sambu or Haschberg, as well as of the American subspecies , like Bob Gordon or Wylewood. Cultivars can have more consistent growing patterns, such as blooming or ripening all at once, and desired chemical compositions, such as increased anthocyanins, thus are more desirable to use in large scale growing of elderberry for commercial use. Blue elderberry does not have any established genotypes to date. If commercial interest inthis subspecies continues to expand, effort should be made to develop cultivars with consistent quality and improved harvestability, which is hampered right now due to flowers and berries ripening throughout a season, instead of a smaller window of time like the American and European subspecies.
Indeed, starting this work can help increase the commercial interest viability of the blue elderberry.A primary driver in interest in the composition of elderberry and elderflower is for their potential health benefits. Several reviews have recently been published on this topic; thus, it will not be explored in depth here. European elderberry has been studied for its antioxidant, antimicrobial, anti-inflammatory, anticancer, immunomodulatory, and antidiabetic properties, as well as neuroprotection and cardiovascular protection in vitro and in vivo. These activities have been mainly attributed to the phenolic compounds like cyanidin 3-glucoside and cyanidin 3- sambubioside, but some other compounds have been shown to be bioactive as well, including terpenes, lectins, pectin, peptides, and malic acid. Using data from randomized, controlled clinical trials, a recent review found that elderberry could reduce symptoms from upper respiratory viral infections, providing support for the use of elderberry supplements by consumers to combat colds and flus without the use of antibiotic medicine. In a more unique application, elderberry and elderflower extracts have both shown to be effect in combatting gingival inflammation using a topical herbal patch and elderflower tea, respectively. A study of the mechanism of cyanidin 3-glucoside to treat against the influenza virus showed that elderberry extract had some inhibitory effect during the early stages of virus cyclewith stronger impacts during post-infection. The mechanism proposed was that the elderberry extract blocks viral glycoproteins which prevent the virus from attaching or entering cells to replicate, and increases expression of IL-6, IL-8, and TNF. Inflammatory modulating activity of elderberry and elderflower extracts have been investigated. Results showed that quercetin, rutin, and kaempferol are strong inhibitors of nitric oxide production, and metabolites from phenolic degradation including caffeic acid and 3,4-dihydroxyphenylacetic acid were also strong inhibitors without cytotoxicity.
Only a few studies have been done on the bioactivity of S. nigra ssp. canadensis. In one, the fruit was evaluated for anticancer properties, which showed chemo-preventative activity by inducing quinone reductase and inhibiting cyclooxygenase-2, as well as inhibiting ornithine decarboxylase. These activities are attributed to flavonoids and lipophilic compounds. Another study evaluated two Canadian cultivars of this subspecies evaluated the antiproliferative efficacy of the fruit and flowers on glioma and brain endothelial cells and results showed that elderberry and elderflower extracts inhibited the proliferation of cells under normoxic and hypoxic conditions. The elderberry extracts performed the best and the bioactivities were attributed to the synergistic work of cyanidin 3-sambubioside-5-glucoside and rutin content of the berries, though the rutin concentration in the flowers still had beneficial effects. Blue elderberry has only been evaluated as antioxidant activity using the ABTS assay, which indicated that this subspecies has 11.62 ± 0.38 mM Trolox kg-1 FW, roughly one third of S. nigra ssp. nigra evaluated in the same study, where all fruit samples were grown in Slovenia. Further work on elucidating the biological activity of this subspecies through in vivo assays and preferably clinical trials should be explored, especially using blue elderberry plants growing in North America to support its use in supplements.Elderflowers have also been evaluated for their biological activities. A review of antioxidant activity in S. nigra ssp. nigra flowers has recently been published 2 , including ABTS, DPPH, FRAP and CUPRAC assays, therefore it will not be re-summarized here. In general, the data showed that elderflower has higher levels of antioxidant activity compared to the elderberry. Similarly, elderflower extracts had higher nitric oxide inhibition compared to elderberry extracts in vitro. Elderflower is antidiabetic by increasing insulin-dependent glucose uptake, diuretic, big round plant pot treat respiratory infections, antiviral. While phenolic compounds like flavonols are presumed to be the most active compounds, pectic polysaccharides are also bioactive in elderberry and elderflower, inducing complement fixing and macrophage stimulation. Flowers of the blue elderberry have been evaluated for their antioxidant activity using the ABTS assay, which showed they have 44.87 ± 0.54 mM Trolox kg-1 DW, significantly less than flowers of S. nigra ssp. nigra . Aqueous extracts of wild elderflowers of this subspecies were also found to have neuroprotective effects, especially related to Parkinson’s disease, by increasing the antioxidant response mediated by Nrf2 in cortical astrocytes and improving mitochondrial function in neurons.13 Unfortunately, that study did not include any growing information about the elderflowers or the concentration of the phenolic compounds in the extract, which would have helped other researchers replicate and expand on the results. While there have been promising studies on the impact of elderberry and elderflower extracts to combat illness and disease, more in vivo studies and clinical trials should be performed to better understand the mechanisms of the bioactivity as well as to determine which compounds are responsible for the bioactivity, particularly in the lesser-known subspecies canadensis andcerulea. This can better inform people involved with the cultivation of elderberry to select for varieties that have the compounds of interest.The market for herbal supplements has been growing in the recent decade and immune system-supporting supplements had a huge spike in sales during the COVID-19 pandemic.
Elderberry products are a popular option of alternative medicine in hopes of improving and protecting health.33 Beverages are a popular use of the elderberry, including syrup or other tonics made by soaking the berries in water or alcohol. It can also be found as an ingredient in various kombuchas, juices, energy drinks, wine, and tea. Elderberry is typically mixed with a variety of other ingredients, including but not limited to ginger, honey, echinacea, and other spices. More recent products using elderberry include gummies typically marketed as health supplements, lozenges, tablets, and powdered berries especially as part of a drink mix. Elderberries are also frequently used in jams and jellies. Pomace, the byproduct of juicing, has been studied for its benefits when incorporated into other products just as baked goods. Beyond its potential for bioactive products to benefit consumers, elderberry can also be used as a natural food dye due to the high concentration of anthocyanins , which can be used in place of artificial red or purple food dyes, particularly in acidic foods. Its application in edible films has recently been investigated, explored various biopolymers that could retain the phenolic compounds of elderberry in the film so that they can remain active to protect foods. Active edible films can be an effective solution to reduce plastic packaging and food waste due to spoilage.Cosmetic and skin care applications are also an area of interest, and current products on the market that include elderberry include lip color, toner, face mask, and Epsom salt.Future chapters will focus on evaluating the blue elderberry and elderflower for their composition. Herein, the data available on the other elderberry subspecies of interest are summarized to provide a basis of the expected composition as well as information to compare the subspecies for their composition. Elderberries have a high amount of water, at about 80%. The main sugars in elderberry are glucose and fructose, with some small amounts of sucrose. Sorbitol was also measured, which was very minor compared to the other three sugars and was seen in the highest concentrations in the wild elderberry. Citric acid is the main organic acid in elderberry, with malic acid the next highest acid. Small amounts of shikimic, tartaric, and fumaric acid have been measured in elderberry as well. Only data on European elderberry is available for microconstituents such as vitamins, minerals, fatty acids, and amino acids. Vitamins found in elderberry include various B vitamins, vitamin C, and vitamin E. The main minerals are magnesium, calcium, and potassium. Because studies of these micronutrients have only been performed on the European elderberry, it is important for further work to include other subspecies, including the American and blue elderberry so that better comparisons can be made.An important group of bioactive compounds found in fruit and vegetables is phenolic compounds, which consist of one or more phenolic groups . Types of phenolic compounds include phenolic acids and flavonoids; flavonoids can be further separated into groups such as anthocyanins, flavonols, flavan-3-ols, and flavones. Phenolic compounds may have some biological activity, although bioavailability can be very low. A common, albeit imperfect, way to measure phenolic content of elderberries is using a colorimetric method like Folin-Ciocalteu which can measure a complex that forms between phenolic compounds and molybdenum-tungsten at 765 nm. Because this method measures all reducing agents in the matrix, reducing sugars and ascorbic acid will also react and increase the absorption thus inflating the total phenolic content . Standard curves are typically constructed using gallic acid, hence the units for TPC are gallic acid equivalents . One study has included blue elderberry grown in Slovenia, which had a TPC of 416 ± 31. However, because of the imprecise nature of this assay, it is important to identify and measure the concentration of each phenolic compound present whenever possible, the results of which is explored in the following sections.Parts of the elderberry plant are known for having toxic compounds called cyanogenic glycosides that, if consumed, can be dangerous due to the release of cyanide. The stems and leaves have the highest concentration of CNGs, followed by unripe berries and flowers, followed by ripe berries and cooked juices. The primary CNG in elderberry is sambunigrin, which is a diastereoisomer of the more commonly known CNG prunisin. Amygdalin is the next most common CNG, though it is not often measured.