**2. Elderberry and elderflower applications**

**1. Introduction**

60 Secondary Metabolites - Sources and Applications

composition.

A growing interest in the exploitation of natural products as sources of bioactive compounds with potential health benefits has been observed, particularly in the consumption of plant-based products that are able to prevent, ameliorate, or even treat chronic diseases with increasing incidence in the advent of the twenty-first century [1]. The elderberry plant (*S. nigra* L.) may be reported to illustrate this trend, especially due to its potential impact on the local economies as a raw material used to produce, specially, food and beverages, but also

*S. nigra* flowers and berries have been widely used in folk medicine for numerous applications that include antimicrobial, antiviral, antioxidant, anti-inflammatory, anticancer, antidiabetic applications, among others [2–6]. The detailed knowledge of the chemical composition of *S. nigra* is not only extremely important to understand its biological effects but also to improve its value and applicability. Elderberries and elderflowers received increased attention due to the presence of phytochemicals with many reported health benefits, comprising, among others, vitamins, terpenic, and phenolic compounds [5]. Volatile and semi-volatile terpenic components (mono and sesquiterpenics), in particular, are plant secondary metabolites that play key roles in their protection and communication processes. They are often reported as toxic to some microorganisms involved in plant-insect interactions [7, 8]. Additionally, they confer plant protection against oxidative stress, namely as thermo-tolerance mediators [9], playing important roles in their adaptation to biotic and abiotic stresses [10]. On the other hand, the transcriptional regulatory network to different biotic and abiotic stresses is reflected on the plant metabolism, as well as phenological processes, such as on ripening [11], which ultimately will impact the plant secondary metabolites' profile. Nonetheless, these effects are

Understanding those effects could be of extreme importance, given that mono and sesquiterpenic-based extracts are commercially important, namely for pharmaceutical/nutraceutical, agronomic, food, sanitary, and cosmetic industries. For instance, limonene and linalool, two of the most used monoterpenic compounds, are often employed in perfumes, creams, soaps, as flavor additives for food, as fragrances for household cleaning products and as industrial solvents [8]. In the particular case of potential health benefits-related applications, these compounds have been reported as exhibiting hepatoprotection [12], anti-inflammatory [13], analgesic [14], and antioxidant [15] activities, among others [16]. These effects are strongly dose-dependent, which reinforce the need to study in detail the terpenic composition of *S. nigra* berries and flowers, in-depth, and the variables that have an impact on their

The challenge to understand the impact of pre- and postharvest processes over the mono and sesquiterpenic compounds is the first step to further establish approaches that can control the variables that have a significant effect over these processes. Hence, the present chapter is devoted to a detailed discussion of *S. nigra* mono and sesquiterpenic composition, and of the parameters, such as pre- and postharvest conditions, that modulate their composition. Also, a

general perspective of *S. nigra* L. berries and flowers relevance and uses is reported.

nutraceutical and cosmetic products derived from berries and flowers.

still poorly explored and understood, particularly in the case of *S. nigra.*

Flowers and berries from *S. nigra* species have long been used in folk medicine for prophylactic and therapeutic purposes, being considered the medicinal "chest" from the days of Hippocrates [17]. The relief of early symptoms of common cold using elderflowers fulfills the requirement of medicinal use according to the Committee on Herbal Medicinal Products [3]. Elderflowers were also used to alleviate bronchial and pulmonary diseases, tumors, and ulcers [18]. Laxative [19], treatment of asthma [20], toothache, colic, cold, and rheumatic conditions [21, 22] have been reported, as well as bronchitis, whooping cough, hemorrhoids, expectorant [20], insect bites, and fever [21]. Elderberry preparations are traditionally used as laxative, diaphoretic [2], for fever reduction [19], anti-rheumatic, and to treat colic in infants [23]. Their juice has also been used to treat sciatica, headache, dental pain, heart pain, nerve pain, while the syrup was recommended to treat cough and cold [2].

This species has gained attention due to its diverse uses, assimilating in markets from food and herbal industries. In 2010, *S. nigra* (flowers and berries) was the most harvested medicinal plant intended for export trade and for infusions and phytopharmaceutical production in Bulgaria and Romania [24]. Additionally, elderberry was ranked on the Top 20 best-selling herbal dietary supplements in the medicinal, food, and mass market in the USA in 2011–2014, with increasing sales of 64% in 2014 [24, 25].

One of the main uses of elderberries is the production of natural food colorants, juices, and concentrates, due to their high content in phenolic compounds [26]. Those are also exploited for the formulations of decoctions [2, 19], infusions [23], juice and syrup/concentrate [2], extracts, supplements, pies, ice creams, jellies, juices, beverages, beers, wines, liqueurs, and fruit bars [27–29]. In addition to color, flavor (taste and aroma) is also an important parameter in the consumer perception and product acceptance [30]. Due to the pleasant and characteristic floral aroma, elderflowers are often used as flavoring agents [31] for the preparation of infusions, decoctions [19–22], pastry products [23], nonalcoholic cordials, and fermented beverages [18, 23]. Elderflowers are characterized by an intense, pleasant, and characteristic aroma, currently named as elderflower aroma [32, 33]. Despite the role of esters, alcohols, and aldehydes, monoterpenes, as limonene, terpinolene, and terpinene, present a relevant contribution for the elderflowers fruitiness aroma [34], and more exotic notes, such as woody and spicy, have been attributed to some mono and sesquiterpenic compounds [32, 34].
