Ocimum basilicum (Basil)
Basil (Ocimum basilicum L.) is an annual plant originally from South Asia, which belongs to the Lamiaceae family and has many and varied uses due to its multiple properties. It is one of the species of aromatic medicinal plants that has a high content of essential oils, especially eugenol, widely used in medicine. In the Middle Ages, basil was among the magic medicinal plants, since its content in essential oils, tannins, glycosides and saponins made it very effective in the treatment of gastric, respiratory and urinary disorders.
In addition, it has anti-inflammatory, antioxidant and antiseptic properties, which is why it is used in the cure of different diseases (Argueta and Cano, 1994; Sam et al., 2002; Salazar, 2003; Lee et al., 2005; Arvy & Gallouin, 2007).
Due to its characteristic fragrance and flavor (Koba et al., 2009) it also has a diversity of uses in food, cosmetics, perfumes, oral and dental products, liquors, pesticides and medicines (Lachowicz et al., 1997; Murillo et al., 2004; Arvy and Gallouin, 2007; Koba et al., 2009). For all these reasons, the chemical composition of the essential oil of basil has been extensively investigated in different countries, and it has been found that it varies greatly according to the geographical origin of the plant (varieties), its state of vegetative development and agronomic conditions in its production (Viña and Murillo, 2003; Lee et al., 2005; Arvy and Gallouin, 2007; Koba et al., 2009). Aromatic compounds, such as methyl chavicol (estragole), methyl cinnamate, methyleugenol, eugenol, linalol, and geraniol, have been reported as major components of O. basilicum oils (Sajjadi, 2006; Wossa et al., 2008).
Salvia officinalis (Salvia)
A series of plants belonging to the botanical genus Salvia. This name derives from the Latin salvere (to be saved) due to its healing qualities, which are known since ancient times (Ortega et al., 2002). In general, the genus salvia includes very aromatic plants, many of them acclimatized to Mediterranean countries.
All the species of this genus present a complex chemical composition with abundant metabolites of terpenic nature: monoterpenes and sesquiterpenes constituted by their essential oils, diterpenes (carnosol, rosmanol, epirrosmanol, carnosic acid) and triterpenes derived from ursane and oleanane.
They also have abundant flavonoids and phenolic acids, mainly rosmarinic acid. More specifically, the species Salvia officinalis contains essential oils in large quantities (0.8-2.5%) whose chemical composition is notable for its abundance of tannins (salviatanin), phenolic acids (rosmarinic, caffeic, chlorogenic, ferulic, etc.), flavonoids (luteolin, apigenin, genkwanin, hispidulin, cirsimaritin, nepetin and cirsiliol), α-D-Thymol, menthol and thujol glycosides, diterpenes (carnosol, carnosic acid and rosmanol), triterpenes (α-amirin and ß-amirin, betulin, ursolic acid and oleanolic acid), and finally phytosterols (ß-sitosterol, stigmasterol) (Lu and Foo, 2000; Wang et al, 2000; Miura et al, 2001).
Salvia officinalis has been attributed numerous pharmacological activities in traditional medicine; however, only a few have been scientifically validated. According to various publications, the leaves show antibacterial, fungistatic and virostatic activity (Jakovljevic et al., 2019; horbani et al., 2017). It is also an astringent and sweat inhibitor, and increases cognitive potential (Zeidabadi et al., 2020; Lopresti, 2019).
Rosmarinus officinalis (Rosemary)
Rosemary (Rosmarinus officinalis) is a Mediterranean plant whose term is derived from the Greek rhops and myrinosque meaning “sea bush“ because of its near-shore growth (Alonso, 2004). Various chemical compounds have been reported in this plant species, which have been generally classified by various authors as phenolic acids, flavonoids, triterpenic acids, and triterpenic alcohols with a high content of essential oils (Caribe & Campos 1991, Botsaris 1995, Atti-Santos 2005).
In general, the chemical composition of rosemary essential oil has been described in works that indicate the type of active molecules present. The presence of α-pinene, β-pinene, camphene, terpenic esters such as 1,8-cineole, camphor, linalol, verbinol, terpineol, carnosol, rosmanol, isorosmanol, 3-octanone, isobanyl-acetate and β-caryophyllene have been identified. This plant specie also produce vanylic, caffeic, chlorogenic, rosmarinic, carnosic, ursolic, oleanolic, butylinic, betulinic, betulin, α-amirin, β-amirin, borneol, and bornyl acetate (Ruiz 2000, Almela 2006, Montes de Oca 2010, Tschinggeri & Bucar 2010).
Studies have been made in countries such as Spain, India, Germany, the United States, Japan, Italy, Libya, etc., because of its potential therapeutic value that has evolved over the years from its popular use. The work of Al-Sereiti et al. (1999) describes the pharmacology of rosemary and its therapeutic potential. Dozens of properties have been reported in rosemary, such as appetite stimulant, digestive, limb circulation enhancer, anti-rheumatic, anti-inflammatory and even anti-cancer effect, to mention just a few (Borges et al., 2019; de Oliveira et al., 2019; Moore et al., 2016).
Origanum vulgare (Oregano)
Origanum vulgare is a species native of the European Mediterranean, and the first references to its culinary and medicinal use are found in Hellenic reviews (Chavez et al., 2007). This species is an aromatic plant, which is sensitive to altitude; in fact it adapts very well to the inter-Andean valleys at around 2600 m.a.s.l. (Vokou et al., 1993). Below that altitude, the concentration of essential oil, especially thymol and carvacrol, decreases (Hernández & Madrid,2004).
Origanum vulgare is one of the plants with the highest antioxidant capacity in nature (Boskovic et al., 2019).
The antioxidant function of various compounds in foods has attracted much attention in relation to their role in the diet and in disease prevention (Kahkonen et al., 1999). A wide variety of phenolic antioxidant compounds have been isolated in some spice studies. The antioxidant effect of plants is due to the presence of hydroxyl groups in phenolic compounds such as carvacrol and thymol (Sharifi et al., 2018; Azuma et al., 1999; Deighton et al., 1993).
In addition to their properties as antioxidants, thymol and carvacrol have properties as antifungal, antibacterial, acaricidal, analgesic, anti-acne, antispasmodic, deodorant or expectorant agents (Vinciguerra et al., 2019; Taleb et al., 2018; Duke et al., 2002). The biological activities of oregano also include antiparasitic, estrogenic and insecticidal activity (Boskovic et al., 2019; Habbadi et al,. 2018; Sharifi et al., 2018; Carezzano et al., 2017).
Lavandula hybrida (Lavender)
Lavandula hybrida is a hybrid plant obtained by crossing common lavender (Lavandula officinalis) with lavender (Lavandula angustifolia). It is hypothesized that the terminology of the genus derives either from λανω in Greek and lǎvo, lǎvātum from the Latin which refers to the use of plant infusions for washing or from the Latin līvěo, referring to the characteristic color of the flowers of such plants (Morales, 1997). They are perennial plants with the corolla of the bilabiate flower and its characteristic lavender or violet colour, widely distributed and especially in the Mediterranean basin.
This hybrid spice looks very similar to real lavender, but it produces twice as many flowers and its stems have a stronger aroma due to the higher content of essential oils; hence it is used much more as an industrial novelty in perfumes and cosmetics. But this species is not only used for commercial purposes in the industry of perfumes or fragrances, but it’s essential oils contain interesting biomolecules mostly 1,8-cineole, borneol, camphor, linalool or linalyl acetate that give it properties as a bactericide, antiviral and antidepressant (Bajalan et al., 2017; Hritcu et al., 2012). In addition, lavandin is considered to share many of the properties of lavender, such as its calming, repairing, anti-fungal, anti-parasitic and even anti-thrombotic effects (Ebani et al., 2017; Nardoni et al., 2017; Ballabeni et al., 2014).
Hypericum perforatum (St John's Wort)
Hypericum perforatum, known as St. John’s wort is an herbaceous plant of the Hypericaceae family, which grows wild, at the roadside and in dry environments. The tradition of St. John’s Wort goes back a long way, as Hippocrates quotes it for its use as an analgesic and against anxiety, and in ancient times it was believed that even its fragrance drove away evil spirits. The chemical composition of St. John’s Wort is very complex; among its components we can highlight substances such as naftoditrones, hypericin, hyperforin, adhiperforin; flavonoids such as hyperoside, quercetol, rutoside, quercitoside, or xanthones, tannins, phenolic acids, carotenoids or sterols of the beta-sitosterol type (Villar del Fresno et al., 2003).
On the edges of its leaves and flower petals there are glandular secretory structures, trichomes, that contain the anthraquinonic pigments such as hypericin which is the main active ingredient (Villar del Fresno et al., 2003). In fact, the molecules hypericin and hyperforin, are the main responsible for improving the discouragement by their antidepressant properties (Oliveira, 2016). They are known to act on various neurotransmitters, chemicals related to emotions and mood in the joints; Barnes et al., 2001; Greeson et al., 2001; Patocka, 2003; Butterweck and Schmidt, 2007).
In addition, the external use of this plant extract has anti-inflammatory properties such as wound healing, minor burns, skin inflammations or joint pain (Barnes et al., 2001; Greeson et al., 2001; Patocka, 2003).
The genus Cannabis, which includes hemp or marijuana, is originally from the highlands of Central Asia, but is now spread globally thanks to human intervention. Because of its fast propagation and environmental adaptability, these species had a great impact on the expressions of various cultures; it was used as a source of textile fibre, to extract the oil from its seeds, as a medicinal plant for more than 4000 years or even as a psychotropic and mystical and spiritual tool (Malpica et al., 2009; Ben Amar, 2006). It is an annual herbaceous plant whose vegetative period is close to a year: and whose peculiar characteristic is that it presents different types of trichomes, or vegetable hairs, which are responsible for synthesizing medicinal biomolecules.
Probably the best known ingredient of Cannabis is the psychoactive molecule a Δ-9-tetrahydrocannabinol (THC), but there are many varieties of this plant species with a minimum and permitted content of this THC molecule but very high content of other molecules with high therapeutic value and permitted by law. In fact more than 480 compounds have been identified in this plant genus (Elsohly M,2005). The functionality of cannabidiol and cannabigerol molecules in medicinal Cannabis spp. species, and with low THC content, are the main reason that this plant extract is starting to be used as a functional food for gastrointestinal diseases, metabolic, neurodegenerative and/or neuroinflammatory diseases (Ben Amar, 2006).
Indeed, in recent years a number of scientific evidences have been published about the therapeutic properties of cannabinoids like analgesia, decrease of intraocular pressure, antiemetic effect in vomits induced by chemotherapy, muscle relaxing properties in several diseases like multiple sclerosis, spinal cord injuries and movement disorders (Byars et al., 2019; Iannotti et al., 2019; Miller et al., 2018; Sanchez-Robles et al., 2012). Furthermore, some recent contributions indicate other possible uses of these substances as neuroprotectors (in animal models of neurodegenerative diseases and brain ischemia), anti-asthmatics and anticonvulsants (Chatkin et al., 2019; Campos et al., 2016).
Cnicus benedictus (St. Benedict's thistle)
Cnicus benedictus is an annual plant of the Asteraceae family, originally from Europe, and very common in areas of the Mediterranean; although it is currently also found in the United States and South America. The term benedictus comes in honor of the Benedictine monks who used it in the Middle Ages to treat bubonic plague (Grieve, 1973). Traditionally, Cnicus benedictus is a plant whose leaves, flowers, fruits and seeds have multiple medicinal uses varying from the treatment of diseases such as anorexia, indigestion, diarrhea, dyspepsia and diabetes to remedies for disorders of the liver and bile duct (Natural Standard Monograph. 2008; Vogel, 2005; van Wyk & Wink 2004; Chevalier, 2000).
In fact, it is a powerful hepatoprotector as it contains silymarin, which helps protect and regenerate liver cells, in quite delicate diseases such as cirrhosis, liver failure and fatty liver (Natural Standard Monograph. 2008; van Wyk & Wink 2004). Apart from this molecule, it has a complex phytochemical profile producing interesting sesquiterpene lactones of the glycoside or germacranolid type, mainly cnidine, accompanied by benedictine; phenolic acids: chlorogenic and synapic or flavonoids such as apigenol oglucosides and luteol. Biomolecules such as cnicin, artemisiifolin or astragalin have properties for arthritis, ulcers, colic, or bacterial infections.
Although there is still a lot of research to be done, in the last few years a possible and important role has been seen in the treatment of some types of cancer, enhancing the medication used in it. The aerial parts of this plant could protect patients from the strong and abrasive effects of chemotherapy (Peng et al., 2017; Vijaylakshmi et al., 2009). Studies of Cnicus benedictus are already underway for acute lymphoblastic leukaemia, prostate, breast and head and neck cancer (Peng et al., 2017).
Artemisia vulgaris is one of many medicinal plant species in the genus Artemisia. Etymological studies of this genus Artemisia: reveal that it probably owes its name to Apollo’s twin sister, Artemis, Greek goddess of hunting and healing virtues.
It is an herbaceous perennial plant native to moderate temperature zones of Europe, Asia and North Africa. In the Middle Ages, this plant was used as a magical protective herb, against fatigue, to repel insects, and to protect travelers from evil spirits.
In a more scientific way, and like several species of the same genus, the species Artemisia vulgaris has digestive, antiparasitic, antibacterial, anti-inflammatory, antioxidant and anti-cancer properties due to biomolecules such as vulgarin, prunasol or tujona (Soon et al., 2019).
Moreover, in the last decades different scientific studies have revealed that this therapeutic potential is also due to other molecules belonging to different types of secondary metabolites such as flavonoids, sesquiterpenes, coumarins, acetylenes and phenolic acids (Abiri et al., 2018; Judzentiene et al., 2018).
Of special relevance are its essential oils containing molecules such as cineol or thujone, flavonoids, triterpenes or coumarin derivatives which are used not only for their therapeutic properties as anthelmintic, hepatoprotective, atopic dermatitis or natural repellent but also for their great and characteristic aroma in perfumery and cosmetics (Jiang et al., 2019; Bedini et al., 2017; Khosravi et al., 2016).
The reference to Artemisia absinthium as a medicinal plant is already found in the Egyptian papyri, the first Mesopotamian texts and in many parts of the Bible. Artemisia absinthium, commonly known as wormwood, is an aromatic, perennial and small shrub. Wormwood essential oil has been widely used mainly for its neuroprotective, anti-inflammatory, anti-fungal, anti-microbial, insecticidal, anti-malarial,hepato-protective properties (Moaca et al., 2019; Wei et al., 2019;) and even antiviral (Nakamura et al., 2015).
In fact, in 2014 (the antiviral properties of extracts of Artemisia absinthium were evaluated both in vitro and in vivo, concluding that they have a very high inhibitory effect on viral activity (Marraiki et al., 2014).
This plant contains a wide range of essential oils, polyphenols, coumarins, polysaccharides, saponins such as quercetin, nerolidol and davanone. But thujones (α-tujona and β-tujona) represent the main component of this variety of Artemisia, sometimes more than 50% of the total essential oil. Thujone, a ketone, also present but in smaller amounts in Artemisia afra, is known to induce immune responses, through increases in T-lymphocytes (Siveen et al., 2011). This molecule is also known for its bactericidal, vermicidal and antimalarial properties (Rusking et al., 2009; Shams et al., 2012).