The Mediterranean basin is among the richest and most complex regions on Earth: geologically, biologically, and culturally. It is a living moving mosaic because the natural landscapes and climate shaped civilizations, and we have in turn shaped nature, in a kind of symbiotic relationship, allowing a high degree of endemism species as well as the adaptation of introduced ones [1]. The Mediterranean peoples have learned to cope with nature and in building resilience to thrive. The same applies to nature in regenerating and adapting. However, the combined stresses faced by the Mediterranean region today are unprecedented and this region has been considered a climate impact hotspot and a global priority place by important international organizations ^[2][3][2,3].

Food production (from farm to fork) plays a key role with respect to Mediterranean natural assets, either by enhancing their conservation or their depletion. Industrialization and globalization brought mass production, overconsumption, different food habits with associated public health burdens, freshwater scarcity, biodiversity loss, and more. However, the combination of ancient wisdom with innovation and awareness-raising has been advocated in ensuring sustainable development and conservation of resources [1].

Food production is a driver of the devastation of natural capital, including massive biodiversity loss, soil degradation, and more ^[4][5][5,6]. There is, however, hope for fixing food systems, since in some regions of the world healthy and sustainable food habits can still be found ^[6][7], as is the case of the Mediterranean Diet (MD), which is a cultural asset recognized by the United Nations Educational, Scientific, and Cultural Organization (UNESCO) as an intangible heritage of the humankind ^[7][8]. Yet, MD is best known for its food pattern, which is well-known for being simultaneously healthy and sustainable ^[1][8][9][1,9,10]. High adherence scores to the MD can significantly enhance the nutrition quality and public health of populations ^{[9][10][11][12][13]}[10,32,33,34,35] while being respectful of the environment ^[14][15][16][36,37,38] and, in certain cases, contributing to the preservation of agro-biodiversity ^[17][18][39,40]. A change in the food system paradigm has been proposed by many, mostly consisting in promoting the adoption of more sustainable diets, with many similarities to the MD (e.g., planetary diet by the EAT-Lancet commission).

2. Phenolic Compounds

Mediterranean aromatic plants are generally rich in phenolic compounds (also known as phenols or phenolics), which are a heterogeneous group of plant secondary metabolites, having in common the presence of at least one aromatic ring and hydroxyl group (OH), which is the root for their name, as phenol is the simplest compound with such features. The designation “phenolic compounds” is broad enough to include from simple molecules to polymers, diverging not only in size but also in chemical properties (as polarity) due to differences in functional groups (such as ester and acid). Given the heterogeneity of this group of compounds, they have been named and categorized differently by different authors according to several viewpoints ^[19][55].They can be found in variable amounts in plant foods and are involved in colour (e.g., pigments), flavour (e.g., responsible for astringency, bitterness), and food safety (due to antimicrobial activity). Phenolic compounds from foods are most often valued for their general antioxidant character and they have been recently categorized as phytonutrients because of the mounting evidence and growing awareness of their health-promoting features ^[20][21][22][47,48,49]. Phenolic compounds exist in fresh vegetables (e.g., leafy vegetables, aromatic herbs, nuts) and processed (fruit juice, tea, coffee, wine) and, although their release kinetics during food digestion and bioavailability afterwards are still unclear, they seem to depend on the food matrix, on the interactions with other nutrients and more ^[23][24][25][50,51,52]. Figure 1 2 summarises the main groups of plant phenolic compounds also found in Mediterranean aromatic herbs. Some examples are included and more information (e.g., culinary uses, bioactivities) can be found in Table 1. When categorizing phenolics regarding plant metabolic pathways, three large groups can be first considered: phenolic acids, chalcones, and coumarins (Figure 12) because they can be precursors of others ^[19][55]. Phenolic acids can be precursors in the synthesis of lignins. In another pathway, chalcones may originate flavonoids, which, in turn, may condensate. Polymerization proceeds; proanthocyanidins are first oligomers and then polymers composed of units of flavanols. These polymers may ultimately originate tannins, of high molecular mass. Based on different properties, two subclasses can be considered, hydrolysable and condensed tannins ^[26][56]. Coumarins, the third large group above-referred, do not undergo any further transformation ^[27][57]. When considering overall function, structure, and occurrence, some types of compounds stand out, as is the case of flavonoids. As roughly overviewed in Figure 12, flavonoids can be subdivided into flavonols, dihydroflavonols, isoflavones, and flavanols, according to the degree of hydrogenation and hydroxylation of their three-ring structure ^[26][28][56,58]. Flavonoids bind easily to sugars resulting in a pigment whose colour grade depends on the nature of the chemical bond established between the phenol moiety and the sugar residue ^[27][57]. Flavanols, also referred to as flavan-3-ols or catechins (Figure 12), are derivatives of flavans and include catechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, proanthocyanidins, and thearubigins ^[29][59]. According to the same authors, catechin is water soluble and can chelate heavy metals and bind to proteins, including bacterial toxins of proteinaceous nature, which may explain its antimicrobial and detoxifying properties. Catechin is mostly found in green tea but is also present in rosemary. Catechin and epigallocatechin may polymerize together in different proportions, and the levels of antioxidant activity seem to depend on the degree of polymerization (Figure 12). Condensed tannins are obtained after a series of condensation and polymerization reactions ^[27][30][57,63]. Condensed tannins are thus flavanol polymers not readily hydrolysed that are responsible for the astringency taste of many plant foods ^[27][57]. As polyphenols in general, they were regarded by nutritionists as antinutrients, to be avoided. However, state-of-the-art knowledge, especially about the human microbiome, has been disclosing their relevance as phytonutrients ^[31][64]. According to Selma et al. ^[32][65], dietary polyphenols act as phytonutrients by first interacting with the gut microbiota and often being transformed by bacteria before entering the bloodstream. Still, according to the same researchers, some health benefits from phenolic compounds may result, to a large extent, from such microbial bioactive metabolites.

3. Role of Aromatic Plants in the MD Cuisine

Culinary traditions between Mediterranean countries changed significantly over the past decades, but the habit of enriching food with flavours and aromas remains across the Mediterranean countries ^[33][34][41,43]. Aromatic herbs are essential ingredients of MD, used as food additives and condiments, and as herbal teas ^[35][44]. Aromatic herbs can be a pleasant and healthier substitute for salt (NaCl) in cooking. Oregano (Origanum vulgare L.), thyme (Thymus vulgarisL.), sage (Salvia officinalis L.), and rosemary (Rosmarinus officinalis L.) are well-known aromatic herbs, which belong to the Lamiaceae family. On the other hand, the mints (a large number of species and subspecies) are widely used as medicinal aids (in folk medicine) because of their reported health-promoting actions on top of their aromas. Lemon balm (Melissa officinalis L.), Peppermint (Mentha piperita L.) and kitchen mint (Mentha spicata L.) are examples of species with subspecies found only in specific habitats. Aromatic herbs used in Mediterranean cuisine are rich in bioactive compounds and, thus, contribute to the MD’s health benefits. Some documented health outcomes of spices and herbs used in Mediterranean cuisine are highlighted in Table 1, which is focused on the native plants of the region. 

Table 1. Prominent phenolic compounds, health-promoting actions and other properties of aromatic herbs commonly used in Mediterranean cuisine.

[please insert table 1 here]

M. cervine	Near Threatened	Algeria; France (mainland); Morocco; Portugal (mainland); Spain (mainland) Possibly Extinct in Italy (mainland)
M. gattefossei	Vulnerable	Morocco
Origanum
O. cordifolium	Vulnerable	Cyprus
O. dictamnus	Near Threatened	Greece (Kriti)
O. ehrenbergii	Vulnerable	Lebanon
O. libanoticum	Vulnerable	Lebanon
Salvia
S. granatensis (formerly Rosmarinus tomentosus)	Endangered	Spain (mainland)
S. herbanica	Critically Endangered	Spain (Canary Is.)
S. peyronii	Critically Endangered	Lebanon
S. taraxacifolia	Endangered	Morocco
Sideritis
S. cypria	Vulnerable	Cyprus
S. cystosiphon	Critically Endangered	Spain (Canary Is.)
S. discolor	Critically Endangered	Spain (Canary Is.)
S. gulendamii	Endangered	Turkey
S. infernalis	Vulnerable	Spain (Canary Is.)
S. javalambrensis	Vulnerable	Spain (mainland)
S. marmorea	Critically Endangered	Spain (Canary Is.)
S. scardica	Near Threatened	Albania; Bulgaria; Greece (mainland); North Macedonia; Serbia; Turkey (Turkey-in-Europe)
S. serrata	Critically Endangered	Spain (mainland)
S. reverchonii	Endangered	Spain (mainland)
S. veneris	Critically Endangered	Cyprus
Thymus
T. albicans	Vulnerable	Portugal (mainland); Spain (mainland)
T. camphoratus	Near Threatened	Portugal (mainland)
T. capitellatus	Near Threatened	Portugal (mainland)
T. carnosus	Near Threatened	Portugal (mainland); Spain (mainland)
T. lotocephalus	Near Threatened	Portugal (mainland)
T. saturejoides	Vulnerable	Algeria; Morocco
Common Name/Species	Culinary and Folk Medicine Uses	Reported Phenolic Compounds	Evidence-Based Health Outcomes	References
Coriander/Coriandrum sativum	Both, the fresh leaves, and seeds can be used as a seasoning, with fresh leaves generally conveying a more intense aroma to rice dishes, salads, stews and more;	The flavonol quercetin 1, is reported along with gallic, protocatecuic and ferulic acids;	Antioxidant, anti-cancer, anti-microbial, anti-thrombogenic, and neuroprotective;	[36][37][38]
Oregano/Origanum vulgare L.	Very popular seasoning for salads and pizza; in folk medicine, it is believed to act as an appetiser, diuretic and anti-flatulence;	Wide range of simple phenols and phenolic acids such as thymol, carvacrol, rosmarinic acid, as well as flavonoids as naringenin, apigenin 1, luteolin 1, quercetin 1 and tannins;	Antioxidant, antimicrobial, immunomodulatory, anticancer;	[36][38][39][40]
Thyme/Thymus vulgaris	Almost mandatory in pesto (a well-known Italian sauce); folk medicine prescribes it to tackle infection and inflammation of the respiratory tract;	Besides the flagship compound, thymol, thyme is rich in flavonoids such as apigenin 1 and luteolin 1; other simple phenols as carvacrol, phenolic acids as rosmaniric and caffeic acids, have also been reported;	Antioxidant, anti-bacterial and anti-fungic activities, prevent atherosclerosis and seems to have some anti-neoplastic action;	[36][38]
Rosemary/Rosmarinus officinalis (syn. Salvia rosmarinus)	Widely used in the Mediterranean and other cuisines to season roasted meats, appetizers, and more; it has been used as food preservative;	Besides the flagship compound, rosmaniric acid, also reported are caffeic and carnosic acids, carnosol and rosmanol, in addition to the flavonoids naringin and apigenin 1;	Antioxidant, neuroprotective and anti-neoplastic activities; it is also referred to lower blood lipid’s level;	[36][37][41][42][43]
Peppermint (Mentha piperita)	The mint group comprises more than 60 species of different aromas, and all rich in phenolic compounds. They are popular kitchen garden herbs with many curative properties, according to folk medicine;	Menthol, catechin 2, cathechin-3-O-Gallate 2; epigallocatechin 2;	Antioxidant, antimicrobial, anti-inflammatory and local analgesic actions;	[37][44][45][46]
Basil (Ocimum basilicum)	The biodiversity within the “basil” group has been economically valorised by marketing varieties with different colours and aromas. Basil is widely used in pasta and salads;	Eugenol and a wide range of other phenolic compounds not identified and/or typical of certain cvs;	Antioxidant, anti-microbial, and anti-neoplastic activities;	[47][48]
Phennel (Foeniculum vulgare)	The whole plant can be used in culinary preparations, with meats, in stews, deserts or liquors;	Besides the flagship compound, p-Anisic acid, other reported phenolic acids are hydroxybenzoic, ferrulic and o- and p-coumaric acids, as well as the flavonoids isorhamnetin (related to quercetin), quercetin 1, myricetin 1, kaempferol 1, and luteolin 1;	Antioxidant, anti-inflammatory, and anti-diabetic properties;	[37][49][50]
Chilli-pepper (Capsicum annuum)	The fruits are used directly or smashed for a hot seasoning; Capsaicin is the pungent compound and the main bioactive molecule.	(Capsaicin); luteolin 1 and quercetin 1.	Antioxidant, analgesic, anti-cancer and anti-inflammatory properties.	[37][51][52]