**3. Active compounds in herbs and spices**

Antioxidants are compounds that prevent or delay the initiation of oxidation. Because of safety concerns regarding synthetic antioxidants, natural antioxidants are becoming increasingly popular. Furthermore, people are becoming

#### **Figure 1.** *Spices and herbs classification [17, 18].*

more interested in natural products and less ingredients in food products [19]. Flavonoids, coumarins, carotenoids, curcumins, saponins, lignans, polyphenolics, terpenoids, sulfides, phthalides, and plant sterols are all found in herbs and spices. The most powerful antioxidants found in herbs and spices are phenolic compounds, which have at least two hydroxylic groups in the ortho or para orientations, such as caffeic acid. These compounds have been employed as antioxidants in the form of herbs, ground spices and extracts, capsules, or emulsions [19, 20]. The antioxidants contained in herbs and spices can be classed based on their chemical structure. Flavonoids, phenolic acids, catechins, volatile phenols, phenolic diterpenes, polyalkoxybenzenes, ligans, sulfuric compounds, and ascorbic acid are the primary families of chemicals [19].

More than 6000 flavonoids have been recognized as ubiquitous in photosynthesizing cells, and they are frequently found in vegetables, fruits, nuts, stems, seeds, flowers, tea, wine, propolis, and honey [21]. Plants use phenolic compounds to defend themselves, build structures and attract pollinators and seed-dispersing animals. Plants produce these compounds to protect themselves from UV radiation and to adapt to their surroundings [19]. Flavonoids may also be beneficial in the human body, treating conditions, such as flu and colds (due to their antiviral, antibacterial, and antifungal activity), cancer (particularly lycopene and quercetin), allergies (quercetin), cardiovascular disease, and neurodegenerative disorders, including Parkinson's disease, multiple sclerosis, Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis. It may also function as a preventative strategy against eye diseases (cataracts and macular degeneration) (anthocyanins and lycopene), and in protecting the eye from the harmful effects of UV radiation (lutein and zeaxanthin) [22]. Some flavonoid metabolites, such as sulfates, omethylated, and glucuronides, may participate directly in plasma antioxidant activities by scavenging reactive oxygen and nitrogen species in the bloodstream [23]. Common antioxidants that occur in herbs and spices are presented in **Table 1**.



*Herbs and Spices' Antimicrobial Properties and Possible Use in the Food Sector DOI: http://dx.doi.org/10.5772/intechopen.108143*


*The botanical names of the plants were verified using the World flora online (http://www.worldfloraonline.org/).*

#### **Table 1.**

*Antioxidants isolated from herbs and spices.*
