**1. Introduction**

The genus *Sideritis*, belonging to the Lamiaceae (Labiatae) family, is comprised of more than 150 species. The genus is further divided in 2 subgenera and 7 sections [1]. The subgenus *Sideritis* divided into four sections includes approximately 125 species, the majority of which are distributed in the Mediterranean [2]. The taxonomy of *Sideritis* species is highly intricate due to frequent hybridization between species, the variation of ecotypes and the degree of polymorphism [3]. It is crucial to distinguish the different *Sideritis* species and it is for this reason that secondary metabolites, in particular diterpenoids and flavonoids, are used for the chemotaxonomic identification of species within the genus [1]. However, modern methods such as high resolution melting analysis (HMR) coupled with polymerase chain reaction (PCR) offer rapid detection of these species [3].

*Sideritis perfoliata* L. (subsp. *perfoliata*) belongs to section Empedoclea, and is distributed mainly in Greece, Cyprus, Turkey and in other Balkan and East Mediterranean countries, where it grows in the wild or is cultivated [4]. This perennial species has a woody base, opposite and entire leaves (dentate or serrate) and is widely distributed in the Mediterranean Basin which is characterized by a rich tradition in phytotherapy, dating back to ancient times [5]. The usage of *Sideritis* species in folklore medicine has been known since the Dioskourides era (1st century) when the plant was used to treat wounds from iron weapons like swords or knives. The name *Sideritis* comes from the word "sidero" which means iron in Greek [1].

Plants of the *Sideritis* genus, commonly known in Cyprus, Greece and other Balkan countries as "mountain tea", are used as teas, for feeding and as flavoring agents. *Sideritis* species are used extensively in European and Mediterranean countries as traditional medicines with anti-inflammatory, antimicrobial, vulnerary, antioxidant, antispasmodic, analgesic, stomachic and carminative activities [1, 6,7]. Decoctions and infusions of *S. perfoliata* are widely used for the treatment of common cold, flu, cough, gastrointestinal disorders such as dyspepsia and as a calmative agent [6,8]. Charami et al. [9] reported the use of *S. perfoliata* for its antirheumatic, anti-ulcerative, digestive and vaso-protective properties. Recently, botanical and pharmacological studies focusing on *Sideritis*, is likely due to the above-mentioned properties which have been proven and have been attributed to the diverse chemical profile of the genus, that is rich in flavonoids, terpenoids, coumarins, sterols and iridoids [1,7]. These properties, the advances in technology and the current popularity and the use of natural products for self-medication, and as dietary supplements, generates a growing interest in the pharmaceutical industry to exploit plant-derived products to serve as discovery leads to new prototypes [10].

Medicinal and aromatic plants are enriched with antioxidants such as polyphenols, which act as scavengers of free radicals by adsorbing and neutralizing reactive oxygen species (ROS), quenching singlet and triplet oxygen or decomposing peroxides [9]. The Mediterranean Basin is characterized by a rich tradition of phytotherapy dating back to ancient times, in addition to being home to the majority of the *Sideritis* species. The aim of the current study was to explore the unknown properties of *S. perfoliata* investigating nutritional, antioxidant, anticancer, antituberculosis, antiwrinkle, anti-acne, hyper/hypo-pigmentation and antibacterial properties.
