Classification (APG IV)
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Lamiales
Family: Lamiaceae
Genus: Marrubium
Species: White horehound - Marrubium vulgare L.

Botanical Description
White horehound (Marrubium vulgare) is a perennial herbaceous plant from the Lamiaceae family, growing 30–60 cm tall. The stems are erect, branching, and covered with white woolly hairs. The leaves are round to ovate, usually toothed to serrated, mosaic-veined, hairy on the upper surface, and arranged in opposite pairs along long stems. [1]

The flowers are arranged in spherical whorls along the stem in the leaf axils. The perianth is double-layered and five-parted, bilabiate. The calyx forms a tube slightly shorter than the corolla and has hooked tips. The corolla is white, with the lower lip slightly notched. The upper lip is narrow, longer than the lower lip, and bilobed with a keel-shaped notch. There are four stamens, two longer and two shorter, attached to the corolla tube. The ovary is bicarpellary and four-chambered. The fruit is a schizocarp, splitting into four nutlets. [2]

Distribution
White horehound is widespread in Europe, America, and Asia and is cultivated as a crop. [2] Its native distribution is believed to be between the Mediterranean region and Central Asia. The plant prefers alkaline soils. [1] In Estonia, it has been found as an alien weed on Saaremaa. [2]

Effects and Uses
The herb is harvested during flowering and dried for use. White horehound contains bitter glycosides, tannins, caffeic acid derivatives, essential oil, saponins, flavonoids, phenolic acids, coumarins, and alkaloids. [2] Its primary active compound is the diterpenoid marrubiin, which has proven effective against certain parasitic fungi. [3,4]

White horehound is a potent expectorant and an effective remedy for coughs. It also stimulates appetite, aids digestion, promotes bile production, and reduces flatulence. The recommended daily dose is 4.5 g. [2] Externally, it is applied as an antimicrobial agent on wounds, and its juice relieves itching caused by insect bites. In homeopathy, fresh leaves are used for stomach and skin inflammation. [2] The plant has been noted to accelerate wound healing. [5]

In folk medicine, white horehound is used for respiratory and digestive disorders and as a calming and sleep-inducing remedy. In ancient times, it was used to treat rabies. [2]

References
1. A´cimovi´c, M., A´cimovi´c, A., Jeremi´cjeremi´c, K., Salaj, N., Gavari´cgavari´c, N., Kiprovski, B., Sikora, V., & Zeremski, T. (2020). Marrubium vulgare L.: A Phytochemical and Pharmacological Overview. Molecules, 25(2898). https://doi.org/10.3390/molecules25122898
2. Raal, A. (2010). Maailma ravimtaimede entsüklopeedia. Eesti Entsüklopeediakirjastus.
3. Rezgui, M., Majdoub, N., Mabrouk, B., Baldisserotto, A., Bino, A., Ben Kaab, L. B., & Manfredini, S. (2020). Antioxidant and antifungal activities of marrubiin, extracts, and essential oil from Marrubium vulgare L. against pathogenic dermatophyte strains. Journal de Mycologie Médicale, 30(1), 100927. https://doi.org/10.1016/j.mycmed.2020.100927
4. Popoola, O. K., Elbagory, A. M., Ameer, F., Hussein, A. A. (2013). Marrubiin. Molecules, 18(8), 9049–9060. https://doi.org/10.3390/molecules18089049
5. Amri, B., Martino, E., Vitulo, F., et al. (2017). Marrubium vulgare L. Leaf Extract: Phytochemical Composition, Antioxidant, and Wound Healing Properties. Molecules, 22(11), 1851. https://doi.org/10.3390/molecules22111851

Süstemaatiline kuuluvus (APG IV)
Riik: Taimed (Plantae)
Klaad: Soontaimed (Tracheophyta)
Klaad: Katteseemnetaimed (Angiospermae)
Klaad: Päriskaheidulehelised (Eudicotyledonae)
Selts: Iminõgeselaadsed / Lamiales
Sugukond: Huulõielised / Lamiaceae
Perekond: Penimünt / Marrubium
Liik: Ürt-penimünt / Marrubium vulgare L.

Botaaniline kirjeldus
Ürt-penimünt on mitmeaastane 30–60 cm kõrgune huulõieliste sugukonda kuuluv rohttaim. Varred on püstised, harunevad, valgevillakarvased. Lehed on ümarad kuni munajad, tavaliselt hambulised kuni täkilised, mosaiikselt soonelised ja pealt karvased ning asetsevad pikal varrel vastakute paaridena. [1] Õied asetsevad piki vart kerajates õiemännastes lehtede kaenaldes. Õiekate kaheli, viietine, huuljas. Tupplehed moodustavad kroonist pisut rohkem kui poole lühema putke, millel on konksjad tipmed. Õiekroon valge. Alumine huul veidi pügaldunud. Ülemise huul kitsas ja laumisest pikem, kahehõlmaline, kiilja sisselõikega. Tolmukaid on neli, kaks pikemad, kaks lühemad, need kinnituvad krooniputkele. Emakas on kaheviljalehine ja neljakambriline. Vili on neljaks pähklikeseks jagunev skisokarp (jaguvili). [2]

Levila
Ürt-penimünt on levinud Euroopas, Ameerikas ja Aasias ning teda kasvatatakse kultuurina. [2] Taime levik on alguse saanud Vahemere ja Kesk-Aasia vahelisest piirkonnast. Taim eelistab kasvamiseks aluselist mulda. [1] Eestis on taime leitud tulnukumbrohuna Saaremaalt. [2]

Toime ja kasutamine
Droogiks on ürt, mida kogutakse õitsemise ajal ja kuivatatakse. Ürt-penimünt sisaldab mõruglükosiide, tanniine, kohvhappe derivaate, eeterlikku õli, saponiine, flavonoide, fenoolhappeid, kumariine ja alkaloide. [2] Oluliseks toimeaineks peetakse diterpenoid marrubiini. Marrubiin on tõestanud oma efektiivsust teatud tüüpi parasiitsete seente vastu. [3,4]

Ürt-penimünt on oma rögalahtistava toime tõttu tõhus köharohi. Samuti parandab taim söögiisu, soodustab seedimist ja sapi teket ning vähendab kõhugaase. Soovituslik päevane annus on 4,5 g. [2] Välispidiselt pannakse teda mikroobivastase vahendina haavadele, mahl võtab ära putukapiste tekitatud nahasügeluse. Homöopaatias kasutatakse värskeid lehti mao- ja nahapõletiku korral. [2] On täheldatud haavade paranemist kiirendavat toimet. [5] 

Rahvameditsiinis kasutatakse ürti hingamisteede haiguste ja seedehäirete korral ning rahustava ja und soodustava vahendina. Antiikajal tarvitati penimünti marutõve korral. [2]

Kasutatud allikad
1. A´cimovi´c, M., A´cimovi´c, A., Jeremi´cjeremi´c, K., Salaj, N., Gavari´cgavari´c, N., Kiprovski, B., Sikora, V., & Zeremski, T. (2020). Marrubium vulgare L.: A Phytochemical and Pharmacological Overview. Molecules, 25(2898). https://doi.org/10.3390/molecules25122898
2. Raal, A. (2010). Maailma ravimtaimede entsüklopeedia. Eesti Entsüklopeediakirjastus. 
3. Rezgui, M., Majdoub, N., Mabrouk, B., Baldisserotto, A., Bino, A., Ben Kaab, L. B., & Manfredini, S. (2020). Antioxidant and antifungal activities of marrubiin, extracts and essential oil from Marrubium vulgare L. against pathogenic dermatophyte strains. Journal de mycologie medicale, 30(1), 100927. https://doi.org/10.1016/j.mycmed.2020.100927
4. Popoola OK, Elbagory AM, Ameer F, Hussein AA. Marrubiin. Molecules. 2013 Jul 29;18(8):9049-60. doi: 10.3390/molecules18089049. PMID: 23899837; PMCID: PMC6269822.
5. Amri, B., Martino, E., Vitulo, F., Corana, F., Kaâb, L. B., Rui, M., Rossi, D., Mori, M., Rossi, S., & Collina, S. (2017). Marrubium vulgare L. Leave Extract: Phytochemical Composition, Antioxidant and Wound Healing Properties. Molecules (Basel, Switzerland), 22(11), 1851. https://doi.org/10.3390/molecules22111851