Leucas zeylanica
{{Short description|Species of flowering plant}}
{{Speciesbox
|image = Leucas_zeylanica.jpg
|genus = Leucas
|species = zeylanica
|authority = (L.) R.Br.
|synonyms = Leucas bancana Miq.
Phlomis zeylanica Linn.
Spermacoce denticulata Walp.
}}
Leucas zeylanica, commonly known as Ceylon slitwort,{{cite web |url=http://www.virboga.de/Leucas_zeylanica.htm |title= Leucas Zeylanica | publisher=virboga.de |access-date=2012-03-28 }} is a small, terrestrial, herbaceous, annual, erect or sometimes tufted, hispid and aromatic plant of the subfamily Lamioideae of family Lamiaceae. It is native to tropical Asia.{{cite web |url=http://www.tropicos.org/namesearch.aspx?name=leucas+zeylanica |title= Leucas Zeylanica List| publisher =tropicos.org |access-date=2012-03-28 }}{{cite web |url=http://www.ipni.org/ipni/advPlantNameSearch.do?find_authorAbbrev=&find_infragenus=&find_includeBasionymAuthors=on&find_isIKRecord=on&find_includePublicationAuthors=on&find_isAPNIRecord=on&find_family=&find_infrafamily=&find_infraspecies=&find_isGCIRecord=on&find_publicationTitle=&find_genus=Leucas&find_species=zeylanica |title=The International Plant Name Index - Leucas Zeylanica List | publisher=ipni.org |access-date=2012-03-28 }}
Description
The plant grows to a height of up to {{convert|120|cm|abbr=on}}. Stipules are absent, the taproot is white or brown, and the stem is quadrangular. Sub-sessile leaves are linear-lanceolate or elliptic-lanceolate, {{convert|2.5-7.5|cm|abbr=on}} long, not lobed or divided, blunt at the tip, obtuse, entire or cerrulate, glandular, hispid and coarsely dentate at the margins. Whorls of many flowers are bisexual, sessile or sub-sessile, usually in terminal whorls {{convert|1-2|cm|abbr=on}} in diameter, grouped together in an axillary, corolla white in color and 2 cm long. Calyx is {{convert|5-7|mm|abbr=on}} long, and obliquely turbinate, with minute teeth, apex acute, base acute, pinnately veined, erect or spreading horizontally. It is reproduced by seed and pollinated by bees moths and flies. Leucas belongs to the subfamily Lamioideae, and is closely related to the small genera Acrotome and Leonotis.{{cite web |url=http://www.oswaldasia.org/species/l/leuze/leuze_en.html |title=Leucas zeylanica (L.) R.Br. - LAMIACEAE - Dicotyledon |publisher=oswaldasia.org |access-date=2012-03-28 |url-status=dead |archive-url=https://web.archive.org/web/20120526164605/http://www.oswaldasia.org/species/l/leuze/leuze_en.html |archive-date=2012-05-26 }}{{cite web |url=http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200019779 |title=Leucas zeylanica in Flora of China | publisher=efloras.org |access-date=2012-03-28 }}
Habitat
Plant occurs in various habitats, a weed of sunny dry localities, often on sandy soils, paddy dams, waste places, open grasslands, road-sides from the lowland up to {{convert|1700|m|abbr=on}} in altitude. It is widely distributed throughout Southeast Asia, but is rather rare in East Asia.{{GRIN | access-date=2012-03-28 }}
Constituents
Uses
=Culinary=
The whole herb has a bitter taste, but is still used as flavoring or potherb.
=Traditional medicine=
The indigenous tribes in the Satpuda region of Dhule and Jalgaon districts of Maharashtra use L. zeylanicain for fever, jaundice, and for scorpion and snake bites.{{cite journal | url=http://nopr.niscair.res.in/bitstream/123456789/7174/1/IJTK%209%281%29%20152-157.pdf | title=Use of medicinal plants among tribes in Satpuda region of Dhule and Jalgaon districts of Maharashtra–An ethnobotanical survey | journal=Indian Journal of Traditional Knowledge | volume=9 | issue=1 | date=2010 | pages=152–157 | first1=DL | last1=Jain | first2=AM | last2=Baheti |first3=SR | last3=Jain | first4=KR | last4=Khandelwal}}
=Agricultural=
Many species in the genus Leucas are becoming serious weeds in rice fields, sugarcane, and banana plantations.{{citation needed|date=August 2017}}
= Cultural =
The flower of Thumba plant is the central part of Onam festival in Kerala. The tiny flower of the plant is very important for laying Pookkalam.{{Cite web |date=August 21, 2015 |first=Sindhu |last=Vijayakumar |title=The allure of Onappookalam |url=https://timesofindia.indiatimes.com/city/kochi/the-allure-of-onappookalam/articleshow/48580554.cms |access-date=2022-05-09 |website=The Times of India |language=en}}
Essential oil
Leucas zeylanica yields a small amount of essential oil on distillation. The major components are oleic acid, hexadecanoic acid, 1-octen-3-ol, and caryophyllene.{{citation needed|date=August 2017}} It has the ability to inhibit of test bacterial growth, especially Escherichia coli and Salmonella enteritidis.{{cite web |url=http://en.cnki.com.cn/Article_en/CJFDTOTAL-AJSH200902016.htm |title=Study on Essential Oil Obtained from the Seed of Leucas zeylanica |publisher=cnki.com.cn |access-date=2012-03-28 |date=2009-02-16 |url-status=dead |archive-url=https://web.archive.org/web/20160303222236/http://en.cnki.com.cn/Article_en/CJFDTOTAL-AJSH200902016.htm |archive-date=2016-03-03 }}{{cite web |url=http://www.scienceengineeringonline.com/article-72934.html |title=Study on Essential Oil Obtained from the Seed of Leucas zeylanica |publisher=scienceengineeringonline.com |access-date=2012-03-28 |url-status=dead |archive-url=https://web.archive.org/web/20111101210510/http://scienceengineeringonline.com/article-72934.html |archive-date=2011-11-01 }}
Research
In a study of 32 plants species collected from serpentine (ultramafic) soils in Sri Lanka and screened for antimicrobial properties, L. zeylanica showed photo-mediated activity against Staphylococcus aureus and Bacillus subtilis. L. zeylanica showed population-level variation in photoactivity. Study suggests plants from serpentine environments may have alterered antimicrobial activities compared to non-serpentine environments, and that attention is needed in deciding on the substrate and habitat when collecting plants to test for antimicrobial properties.{{cite journal | url = http://www.biology.sjsu.edu/facultystaff/nrajakaruna/18Rajakaruna%20et%20al2002.pdf | title = Antimicrobial Activity of Plants Collected from Serpentine Outcrops in Sri Lanka | author = Nishanta Rajakaruna, Cory S. Harris and G.H.N. Towers | journal = Pharmaceutical Biology | date = 2002 | volume = 40 | issue = 3 | pages = 235–244 | doi=10.1076/phbi.40.3.235.5825| s2cid = 53004266 }}