Leonurus japonicus Houtt.

Leonurus japonicus Houtt., Nat. Hist. 9: 366 1778.

Leonurus japonicus Houtt.; Lamiaceae

Vietnamese name: Ích mẫu; Sung uý; Chói đèn.

Chinese name: 益母草 yi mu cao

English Name: oriental motherwort, Chinese motherwort

Latin Name: Leonurus japonicus Houtt.

Synonym Name: Leonurus altissimus Bunge ex Benth.; Leonurus artemisia (Lour.) S.Y.Hu    ; Leonurus artemisia var. albiflorus (Migo) S.Y.Hu; Leonurus cuneifolius Raf.; Leonurus heterophyllus Sweet; Leonurus heterophyllus f. leucanthus C.Y.Wu & H.W.Li ; Leonurus intermedius Didr.; Leonurus japonicus f. albiflorus (Migo) Y.C.Zhu; Leonurus japonicus f. niveus (A.I.Baranov & Skvortsov) H.Hara; Leonurus manshuricus Yabe; Leonurus mexicanus Sessé & Moc.   ; Leonurus sibiricus var. albiflorus Migo; Leonurus sibiricus var. grandiflora Benth.; Leonurus sibiricus f. niveus A.I.Baranov & Skvortsov; Stachys artemisia Lour.

Family: Lamiaceae

Description: Herbs annual or biennial. Taproots with dense, fibrous rootlets. Stems erect, 30-120 cm, retrorse strigose, nodes and angles densely strigose. Petiole of stem leaves 0.5-3 cm, narrowly winged at apex; lower stem leaf blades ovate, base broadly cuneate, 3-palmatipartite; lobes oblong-rhombic to ovate, 2.5-6 × 1.5-4 cm, pinnately divided, adaxially strigose, abaxially pilose, glandular; mid stem leaf blade rhombic, palmatipartite, lobes oblong-linear, base narrow cuneate. Verticillasters 8-15-flowered, 2-2.5 cm in diam.; floral leaves subsessile, linear to linear-lanceolate, 3-12 × 2-8 mm, entire or dentate; bracteoles spiny, shorter than calyx, ca. 5 mm, appressed puberulent. Flowers sessile. Calyx tubular-campanulate, 6-8 mm, appressed puberulent; teeth broadly triangular, 2-3 mm, apex spinescent. Corolla white or reddish to purplish red, 1-1.2 cm, villous; tube ca. 6 mm, inconspicuously scaly annulate inside; upper lip straight, concave, oblong, ca. 7 × 4 mm, margin entire, ciliate; lower lip slightly shorter, base sparsely scaly; middle lobe obcordate, base constricted, margin membranous, apex emarginate; lateral lobes ovate. Filaments sparsely scaly. Nutlets brownish, oblong, triquetrous, ca. 2.5 mm, base cuneate, apex truncate, smooth. Flowering. Jun-Sep, fruiting. Sep-Oct.

Distribution: It is found in E. Asia - China, Japan, Korea, India, Nepal, Bangladesh, Myanmar, Thailand, Cambodia, Laos, Vietnam, Malaysia, Indonesia, Philippines, Australia

Ecological: Sunny areas; 0-3400 m.

Cultivation Details:

- The plant originates in the temperate zone, but has spread and is now found widely in the subtropics and tropics.

- Succeeds in most soils. Prefers a poor soil.

- The plant has spread widely from its original range in east Asia and can now be found naturalized in much of the tropics and subtropics.

Chemistry: Approximately 140 chemical compounds have been isolated from Leonurus japonicus, and the major components have been determined to be alkaloids, diterpenes and flavones

Pharmacology: Effects on the uterus as well as cardioprotective, anti-oxidative, neuroprotective and anti-cancer activities

Uses:

- The leaves are diuretic and are placed in bath water to relieve itching and painful shingles.

- The aerial parts of the plant are alterative, antibacterial, antifungal, depurative, diuretic, emmenagogue, hypotensive, vasodilator and vulnerary. The whole plant is decocted, either on its own or with other herbs, as an ophthalmic. The plant is commonly used by women to treat a range of menstrual disorders; to hasten the contraction of the uterus and expulsion of the placenta after giving birth; to relieve postpartum abdominal pain; to act as a restorative after child birth; to treat uterine bleeding, leucorrhoea. It is also used to improve the blood circulation and reduce blood pressure, to treat tumours, oedema, eczema and purulent abscess.

- The plant is used externally as a poultice on bruises.

- Stimulates blood circulation. (The part of the plant used is not made clear.)

- The juice of the stems is vulnerary.

- The dried flowers are emmenagogue and are also used in pregnancy and to help expel the placenta after giving birth.

- The fruit is antibacterial, diuretic, emmenagogue, hypotensive, ophthalmic and vasodilator. It is used in the treatment of abnormal menstruation, nebula and conjunctivitis.

- The seed has a sweet, pungent flavour. It is aphrodisiac, diuretic, emmenagogue, ophthalmic and is also used in the treatment of various women's complaints. The plant was ranked number one in a survey of 250 potential antifertility plants in China. The seed is used in the treatment of conjunctivitis and night blindness.

- The plant is considered a substitute for opium in Java, but its chemical properties are harmless.

Reference:

- theplantlist.org

- efloras.org

- ipni.org

- tropical.theferns.info

- Shang X, Pan H, Wang X, He H, Li M. Leonurus japonicus Houtt.: ethnopharmacology, phytochemistry and pharmacology of an important traditional Chinese medicine. Journal of Ethnopharmacology. 2014 Feb;152(1):14-32