Hyptis suaveolens
(pignut)

Preferred Scientific Name

• Hyptis suaveolens (L.) Poit.

Preferred Common Name

• pignut

Other Scientific Names

• Ballota suaveolens L.
• Bystropogon graveolens Blume
• Bystropogon suaveolens (L.) L'Hér.
• Gnoteris cordata Raf.
• Gnoteris villosa Raf.
• Hyptis congesta Leonard
• Hyptis ebracteata R.Br.
• Hyptis graveolens Schrank
• Hyptis plumieri Poit.
• Marrubium indicum Blanco
• Mesosphaerum suaveolens (L.) Kuntze
• Schaueria graveolens (Blume) Hassk.
• Schaueria suaveolens (L.) Hassk.

International Common Names

• English: bushmint; chan; chao; horehound; mintbush; mintweed; mumutun; spikenard; stinking Roger; wild spikenard
• Spanish: chia grande; hierba de las muelas
• French: chan; gros baume; hyptide perfume; hyptis à odeur
• Portuguese: alfavaca-brava; betônica-brava; chan; hortela do campo; mentrasto do grande

Local Common Names

• Benin: azongbidi; disibu; efintin aja; emugbé; fioho; kukubi; kuwi; tiname tieti; wusakadi; xweflu
• Burkina Faso: fè; gbè; sosso
• China: shan xiang
• Congo Democratic Republic: mvouamvoua; nvonanvona
• Côte d'Ivoire: sésémoro
• Ghana: brong peeah; filingoro
• Guam: mumutun
• Guatemala: chía; chichinguaste; salvia blanca; turturitillo
• India: bhustrena; bhustrna; bilatti tulas; darp tulas; ganga tulasi; jungli tulas; nattapoochedi; sirna tulasi; walayati tulsi
• Indonesia: babadotan; jakut bau
• Malaysia: malbar hutan; pokok kemangi; sělaséh hutan
• Mexico: chana; chia de Colima; chia gorda; confitura; confiturilla; conivaria; la-pil; xóotle'xnuuk
• Micronesia, Federated states of: lamar nuteth; lekenek; mengit; nekenek; nokonok
• Nigeria: jogbo; koulouvi; koutoubi
• Philippines: kablíng kabáyo
• Senegal: brégé; gumgûné; kuyhuye; ngungun
• Tanzania: kifumbasi
• Thailand: kaaraa; maeng lak khaa
• Togo: awussakadi; mugbé
• Vietnam: esthowm; tiastoodaji

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Lamiales
•                         Family: Lamiaceae
•                             Genus: Hyptis
•                                 Species: Hyptis suaveolens

Hyptis is a genus of the mint family (Lamiaceae) that comprises about 300 species (The Plant List, 2013) and is indigenous in the American tropics and subtropics (Handayani, 2003). The name of this genus stems from the Greek huptios (turned back), referring to the abrupt turning down of the lobes of the lower lip of the corolla (Parsons and Cuthbertson, 2001).

Hyptis suaveolens presents high levels of genetic polymorphism and plasticity in morphological and physiological responses (Wulff, 1987), a quality that allows it to adapt to environmental alterations and that results in interpopulational and intrapopulational variability of its chemical components (Barbosa et al., 2013), as well as flower and seed polymorphism (Gadidasu et al., 2011; Wulf, 1973). However, these differences are so minimal that a taxonomic status does not need to be assigned to variants (Gadidasu et al., 2011).

The species was first described in 1806 by French botanist Pierre-Antoine Poiteau. The Latin epithet suaveolens means “sweet scented,” referring to this species’ odour (Hyde et al., 2016).

Adapted from the Queensland Government (2012):

H. suaveolens is an erect, annual or short-lived perennial herbaceous plant usually growing 1-1.5 m tall, but occasionally reaching up to 3 m in height. The branching stems are green or reddish-green in colour and square in cross-section when young. On the upper parts of the plant the stems are about 5 mm thick and somewhat hairy. The lower parts are thicker and become slightly woody towards the base.

Leaves (2-10 cm long and 1-7 cm wide) are oppositely arranged and borne on petioles that are 5-40 mm long. Leaves are ovate (egg-shaped), elliptic (oval), or slightly cordate (heart-shaped). Margins are shallowly toothed and pubescent.

Flowers are small (5-7 mm long), pinkish, bluish-purple or lavender in colour and arranged at the axils in 1-5 flowered clusters. Pedicels are 1-5 mm long. Flowers are tubular in appearance with two 'lips' (two-lipped or bi-labiate). The upper lip is divided into two lobes and the lower lip divided into three lobes. The central lobe is saccate (having an inflated appearance). These flowers are surrounded by a green tubular structure that is formed from the five fused sepals (i.e. a calyx tube). It has five lobes, each being topped with a short bristle (about 5 mm long), and turns brown in colour after the flower dies. The fruit is a schizocarp (lobed structure) that divides into two 'seeds' (mericarps). These 'seeds' (3-4 mm long and 2.5-3 mm in wide) are dark brown to black in colour with whitish markings at one end. They are flattened, shield-shaped and slightly rough in texture.

Although the exact year of its introduction is not known, in Australia, this species was first recorded in 1845 (Cullen et al., 2012). It is spreading in India (Padalia et al., 2014), and was first recorded in Zhejiang, China in 2013 (Xiong et al., 2013).

Soil drainage

• free

Soil texture

• light

Natural Dispersal

This species is dispersed by water (Cullen et al., 2012).

Vector Transmission (Biotic)

The seeds of H. suaveolens remain in the bristly fruit, which easily attaches to fur and clothing (Cullen et al., 2012). The mucilaginous coating of the seeds, when wet, adhere to potential vectors as well (Merril, 1981).

Accidental Introduction

This species is spread as a contaminant of hay, as well as in mud on animal hooves, machinery, and vehicles (Raizada, 2006; Cullen et al., 2012).

Although the economic losses due to the invasion of H. suaveolens in agricultural fields have not been assessed, it is possible to state that substantial resources go annually to controlling this weed (Schwarzkopf et al., 2009). Wiersema and León (1999) consider this species an economically important weed due not only to its potential as a seed contaminant, but also from the positive impact because of its medicinal value. In northwest India, the absence of several species of economic importance to local people in areas heavily invaded by S. suaveolens may pose socioeconomic problems for local people in periurban ecosystems (Sharma et al., 2017).

Because of its unpalatability to livestock, H. suaveolens has the ability to dominate improved and native pastures, especially when they are overgrazed. Hence, this species can significantly reduce the carrying capacity and/or productivity of pastures (Queensland Government, 2012). Sharma et al. (2017) investigated the impact of H. suaveolens on the natural vegetation in periurban ecosystems of Chardigarh, northwestern India, and found that species numbers declined by 46-52% in heavily invaded areas. Several economically important species were absent from invaded areas, but present in areas without H. suaveolens. In Pakhal Wildlife Sanctuary, Andhra Pradesh, India, H. suaveolens has become widespread, occupying grazing areas of wild animals and preventing the native ground flora from growing (Murthy et al., 2007). It may also enhance the risk of forest fire in the dry seasons (Murthy et al., 2007).

• Invasive in its native range
• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Pioneering in disturbed areas
• Highly mobile locally
• Benefits from human association (i.e. it is a human commensal)
• Fast growing
• Has high reproductive potential
• Gregarious
• Has propagules that can remain viable for more than one year
• Reproduces asexually
• Has high genetic variability

• Monoculture formation
• Negatively impacts agriculture
• Transportation disruption

• Allelopathic
• Competition - shading
• Rapid growth

• Highly likely to be transported internationally accidentally
• Highly likely to be transported internationally deliberately
• Difficult to identify/detect as a commodity contaminant
• Difficult/costly to control

In spite of its detrimental impacts, H. suaveolens has been regarded as a beneficial plant due to its fungicidal activity (Cowie, 2012), bacterial growth suppression, and weed seed germination inhibition (Schwarzkopf et al., 2009).

Economic Value

This species has a potential economic value for small farmers. In Southern Benin, both aqueous extracts and living specimens of H. suaveolens have been proven to significantly reduce population densities of stemborers (Sesamia calamistis (Lepidoptera: Noctuidae)), a problematic pest that constrains maize production of resource-poor farmers (Adda et al., 2011). In several parts of Asia, peasants use this species to protect livestock from vermin (Handayani, 2003). The leaves can be used as a bedbug repellent.

Social Benefit

In many regions of Central America, the seeds of H. suaveolens are made into a drink which is prepared in the same fashion as chia (Salvia hispanica) (Standley and Williams, 1973). In Mexico, this species is also used in the treatment of cataracts by the Raramuri of Chihuahua (Irigoyen-Rascón, 2015), and as fodder for poultry by the Mayas of Yucatán (Flores and Bautista, 2012). Moreover, antimicrobial, antifungal, hypoglycemic, antiinflamatory, and antioxidant activity has been found in this species (Rojas Chavez and Vibrans, 2011).

Outside of its native range, this species has also become an important useful species with applications similar to those of the Neotropics. In Benin, this species is used externally in combination with other medicinal plants to treat jaundice, hyperthermia, haemorrhoids, breast abscess, oedemas and perianal candidiasis (Adjanohoun et al., 1989), and in the treatment of sexually transmitted diseases (Towns and Andel, 2014). In Nigeria, this plant is used in the treatment of cougha, fever, and anemia (Odugbemi, 2008).

Handayani (2003) has listed some of the uses people give to this species in Asia: In several parts of the continent, leaves and stems are employed in the treatment of cuts, wounds, eczema, bruises, and other skin diseases. In the Philippines, leaves are used externally to treat rheumatism, and internally as an antispasmodic. Leaves and roots are used as as insecticide and against rheumatism, respectively. In Papua New Guinea leaves are used internally to treat catarrh and fever. In Indonesia, this species is used as a galactagogue. In Thailand, pounded leaves and branches are used as a lice repellent for chickens. The whole plant is occasionally used as fodder for livestock (Handayani, 2003).

Other uses include potential as a monitor of trace metals (Pb, Fe, Zn, Cu, and Cr) in soil from automobiles (Usman, 2013).

Environmental Services

Mandal et al. (2007) found that the seeds of H. suaveolens are an absorbent capable of removing up to 64% of arsenic as arsenate from water. For this purpose, seeds preteated with boiling water low in pH (3.5-4.5) have proven cost effective and might be used for large-scale water treatment systems (Mandal et al., 2007).