Hyptis (PROSEA)
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Introduction |
Hyptis Jacq.
- Protologue: Collectanea 1: 101, 103 (1787).
- Family: Labiatae
- Chromosome number: x= 14, 15, 16; H. capitata: 2n= 30, 32, H. pectinata: 2n= 32, H. spicigera: 2n= 32, H. suaveolens: 2n= 24, 28, 30, 32
Origin and geographic distribution
Hyptis comprises about 250 species and is indigenous in the American tropics and subtropics. Some weedy species are also found in the tropics of Africa, Asia and Australia. In the Malesian region 5 species have been introduced and are naturalized.
Uses
All Hyptis species occurring in South-East Asia are used medicinally, although sometimes outside this region. The leafy parts are most commonly used, the roots less commonly. The major applications are externally to treat wounds, skin diseases and rheumatism, and internally against bronchial and gastro-intestinal problems, headache and fever. The leafy parts are commonly used as insect repellent, and sometimes as food flavouring.
Properties
The leaves of many Hyptis species contain an essential oil (usually 0.05-0.5%) with a high amount of sesquiterpenes. Crude extracts of several Hyptis species (e.g. H. pectinata and H. suaveolens) showed significant antimicrobial activity against Candida albicans and selected gram-positive and gram-negative bacteria, which supports their use as an antiseptic on wounds. Cytotoxic activity has been demonstrated for a number of Hyptis species.
The triterpenoids oleanolic acid and pomolic acid have been isolated from whole H. capitata plants. These compounds showed anti-human immunodeficiency virus (HIV)-activity. Derivatives of ursolic acid isolated from H. capitata exhibited cytotoxicity.
Three 5,6-dihydro-α-pyrones, pectinolides A, B and C, have been isolated from H. pectinata. They showed antimicrobial activity and, moreover, exhibited significant in-vitro cytotoxic activity against a variety of tumour cell lines. An aqueous extract of dried H. pectinata leaves exhibited analgesic and anti-inflammatory activities in experimental animals. Inflorescences showed considerable molluscicidal activity. The lactonoid bitter principle ovatolide has been isolated from H. pectinata leaves.
The unsaponifiable fraction of dried H. suaveolens leaves and flowers exhibited chronotropic effect in frogs, hypotensive effect in dogs, inotropic and spasmogenic effects in rabbits, and spasmolytic and vasodilator effects in rats. An extract of H. suaveolens showed moderate inhibition of mycelial growth of the keratinophilic fungi Chrysosporium tropicum, Microsporum gypseum and Trichophyton terrestre. A test in Africa (Guinea Bissau) showed that fresh and smouldering H. suaveolens has significant mosquito repellent activity.
A water extract of the whole plant of the South and Central American H. lantanifolia Poit. was a potent inhibitor of human immunodeficiency virus-reverse transcriptase (HIV-RT) with an IC50of 6-8 μg/ml. Ethanol extracts of H. lantanifolia and H. obtusiflora C. Presl ex Benth. (also from tropical America) showed considerable xanthine oxidase inhibitory activity. Extracts of another tropical American species, H. verticillata Jacq., showed antibacterial, antisecretory and cytotoxic (KB and Ht 29 cell lines) activities. The essential oil (with main components α-pinene, β-pinene and thymol), (R)-5-hydroxypyrrolidin-2-one, rosmarinic acid and dehydropodophyllotoxine contributed to the antibacterial effects; rosmarinic acid showed significant capillary stabilizing effects and sideritoflavone inhibited prostaglandin synthase to a significant extent and also had antisecretory effects. In addition, several lignans with cytotoxic activity against a number of human cancer cell lines have been isolated from H. verticillata. Several H. verticillata extracts showed anti-inflammatory activity.
Botany
- Herbs or shrubs, often aromatic.
- Leaves decussately opposite, simple, serrate, gland-dotted, shortly to long-petiolate; stipules absent.
- Inflorescence a usually axillary dense spurious head, spike, raceme or a few-flowered cluster, often secund; bracts subulate or setaceous.
- Flowers bisexual, 5-merous, zygomorphic; calyx tubular or campanulate, straight or oblique, tube 10-veined, teeth subequal; corolla 2-lipped, upper lip 2-lobed, lower lip 3-lobed with midlobe abruptly deflexed; stamens 4, free, declinate; disk entire; ovary superior, 4-celled, style subentire or shortly 2-fid.
- Fruit consisting of 4 oblong or ovoid, 1-seeded nutlets enclosed in the persistent calyx.
All Hyptis species treated here can be found flowering and fruiting throughout the year.
Hyptis is classified in the tribe Ocimeae, subtribe Hyptidinae, characterized by the stamens held in the lower lip of the corolla, which is usually strongly compressed to form an explosive pollination mechanism, powdering visiting insects from below with pollen. Cladistic studies showed that Hyptis, as usually delimited, is a paraphyletic group. For this reason, about 45 species have been transferred recently to other genera: Hypenia, Hyptidendron and Eriope.
The name H. rhomboidea is often used for the species here treated as H. capitata. It is not clear to which species (H. capitata Jacq. or H. rhomboidea M. Martens & Galeotti) the South-East Asian material with long-stalked spurious heads belongs, or whether these species are even conspecific.
Ecology
The Hyptis species of South-East Asia occur in waste places, as a weed in fields, grassland and sometimes in open forest, usually in the lowland, sometimes up to 1300 m altitude. They are usually weeds of minor importance, e.g. in rice fields.
Genetic resources
The Hyptis species treated here are very widespread, often weedy herbs that do not merit attention concerning genetic erosion and conservation.
Prospects
Hyptis definitely deserves more attention for medicinal and insecticidal applications in South-East Asia. Comparatively much research has been done on bioactivity of Hyptis extracts and compounds, and these studies showed promising results for the development of plant-based drugs for possible treatment of important diseases such as AIDS and different forms of cancer, as an antiseptic agent for external application, and as an insect repellent. The worldwide use in traditional medicine is another indication of the efficiency of Hyptis drugs.
Literature
319, 516, 604, 796.
Selection of species
Authors
Rini Sasanti Handayani
