Oxystelma
| Oxystelma | ||||||||||||
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Oxystelma bornouense , Burkina Faso |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Oxystelma | ||||||||||||
| R.Br. | ||||||||||||
Oxystelma is a genus of plants in the subfamily of the silk plant family (Asclepiadoideae) within the family of the dog poison plants (Apocynaceae). Currently only two species are included in the genus Oxystelma . The fruits of Oxystelma esculentum are eaten in some regions of Asia. They also appear to be pharmaceutically effective, as ongoing research shows.
features
The two species of the genus Oxystelma are at the base of woody roll that can be high to m. 4 The milky sap is whitish, rhizomes are present. The shoots are bald, without hair, etc. The leaf blades are paper-like, 6 to 11 cm long and 0.7 to 2 cm wide. The leaf shape varies from linear to oval, rounded at the base to heart-shaped and apically pointed.
The inflorescence does not sit in the leaf axes, is solitary and usually longer than the neighboring leaves. It has 1 to 4, usually two to four flowers. The peduncle of the inflorescence is usually longer than the peduncle; both are bald.
The calyx is shorter than the corolla and glabrous. The sepals are ovate to lanceolate. The bud is rounded. The corolla measures 8 to 12.5 mm in length; it is broadly bell-shaped. The petals are fused from the base to half or 3/4 of the length. The flowers are cream to white with a reticulate pattern of purple-brown veins. The corolla lobes are triangular, somewhat blunted towards the apex, turned over and turned slightly to the right. They are densely covered with fine hair. The secondary crown sits near the base of the corolla and is significantly shorter than the crown and gynostegium . It is thickly covered with hair. The lobes are laterally fused and ring-shaped. The gynostegial secondary crown consists of free staminal lobes that attach below the stamens . The gynostegium sits right at the base of the corolla. The pollinia are elongated and attached apically to the caudicles.
The follicle has one or two pods. In Oxystelma esculentum , the two fruit sheaths are spindle-shaped, about 50 mm long with a diameter of 4 mm. The seeds are about 2 mm long, 1.5 mm wide with a side "wing" about 0.1 mm wide. The edge is smooth, as is the surface. The tuft of hair is about 8 mm long. One of the fruit shells in Oxystelma bournouense is approx. 50 mm long and has a diameter of 35 to 40 mm. The seeds are about 4 mm long and 2.5 mm wide. The tuft of hair is approx. 15 mm long.
The chromosome number is 2n = 22 in Oxystelma bornouense (Lf) R.Br. and Oxystelma esculentum R.Br.
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Geographical occurrence and habitat
The two species of the genus occur in the tropics and subtropics of East and West Africa as well as in Bangladesh, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Pakistan, Sri Lanka, Thailand and Vietnam.
Pharmaceutical importance
Methanol extracts from Oxystelma esculenta are currently being tested for anti-tumor effects in the fight against cancer. According to a new study, the extract of Oxystelma esculentum has a significant anti-tumor effect, which is attributed to the antioxidant effect of the extract on EAC (Ehrlich's ascites carcinoma cell line).
Systematics
According to Sigrid Liede-Schumann & Ulrich Meve, the position within the Asclepiadoideae and their four tribes (each with further subtribes) is uncertain, i.e. H. the genus is isolated. Currently, only two species are assigned to the genus:
- Oxystelma bornouense (Lf) R.Br. : It occurs from tropical West Africa to Somalia.
- Oxystelma esculentum R.Br. : It occurs from Egypt to northeastern Tanzania, from the Sinai Peninsula to southern China and western Malesia and northern Australia.
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On-line
- Sigrid Liede-Schumann & Ulrich Meve: The Genera of Asclepiadoideae, Secamonoideae and Periplocoideae (Apocynaceae) - Oxystelma R. Br. (Asclepiadeae). Online status 2006.
literature
- PT Li, MG Gilbert and WD Stevens: Asclepiadaceae, Flora of China. Science Press & Missouri Botanical Garden, 447 pp. 1995 Oxystelma - Online
Individual evidence
- ↑ a b c Rafaël Govaerts (ed.): Oxystelma - World Checklist of Selected Plant Families of the Royal Botanic Gardens, Kew. Last accessed on November 7, 2018.
- ↑ N. Poornima, KM Umarajan and K. Babu: Studies on Anatomical and Phytochemical Analysis of Oxystelma esculentum (Lf) R.Br. Ex Schltes. Botany Research International, 2 (4): 239-243, 2009 ISSN 1995-8951 PDF
