Some species of Plectranthus are difficult to identify because of a lack of clear-cut morphological criteria to discriminate not only among species within the genus but also among the closely related genera. This has resulted in numerous taxonomic problems in the naming of species with the result that species have often been placed in several closely related genera like Coleus, Solenostemon and Englerastrum. In addition, some species formally placed in Plectranthus, are now recognized as the more distantly related genus Isodon.
Because of these taxonomic issues, different names have often been used for the same species of Plectranthus and thus it has been difficult to collate information about the ethnobotanical uses of this genus. Furthermore, the most commonly used medicinal species of Plectranthus have a high degree of synonymy[
This report is very much indebted to the work of C.W. Lukhoba et al. - Journal of Ethnopharmacology 103 (2006) 1â€“24[
] in untangling much of this mess of names, and utilizes the on-line Kew database â€˜World Checklist of Selected Plant Families (http://wcsp.science.kew.org/home.do) for determining currently accepted names and synonyms (as of 2018).
Coleus barbatus (Andrews) Benth.
Coleus coppinii Heckel
Coleus dazo A.Chev.
Coleus esculentus (N.E.Br.) G.Taylor
Coleus floribundus (N.E.Br.) Robyns & Lebrun
Coleus forskohlii Auct.
Coleus langouassiensis A.Chev.
Englerastrum floribundum (N.E.Br.) T.C.E.Fr.
Plectranthus floribundus N.E.Br.
Common Name: Livingstone Potato
Plectranthus esculentus is an erect, herbaceous perennial plant growing around 1 metre tall[
]. The plant occasionally produces bulbils in the leaf axils[
The plant is cultivated in some parts of tropical Africa for its edible tubers[
]. It is sometimes grown as an ornamental in S. Africa[
Tropical Africa - Nigeria to the Central African Republic and DR Congo, south to Angola, Botswana, Swaziland, Tanzania and Mozambique..
|Other Uses Rating||
|Cultivation Status||Cultivated, Wild
Plectranthus esculentus is a plant of the tropics. It grows best in areas where annual daytime temperatures are within the range 15 - 28Â°c, but can tolerate 10 - 36Â°c[
]. It prefers a mean annual rainfall in the range 700 - 1,100mm, but tolerates 550 - 1,600mm[
Prefers a light, rich, well-drained soil and a position in full sun or light shade[
]. Prefers a pH in the range 6.5 - 7, tolerating 6 - 7.5[
The plant is very adaptable and is said to be suitable for growing in any climatic region in S. Africa[
]. Various cultivars have been developed in the different parts of tropical Africa where the plant is grown.
The tubers are ready to harvest about 6 - 7 months after planting[
Yields of 2 - 6 tonnes per hectare have been obtained[
Root - raw or cooked[
]. Rich in starch[
]. Boiled or roasted and eaten like sweet potatoes (Ipomoea batatas)[
]. Much esteemed by native peoples[
]. Whilst the tubers are usually cooked, at least one cultivar (from northern Nigeria) has tubers that can be eaten raw[
]. The tubers can be dried and stored for winter use[
]. They are about 10cm long and 2cm in diameter[
The stems are used to sweeten gruels[
The Livingstone potato is an aromatic herb that affects heart contractions and blood clotting[
]. The plant also has cytotoxic and anti-tumour promoting activity and can be used in the treatment of cancer[
A traditional treatment in India, the herb is used to treat a wide range of digestive problems including, wind, bloating and abdominal discomfort[
]. It has an antispasmodic action, making it valuable in the treatment of respiratory complaints, including asthma and bronchitis[
]. It is used as a remedy for headaches and is also said to be anthelmintic[
Applied topically, the plant is used to treat skin conditions[
The plant contains the substance forskolin[
]. Research has shown that forskolin has various medical properties including: it lowers high blood pressure; it relaxes the smooth muscle; it increases the release of hormones from the thyroid gland, it stimulates digestive secretions; and it reduces pressure within the eye[
]. It has been under scientific investigation as a possible treatment for congestive heart disease, glaucoma and chronic bronchial disease[
The leaves have a strong camphoraceous aroma and are used as a body rub to cleanse and deodorize the skin[
Seed - not normally used for propagation[
Cuttings about 10 - 20cm long[
]. They can be difficult to root[
Division of sprouting tubers[
Bulbils. Produced in the leaf axils, these can be potted up and grown on until large enough to plant out.
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