[From Greek, coleus = sheath and Latin, scutellarioides = Like the genus Scutellaria]
Physical description: It is a herb native to the Southeast part of Africa. The plant is aromatic and grown as ornamental in the Asia-Pacific. The stems are quadrangular. Leaves: simple, 2.5cm-7.5cm x 1 cm-5cm,
Synonymy: Coleus atropurpureus Benth., Coleus blumei Benth., Plectranthus scutellarioides (L.) R. Br., Solenostemon scutellarioides, Coleus blumei var. vershaffeltii, Ocimum scutellarioides L.
Common names: Common coleus; ati-ati (Malay); jawer kotok (Indonesian).
Uses: In Indonesia, the juice extracted from the leaves is drunk believing to threaten abortion. A decoction is used to heal hemorrhoids, promote menses, expel impurities after childbirth, and to soothe inflamed eyes. In Malaysia, a decoction of the leaves or the juice extracted from the leaves is drunk to stop flatulence, to treat congestion of the liver, to assuage heart and liver pain, to treat smallpox, to soothe swollen parts and to induce vomiting. In the Philippines, a paste of leaves is used to assuage headache and to soothe bruises. In Vietnam, the plant is pectoral.
without stipules and decussate. The petiole is up to 7.5 cm long. The blade is lozenge-shaped, and variously colored according to the variety. The base of the blade is broadly round and the apex is tapered. The margin is crenate. The flowers are arranged in 10cm-20cm long spikes. The calyx is bilobed,
3 mm long with the upper lip broad and round, and the lower one, bifid. The corolla tube is blue with a white tube, 6 mm long, bilobed, with the lower lobe in boat-shaped. The andrecium comprises of 4 stamens. The fruit consists of
4 seeds enclosed in accrescent calyx (Fig. 304).
Pharmaceutical interest: The pharmacological properties of Coleus scutel-larioides (L.) Benth. are unknown.
Cardiovascular properties: Coleus species have attracted a great deal of interest due to forskoline (or coleonol) characterized from Coleus forskohlii (Willd.) Brig. Forskoline is a diterpene that shows encouraging signs in the treatment of hypertension, heart failure and asthma. The precise mechanism of the action of this diterpene is based on its ability to boost the enzymatic activity of activated adenylate cyclase, hence increasing the intracellular cyclic adenosine monophosphate (AMPc) (Marone G et al., 1987; Tsukawaki M et al, 1987).
The increase of cyclic monophosphate adenosine in the cardiac muscle cells results in an inotropic positive effect, whereas the increase of the cyclic adenosine monophosphate in the smooth muscle cells causes relaxation (bronchioles, vessels; Fig. 305). Forskoline given to dogs and cats causes a positive inotropic activity and lowers their blood pressure (Lindner E et al., 1978).
Fig. 305. Mechanism of action of forsko-line: forskoline binds to an extracellular receptor (R) which activates adenylate cyclase (A) in cell membrane (M) through the protein G (G). Increase of intracel-lular cyclic adenosine monophosphate (AMPc), hence contraction of the cardiac muscle cells (CM). The relaxation of the smooth muscle cells (SM) of the bronchioles and vessels.
Cytotoxic properties: Forskoline (82 ^g/mouse) given by intraperitonneal injection 30 minutes or 60 minutes prior to the tail vein injection of cultured B16-F10 cells (2 x 105 cells/mouse-3 x 105 cells/mouse), cut tumor colonization in lungs by more than 70%. Similar results are obtained in 3 separate experiments. These findings raise the possibility that forskoline could be useful in preventing the proliferation of cancer metastasis (Argawal KC et al., 1983).
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