Pharmaceutical interest

Cardiovascular properties: The main symptoms of Oleander poisoning are gastrointestinal irritation, a marked hyperkaliemia, A-V block, ventricular dysrhythmia, and if the dose is too high, death (Markov AK et a/., 1999). Oleandrin and related derivatives (the glycoside of gitoxigenin and 4-0-^-D-digitalose) are responsible for life threatening intoxication and digoxin-like cardiotonic properties.

These steroidal glycosides (1.5% in the leaves) consist of tetracyclic aglycones of the (C23) cardenolide type. Oleandrin is listed in the Russian Pharmacopoeia (100 ^g/tablet) for the treatment of low pulse pressure. Oleandrin and other car-denolides such as digoxin (Lanoxin®) inhibit the myocytes membrane Na+/K+

Uses: In the Asia-Pacific, Nerium oleander L. is used to invigorate the heart and to promote urination. In Indonesia, decoction of the leaves in oil is used to destroy maggots found in wounds. In the Philippines, the bark and leaves are mixed with oil and used to treat herpes infection. In Vietnam, the plant is used to treat mycosis and to soothe inflamed parts.

ATPases. As a result, the myocardial contraction forces are increased and the heart rate is decreased. These two pharmacological effects are of value in treating patients diagnosed with supraventricular tachycardia and heart failure. A methanolic extract of the leaves given at doses of 1 mg/mL-2.5 mg/mL, increases both the spontaneous and electrically-induced contraction of rat vas deferent and guinea-pig ileum without inhibition by the adrenergic blocking agent tolazoline. This extract inhibits electrically-stimulated neurogen twitch skin responses of rat phrenic nerve diaphragm preparations and the rate of spontaneously beating atria (Mazumder PK et al., 1996).

Neurological properties: A number of glycosides characterized from Ner-ium oleander L. are anxiolytic in rodent (Siddiqui BS et al, 1997; Begum S et al., 1999). The precise central mechanism of action of cardenolides and, more generally, of triterpenoid saponins (Sokolov SY, 1986) is an enigma and it is possible that further investigation will result in the discovery of original neuropharmacological pathways.

Chemotherapeutic properties: A fraction of the plant is several orders of magnitude more molluscicidal than niclosamine, formothion and phor-ate against Lymnea acuminata (Singh S et al., 1997). cis-Karenin (IC50 = 15 ^g/mL) and trans-karenin (IC50 = 7.5 ^g/mL), 2 pentacyclic triterpenoids characterized from Nerium oleander L destroy significantly KB cells cultured in vitro (Siddiqui BS et al., 1995). Note that Oleandrin inhibits12-0-tetradecanoylphorbol-13-acetate-induced skin tumor promotion (Afaq F et al, 2004).

Oleandrin inhibits experimentally the activation of NF-kB and activator protein-1 and their associated kinases. Natural products which can suppress the activation of nuclear factor kB (NF-kB) and activator protein-1 (AP-1) might have the potential to block tumorigenesis and inflammation. Oleandrin blocks the activation of NF-kB by the tumor necrosis factor a, both in concentration-and time-dependent manner. This property is mediated through the inhibition of phosphorylation and degradation of Ik Ba, an inhibitor of NF-kB. Oleandrin blocks the activation of NF-kB caused by phorbol ester and lipopolysaccharide.

Oleandrigenin

Oleandrigenin

It blocks the activation of AP-1 caused by the tumor necrosis factor a and other agents, and inhibits the activation of c-Jun NH2-terminal kinase caused by the tumor necrosis factor a. This may provide a molecular basis for the ability of oleandrin to suppress inflammation and perhaps tumorigenesis (Manna SK et al., 2000).

Your Heart and Nutrition

Your Heart and Nutrition

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