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Thevetia Nerifolia

This shrub is very common in gardens, well known by its pretty yellow, bell-shaped flowers.

USES.—This shrub is very common in gardens, well known by its pretty yellow, bell-shaped flowers. The trunk bark possesses antiperiodic properties first described by Descourtilz and confirmed later by Dr. G. Bidie and Dr. J. Short.

Both the latter used the tincture in 10–15-drop doses 3 times a day. This tincture was prepared by macerating for one week in 150 grams of alcohol 30 grams of fresh bark finely divided. This preparation operates as an emetic and purgative in doses of 30–60 drops. It is evident that the plant possesses very active, even poisonous properties and should be employed with great caution. The decoction of the bark is given as an emetic and cathartic, but very imprudently because there is no means of determining the quantity of active principle, shown by chemical analysis to be a dangerous product.

The fruit is very bitter and acrid. The seeds yield by expression 35 to 41% oil (De Vry) and 57% when treated with benzol. It has an agreeable odor resembling that of sweet almonds, its density is 0.9148 at 25° and it is perfectly clear and transparent at that temperature. At 15° it thickens and at 13° solidifies.

According to Oudemans it consists of 63% triolein and 37% tripalmin and tristearin; it is not poisonous. After expression De Vry obtained from the caked residue 4% of a crystalline glucoside called by him thevetin. Blas, of the Academy of Medicine of Belgium, studied it later and described it as a white powder of small colorless scales, odorless, very bitter, soluble at 14° in 122 parts of water, in alcohol, in crystallizable acetic acid, insoluble in ether; formula C54H34O24. Concentrated sulphuric acid dissolves it, producing a dark red color that changes to cherry red and then after several hours to violet. The color disappears if water be added. Boiled in acid solution the glucoside changes to a new substance, theveresin (C48H70O17), white, amorphous, slightly soluble in boiling water and in alcohol, insoluble in benzine or chloroform, soluble in alkalies, very bitter. Both substances are energetic narcotic poisons; but the plant contains another even more powerful poison isolated by Warden, of Calcutta; it does not form crystals, it is very bitter, freely soluble in water, and is turned yellow by sulphuric and nitric acids.

Thevetin and theveresin exercise a marked toxic effect on the heart. The former induces emetic and cathartic phenomena, trembling and progressive weakness.

The latter does not cause vomiting or diarrhoea, but anæsthesia and rigidity of the limbs. Both poisons arrest the heart in systole. Injected hypodermically they are irritant, are eliminated by the liver, but are not found in the urine.

BOTANICAL DESCRIPTION.—A shrub, about 10° high, with leaves nearly sessile, somewhat bunched at the ends of the branches and overlapping, lanceolate, entire, glabrous. Flowers about 2′ long. Calyx 5-toothed. Corolla straw-colored, cylindrical, very narrow below, but the limb very large, spreading into 5 lobes with greenish, superimposed borders. Stamens 5, inserted in the throat, anthers lanceolate. Ovaries 2, united at base, free above, unilocular. Style simple, enlarging at the base in a bilobed stigma. Fruit a fleshy drupe resembling somewhat a small apple, the pit very hard, semilunar, flattened, with 4 compartments and as many solitary seeds.

HABITAT.—Common in all gardens and on the seashore.

Reference book: The Medicinal Plants of the Philippines

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