PITTOSPORUM RESINIFERUM Hemsl.
Local names: Abkel (Ig.); abkol (Ig.); apisang (Ig.); botiak (Ig.); dael (Ig.); dingo (Ig.); kabilan (Ig.); kalapakab (Bon.); kiligto (Ig.); langis (Ig.); obkol (Ig.); pilai (Bon.); sagaga (Ting.); petroleum nut (Eng.).
Abkel is an endemic species, which commonly grows as an epiphyte or pseudoepiphyte on trees in mossy forests at an altitude of from 900 to 2,400 meters in Bontoc to Sorsogon Provinces in Luzon and in Mindoro and Catanduanes.
The leaves of Abkel are crowded towards the ends of the branchlets, leathery, smooth, oblanceolate, the average ones 15 centimeters long, and 4 centimeters wide, and pointed at both ends. The flowers are fragrant, short-pedicelled, and smooth, and are borne in clusters on the stem. The calyx is thin and cupular. The petals are oblong. The fruit is yellow, ellipsoid, 3 to 3.5 centimeters long, and dehiscent at the apex. The seeds are shining and black.
According to Bacon the fruit of Pittosporum resiniferum is known in the Philippines as petroleum nut, because even the green, fresh fruit will burn brilliantly when a match is applied to it. He says that the oil from the petroleum nut proved to very interesting as it contains considerable quantities of normal heptane, which has only once before been found in nature, occurring in the bigger pine of California, Pinus sabiniana Dougl., and also a dihydroterpene, C10H18. The oil has specific gravity, 0.883; N 30°/D = 1.4577. It is quite sticky and in a thin layer rapidly becomes resinous. In an open dish it burns strongly with a sooty flame. It distills unchanged up to 165°; then with decomposition it gives a resin oil. The oil distilling from 100° to 165° is colorless with an orange like odor; specific gravity, 30°/4° = 0.7692; A 30°/D = 37°.0.
Fraction No. 1 had a pleasant odor recalling oranges, and the following properties: specific gravity, 25°/4° = 0.6831; N 30°/D = 1.3898; optical rotation = 0.
Fraction No.7 had a turpentinellike odor; specific gravity, 30°/4° = 0.8263; N 30°/D = 1.4630.
The properties of fraction No.1, leaves little doubt as to the identity of this compound with normal heptane.
The “curanderos” use the petroleum nut as a universal medicine. An infusion of the fruit is considered a remedy for intestinal and stomach pains. The oleoresin is used as a cure for leprosy and other skin diseases; and a means of relief in muscular pains.