Cotylelobium melanoxylon (Hook.f.) Pierre

Kayu raru (Cotylelobium melanoxylon) is a giant tree up to 50 meters tall of the Dipterocarpaceae family, distributed across Thailand, Malaysia, and Indonesia, especially Sumatra and Kalimantan, now classified as nearly extinct due to continued harvesting from the wild. Its bark has long been used by the Karo people as a mixture in making tuak as well as traditional medicine, with a sample recorded as found by the Socfindo Conservation team in Aceh Singkil. Kayu raru is believed to be antidiabetic and help the blood clotting process in wounds.

This lowland tropical plant can be found up to elevations of 300 m above sea level and grows in humid to wet areas. The required rainfall averages between 2,100-2,700 mm/year, pH 4-4.5. Prefers full sunlight conditions, and dry or sandy soil.

• Stem bark greenish-white in color with a bark thickness of around 0.6-1 cm, wood yellowish-brown in color.
• Leaves oval shaped, wedge-shaped base, tapering tip, secondary veins, consisting of 5-7 pairs, panicle up to 9 cm long. Leaf stalk 10-18 mm long.
• Sap releases a very strong odor, its sap characteristics are sometimes white and soft, sometimes yellow and bright orange.

Propagated generatively (by seed) and vegetatively (tip cuttings).

Triterpenoid, flavonoid, tannin and β-sitosterol, stilbene dimer (ampelopsin, isoampelopsin F, epsilon-viniferin), aliphatic compounds.

Treats wounds, has antidiabetic activity, astringent (reduces secretion in skin care), antilaxative (prevents constipation), antibacterial, antiseptic, antidiarrheal, and blood-clotting properties.

• Prepare fresh kayu raru bark.
• Dry using an oven at 40 °C.
• Once the bark is dry, grind and sift to produce 40-60 mesh powder.
• Store the dried material in an airtight plastic/container. 

Rasak, Resak daun lebar (Sumatra), Awing, Damat resak, Gagil, Resak (Kalimantan).