Gen info
- Etymology: The genus name Dipterocarpus derives from Greek words di meaning "two", pteron meaning "wing", and karpos meaning "fruit", referring to the two-winged fruit. The species epithet derives from Latin grandiflorus meaning "large flowers".

Botany
• Apitong is a medium size to large resinous tree growing to a height of about 40 meters. Trunk is straight, cylindrical, branchless up to 30 meters, up to 125 centimeters in diameter. Buttresses are absent or few, up to 1.5 meters high and 1 meter long. Bark surface is light gray and slightly fissured, 6 to 8 millimeters thick, with a reddish inner bark. Leaves are alternate, ovate, leathery, glabrous, 10 to 20 centimeters long, 9 to 12 centimeters wide, with 15 to 17 pairs of secondary veins, pointed at the tip and rounded at the base. Petioles are 5 to 7 centimeters long, thickened at the end of the base. Flowers are large, about 5 centimeters long, rose-colored, and fragrant. Petals are large, oblong to narrowly oblong, creamy white with a prominent stripe down the center, stamens 30, ovary 3-celled, with the base enclosed in the calyx tube. Fruit is oblong, about 5 centimeters long, with five winglike projections from the sides.

• Dipterocarpus grandiflorus is a tree, up to 45 m tall. Foliage: Its alternate, stalked leaves have thick leathery leaf blades that are broadly elliptic, and 10-18 cm by 5-12 cm. Flowers: Flowers are found on unbranched, slender shoots that are up to 18 cm long. Fruit: Stoutly-stalked 5-flanged, ellipsoid fruit is 6-7 by 3.5 cm, and winged by two enlarged sepals to 22 by 3 cm, and three minor sepals to 2 by 1.5 cm. (15)

Distribution
- Native to the Philippines.
- Also native to Andaman Is., Bangladesh, Borneo, Laos, Malaya, Myanmar, Sumatera, Thailand, Vietnam.
- Found throughout the Philippines.
- Wilding blight caused by Lasiodiplodia theobromae and apitong wilt caused by Polysporus sp. are common problems for the natural reproduction of D. grandiflorus in the Philippines. (7)
- At one time, reputed to be the most abundant (ca. 20%) in commercial Philippine forests. (10)
- D. grandiflorus was declared critically endangered by the International Union for Conservation of Nature (IUCN) in 2006. (9)
- Also found in India, Indonesia, Malaysia, Myanmar, Singapore, Thailand and Vietnam.

Constituents
- Yields grandiphenols A, B, C and D.
- Study isolated the ascrobyl-resveratrol derivative shorealactone from the stem.
- Balau resin is obtained from the trunk of the apitong.
- Study of oleoresin for essential oil indicated it was mainly sesquiterpene hydrocarbon in nature. (10)
- Study of Philippine oil (% composition) yielded a-gurhunene 20, caryophyllene 4, allo-aromadendrene 50, a-humulene 20. (Bisset, 1966) (10)
- Study of stem yielded two new stilbene tetramers, grandiphenols A (1) and B (2), along with ten known stilbene oligomers and bergenin. (11)
- Stems yielded two new resveratrol trimers, (=5‐[(E)‐ 2‐  (4‐hydroxyphenyl)ethenyl]benzene‐1,3‐diol) trimers, grandiphenols C (1) and D (2). (5)

Properties
- Bark is considered tonic.

Parts used
Bark, oil.

Uses
Edibility
- Nut reportedly edible; boiled and eaten.
Folkloric
- Bark, soaked in water, used to treat dizziness.
- Bark considered tonic.
- Hot decoction of bark used to treat rheumatism and liver complaints. (7)
- In Pakistan, Gurjan oil from oleoresin used for treatment of ulcers and various ailments. (14)
Others
- Wood: Moderately heavy and hard; resistant to dry wood borers, fairly resistant to fungi, but susceptible to termites. Used for general construction, carpentry, paneling, joinery, framework for boats, flooring, pallets,veneer, plywood.
- Fuel: Wood makes a good quality charcoal. (3)
- Fiber: Pulp used for paper production. (3)
- Timber: Used for medium and heavy construction; making toys and agricultural implements.
- Gum or resin: Wood yields large quantities of oleo-resin (balau or minyak keruing), used as coat for waterproofing paper, caulking baskets and boats, varnishing walls and furniture. (3) Resin also used as torch fuel. (see study below: 13)
- Tannin or dyestuff: Tannin-formaldehyde adhesive produced from bark extracts. (3)
- Erosion control: Tree used in erosion control on slopes and resultant sedimentation of streams, lakes, and reservoirs. (3)
- Oil: Oil has been extracted through water distillation from the balau resin and found to be a potential substitute for diesel fuel. Oil yield is around 38% to 40%. (8)

Studies
• Fiberglass from Sap: Study evaluated the potential for apitong sap as a source for making fiberglass. Air-drying a boiled mixture of the Apitong sap and acetone caused hardening, turning the mixture into "fiberglass." (4) Durability of the fiberglass was conducted by breaking the product. Based on the data and T-test computation at 0.5 level of significance with degree of freedom, T-value is -0.91959 lesser that the P-value which is 2.306. Results suggest is significant difference between the experimental fiberglass and commercial fiberglass. (6)
• Resveratrol / Stem: Study isolated two new resveratrol (=5-[(E)-2-(4-hydroxyphenyl)ethenyl]benzene-1,3-diol) trimers, grandiphenols C (1) and D (2) from the stems. (5)
• Essential Oil from Oleoresin: The wood yields large amounts of oleoresin. Study evaluate the chemical composition of essential oil obtained from water distillation of the oleoresin of D. grandiflorus. Distillation method yielded 38-40% oil from the oleoresin. Oil was light yellow, turning slightly darker on standing, with an aroma akin to gurjun balsam. It was insoluble in water, but very miscible with gasoline, diesel oil, and kerosene. Aside from sesquiterpenes reported on previous studies on D. grandiflorus essential oil, study identified copaene, ß-elemene, germacrene D, and y-gurjunene for the first time. (see constituents above) (10)
• Oleoresin Potency as Coating on Wood and Zinc: Study evaluated the stability of dimensions of oleoresin keruing resistance as wood coating and the corrosion resistance of zinc coated with oleoresin. Results showed meranti wood coated with oleoresin keuring has more stable dimensions compared to uncoated and oleoresin-coated zinc is more resistant to corrosion that uncoated zinc. (13)

Availability
- Wild-crafted.
- Critically endangered.

Additional Sources and Suggested Readings
(1)
Apitong / RAFI: Ramon Aboitiz Fooundation Inc.
(2)
Local names / Tree Facts: Dipterocarpus grandiflorus / Tree For The Future Database
(3)
Dipterocarpus grandiflorus--keruing, apitong / World AgroForestry
(4)
FIBERGLASS FROM APITONG TREE (DIPTEROCARPUS GRANDIFLORUS) SAP / Vidal, Florence Jane; Rafaela, Kylie Dave; Suson, Ruskin Flexner; Capangpangan, Remegio / South Philippine Adventist College
(5)
Two Novel Resveratrol Trimers from Dipterocarpus grandiflorus / Tetsuro Ito, Naohito Abe, Masayoshi Oyama, Toshiyuki Tanaka, Jin Murata, Dedy Darnaedi andMunekazu Iinuma / Helvetica Chimica Acta
Volume 92, Issue 6, pages 1203–1216, June 2009 / DOI: 10.1002/hlca.200800429
(6)
Fiberglass from apitong sap (Dipterocarpus grandiflorus) / Ortezuela, Edwin Cleo / An Investigatory project submitted as an entry to the 2002-2003 INTEL-Regional Science Fair, Zamboanga City / DOST Union Catalog
(7)
Dipterocarpus grandiflorus / The CABI Encyclopedia of Forest Trees / CABI
(8)
Balau resin / Non-Wood Forest Products in Asia / FAO Corporate Document Repository
(9)
Diterocarpus grandiflorus / IUCN Red List
(10)
ESSENTIAL OIL OF DIPTEROCARPUS GRANDIFLORUS BLANCO: CHEMISTRY AND POSSIBLE SOURCE OF ENERGY / Luz 0. Belardo, Brian M. Lawrence,1 Armando Coronel and Maria Fe Mata / Philippine Women 's University, Manila, Philippines / Trans. Nat. Acad. Science & Teclmol. 1983.5: pp 233-241
(11)
Two New Resveratrol (=5‐[(1E)‐2‐(4‐Hydroxyphenyl)ethenyl]benzene‐1,3‐diol) Tetramers with a Tetrahydrofuran Ring from Dipterocarpus grandiflorus / Tetsuro Ito, Toshiyuki Tanaka, Munekazu Iinuma, Ken-ichi Nakaya, Yoshikazu Takahashi, Ryuichi Sawa, Jin Murata, Dedy Darnaedi / Helvetica, Feb 2004; Vol 87, Issue 2: pp 479-495 / https://doi.org/10.1002/hlca.200490046
(12)
Dipterocarpus grandiflorus / KEW: Plants of the World Online
(13)
Dipterocarpus grandiflorus oleoresin potency as coating on wood and zinc in Borneo coastal building / Arif Wahyudianto, Wajilan, A Fernandes /  AIP Conference Proceedings, 2020; 2262: 050012 /
DOI: 10.1063/5.0015709
(14)
Chemistry and biosynthesis pathways of plant oleoresins: Important drug sources / Iram Shahzadi et al / International Journal of Chemical and Biochemical Studies, 2017; 12: pp 18-52 / ISSN: 2226-9614
(15)
Dipterocarpus grandiflorus / National Parks: FLORA & FAUNA WEB

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