A review of dipterocarps - Center for International Forestry Research

Non-Timber Forest Products from Dipterocarps
to mucous surfaces and also a diuretic (Kirtikar and Basu
1935, Martindale 1958). It is an ingredient of
lithographic ink and varnish and an anticorrosive coating
composition for iron. It is occasionally used as a
preservative for timber and bamboo. Mixed with
powdered dammar from Shorea robusta or S. siamensis
it forms a dark brown paste used for caulking boats and
water proofing bamboo baskets used for carrying water.
Gurjan oil is a good solvent for caoutchouc
(unvulcanised rubber) which is applied to cloth to make
it water-proof. This cloth resists insect-attacks.
Traditional Uses
a) Medicine: Ancient literature reveals that gurjan oil
was used by the Mohammedans and it was first
mentioned in the ‘Makhzan’ Materia Medica as ‘Duhnel-Garjan’.
Its essential oil is effective in the treatment
of genito-urinary diseases. The Pharmacopoeia of India
1868, officially describes it as a stimulant of mucous
surfaces, particularly those of the genito-urinary system,
and as diuretic (Watt 1899). However, users of
indigenous systems of medicine in India find it less
powerful than copaiba. It is useful in leucorrhoea and
other vaginal discharges, psoriasis, including lepravulgaris
and also in the treatment of leprosy (used both
externally and internally). All varieties of gurjan oil are
equally useful as local stimulants but red, reddish brown,
pale or pale white varieties are best for internal use.
The efficacy of this oil is enhanced with the addition of
chaulmugra oil.
An ointment is prepared by mixing equal parts of oil
and lime water. In European medicine gurjan oil was
mainly used as an adulterant for copaiba.
b) Domestic and Industrial Uses of Gurjan Oil: Gurjan
oil was used in Burma for torches, and later, as lamp
oil. It could be used as a varnish by mixing it with some
good drying oil or by evaporating the essential oil. The
oil was a good substitute for linseed oil and balsam of
copaiba and prized as a colourless varnish and for drying
paints.
c) Trade of Gurjan in the 19th Century: In Burma and
Bangladesh gurjan oil was mainly used for torches but
its trade was limited due to the cheap price of kerosene.
However, gurjan oil from Singapore and Malaya
was a common article of trade in Thailand. The oil produced
in South India and Andaman Islands was traded in
Europe for use in artworks. The price of the black or
dark brown varieties (‘Kala gurjan Tel’) was half the price
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of the red or reddish brown (‘Lal gurjan Tel’) and pale
white (‘Sufed gurjan Tel’) varieties.
Other Sources of Oleoresin
Other South Asian species important for the production
of oleoresins include Dipterocarpus alatus and D.
tuberculatus. The former is found in Chittagong
(Bangladesh), Andamans (India) and Burma. D.
tuberculatus occurs in Burma, and to a restricted extent
in India and Bangladesh.
Dipterocarpus alatus produces an oleoresin that
contains 71.6% volatile oil. The oil known as ‘kanyin
oil’ in Burma is an antiseptic applied to clean wounds
and has been used as a substitute for copaiba in the
treatment of gonorrhoea. In Burma, it is also used for
treating ulcers and sores in the hoof and foot disease of
cattle. The oil is used by forest dwellers to fuel torches
made of rotten wood and for waterproofing the oil cloth
used for Burmese umbrellas. It has been used in the
preparation of lithographic inks and has been tried as a
varnish and as a substitute for linseed oil in zinc paints.
Its bark is a tonic given for rheumatism.
The method of tapping oleoresins from almost all
other species resembles that of D. turbinatus. A notch
is made into the trunk and the wound blazed to stimulate
resin flow. Resin is collected periodically and either the
wound is scraped for new flow or another wound made.
The trees eventually succumb to the regular wounding,
and the timber, unsuitable for construction work, is used
as fuelwood. The oil and resinous thicker substance
mixture is strained through a cloth whereby the clear oil
separates itself from the resinous portion. Dipterocarpus
alatus provides the wood-oil, pegu.
Dipterocarpus tuberculatus is the principal source
of oleoresin known as ‘In oil’ in Burma and ‘gurjan oil’
in India. Its exudate is thicker than ‘kanyin oil’ from D.
turbinatus and flows freely from the wound without the
aid of fire. Throughout the year, resin oozes
simultaneously from several niches on a tree. The oil
was collected 4-10 times a month from August-February
and 300 trees yielded about 36 kg a month. At the end of
the season the dried resin was scraped off and used to
make torches. Freshly collected oleoresin is a pale brown
substance with specific gravity 1.029; acid value 17.8
and ester value 0. It yields a yellow brown essential oil
on steam distillation. The oil is used for varnishes and
for water proofing umbrellas and bamboo well-baskets.
The oleoresin is used with assafoetida and coconut oil
as an application for large ulcers (Watt 1889).