Leung's Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics

BENZOIN

Source: Styraxspp. (Family Styraceae).

Common/vernacular names:Gum benjamin,
gumbenzoin,Siambenzoin,Sumatrabenzoin.

GENERAL DESCRIPTION

Benzoin is the balsamic resin obtained from
the bark of variousStyraxspp.Styrax benzoin
Dryand and S. paralleloneurum Perkins
yield Sumatra benzoin;S. tonkinensis(Pierre)
Craib ex Hartwich and other relatedStyrax
species yield Siam benzoin.
Benzoin-producing Styrax species are
mostly small to medium trees (up to 20 m
high) growing in tropical Asia. Sumatra ben-
zoin is largely produced from cultivated trees
growing in North Sumatra, although the tree
occurs natively in Borneo, Java, and the Malay
Peninsula; Siam benzoin is produced from
trees growing in Thailand in the Province of
Luang Probang, although the tree also occurs
in Laos, Vietnam, Cambodia, and China.
Benzoin is a pathological product formed
when the tree trunk is injured.It is produced by
incising the bark; the exuded balsamic resin
hardens on exposure to air and sunlight, and is
collected. Benzoin resinoid is prepared from
crude benzoin by extraction with solvents
such as benzene and alcohol, followed by their
subsequent removal.

CHEMICAL COMPOSITION

Benzoin contains chiefly esters of cinnamic
and benzoic acids together with free acids.
Amounts and types of esters and acids vary
widely depending on the source.1,2
The major constituents of Sumatra benzoin
are p-coumaryl cinnamate, cinnamic acid,
cinnamyl cinnamate (styracin), p-coumaryl
benzoate, pinoresinol, benzoic acid, coniferyl
cinnamate, and coniferyl benzoate. The major
constituents of Siam benzoin arep-coumaryl
benzoate, benzoic acid, pinoresinol, cinnamic

acid, benzoic acid ester, and p-coumaryl

cinnamate. Both Sumatra and Siam benzoin

contain small amounts of vanillin and ap-

proximately 2–3% triterpenoid compounds^2

(e.g., siaresinolic acid and sumaresinolic acid)

(EVANS). The major component of the oils de-

rived from Sumatra and Siam benzoins is ben-

zyl benzoate (76.1–80.1%). Other major con-

stituents in Sumatra benzoin oil are cinnamic

acid, benzyl cinnamate, and styrene, whereas

those in the oil of Siam benzoin are benzoic

acid, allyl benzoate, and methyl benzoate.^3

PHARMACOLOGY AND BIOLOGICAL

ACTIVITIES

Benzoin vapor (with steam) has expectorant

properties; its solutions (e.g., tincture) have

local antiseptic properties. Following topical

application in monkeys, benzoin is partly

absorbed through the skin resulting in system-

ic exposure.^4

TOXICOLOGY

Benzoin is regarded as moderately toxic,

probably due to occasional contact dermatitis

developed in some individuals when using

Compound Benzoin Tincture, which contains,

in addition to benzoin, aloe, storax, balsam

tolu, and others (GOSSELIN;MARTINDALE).5–7

Use of benzoin as a surgical adhesive has

resulted postoperative contact dermatitis in

some individuals,^8 and produced adverse ef-

fects in children when used as a circumcision

dressing.^9 The use of tincture of benzoin as a

pressure bandage in enucleation of the eye has

resulted in necrotizing dermatitis.^10

USES

Both Siam benzoin and Sumatra benzoin are

official in pharmacopoeias of many countries;

however, only Sumatra benzoin is found in the

BP. Both types are official in U.S.P., but in the

United States Sumatra benzoin is more cus-

tomarily used in pharmaceutical preparations,

90 Benzoin