L. orientalis grows and is cultivated in the states of Asia Minor. It is the source of the balsam known as the Levantine styrax.
L. styraciflua grows and is cultivated in the south of North America, in the Central and Northern zones of South America. It is the source of the American styrax.
Both species are subtropical trees from 15 m (L. orientalis) to 40 m (L. styraciflua). Leaves alternate, 5-7, upper 3-finger-lobed, on long petioles, serrate at the edges, glabrous, whitish-green below, angular inflorescences; male – collected in complex capitate ears, female – single drooping heads. Flowers inconspicuous; the fruit is dry, collapsible, in spherical prickly heads.
Balm is a pathological formation produced by plants as a result of damage to the cortex. The balm flows out of the incisions in the form of a thick, gray, opaque liquid; on standing, it separates into an upper, aqueous layer and a lower, thick, resinous one. The latter contains within 20-30% water and is contaminated with pieces of bark and other random particles. This crude product is purified by dissolving in alcohol followed by filtration and evaporation. Purified balm is a gray-brown thick, viscous liquid of the consistency of honey with a pleasant smell (Balsamum Styrax liquidus).
Balm is a mixture of resin and essential oil. The share of essential oil is from 1% (Levantine styrax) to 7% (American styrax). Otherwise, the composition of both varieties of styrax is approximately the same. Up to 50% falls on two resinols – a- and b-storesin (triatomic triterpene alcohols of the formula Cs 5 H 55 (OH) 3 ), which are mostly esterified with cinnamic acid. Significant amounts are accounted for by phenylpropyl ester of cinnamic acid (10%) and styracin (5-10%). The pleasant smell of the balm is due to styrene C 6 H 5 —CH—CH 2 (phenylethylene), which can be up to 5%, and essential oil.
It is used as a benzoin resin and mixed with it as an antiseptic externally for the treatment of wounds and skin diseases (scabies) and for inhalation.
The plant contains balsams (oil-resins).
PLANTS CONTAINING RESINS AND BALMS
Like essential oils, resins are complex mixtures of various organic compounds. In plants, they are often present simultaneously with essential oils, but may be accompanied by substances from other groups of natural compounds – gums, tannins, sterols, sometimes rubber.
According to the primary composition, there are three main groups of natural resins:
– resins (actually) – Rsina;
– oil-resin, or balms, – Olea-resina, or Balsama. These are liquid resins, which are natural solutions of resins in their own essential oil;
– gum resins – Gummi-resina. These are liquid (in living plants) mixtures of gums and resins dissolved in essential oil (more precisely, Cummi-olea-resina).
The resins themselves, freed from accompanying substances, like the components of essential oils, are also terpenoids, but more complex, belonging mainly to the class of diterpenes (C 20 H 32 ).
Resin hydrocarbons (for example, pimaradiene), their oxygen derivatives, resinol or resin acids (for example, abietic and pimaric acids) and resinol or resin alcohols (for example, cafestol) are distinguished among resin diterpenes.
Among the resinols, rezitannols or tannols, which have the properties of tannins, are distinguished into a special group. Resinols can form esters.
The constituent substances of resins can be triterpene acids and alcohols – derivatives of a- and b-amirin (for example, mastic tree), lignans (for example, guaiac resin), etc.