Frankincense tree. Frankincense – Boswellia carterii Birdw.
The incense tre grows on the dry slopes of the mountains of Somalia, on about. Socotra, in Southeast Arabia.
Small trees, from 3 to 5 m. The leaves are alternate, collected in close whorls at the ends of the branches, pinnate; margins of almost sessile leaflets are rounded-toothed, in some places short-lobed. Inconspicuous white or light yellow five-membered, actinomorphic bisexual flowers are collected in short brushes.
To obtain incense, cuts are made on the trunks: gum resin flows out of the wood, hardening on the bark or at the base of the trunk.
Raw materials of the highest grade Gummiresina Olibanum consist of separate dry transparent light yellow “tears”, the worst grades – from a darker sticky uneven resinous mass with interspersed “tears”. Various varieties contain resin (50-70%), gum (30-47%), essential oil (2.5-8%), bitter substance. The composition of the essential oil includes dipentene, a-pinene, phellandrene, camphene and other terpenes. The composition of the resin includes triterpene acids – the so-called air-boswellic acids. Gum is similar to gum arabic.
Frankincense is used for fumigation as an antiseptic and in emulsions for catarrh of the respiratory tract. The most ancient incense and an integral part (along with myrrh) of religious practices.
The plant contains gum 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.