2.10 Balsams
Balsams are the resinous mixtures that essentially contain large quantum of benoic acid, cinnamic acid or both, or esters of these organic aromatic acids.
A galaxy of typical examples of naturally occurring balsams will be discussed in the sections that follow, namely: Storax; Peruvain Balsam; Tolu Balsam; and Benzoin.
1. Storax
Synonyms Styrax; Sweet oriental gum; Levant Storax; Purified or prepared Storax; American Storax; Liquid Storax;
Biological Source Storax is the balsam obtained from the trunk of Liquidamber orientalis Mill., termed as Levant Storax, or of L. styraciflua L., known as American Storax belonging to the natural order Hamamelidaceae.
Preparation The natural balsam storax is a pathological product formed as a result of injury caused to the plant. It generally, exudes into the natural pockets between the bark and the wood and may be located by exerscences on the outerside of the bark. These pockets, that may contain upto 4 kg of the balsam, are conveniently tapped with the help of strategically positioned gutters, and the product is ultimately allowed to fill into containers. The crude storax, thus collected, is further purified by dissolving in ethanol, filtration and subsequent evaporation of the solvent to obtain the pure storax.
Characteristic Features The balsam storax is a semiliquid grayish, sticky, opaque mass (Levant Storax), or a semisolid sometimes solid mass softened by gentle warming (American Storax). In general, storax is transparent in thin layers, possesses a characteristic agreeable balsamic taste and odour. It is, however, denser than water. It is almost insoluble in water, but completely soluble in 1 part of warm ethanol, ether, acetone and CS2.
Chemical Constituents Storax contains the following chemical compounds, namely: α-and β-storesin and its cinnamic ester (30-50%), styracin (5-10%); phenylpropyl cinnamate (10%); free-cinnamic acid (5-15%); levorotatory oil (0.4%); small amounts of ethyl cinnamate, benzyl cinnamate, traces of vanillin and styrene ( (C6H5CH=CH2).
Besides, Levant storax contains free storesinol, isocinnamic acid, ethylvanillin, styrogenin, and styrocamphene.
In addition to these, American Storax contains styaresin (i.e., -cinnamic acid ester of the alcohol styresinol, an isomer of storesinol) and styresinolic acid. It also yields upto 7% of a dextrorotatony volatile oil, styrol and traces of vanillin.
Chemical Tests
1. Benzaldehyde Test—Treat 1 g of storax with 5 ml of K2Cr2O7 solution (10% w/v) followed by a few drops of concentrated sulphuric acid (36 N) it produces benzaldehyde, which may be detected easily as the odour of bitter almonds.
2. Mix 1g of storax with 3 g of pure sand (SiO2) and 5 ml of KMnO4 solution (5% w/v) and heat it gently. It gives a distinct odour of benzaldehyde.
Uses
1. It is used in fumigating pastilles and powders.
2. It finds its application in perfumery.
3. It is employed as an imbedding material in microscopy.
4. It is used as an expectorant, antiseptic and stimulant.
5. It is employed as a preservative for fatty substances e.g., lard and tallow.
6. It is also used as a flavouring agent for tobacco.
7. It is a vital ingredient of “Compound Benzoin Tincture”.
2. Peruvian Balsam
Synonyms Balsam Peru; Indian balsam; Black balsam; China oil; Honduras balsam; Surinam balsam.
Biological Source Balsam Peru is obtained from Toluifer pereiare (Klotzsch) Baill. (Myroxylon pereiare Klotzsch) belonging to family: Leguminosae.
Preparation Peruvian Balsam is a pathological product and is obtained usually by inflicting injury to the trees. Most of the world's commercial supply comes from El Salvador, although some is also produced in Honduras.
It is prepared by beating the stems of the trees with mallet. After a week the injured areas of the stem are scorched so as to separate the bark from the stem and after a similar duration the bark is peeled off completely. The desired balsam starts exuding freely from all the exposed surfaces, which are then covered carefully with cloth or rags to absorb the exuding balsam. The cloth or rags that are completely soaked with the balsam is then removed and boiled with water in a large vessel slowly.
Thus, the balsam gets separated and settles at the bottom of the vessel. The supernatant layer of water is removed by decantation and the residual balsam is dried and packed in the containers.
Characteristic Features It is a dark brown, viscid liquid having a pleasant aromatic odour. It has a peculiar warm bitter taste and persistent aftertaste which resembles like vanilla. The Balsam Peru is transparent in thin films. It does not harden on being exposed to atmosphere. It is brittle when cold. It is almost insoluble in water and petroleum ether but soluble in ethanol, chloroform and glacial acetic acid.
Chemical Constituents Peruvian balsam contains free benzoic and cinnamic acids (12-15%); benzyl (40%); esters of these acids (5.2-13.4% cinnamein); and volatile oil (1.5-3%).
The fragrant volatile oil contains toluene, styrol, benzoic and cinnamic acids.
It also contains total balsamic acids, which is calculated on the basis of dry alcohol-soluble matter ranging between (35-50%).
The resins esters (30-38%) are chiefly composed of peruresinotannol cinnamate and benzoate, vanillin, free cinnamic acid and peruviol (or nerolidol).
Uses
1. Peru balsam is a local protectant and rubefacient.
2. It also serves as a parasiticide in certain skin disorder.
3. It is used as an antiseptic and vulnerary* and is applied externally either as ointment or alone or in alcoholic solution.
4. It acts as an astringent to treat hemorrhoids.
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* Vulnerary: A folk remedy or herb to promote wound healing.
3. Tolu Balsam
Synonyms Thomas balsam; Opobalsam; Resin Tolu; Balsam of Tolu.
Biological Source Tolu Balsam is a balsam obtained from Toluifera balsamum L., (Myroxylon toluiferum H.B.K.), belonging to family: Leguminosae. It is also obtained from Myroxylon balsamum (Linne') Harms. Family: Fabaceae.
Preparation Tolu Balsam is considered to be a pathological product produced in the new wood formed as a result of inflicted injury. For its preparation, it is an usual practice to make ‘V’ shaped incisions deep into the body of the main trunk. The exudate thus produced is collected either in cups or gourds held strategically just at the base of each incisions. Balsam of Tolu is collected from these cups, mixed and packed in air-tight sealed tins.
Characteristic Features It is a yellowish-brown or brown semifluid or nearly solid resinous mass. It has a characteristic aromatic vanilla-like odour and slightly pungent taste. It is usually brittle when cold. It is found to be transparent in thin layers, and shows numerous crystals of cinnamic acid. It is almost insoluble in water and petroleum ether, but freely soluble in ethanol, benzene chloroform, ether, glacial acetic acid and partially in CS2 or NaOH solution.
Chemical Constituents The drug contains resin esters (75-80%) viz., toluresinotannol cinnamate along with a small proportion of the benzoate; volatile oil (7-8%)-containing chiefly benzyl benzoate; free cinnamic acid (12-15%); free benzoic acid (2-8%); vanillin and other constituents in small quantities. It also contains cinnamein (5-13%).
Chemical Tests
1. An alcoholic solution of Tolu Balsam (0.2% w/v) where treated with a FeCl3 solution (0.5% w/v), the appearances of a green colour takes place.
2. Treatment of 1 g of the drug with 5 ml of 10% w/v KMnO4 solution when subjected to gentle heating yields benzaldehyde.
Uses
1. It is used extensively in perfumery, confectionery and chewing gums.
2. It is used widely as an expectorant in cough mixture.
3. It also finds its application as an antiseptic in the form of its tincture.
4. Benzoin
Synonyms Bitter-almond-oil camphor.
Biological Source Benzoin in the balsamic resin obtained from Styrax benzoin Dryander and Styrax paralleloneurus Perkins, generally known in trade as Sumatra Benzoin; whereas, Styrax tonkinensis (Pierre) Craib ex Hartwich, or other species of the section Anthostyrax of the genus Styrax, known commonly in the trade as Siam Benzoin both belong to the family: Styraceae.
Preparation Benzoin is also a pathological product that is obtained by incising a deep-cut in the bark. It has been observed that after a span of about eight weeks, the exudating balsamic resin tends to become less sticky in nature and firm enough to collect. The entire exudate is usually collected in two stages, namely:
Stage 1: First tapping-yields almond tears, and
Stage 2: Second tapping-yields a more fluid material.
Characteristic Features
Sumatra Benzoin: It is pertinent to mention here that in pharmacy, only the Sumatra Benzoin is used. It occurs as blocks or irregular masses of tears having variable sizes usually imbedded either in an opaque or translucent matrix. It is rather brittle, and from within the tears are milky white in appearance. It generally becomes soft when warmed and gritty when chewed. The matrix is grayish brown to reddish in colour. Its taste is quite agreeable, balsamic and resembles to that of storax. It has a resinous and aromatic taste.
Siam Benzoin: The smaller tears of Siam Benzoin are darker in colour. It occurs largely in separate concavo-convex tears which are yellowish brown to rusty brown externally, whereas milky white internally. The tears are fairly brittle but normally become soft and plastic like on being chewed. It has a vanilla-like fragrance.
Chemical Constituents The chemical constituents of the two types of Benzoin are given below:
(a) Sumatra Benzoin: It contains free balsamic acids, largely cinnamic acid (10%), benzoic acid (6%)-along with their corresponding ester derivatives. Besides, it also contains teriterpene acids, namely: 19-hydroxyloleanolic and 6-hydroxyoleanolic acids, cinnamyl cinnamate, phenyl propyl cinnamate, phenylethylene and lastly the traces of vanillin. It yields not less than 75% of alccohol-soluble extractives.
(b) Siam Benzoin: It chiefly comprises of coniferyl benzoate (60-70%), benzoic acid (10%), triterpene siaresinol (6%) and traces of vanillin. It yields not less than 90% of alcoholsoluble extractives.
Chemical Tests
1. When 0.5 g of Sumatra Benzoin powder is warmed with 10 ml of KMnO4 solution (5% w/v) in a test tube, a faint and distinct odour of benzaldehyde is developed. Siam Benzoin gives a negative test.
2. When 0.2 g of Siam Benzoin powder is digested with 5 ml of ether for 5 minutes and filtered; 1 ml of the filtrate is poured into a clean china-dish containing 2-3 drops of concentrated H2SO4 and mixed carefully, a deep purplish red colouration is developed instantly. Sumatra Benzoin gives a negative test.
Uses
1. Compound benzoin tincture is frequently employed as a topical protectant.
2. It is valuable as an expectorant when vapourized.
3. It finds its usage as a cosmetic lotion usually prepared from a simple tincture.
4. Siam Benzoin has been proved to be a better preservative for lard than the Sumatra Benzoin.
