“As the valleys are they spread forth, as gardens by the river’s side, as the trees of lign aloes which the Lord hath planted, and as cedar trees beside the waters.”
“All thy garments smell of myrrh, and aloes and cassia, out of the ivory palaces, whereby they have made thee glad.”
“I have perfumed my bed with myrrh, aloes, and cinnamon.”
“Spikenard and saffron; calamus and cinnamon, with all trees of frankincense; myrrh and aloes, with all the chief spices.”
Song of Solomon 4:14
“And there came also Nicodemus, which at the first came to Jesus by night, and brought a mixture of myrrh and aloes, about an hundred pound weight.”
ORIGIN AND CULTIVATION
The Aloe species are native to tropical and Southern Africa, Madagascar, and Arabia, but have been introduced to many parts of the world. Botanists have identified about 300 species of this plant. The Aloe plant has typically been viewed as a medicinal plant but there are a number of ornamental species that serve no real therapeutic purposes. Two major products are derived from the leaves of Aloe species:
(a) A yellow bitter juice from specialized cells beneath the leaf skin, or epidermis which is processed to give the drug “aloes.” This yellow bitter juice can be obtained from all species of the aloes plant;
(b) A mucilaginous gel from the soft tissue in the centre of the leaf that gives the drug “aloe vera” or “aloe vera gel.” This gel is principally obtained from the Aloe vera (syn. A. barbadensis), which is much cultivated in Africa and Latin America. Other species of Aloes which are of economic importance are
- feroxand its hybrids (Cape aloe, South Africa), and
- (Socotrine or Zanzibar aloe).
Aloe species are perennial succulents with dense rosettes of thick, spiky, grey-green leaves with aerial stems bearing yellow, reddish, or orange tubular flowers. Aloe vera has 15–30 leaves, each up to 0.5 m (1 ft) long and 8–10 cm (4 in) wide; the flowering stem is 60–90cm (34 in) in height and it grows best in shady places. It is best potted when cultivated at home and does not need any specialised horticultural skills for it to survive. Too much of direct sunlight, however, will burn its fronds. Ensure that you water it regularly if it’s one of your garden plants, because its fronds require water to remain turgid.
CULINARY AND NUTRITIONAL VALUE
Aloe plant is hardly in use for any culinary purposes because of its very bitter slimy taste. However, African tribes have used it chiefly for medicinal purposes. In today’s increasing market of natural healthcare products, the plant is often used in beverages and confectionery to impart a bitter taste and it is often diluted before such use.
HISTORY OF USAGE, CLAIMS AND FOLKLORE
The aloe plant has been used since ancient times. Archeologist and historians have identified this plant in wall paintings of Ancient Egypt, dating to the fourth millennium BC. It was a traditional funeral gift for the pharaohs. In the Egyptian Book of Remedies (about 1500 BC), aloe was recommended for curing infections, treating skin disorders, and as a laxative. It was recorded in Ancient Greece in the Fourth Century BC. From the Bible verses above, we also find that this plant was in regular use by the Jewish people. The body of Jesus was wrapped in linen impregnated with myrrh and aloes. It is contentious to assert that Jesus was embalmed with aloes and myrrh. The matrix of embalmment was Ancient Egypt where the pharaohs were buried alongside with aloe. However, if we recourse to the burial practices of Jews, it is doubtful to assert that Jesus was embalmed simply because aloe is mentioned. Jewish burial traditions simply involved washing the corpse and burying it without any form of embalmment. If a corpse was to be embalmed (as in Egypt), incisions had to be made and to preserve it. Making such incisions on Jesus’ body would not have been acceptable to custom and norms of his people.
Pedanius Dioscorides, the Ancient Roman physician, pharmacologist and botanist of Greek origin, used aloes to heal wounds, stop hair loss, treat genital ulcers, and eliminate hemorrhoids, as recorded in his De Materia Medica – a 5 volume encyclopedia about herbal medicine and related medicinal substances. In the sixth century, it is recorded that Arab traders carried this plant to Asia and, in the sixteenth century, Spaniards transported it to the New World.
In more modern times, “bitter aloes,” which is obtained by allowing the yellow leaf juice to dry out and to give a brown mass, has been used as a purgative. Its action depends on the anthraquinones (glycosides) present. On the other hand, “Aloe vera” gel (containing glucomannan and other polysaccharides, lipids, and some other substances) is used in the cosmetics industry in creams, shampoos, cleansers, soaps, and suntan lotions, with claims for moisturizing and revitalizing properties. It is claimed as a cure or remedy for burns, wounds, and various skin conditions (e.g. acne, dermatitis, psoriasis, hair loss). These days, it is not uncommon to find drinks containing “aloe vera” which are said to relieve irritable bowel syndrome, peptic ulcers, and indigestion – and to be helpful for general detoxification.
Aloe vera is considered to be the most biologically active of all the over 300Aloe species.1
About 75 potentially active constituents have been identified in the plant including vitamins, minerals, saccharides, amino acids, anthraquinones, enzymes, lignin, saponins, and salicylic acids. As earlier pointed out, its leaf exudate contains anthraquinones, particularly barbaloin, which is responsible for its bitter taste and cathartic effect. 2
Barbaloin and other products of the phenylpropanoid pathway are commonly referred to as polyphenolic compounds. These are derived from the precursor phenolic acids, and they may act as antioxidants to inhibit free radical–mediated cytotoxicity and lipid peroxidation. 3
Aloe vera also contains products of the isoprenoid pathway, including carotenoids, steroids, terpenes, and phytosterols. Isoprenoids can be regarded as sensory molecules because they contribute to the color and fragrance of the products in which they exist.4
There is scientific evidence that “bitter aloes” is an effective laxative. Indeed from observational studies, it has been concluded that its purgative action can sometimes be too drastic, and other, milder laxatives are recommended in its place. It should not be given to patients with hemorrhoids, or used during pregnancy and lactation. A number of experimental investigations (both with animals and humans) have been carried out using “aloe vera.” The results are difficult to interpret because:
(a) sometimes homogenized leaf extracts have been utilized, that contain both “aloes” and “aloe vera”; and
(b) precise active constituents have not been isolated and characterized. In general, the literature on burn management and wound healing is confused, and further studies are required.
However, the gel freshly extracted from the leaves is effective in dealing with minor burns, often as a home cure. Aloe vera in commercial preparations is usually stabilized and in sufficient concentration. There is a little support for “aloe vera” gel as a remedy for acne and eczema. Internal administration of “aloe vera” (e.g. in drinks) does not seem to exert any consistent therapeutic effect. External application of the gel during pregnancy and lactation would appear to be safe but internal administration, because of possible admixture with bitter “aloes”, is to be avoided. 5
With regard to malaria and typhoid fever, there is also little scientific proof based on clinical trials which have confirmed that aloe vera can treat malaria or typhoid fever. However, many people have continued to maintain that aloe vera has proved useful as a preventive medication for malaria when ingested on a regular basis, like say once a week but no dosage was also indicated. Aloe vera has minimal adverse or toxic effect so it’s okay to give a trial.
- World Health Organization. WHO Monographs on Selected Medicinal Plants. Vol. 1. Geneva: World Health Organization; 1999)
- Naturally Occurring Bioactive Compounds, Edited by Mahendra Rai & Maria Cecelia Carpinella,  Elsevier Publications.
- Cook N.C, Samman S. Flavonoids: Chemistry, Metabolism, Cardioprotective Effects and Dietary Sources Nutr. Biochem. 1996; 7: 66–76.
- Samman S. Lipid metabolism. In: Kuchel P.W, Ralston G.B, editors. In Schaum’s Outlines of Theory and Problems of Biochemistry. New York: McGraw-Hill Book Company; 1998. pp. 362–401.
- The Oxford Book of Health Foods, J. G. Vaughan & P. A. Judd, 2003.