Medicinal Properties Of Liquid Gold: Honey

Mrs. Lakshmi Sivasubramaniam

Honey is the natural sweet substance produced by honeybees from the nectar of blossoms or from the secretion of living parts of plants or excretions of plant sucking insects on the living parts of plants, which honeybees collect, transform and combine with specific substances of their own, store and leave in the honey comb to ripen and mature.

Physical characteristics of honey

Viscosity¹⁵

Its viscosity depends on a large variety of substances and therefore varies with its composition and particularly with its water content (Table 1 & 2). Viscosity is an important technical parameter during honey processing, because it reduces honey flow during extraction, pumping, settling, filtration, mixing and bottling. Raising the temperature of honey lowers its viscosity (Table 3) a phenomenon widely exploited during industrial honey processing. Some honeys, however, show different characteristics in regard to viscosity: Heather (Calluna vulgaris) Manuka (Leptospermum scoparium) and Carvia callosa are described as thixotrophic which means they are gel-like (extremely viscous) when standing still and turn liquid when agitated or stirred. By contrast a number of Eucalyptus honeys show the opposite characteristics. Their viscosity increases with agitation.

Table 1: Variation of the viscosity of honey at 25C, containing 16.5% water, according to the botanical origin and therefore the composition of the honey

Table 2: Variation of the viscosity of white clover honey at 25 C according to its water content

Table 3: Viscosity of sweet clover honey containing 16.1% water according to temperature

Density¹⁵

Honey density, expressed as specific gravity in Table 4, is greater than water density, but it also depends on the water content of the honey (Table 4). Because of the variation in density it is sometimes possible to observe distinct stratification of honey in large storage tanks.

Hygroscopicity¹⁵

The strongly hygroscopic character of honey is important both in processing and for final use. It can be readily seen that normal honey with water content of 18.3 % or less will absorb moisture from the air at a relative humidity of above 60%.

Surface tension¹⁵

It is the low surface tension of honey that makes it excellent humectants in cosmetic products The surface tension varies with the origin of the honey and is probably due to colloidal substances. Together with high viscosity, it is responsible for the foaming characteristics of honey. 

Thermal properties¹⁵

The heat absorbing capacity, i.e. specific heat, varies from 0.56 to 0.73 cal/g/C according to its composition and state of crystallization. The thermal conductivity varies from 118 to 143 x 10-~ cal/cm²/sec/C.

Colour¹⁵

Colour in liquid honey varies from clear and colourless (like water) to dark amber or black. The various honey colours are basically all nuances of yellow amber. Less common honey colours are bright yellow (sunflower) reddish undertones (chestnut) grayish (eucalyptus) and greenish (honeydew). Once crystallized, honey turns lighter in colour because the glucose crystals are white. Darker honeys are more often for industrial use, while lighter honeys are marketed for direct consumption.

Crystallization¹⁵

In temperate climates most honeys crystallize at normal storage temperatures. This is due to the fact that honey is an over saturated sugar solution

The crystallization results from the formation of monohydrate glucose crystals. The lower the water and the higher the glucose content of honey, the faster the crystallization.

The composition of honey¹⁵

The average composition of American honeys, more or less representative of all honeys, is shown in Table 6. Table 7 lists the various components identified in honeys from all around the world.

Sugars account for 95 to 99% of honey dry matter. The majority of these are the simple sugars fructose and glucose, which represent 85-95% of total sugars.

Water is quantitatively the second most important component of honey. Its content is critical, since it affects the storage of honey. Only honeys with less than 18% water can be stored with little to no risk of fermentation. It can be reduced before or after extraction by special techniques.

Among the minor constituents organic acids are the most important. The organic acids are responsible for the acidity of honey and contribute largely to its characteristic taste.

Minerals are present in very small quantities, potassium being the most abundant. Dark honeys, particularly honeydew honeys are the richest in minerals.

Other trace elements include nitrogenous compounds among which the enzymes originate from salivary secretions of the worker honeybees. They have an important role in the formation of the honey. The main enzymes in honey are invertase (saccharase) diastase (amylase) and glucose oxidase.

Traces of other proteins, enzymes or amino acids as well as water-soluble vitamins are thought to result from pollen contamination in honey.

Virtually absent in newly produced honey, hydroxvmethylfurfural (HMF) is a byproduct of fructose decay, formed during storage or during heating. Thus, its presence is considered the main indicator of honey deterioration.

It is more than likely that honeys from different botanical origins contain different aromatic and other substances, which contribute to the specific colours and flavours and thus allow to distinguish one honey from another. Similarly, it is very likely that, depending on their botanical origin, honeys contain traces of pharmacologically active substances. Some of them have been identified, such as those responsible for the toxicity of certain honeys.

Table 6: Average composition of U.S honeys and ranges of values¹⁵

The physiological effects of honey

Unconfirmed circumstantial evidence

Many of the traditional medicinal uses has continued until today. Few of these medicinal benefits have seen scientific confirmation and they are not always exclusive to honey. The majority is due to the high sugar content and therefore can also be found in other sweet substances with high sugar contents.

Nutritional benefits¹³

Honey is said to facilitate better physical performance and resistance to fatigue, particularly for repeated effort; it also promotes higher mental efficiency. It is therefore used by both the healthy and the sick for any kind of weakness, particularly in the case of digestive or assimilative problems. Improved growth of non-breast fed newborn infants, improved calcium fixation in bones and curing anaemia and anorexia may all be attributed to some nutritional benefit or stimulation from eating honey.

Benefits to the digestive apparatus^{6, 7}

Honey is said to improve food assimilation and to be useful for chronic and infective intestinal problems such as constipation, duodenal ulcers and liver disturbances. They have reported successful treatment of various gastrointestinal disorders.

Benefits to the respiratory system⁷

In temperate climates and places with considerable temperature fluctuations, honey is a well-known remedy for colds and mouth, throat or bronchial irritations and infections. The benefits, apart from antibacterial effects, are assumed to relate to the soothing and relaxing effect of fructose.

Benefits to skin and wound healing⁷

Honey is used in moisturizing and nourishing cosmetic creams, but also in pharmaceutical preparations applied directly on open wounds, sores, bedsores, ulcers, varicose ulcers and burns. It helps against infections, promotes tissue regeneration, and reduces scarring also in its pure, unprocessed form. If applied immediately, honey reduces blistering of burns and speeds regeneration of new tissue. A cream, applied three times per day and prepared from equal parts of honey, rye flour and olive oil, has been successfully used on many sores and open wounds -even gangrenous wounds in horses. They successfully tested a honey and cod liver oil mixture suspended in a simple non-reactive cream base on open wounds in humans, but he gave no details on proportions.

Benefit to eye disorders¹⁴

Clinical cases or traditional claims that honey reduces and cures eye cataracts, cures conjunctivitis and various afflictions of the cornea if applied directly into the eye. There are also case histories of ceratitis rosacea and corneal ulcers, healed with pure honey or a 3 % sulphidine ointment in which Vaseline was replaced by honey.

Medicine-like benefit¹⁴

Even if no transfer of active ingredients is involved, mechanisms similar to homeopathic potentiation are possible. Empirically effective therapies such as Bach flower therapy and aromatherapy suggest that there can be much more to the medicinal value of honey than chemical analysis and quantification reveals.

Diabetes¹⁴

Honey is good for diabetics. A study revealed that insulin levels were lower when compared to the uptake of equal caloric values of other foods, but blood sugar level was equal or higher than in the other compared products shortly after eating. In healthy individuals, the consumption of honey produced lower blood sugar readings than the consumption of the same quantity of sucrose.

Ayurvedic medicine¹⁴

Traditional, but well-studied medicinal systems as the ayurvedic medicine of India, use honey predominantly as a vehicle for faster absorption of various drugs such as herbal extracts. Secondarily, it is also thought to support the treatment of several more specific ailments, particularly those related to respiratory irritations and infections, mouth sores and eye cataracts. It also serves as a general tonic for newborn infants, the young and the elderly, the convalescent and hard working farmers. In general, no distinction is being made between honey from Apis mellifera, A. cerana or A. dorsata.

Other benefits¹³

Honey is said to normalize kidney function, reduce fevers and help insomnia. It is also supposed to help recovery from alcohol intoxication and protect the liver; effects also ascribed to fructose syrups. Heart, circulation and liver ailments and convalescent patients in general improved after injection with solutions of 20 and 40% honey in water.

Energy source¹⁴

As food, honey is mainly composed of the simple sugars fructose and glucose, which form the basis of almost all indications on how, when and why to use it. The main consideration is the fact that honey provides immediately available calories, from which it derives its energy value for healthy and sick people: quick access to energy without requiring lengthy or complicated digestive action. The same direct absorption also carries a risk of pathological sugar metabolism, such as diabetes and obesity.

Non-energetic nutrients¹⁴

Often honey is recommended because of its content of other nutrients like vitamins and minerals, but their quantity is so low that it is unrealistic to think they can provide any significant supplement in a deficient diet (Table 7). Similar arguments are made for the nutritional and health benefits from most other bee products, particularly pollen and royal jelly. Although their beneficial characteristics have been shown in numerous cases, they cannot be based on simple numeric values, i.e. X amount of substance Y. Yet, it is well known that the quality and availability of a nutrient is important for its usefulness to the body. Micronutrients in unprocessed honey can be assumed to be of the highest quality possible. Thus from a nutritional point of view, a synergistic balancing effect or one that unlocks the availability of other nutrients already present, is one of the more plausible yet untested hypotheses.

Topical applications^{10, 12, 13}

Topical applications under controlled conditions have shown accelerated wound healing in animals and of experimental burn wounds in rats but also of various types of wounds, including post-operative ones in humans. The simultaneous stimulation of tissue regeneration by honey reduces scarring and healing times. In many tropical field hospitals, where antibiotics and other medicines are scarce, honey has been employed successfully for a long time.

Table 7: Nutrients in honey

Antibacterial activity^{7, 8}

In normal honey it is attributed to high sugar concentration and acidity (pH range 3.5 to 5.0). The active ingredient was attributed to an elusive substance generically termed "inhibin". Much of this activity was later attributed to hydrogen peroxide (H₂₂) an enzymatic by-product during the formation of gluconic acid from glucose. The responsible enzyme, glucose oxidase is basically inactive in concentrated normal honey. Thus, in honey solutions (diluted honey) with the right pH, antibacterial activity is largely due to the presence of hydrogen peroxide.

The use of honey today⁶

· As a food

Honey is most commonly consumed in its unprocessed state. In these forms it is taken as medicine, eaten as food or incorporated as an ingredient in various food recipes. Different storage temperatures in different climates, among other factors influence the crystallization and speed of re-liquefaction of honeys. Stored above 25°C, most honey remain liquid or reliquify slowly, but lose much of their aroma in just a few months.

· As a food ingredient

The traditional use of honey in food preparations has been substituted in most cases by sugar and more recently by various sugar syrups derived from starches. Many honey containing industrial products were developed in the last decades. Honey is largely used an a small scale as well as at an industrial level baked products, confectionary, candy, marmalades, jams, spreads, breakfast cereals, beverages, milk products and many preserved products.

§ Baked products

§ In confectionary production

§ In breakfast cereal industry

§ Numerous snack bars (candy bars)

§ In wide variety of spreads for bread

§ To honeys with added aromas or essences, be it fruit or other aromatic essences

§ In preparation of marmalades and jams

§ The use of honey with milk or milk products is a very common home remedy against colds and infections of the throat

§ Adding to ice creams - The addition of more than 7.5% honey softens ice creams significantly, due to its lower freezing point.

§ In the non-alcoholic beverage

§ Honey is also used in the manufacturing of sauces

 As an ingredient in medicine-like products^{7, 8}

The medicinal use of honey is probably its most widely known use, but such uses do not require special preparations. The pharmacopoeias of many countries describe a honey-based preparation, which can be prepared by pharmacists (honey rose water), which is used for topical application in infected throats and various ulcers of the mouth.

More common is the use of honey in herbal and other traditional extracts. Fermented honey syrups are used as a base. The addition of honey to herbal extracts and also prior to fermentation (as described above) is commonly practised in ayurvedic medicine. Honey is also a fundamental ingredient in some medicinal wines and vinegars.  

References

1. Accorti, M. 1992. [The influence of the environment on the behaviour and biology of bees in environmental monitoring]. In Proc. of Symp. on "The honeybee as monitoring insect for agricultural pollution^1~, 1992, Florence 41-53

2. Adam, Brother 1953. Mead. Bee World, 34(8): 149-156

3. Adams, F. 1939. The genuine works of Hippocrates. Williams & Wilkins, Baltimore, U.S.A.

4. Adjare, S.O. 1984. The golden insect, A handbook on beekeeping for beginners. IT Publications, Russell Press Ltd., Nottingham, UK, 104 pp.

5. Adjare, S.O. 1990. Beekeeping in Africa. FAO Agricultural Series, Bulletin 68/6, Rome, Italy, 130 pp.

6. Apimondia 1975b. The hive products: food health and beauty. Proc. of Intern. Symp. on Apitherapy. Apimondia Publishing House, Bucharest, Romania, 154 pp.

7. Armon, P.J. 1980. The use of honey in the treatment of infected wounds. Tropical Doctor, 10: 91.

8. Arora, D.D. and Kual, K.K. 1973. Feeding practices during the first five years among central Indian communities. Indian Journal of Pediatrics, 40: 203-216.

9. Ask-Upmark, E. 1967. Prostatitis and its treatment. Acta Med. Scand., 181: 355-357

10. Bergman, A. Yanai, J., Weiss, I., Bell, D. and Menachem, P.D. 1983. Acceleration of wound healing by topical application of honey. An animal model. The American J. of Surgery, 145 : 374-376

11. Berthold, R. 1993. Beeswax crafting. Wicwas Press, Cheshire, Conn., U.S.A., 128 pp. Berthold. R. 1988a. A new concept in mead making. Amer. Bee J., 128: 820-824 Berthold, R. 1988b. A delicious way to increase sales, honey and fruit, Glean. Bee Cult., 116 (7): 408-410

12. Burlando, F. 1978. [About the therapeutic action of honey on burn wounds.] Minerva dermatolog. 113: 699-706

13. Cartland, B. 1970. The magic of honey. Corgi Books, London, UK, 160 pp.

14. Codex Alimentarius 1994. Honey. 2nd Edition, FAO/WHO, Vol.11: 21-24

15. Codex Alimentarius 1995. Standards for honey. 2nd Education, FAO/WHO Vol.13 (in preparation).

About Authors

Madhumathi Seshadri^b and Mrs. Lakshmi Sivasubramaniam ^a, *

Mrs. Lakshmi Sivasubramaniam

^a Lecturer, Department of Pharmaceutical Analysis, College of Pharmacy, SRM Institute of Science and Technology, Deemed University, Katangulathur, Chennai, India.

* ^aAuthor for Correspondence: Lakshmi Sivasubramaniam, Lecturer, Department of Pharmaceutical Analysis, College of Pharmacy, SRM Institute of Science and Technology, Deemed University, Katangulathur, Chennai, India. E mail: laxmisiva@rediffmail.com.

Madhumathi Seshadri

^b Department of Chemistry, Pharmaceutical Chemistry unit, Vellore Institute of Technology, Vellore - 632 014, India.

Madhumathi Seshadri successfully completed M. Tech. in Pharmaceutical Chemistry at Vellore Institute of Technology, Vellore (a deemed university) in I Class with Distinction.