Terpenes are a family of compounds that are widely distributed in the plant world. Some have biological activity while others are used only for various commercial purposes. These are the substances that occur in most of the essential oils and resins in plants. For instance terpenes are the major components in the oils of citrus fruits and they include the bioflavanoids and the carotenoids.
These substances combat fungal and bacterial infections and there are many stories claiming that terpenes are helpful in the treatment of glaucoma, spastic symptoms of multiple sclerosis, spinal lesions and in reducing the severity of side effects of chemotherapy.

Eugenol is a terpene, which is an active germicide and flavouring. It is the chief constituent of the oil of cloves and is widely used in dental treatment as an analgesic.

Eugenol induces anesthesia of the trigeminal nerve found in the head which is asociated with trigeminal neuralgia or tic doulureux. This condition expresses itself with sudden and intense pain along the side of the face. Eugenol has been shown to be anti-tumour and while little is known about how eugenol works some research studies have turned up interesting information concerning its biological activities. One study has discovered that eugenol relaxes smooth muscle by interfering with the muscle's contraction.

Eugenol is also found in a variety of aromatherapy oils including Melissa (Lemon Balm), Myrrh, Nutmeg and Ylang Ylang, all of which are used for their soothing, calming and comforting effect. The traditional use of these oils may be attributed to the relaxing effect eugenol has on the smooth muscles of the body.

Fats within our bodies (especialhy in our cell membranes) become rancid or oxidised as do our minerals also. Free radicals are destructive molecules found in our bodies that cause oxidative damage to the i fats and may be created by our body's exposure to chemicals, drugs, radiation, gases and heavy metals such as mercury and lead. This can lead to chemical sensitivity, inflammation in body tissues and over stimulation of the immune system, creating allergies etc.

Beta-carotene, another terpene, is a carotenoid, a member of the most widespread group of naturally occurring pigments in nature. Carotenes are the most potent quenchers of the singlet oxygen free radical and are many times more potent than vitamin E in this regard. Research studies in human subjects have demonstrated that a high intake of beta-carotene is associated with a reduced rate of cancers of the cells of the lung, skin, cervix, respiratory tract and the gastrointestinal tract.

The reason for this protection may be that beta-carotene reduces the oxidative damage caused by free radicals by "mopping them up".

Supplementing the diet with beta-carotene will also offer benefit to the immune system. The thymus gland gradually deteriorates with age and stress, primarily from oxidative damage. Beta-carotene should offer significant protection to the thymus gland from this damage thus maintaining optimum immune function. A study conducted in 1985 discovered that after one week of supplementation with beta-carotene (180 mg/day) the number of all T cells significantly increased in normal volunteers.

The thymus gland (which is found between the lungs) is important to our immunity as it helps produce and distribute T cells that destroy invading microbes. It is large in infants and youth but gradually is replaced by, at and connective tissue as our bodies age.

Because of its antioxidant properties the presence of beta-carotene in our bodies offers protection to the large bacteria-"eating" immune cells called phagocytes as well as increasing- the production of other immune cells. The cytotoxic or natural killer cells which kill tumours are also more active.
Beta-carotene was one among a number of natural products selected for testing to determine if daily dietary supplementation would reduce blood cholesterol levels. Beta-carotene was found to significantly reduce cholesterol levels, making it an important nutrient to be included in the human diet.

Supplementation with beta-carotene has also been found to reduce the risk of heart attack in women

Beta-carotene, of the three carotenes, alpha, beta and gamma, is the most significant to human nutrition as it is the carotene that most commonly gives rise to vitamin A within the human body. In fact it supplies about two thirds of the necessary vitamin A for our bodies.

The beta-carotene molecule consists of two vitamin A units joined together. The bond hetweeu these units can he broken down by the body to release vitamin A for use in the tissues. This structure allows beta-carotene to he a good plant source of vitamin A eliminating the toxic side effects that may arise from ingesting too much vitamin A from animal sources.

Vitamin A is important for our night sight and the formation and maintenance of the healthy functioning of skin and mucous membranes which are the body's first barrier against infection and injury. This important vitamin also cares for our gastro-intestinal tract, respiratory system and the genito-urinary tract.

It is apparent then, that consumption of fruits and vegetables rich in beta-carotene should be included in the daily diet. The daily intake of Noni juice is a good source of this vitamin.

Limonene, another terpene has been involved in some early studies concerning alzheimers disease.

The results show some promise for future investigations with limonene and its efficacy in improving the symptoms of this distressing disorder. Limonene has also demonstrated some antagonism to tumour formation and antimicrobial activity.

Ursolic Acid is one of the unsung heroes among the components of Noni juice. This terpenoid, also known as urson, and prunol, occurs naturally in a large number of foods, medicinal herbs and plants. For some time it was considered biologically inactive and was primarily used in pharmaceuticals, cosmetics and food preparations as an emulsifier. However, after numerous research studies it was discovered to be medicinally active when used both topically (on the skin) and internally. The action of ursolic acid is probably one of the reasons Noni juice has reportedly worked so well in relieving the symptoms of inflammatory and fungal infections of the skin when applied topically.

When ursolic acid is applied to the skin it has been shown to inhibit the formation and growth of tumors of the skin, as well as being strongly anti-inflammatory. It also has alopecia- and dandruff-preventing properties. Because ursoli.c acid is not dangerous to the human body and because it greatly reduces irritation to the skin it is deemed by the experts as dermatologically innocuous.

Alopecia is a condition where an individual loses their hair. It may he isolated to a bald patch on the head or it may include most body hair including eyebrows and eyelashes. In Japan ursolic acid is used in formulae to enhance hair growth and reduce scalp inflammation.
This remarkable substance is also anti-microbial for several strains of staphylococci as well as fighting the fungal infections of Candida albicans and Microsporium lenosum. Considering the number of individuals in the population who have been diagnosed with candidiasis and yeast overgrowth then Noni juice, with its supply of ursolic acid and caprylic acid (another well know anti-candida agent) becomes valuable in the diet of afflicted persons.
Research has also revealed that ursolic acid is useful in fighting leukemia and AIDS and is anti-histaminic thereby reducing allergic reactions.