Borage, also known as cucumber herb and under many other regional names, is a time-honored culinary and medicinal herb: Borago officinalis L. The genus gives its name to the associated family Boraginaceae, the broad-leaved plants, which bear predominantly bristle-like hairy leaves and stems. Borage grows to a height of about 70 centimeters as an annuelle. Short-stemmed, initially pink and later becoming bright blue, five-petaled flowers with white throat scales appear on long inflorescences. The cone-shaped purple stamens surrounding the ovary are also striking. Bees and other pollinators are responsible for fertilization. The four seeds of the clover fruit, each up to 6 millimeters in size, contain 26 to 40 percent of the uniquely composed borage oil.
Borage originated in Mediterranean North Africa and has naturalized in many warmer regions of Europe. Since at least the Middle Ages, the herb has been cultivated for its flowers, leaves (both containing liver-toxic pyrrolizine alkaloids) and oil seeds in Central Europe and North to South America, and now worldwide in all mild to temperate climates. In the latter, the flowering period extends from June to September, in milder climates almost throughout the year. Fruit ripening is also uneven, which makes harvesting the easily decaying clauses even more difficult. As a result, combine harvesters are used on several occasions with seed losses of up to 60 percent, in some cases also special suction machines and a maximum yield of 750 kilograms per hectare.
Since it is a matter of preserving the sensitive polyunsaturated fatty acid esters, cold pressing is the preferred production method for borage oil virgin. A possible subsequent refining increases purity and shelf life of the crude oil for pharmaceutical purposes.
Borage seeds, well ahead of evening primrose seeds, are the richest plant source of the rare gamma-linolenic acid (GLA), a triple-unsaturated (18:3?) omega-6 fatty acid. They can make up 20 to as much as 40 percent in the oil's trigylcerides. Its fatty acid esters also contain linoleic acid (35-38 percent), oleic acid (16-20 percent), palmitic acid (10-11percent), stearic acid (3.5-4.5 percent), eicosenoic acid (3.5-5.5 percent) and erucic acid (1.5-3.5 percent).
Otherwise physiologically synthesized from linoleic acid, GLA is a precursor of both anti-inflammatory eicosanoids (prostaglandin, thromboxanes and leukotrienes) and pro-inflammatory arachidonic acid. Directly orally supplied GLA from borage oil eliminates this intermediate synthesis step.
Overall, borage oil can have several effects as an adjuvant pharmacon, dietary supplement or edible oil: anti-inflammatory in arthritis, respiratory inflammation, arteriosclerotic cardiovascular disease, multiple sclerosis and many other autoimmune diseases; pressure-lowering in hypertension; improvement of nerve conduction in neuropathies (diabetic polyneuropathy, for example). Beneficial effects have also been observed in malignant diseases or premenstrual syndrome.
Patients with neurodermatitis, seborrheic dermatitis, eczema and other chronic inflammatory skin diseases can benefit particularly successfully from systemic and topical treatment with borage oil. This is because human skin in particular is not capable of biosynthesis of GLA from linoleic acid. Substitution has been shown to improve clinical symptoms such as swelling, scaling and itching.
Herb of Borago officinalis contains hepatotoxic and carcinogenic pyrrolizidine alkaloids (among others amabiline and supinidine). Only occasional consumption of borage leafy vegetables is considered safe. These substances may be present in trace amounts in the pressed oil of borage seeds.
There are also indications of teratogenicity and lowering of seizure thresholds, which is why pregnant women and epilepsy sufferers should better refrain from regular use of borage oil.