Sage is a herb commonly used in European cuisines; it has a savoury, peppery flavour. In Britain, sage is considered as an essential herb along with parsley, rosemary and thyme. Oil is distilled from sage and contains cineole, borneol, and thujone. 

The leaf contains  various acids like- tannic acid, oleic acid, ursonic acid, ursolic acid, carnosol, carnosic acid, fumaric acid, chlorogenic acid, caffeic acid. In addition, the leaf has niacin, nicotinamide, flavones, flavonoid glycosides, and estrogenic substances.

Various cultivars are grown for either medicinal or culinary purposes. The leaves are used to make sage tea, as flavouring for drinks and desserts, for throat gargling and clary sage is used as an infusion to make perfumes.

As seen, Sage has many useful plant-derived chemical compounds, essential oils, minerals and vitamins that play a role in disease prevention and health promotion.

Cholesterol

Animal studies have shown an extract of sage was able to lower the plasma cholesterol, low density lipoprotein (LDL), and triglycerides (TGs), as well as increase the high density lipoprotein (HDL) levels. This mechanism activates receptors responsible for energy, glucose and lipid metabolism. The studies showed a marked improvement in the HDL/LDL ratio, lowered Triglycerides in serum, reduced insulin resistance and reduced size of adipose (fat) tissue. (Christensen KB  et al., Activation of the nuclear receptor PPARγ by metabolites isolated from sage (Salvia officinalis L.). J Ethnopharmacology. 2010 Oct 28; 132(1):127-33.)

Memory and attention

Studies done, have shown the effectiveness of sage in treating depression, memory loss and Alzheimer’s. Chinese sage has been shown to restore lost or declining memory and increase mental function. Sage oil works by inhibiting enzymes that affect neurotransmitters (which help transfer signals to the brain). The oil also helps improve memory and cognition. 
Increasing the dosage results in mood elevation as well as alertness, calmness, and contentedness.  (Tildesley NT, Positive modulation of mood and cognitive performance following administration of acute doses of Salvia lavandulaefolia essential oil to healthy young volunteers. Physiol Behav. 2005 Jan 17; 83(5):699-709.)

Sage works by providing a neuroprotective effect. (Iuvone T et al., The spice sage and its active ingredient rosmarinic acid protect PC12 cells from amyloid-beta peptide-induced neurotoxicity. J Pharmacol Exp Ther. 2006 Jun; 317(3):1143-9.)

Women’s Health

As a cure, fresh sage helps treat painful periods and reduces hot flashes during menopause.  This can be used as a safe alternative approach to treat menopausal symptoms. (Bommer S, First time proof of sage's tolerability and efficacy in menopausal women with hot flushes. Adv Ther. 2011 Jun; 28(6):490-500.)

Some women use sage to stop excessive breast milk production. Sage (as a tincture or concoction) is a lactation inhibitor as it has an estrogenic effect, it should be used with caution though, with the primary focus being on decreasing milk supply rather than lactation suppression. (Caroline S, Overabundant milk supply: an alternative way to intervene by full drainage and block feeding, International Breastfeeding Journal2007)

Antibacterial activity

The antibacterial activity of sage oil protects against Bacillus strains and can be used as an alternative to antibiotics and as a food preservative. Sage extracts are effective against dental caries and this antibacterial effect could be used to treat mouth and teeth diseases. (Kermanshah H et al. In vitro evaluation of antibacterial activity of hydroalcoholic extract of Salvia officinalis and Pimpinella anisum against cariogenic bacteria. J Dent Med. 2009;22:149–54.)

Nutritional Profile:

100g of sage contains 
•    315 calories, 
•    13 g of fat, 
•    1070 mg of potassium, 
•    40g of dietary fiber, 
•    11 g of protein, 
•    Vitamin A- 5900 IU
•    Calcium- 1.6 g
•    Vitamin C- 32.4 mg
•    Iron- 28.1 mg
•    Vitamin B6 – 2.7 mg
•    Magnesium-  4.3 g

Uses:

•    Sage was used as a preservative in ancient times due to its antibacterial properties
•    The leaves should be added toward the end of cooking as heat can destroy its nutritional properties
•    Sage can be added to omelettes, salads, while baking chicken or fish
•    The leaves can be rubbed on teeth for dental health
•    Tea can be prepared using the leaves to reduce menstrual cramps and hot flashes (however, do this only after consulting your doctor)
•    Sage has excellent antibacterial and astringent properties and can be used for sore throats, gingivitis and sore gums. 
•    Some cosmetics use sage for skin health and to darken hair

Interesting fact:

The Greeks and Romans valued the healing properties of sage and treated this herb as sacred. The Romans would organize a special ceremony for gathering sage.