Hand-colored scanning electron micrograph of the Sage (Salvia officinalis) leaf surface, by Martin Oeggerli.
Salvia officinalis is a perennial, evergreen subshrub, with woody stems, grayish leaves, and blue to purplish flowers. It is a member of the mint family Lamiaceae and native to the Mediterranean region. Sage is well known as a herb, and has a long history of medicinal and culinary use. The leafs are containing aetheric oils which are stored in thousands of smaller and larger secretory glands.
Sage leafs contain tannic acid, oleic acid, ursonic acid, ursolic acid, carnosol, carnosic acid, fumaric acid, chlorogenic acid, caffeic acid, niacin, nicotinamide, flavones, flavonoid glycosides, and estrogenic substances, and are often used to make medicine for digestive problems, including loss of appetite, gas (flatulence), stomach pain (gastritis), diarrhea, bloating, and heartburn. Sage is also used for reducing overproduction of perspiration and saliva; and for depression, memory loss, and Alzheimer’s disease. Women use sage for painful menstrual periods, to correct excessive milk flow during nursing, and to reduce hot flashes during menopause. Sage is applied directly to the skin for cold sores; gum disease (gingivitis); sore mouth, throat or tongue; and swollen, painful nasal passages. Some people inhale sage for asthma. In foods, sage is used as a commonly used spice.
Scanning electron microscopy of sage leaves confirmed the presence of two basic types of glandular trichomes (capitate stalked, capitate sessile with one and with eight secretory cells). Gas liquid chromatographic analysis of the oil content of both gland types indicate only minor quantitative differences in essential oil composition. Thus, each gland type is capable of producing the four major monoterpene families (p-menthanes, pinanes, bornanes and thujanes) characteristic of sage.