Sage (S. officinalis) is a perennial shrub with a woody base. This plant has a rounded shape, (Figure 1), and can grow up to a maximum of 60-70 cm in both height and width (Ghorbani, 2016). The stem fragments of S. officinalis are four sided, as are the branches coming off the base, which itself varies from a wedge-shaped to a rounded shape. The petiole, which connects the leaf to the stem is long, approximately 4.5 cm in length, and is covered in hairs (American Botanical Council, 2016).
The leaves of this shrub vary in size and can achieve a size of 6.4 cm in length and 2.5 cm in width; however, the leaves situated near the base are more narrowed (Ghorbani, 2016). Furthermore, the leaves differ when their upper side is compared to the underneath. While both surfaces are covered with short white hairs, the upper surface is rugose and green, and the underneath surface is a pale green or white. (American Botanical Council, 2016). Additionally, these broad aromatic leaves are crenate, tough, and wrinkled, and can exhibit purple, rose, cream, or yellow among many other different colours depending on the cultivar (Ghorbani, 2016). The small flowers of S. officinalis bloom in the summer, and are pale violet, white or pink in colour, as shown in Figure 1. The flower blossoms with 6-12 petals, which are organized in 4-8 rows.
Origin, Distribution and Habitat
There are 900 different species in the Salvia genus located globally, making it the largest genus in the Lamiaceae family.The native origin of S. officinalis is not completely understood, but it is agreed upon that it originated in the Balkan Peninsula and is also said to be native to the Middle Eastern regions and the Mediterranean (Ghorbani, 2016). However, it has now naturalized throughout the world, and is cultivated particularly in European regions, such as France, North Africa, but also in China and North America (Allen, 2014; Ghorbani et al. 2017, Hao et al. 2015) A map of the European locations of S. officinalis is shown in Figure 2. It can be found in several terrestrial habitats, including dry meadows, rocky unforested grasslandsand mountain slopes. S. officinalis is often found where limestone is present in the soil, which is rocky, dry, and not deep. It is important for this plant to grow in an area where it can receive a large amount of sun, and in dry conditions, where it will not be subjected to too much water (Hao et al. 2015). Reportedly, the “life zone” of S. officinalis is 5oC-26oC with less than 3m of precipitation annually (Kintzios, 2000). If the roots of S. officinalis become saturated for a prolonged time, the plant could die due to root rot (Hao et al. 2015).
History and Traditional Uses
S. officinalis belongs to a medicinally important genus. Many of the Salvia species have been used since ancient times in traditional medicine due to their bioactivity. Even the name Salvia has significance; derived from the Latin word salvere, it means “to heal”, “to save” or “to cure” (Petrovska, 2012). Various cultures used different names to describe Salvia, some of which translate to similar meanings, like the Roman word “sacra”, which means “sacred”. The different words used to describe the species in the Salvia genus are summarized in Table 1. Officinalis also refers to the medicinal uses and properties of this species of sage, as it translates to “officina”, referring to a location in a monastery which houses plants and medicines (Ghorbani, 2016).
For Millenia, sage has been associated with healing, and its application in medicine likely dates to even earlier than Roman times. Sage was very popular during the Medieval times, due to the belief that sage could cure all illnesses, a notion shared across cultures. In fact, during this period, Arab physicians held the belief that S. officinalis could extend human life. In the Middle Ages, the uses and characteristics of sage were commonly mentioned in medical texts and in almost all “early botanies”. The extent of medicinal power that sage was believed to have held is demonstrated by an old English proverb, which states: “He that would live for aye [ever] must eat sage in May” (Hanson et al. 1957).
In Asia, sage was prescribed/applied by traditional healers to treat various ailments such as gout, paralysis, ulcers, coughs and night sweats (Ghorbani, 2016). For example, China, a major cultivator of sage, has been using some species of Salvia for thousands of years to treat complex medical conditions, such as heart disease (Hao et al. 2015). The earliest account of sage in American gardens was 1806; however, it is likely sage was cultivated in America before then (Hanson et al. 1957). Like Asian folk healers, American traditional healers also used sage to treat a range of health issues, including insomnia, measles, epilepsy, seasickness, and gastrointestinal worms (Ghorbani, 2016). American medical documents from the 1920s describe two additional medicinal uses for sage: sage leaf dressings to help with swelling or a sprain and tea infused with sage to treat sore throats. Aside from medicinal purposes, sage has been used as a spice for centuries due to its aromatic properties and its strong bitter taste.For example, in Italy, potatoes are commonly seasoned with sage to add flavouring. In addition, sage was infused in teas, known as “sage-teas”, by both the English and the Chinese (Hanson et al. 2016).
|Culture/Groups||Name for Salvia|
|Romans||“herb sacra”; the “salve”|
|Spanish, Moroccan, Arab||“salima”, “asphacus”|
|Greek||“elelisphakon”, “elifagus”, “spahkos”|
S. officinalis is an evergreen perennial that germinates in two to three weeks in an optimal soil temperature of 15-21°C with an optimal soil pH of 6-6.5. As mentioned earlier, S. officinalis cannot survive in very wet conditions, thus it is important that the cultivation soil is coarse or clay-loam, well drained, and nutrient rich (Herbalpedia, 2014). Sage can be grown from seeds, cuttings, or “layering” of established branches, and each method has its advantages or disadvantages (Mahr, 2013). For example, propagation from a seed is beneficial for identifying a plant with desirable traits, the plants produced tend to vary in leaf size and vigor. However, germination is often poor when S. officinalis is propagated from a seed (Hanson et al. 1957). Sage can also be planted indoors six to eight weeks before the last frost.Sage is usually planted in rows, with spacing changing depending on the fertility of the soil. For maintenance, six to eight inches of the vegetative top is cut at least twice annually (Mahr, 2013). Overall, a few thousand plants can occupy one acre of land (Kintzios, 2000).
Harvesting, Processing and Extraction
In the first year of growth, S. officinalis can be harvested once, and while this initial harvest can occur as early as 75 days after planting, it typically occurs in the autumn of the first year. After this, sage can be harvested two to three times a year, generally immediately before blooming (Hanson et al. 1957, Mahr, 2013). The timing of harvest should be carefully considered, as the chemical composition and yield of sage has been found to vary depending on the time of harvest due to differences in growth stages (Baranauskiene et al. 2010). Most often only the leaves of sage are harvested, as this leads to a high-quality final product; however, this method tends to be more expensive and time consuming. Although one can pick the leaves if desired, it is important to ensure that at least half the plant remains to allow for future growth (Mahr, 2013).
The harvested sage is first cleaned by washing, and it may be subsequently kept in a fresh form or processed into a dried substance (Hanson et al. 1957). Fresh sage can be frozen to preserve its flavours and aroma. To obtain a high-quality dried product, harvested sage leaves should be air-dried in either the sun or the shade by collecting leaves in a loose bundle or by thinly spreading the leaves (Mahr, 2013).Additionally, the harvested material can be cut into pieces to be dried in a well-ventilated room in an ambient temperature (Ghorbani, 2016). The preservation of the plant’s chemical composition is of high importance due to specific uses of sage. Two factors regarding the drying which should be considered are microbial contamination and ultra-violet (UV) light. It is important that the drying material is safe from bacterial contamination because this process can degrade the valuable secondary metabolites. If present, UV rays can chemically interact with components in sage, which could reduce its quality (Ghorbani, 2016). An additional method of drying of sage is using a dehydrator, where the sage is first subjected to 37.8°C for four hours, and then increased to 47.8°C for four hours. Dehydration with this technique can reduce the moisture content of a plant to about 13% (Kintzios, 2000).
The final stage of processing is to grind the dried sage. Grinding serves to benefit the extraction process by: (1) increasing the surface of area of material; and (2) improves the ability of solvent to enter the cells (Ghorbani, 2016). Sage can be grinded into a powdered form by either using a blender or a hammer mill, and subsequently stored in a dry and cold (4oC) location. To maintain the quality and quantity of the bioactive contents, dried and ground sage should only be stored on a shorter-term basis (Ghorbani, 2016). Powdered fresh or dried sage can be used to make tablets for commercial sale.
Currently, there are four main methods of extraction applied to S. officinalis including maceration, Soxhlet, and percolated extractions, as well as steam distillation (Ghorbani, 2016). The maceration extraction method is the simplest and widely used, involving the suspension of leaf power, incubation and eventual extraction using an appropriate solvent. The Soxhlet extraction takes less time than the maceration extraction and is good for a small amount of sage. It also uses sage powder, but the extraction is done using heat. The percolated extraction method is used for larger scale extractions and involves soaking grounded sage leaves in a solvent for collecting the extract. Finally, steam distillation is used to extract volatile compounds from fresh or dried leaves. Leaves are soaked in a solvent and exposed to heat to collect a distillate which is recirculated to separate it even further into the required compounds (Ghorbani, 2016).
Both the dried and fresh forms of sage are used throughout the world for flavouring and taste. Currently, it is still a widely used spice in the food industry, and is added in dressings, cheeses, meats, poultry, stuffing, soups, and fats. Additionally, sage oil can be prepared into a condiment (Herbalpedia, 2014). Due to its stronger flavour, dried sage is not extensively used for culinary purposes. For example, in Italian cultures, only fresh sage is used for a variety of dishes, such as veal, pasta, focaccia, and potatoes. In England, sage honey is spread over bread, dumplings, and baked goods.Additionally, there are numerous sage beverages that exist, such as sage liqueur, sage wine, and sage teas (Herbalpedia, 2014). Sage is even laid on coals before cooking to add a sage flavour to the food. Essentially, there are a boundless number of foods and beverages that are flavoured with sage.
Recent research has established that various extracts of sage can reduce blood glucose in animals, suggesting that it might be an effective diabetes treatment. Additionally, treatment with sage was shown to decrease the levels of different triglycerides and bad cholesterols like low-density lipoprotein. Sage has also been observed to lower uric acid, creatinine, and some liver enzymes in diabetic animals. Overall, sage may act as an antidiabetic in three main ways; by increasing available plasma insulin, decreasing insulin resistance; and raising liver activity in response to insulin (Ghorbani, 2016).
As antibiotic resistance continues to increase as an issue, the antimicrobial activity of sage has gained recognition (Ghorbani, 2016). Several components of S. officinalis such as the essential oils; saffinolide and sageone demonstrate its potent antimicrobial activities (Ghorbani, 2016). The essential oil of sage can inhibit Gram-positive bacteria with bactericidal and bacteriostatic effects. Ursolic acid and oleanoloic acid have been demonstrated to possess antimicrobial effects against several bacteria with multidrug resistance, such as Staphylococcus aureus (Ghorbani, 2016).
Numerous studies have established that the phenolic compounds in S. officinalis display antioxidant activity against superoxides with up to 20 times more potency than the standard antioxidants (Lu et al. 2001).Essential oil and water extracts of sage demonstrate anti-tumour properties, promoting cell death and inhibiting the growth of various cancer cell lines. In addition to these activities, sage displays other anti-tumour properties, including anti-migratory and anti-proliferative effects (Baricevic et al. 2001).
Sage has also been shown improve memory, mood and cognition due to the interaction that the ethanolic extract has with our cholinergic systems. Additionally, sage has been shown to benefit memory retention, and has a demonstrated effect of increasing the cognitive abilities of Alzheimer’s patients (Baricevic et al. 2001).
Sage is used for a variety of cosmetic purposes, including an oily skin cleanser and a lip moisturizer (Herbalpedia, 2014). Furthermore, sage has been shown to help improve hair health by preventing dandruff, improving luster, and adding shine (Baranauskiene, 2010). Moreover, sage perfumes and soaps are also sold commercially (Eidi et al., 2006).
Sage is often burned to absorb negative energy in order to create a ritual space or a protective environment (Herbalpedia, 2014). It is believed that sage can bring wisdom, wealth, money, and even immortality. In addition, it is believed that sage flowers help with self-learning, reflection, achieving perspective, and experiencing inner peace (Herbalpedia, 2014).
S. officinalis is one of the most commercialized species in the Salvia genus and is also grown in residential homes or yards (Mahr, 2013). There are many countries around the world that grow sage and produce sage goods. Albania is a leading producer and exporter of sage, where in 2001, 1500 tons were reported with a monetary value of approximately $2.5 million (USD) (Eidi et al., 2006).
The population of S. officinalis is stable, according to IUCN, and has been categorized as “Least Concern” due to its vast distribution, widespread cultivation, and lack of major threats to survival (Allen, 2014).
About the Author
Hailey Silver received her undergraduate degree in Biological Sciences at the University of Guelph and has continued to pursue her studies in the Master of Public Health program. She has always been passionate about helping others and is currently working for the Public Health Agency of Canada, studying food and waterborne pathogens.