Savory, carvacrol and kekik water

Your romantic images of distillation may quickly be shattered when it comes to savory. Sure, not all aromatic plants are fragrant roses.

 

I got familiar with winter or mountain savory about ten years ago and spent a good amount of time with it: growing it from the seeds, distilling and extracting aromatic constituents, and testing their antioxidant potential.

 

Since the ISO standard for savory prescribes distillation time no less than five hours, distillation is quite an intense experience – especially if you have to do it in a closed room with bad ventilation. Its sharp and intense smell is the main reason I couldn’t stand it in food for a couple of years since then. Today, I enjoy leading workshops with savory at a local festival dedicated specifically to winter savory.

 

picking wild winter savory

Picking wild winter savory in its natural habitat – that was a long time ago!

 

SAVORY HERB AND ESSENTIAL OIL

Savory is one of the 245 genera of the mint family (Lamiaceae), together with oregano, thyme, sage, lavender, mint, basil, hyssop and lemon balm. Of about 50 species in the genus Satureja, the two most well-known are summer savory (Satureja hortensis), an annual garden plant, and perennial winter savory (Satureja montana) that grows wildly on dry and rocky open slopes and meadows with calcareous soil.

 

Although mainly distributed in the Mediterranean, we can find it in regions of Western and Central Europe and in the Middle East. It is not native to America but was brought there by the first European colonists.

 

The origin of the name Satureja is somewhat mysterious. According to one explanation, it is named after satyrs, mythological creatures with horse-like ears and goat-like horns and legs (also known as fauns in the Roman mythology) known for their sexual desire, who lived in the fields of savory. The aphrodisiac association may have originated further back in time, however, in the Middle Ages, it was believed that only summer savory increases sexual drive while winter savory acts in the opposite way. Not surprisingly, the former was far more popular, and only the latter was allowed to grow in the monasteries.

Another explanation comes from za’atar (or satar), known as a Middle Eastern condiment that may include savory, oregano, thyme, hyssop, sesame seeds and sumac, but it may also refer specifically to savory and related plants.

 

The culinary and herbal use of savory go hand in hand. It is mainly added to meat, beans and mushroom dishes to enhance the favour, reduce flatulence and help digestion. Traditional use includes easing abdominal tension and diarrhoea, as well as respiratory problems such as colds, cough, bronchitis and excess mucus.

 

winter savory essential oil Satureja montana

Savory essential oil (appr. 0.15 mL) in Clevenger apparatus

 

In phytotherapy, all aerial parts of the plant can be used (Saturejae herba). The drug contains essential oil, tannins, phenolic acids and flavonoids. The essential oil has a light yellow to dark coppery colour. Its content varies considerably, between 0.3% and 2%, and so does its composition.

 

Savory oil has a very strong antimicrobial and antioxidant action, and also shows anti-inflammatory, analgesic, diuretic, insecticidal and repellent activity. The main active constituent is carvacrol (usually between 45% and 75%), a phenol that is also responsible for the characteristically sharp spicy odour reminiscent of oregano, whose essential oil has a comparable or slightly higher proportion of carvacrol.

 

 

KEKIK

In Turkey, kekik is a collective term for plants rich in carvacrol or thymol: Thymus, Origanum, Thymbra, Coridothymus and Satureja. These plants have a long history of use as a folk medicine against diarrhoea, gingivitis, common cold, intestinal parasites, as expectorants, analgesics and cardiovascular stimulants. They have been traditionally used in the form of tea and condiments, as well as distilled kekik oil and kekik water (Aydin et al. 1996).

 

Besides carvacrol and thymol (an isomer of carvacrol), γ-terpinene and p-cymene comprise the vast majority of volatiles in kekik plants. Thymol and carvacrol are synthesised from p-cymene, an aromatic monoterpene, which in turn forms from γ-terpinene, a monoterpene hydrocarbon (see diagram below). Taken as a whole, these constituents are in a dynamic equilibrium.

 

biosynthesis carvacrol thymol

 

Higher temperature favours the production of carvacrol, and in lower temperature, the balance shifts towards thymol – the ratio between the two oscillates with the day-night cycle. Moreover, carvacrol and thymol show an inversely proportional relationship with p-cymene: summer plants produce more carvacrol and thymol, but in the autumn and when growing, p-cymene may be the dominant constituent (Kokkini et al. 1997). Thus, if p-cymene in your oil is unusually high, it may indicate early harvest.

 

 

ANTIMICROBIAL MECHANISM OF CARVACROL

Carvacrol is one of the strongest antimicrobial plant secondary metabolites, and besides has a remarkably broad antibacterial and antifungal activity (e.g., Lang and Buchbauer 2012). The reason for such a wide antimicrobial spectrum is its non-specific mode of action. Like other phenols, carvacrol can easily cross the cellular membrane. Several experiments indicated that it acts as a transmembrane carrier of ions (see animation below). 

 

p-cymene, on the other hand, prefers to accumulate within the membrane, where it presumably enhances the passive permeability to ions, and likely carvacrol as well. Interestingly, p-cymene on its own shows quite weak antimicrobial effects, but appears to act synergistically with carvacrol (Saad et al. 2013).

 

Antimicrobial mechanism of carvacrol: once inside a cell, hydrogen from the hydroxyl (OH) group dissociates, and the negatively charged molecule can then attach another cation such as potassium and transport it out of the cell. As carvacrol can move repeatedly between the cell interior and exterior, the net result is disruption of ionic balance, depletion of ATP (basic energy units of cells) and ultimately cell death (Saad et al. 2013).
 

Due to mild irritability, essential oils high in carvacrol or thymol should be used with caution. Recommended maximum dermal concentration is 0.5% (CIR, 2006) and 1% (Tisserand and Young 2014). Oral dosing of high amounts of carvacrol and thymol is cautioned due to mild irritability to mucous membranes and the potential to affect platelet aggregation (Tisserand and Young 2014).

 

 

KEKIK WATER

Indeed, hydrolatsand tinctures of savory, thyme and oregano may be a safer and handier option for home use. Both carvacrol and thymol have relatively good solubility in water (1250 and 900 mg/L at room temperature, respectively), and therefore the ‘kekik waters’ are quite strong and rich with those constituents (but not with unoxygenated terpenes that have very poor solubility in water).

 

In an experiment, among 16 hydrolats from spices, only hydrolats from savory and oregano were able to inhibit the growth of all 15 species of common and food spoilage bacteria tested (Sağdiç and Özcan 2003). In a similar experiment, among 20 hydrolats only those from cloves and thyme (the only kekik representative) were effective against all four tested fish spoilage bacteria (Oral et al. 2008).

 

winter savory Satureja montana flowering plant

A semi bush of flowering winter savory, about 40 cm height.

 

Another study showed that both essential oil (1%) and hydrolat of savory (Satureja thymbra) were able to kill food spoilage and other pathogenic bacteria in biofilms, in contrast to standard chemical disinfectants (Chorianopoulos et al. 2008). It is well-known that biofilms, where bacteria are tightly packed and ‘glued’ on the surface, are significantly more resistant to antimicrobial agents than free-floating bacteria. Thus, the hydrolat can be used as an efficient and natural alternative for disinfecting food preparation surfaces and equipment.  

 

Some studies indicate that 15% or even higher dilutions of hydrolats from kekik plants (as well as from some other spices such as cardamom, cinnamon and cloves) can stop or reduce the growth of common plant and human microbial pathogens (Boyraz and Özcan 2006, Hussien et al. 2011). The combination of potent antimicrobial and antioxidative activity makes kekik plants particularly suitable for use in the food packaging and sanitisation, where they can prolong freshness (by slowing down fat oxidation, for example) and microbiological stability of meats, fruits and vegetables.  

 

In a pilot human trial, a mixture of sage, thyme and peppermint hydrolats applied as an oral rinse reduced chemotherapy-induced oral mucositis (Mutluay Yayla et al. 2016). This is consistent with the traditional use and indicates the potential for using certain hydrolats as mouthwashes, gargles or sprays for treating infections and other inflammations in the oral cavity and oesophagus.

 

The taste of pure hydrolats from savory, thyme and oregano is sharp and ‘spiky’. However, when sufficiently diluted (1 tsp per 2 dL or more water) they taste very pleasant. You can make a natural refreshing drink on their own or mixed with herbs, spices and fruits. Last but not the least important: the shelf life is – for obvious reasons – longer compared to many other hydrolats. A little goes a long way…

 

 

 

 

REFERENCES

Aydin S., Başer K.H.C. & Öztürk Y. 1997. The Chemistry and Pharmacology of Origanum (Kekik) Water. In: Franz C., Mathe A. & Buchbauer, G. (Eds.) Essential Oils: Basic and Applied Research, Proceeding of the 27th International Symposium on Essential Oils, 8-11 September 1996, Vienna, Austria, p. 52-60.

Boyraz, N., & Özcan, M. 2006. Inhibition of phytopathogenic fungi by essential oil, hydrosol, ground material and extract of summer savory (Satureja hortensis L.) growing wild in Turkey. International journal of food microbiology, 107(3), 238-242.

Chorianopoulos, N. G., Giaouris, E. D., Skandamis, P. N., Haroutounian, S. A., & Nychas, G. J. 2008. Disinfectant test against monoculture and mixed‐culture biofilms composed of technological, spoilage and pathogenic bacteria: bactericidal effect of essential oil and hydrosol of Satureja thymbra and comparison with standard acid–base sanitizers. Journal of applied microbiology, 104(6), 1586-1596.

CIR (Cosmetic Ingredient Review Expert Panel) 2006. Final report on the safety assessment of sodium p-chloro-m-cresol, p-chloro-m-cresol, chlorothymol, mixed cresols, m-cresol, o-cresol, p-cresol, isopropyl cresols, thymol, o-cymen-5-ol, and carvacrol. International journal of toxicology, 25, 29-127.

Hussien, J., Teshale, C., & Mohammed, J. 2011. Assessment of the antimicrobial effects of some ethiopian aromatic spice and herb hydrosols. Int J Pharmacol, 7(5), 635-40.

Kokkini, S., Karousou, R., Dardioti, A., Krigas, N., & Lanaras, T. 1997. Autumn essential oils of Greek oregano. Phytochemistry, 44(5), 883-886.

Mutluay Yayla, E., Izgu, N., Ozdemir, L., Erdem, S. A., & Kartal, M. 2016. Sage tea–thyme–peppermint hydrosol oral rinse reduces chemotherapy-induced oral mucositis: A randomized controlled pilot study. Complementary therapies in medicine, 27, 58-64.

Oral, N., Vatansever, L., Güven, A., & Gülmez, M. 2008. Antibacterial activity of some Turkish plant hydrosols. Kafkas Üniversitesi Veteriner Fakültesi Dergisi, 14(2), 205-209.

Saad, N. Y., Muller, C. D., & Lobstein, A. 2013. Major bioactivities and mechanism of action of essential oils and their components. Flavour and fragrance journal, 28(5), 269-279.

Saǧdıç, O., & Özcan, M. 2003. Antibacterial activity of Turkish spice hydrosols. Food Control, 14(3), 141-143.

Tisserand, R., & Young, R. 2014. Essential Oil Safety-E-Book: A Guide for Health Care Professionals, 2nd Edition. Elsevier Health Sciences.

 

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