Asthma, bronchitis and chronic cough, respiratory infections and congestion.
Mechanism of Action
The main constituents of Hyssopus officinalis L. include polyphenolic compounds and essential oils generally known to have antimicrobial and antioxidant properties. Essential oils can also act as expectorants and antispasmodics. They are aromatic and generally impart the characteristic odor of a plant because of their volatility. Polyphenols generally taste bitter, are astringent, or both.
Of the different types of polyphenols in Hyssopus the most abundant phenolic acids were ferulic acid (13.2 mg/100 g) and caffeic acid (6.5 mg/100 g). Three flavonoid glycosides, isoquercitrin, rutin, and quercitrin, and two flavonoid aglycones, quercetin and luteolin, were also found. Isoquercitrin was the flavonoid found in the largest amount (32.78±0.23 µg/g). Many of the polyphenols in Hyssopus have significant antioxidant and antimicrobial properties.1
A detailed examination of the essential oil of H. officinalis (var. decumbens) revealed linalool (49.6%); 1,8-cineole (13.3%); limonene (5.4%); β-caryophyllene (2.8%); β-pinene (3.0%); and α-pinene (2.4%); however, climate, environmental factors, species subtypes, and extraction methods can considerably affect the plant’s essential oil profile.2 For example, Hyssopus from Italy has been shown to differ in its essential oil compounds from that found in France (H. officinalis var. decumbens). The Italian form contains pinocamphone and isopinocamphone (4.4% and 43.3%, respectively), whereas the French species do not; instead, linalool, 1,8-cineole, and limonene are predominant.
The essential oils in both varieties significantly inhibited yeasts (seven strains of Candida albicans, Candida krusei, and Candida tropicalis), but only H. officinalis var. decumbens showed inhibition of both gram-positive and gram-negative bacteria. Comparatively, this variety is also thought to have greater antimicrobial activity because of its linalool, and to a lesser extent, 1,8-cineole contents. Limonene is present in both varieties of hyssop and may also be responsible for inhibition of the yeasts.3
Of the various constituents of the essential oil, linalool seems to have the strongest antispasmodic action.4
The effect of Hyssopus officinalis on respiratory immune regulation and respiratory inflammation was investigated in a mouse model of chronic asthma. In total, 32 BALB/c mice were were randomly divided into four groups: normal, chronic asthmatic, dexamethasone (anti-inflammatory drug) treatment, and H. officinalis treatment. Ovalbumin in commonly used in studies to stimulate an allergic reaction; and in this study, it was used to establish an asthma model. The mice were sensitized and challenged with ovalbumin, and the ratio of eosinophils (EOSs) in the bronchoalveolar lavage fluid (BALF) was recorded. In addition, an enzyme-linked immunosorbent assay was used to measure levels of immunoglobulin (Ig)E and IgG, and the periodic acid-Schiff stain method was used to observe the degree of airway mucus secretion. The results showed that the ratio of EOS in the BALF and the level of serum IgE in the chronic asthmatic and dexamethasone treatment groups increased, whereas the level of serum IgG decreased compared with the normal group. Excessive secretion of airway mucus was also observed in these two groups. However, the EOS ratio in the BALF and the levels of serum IgE and IgG in the H. officinalis treatment group were similar to the results observed in the normal group. In conclusion, H. officinalis seems to play an anti-inflammatory role by inhibiting EOSs and decreasing the levels of IgE.5
Safety in Pregnancy and Breastfeeding
In traditional herbal literature, Hyssopus is listed as an emmenagogue and abortifacient. Although research on the subject is lacking, use during pregnancy is cautioned.6
There is insufficient information about the safety of Hyssopus in breastfeeding.7
Hyssopus has generally recognized as safe status in the United States. This means that there is a consensus of expert opinion regarding the safety of its use.8
Hyssopus is generally considered safe at doses of the powdered herb up to 2–3 g/day. Typical doses are taken alone as 450–900 mg up to three times daily; and when combined in a formula with other respiratory herbs, 100–300 mg is used up to three times daily.
Going back to ancient Greece, Hippocrates prescribed Hyssopus for pleurisy. Dioscorides recommended it in a formula along with rue, fig, and honey to treat pleurisy, respiratory congestion, asthma, and chronic couch.
In traditional and modern literature, hyssop is often included as an important expectorant to increase the fluidity of the mucus in the lungs and gently promote its expulsion from the body.9
Molecules. 2014;19(5):5490–507; doi:10.3390/molecules19055490. Evaluation of antioxidant and antimicrobial activities and phenolic profile for Hyssopus officinalis, Ocimum basilicum and Teucrium chamaedrys. Vlase L, Benedec D, Hanganu D, Damian G, Csillag I, Sevastre B, Mot AC, Silaghi-Dumitrescu R, Tilea I.
2 Afr. J. Pharm. Pharmacol. 2011;5:1959–66. Review on Hyssopus officinalis L. Composition and biological activities. Fathiazad F, Hamedeyazdan SA.
3 Flavour Fragr J. 1998;13(5):289–94. Antimicrobial properties of the linalool-rich essential oil of Hyssopus officinalis L. var decumbens (Lamiaceae). Mazzanti G, Battinelli L, Salvatore G.
4 Phytother Res. 1998;12(S1):S92–4. Spasmolytic action of the essential oil from Hyssopus officinalis L. var. decumbens and its major components. Mazzanti G, Lu M, Salvatore G.
5 Exp Ther Med. 2014;8(5):1371–4. Epub 2014 Sep 18. Effect of Hyssopus officinalis L. on inhibiting airway inflammation and immune regulation in a chronic asthmatic mouse model. Ma Z, Wang J, Sun Z, Yu W, Li F, Ding J.
6 American Herbal Products Association’s Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC; 1997. McGuffin M, Hobbs C, Upton R, Goldberg A, eds.
7 American Herbal Products Association’s Botanical Safety Handbook. 2nd edn., Boca Raton, FL: CRC Press, LLC; 2013. McGuffin, Gardner, eds.
8 Electronic Code of Federal Regulations. Title 21. Part 182 – Substances Generally Recognized As Safe.
9 The Essential Book of Herbal Medicine. Penguin Books Ltd, London, England; 1991. p. 484. Mills SY.