Bugleweed, Ajuga reptans (Lamiaceae)

Bugleweed (Ajuga reptans) is a perennial herbaceous plant belonging to the Lamiaceae family, native to much of Europe and widely distributed in temperate regions. It is valued primarily as an ornamental groundcover, appreciated for its dense, spreading habit and its ability to form decorative flowering carpets.

From a morphological standpoint, Ajuga reptans is characterized by:
– a creeping growth habit, with stoloniferous stems that enable rapid lateral spread;
– opposite leaves, oval to spatulate, typically dark green, with ornamental cultivars showing bronze or purplish tones;
– upright spike-like inflorescences, bearing small tubular flowers, most commonly blue to violet in color;
– a shallow fibrous root system, effective in stabilizing surface soil.

Flowering generally occurs in spring, creating visually striking ground coverage. The plant exhibits typical structural features of the Lamiaceae family and shows good ecological adaptability.

From a phytochemical perspective, Ajuga reptans contains:
– iridoid glycosides (including aucubin and catalpol);
– flavonoids and other polyphenolic compounds;
– phytosterols;
– tannins, associated with its traditional interest.

In ecological and horticultural contexts, bugleweed is valued for its hardiness, low maintenance requirements, and soil-covering capacity. It is commonly used in shaded gardens, woodland settings, and as an alternative to turf in low-traffic areas.

In terms of applications, Ajuga reptans is mainly used in:
– ornamental gardening, as a groundcover for borders, beds, and underplanting;
– landscape management, for surface erosion control;
– traditional herbal practices, mainly for external use in local contexts;
– sustainable landscaping projects, due to its resilience and spreading ability.

How to grow it

Bugleweed is considered easy to cultivate and suitable for both amateur and professional gardeners. Optimal conditions include:
– exposure: partial shade to light shade; tolerates full sun if soil moisture is adequate;
– soil: well-drained, moderately fertile to humus-rich soils;
– watering: regular during establishment, then moderate once established;
– propagation: by division of stolons or clumps, preferably in spring or autumn.

Once established, Ajuga reptans requires minimal maintenance and provides stable, long-lasting ground cover.

The combination of ornamental value, growth reliability, and botanical interest makes bugleweed a widely used species in temperate landscape design.

Botanical classification (APG IV system)

Indicative nutritional values per 100 g (fresh aerial parts of Ajuga reptans)

Average values estimated for fresh leaves and young stems. Food use is traditional and occasional, with typical quantities far below 100 g.

Nutritional use note

At typical usage portions (approximately 2–5 g of fresh leaves, traditionally used in rustic salads or decoctions), caloric intake is negligible.
The nutritional interest of bugleweed is qualitative, mainly related to dietary fiber, micronutrients, and phenolic compounds, rather than macronutrients or energy value.

Lipid profile note

Bugleweed shows a very low fat content.

• SFA (Saturated Fatty Acids) are present in limited amounts; excessive dietary prevalence of SFA is generally considered less favorable for cardiovascular health.

• MUFA (MonoUnsaturated Fatty Acids) and PUFA (PolyUnsaturated Fatty Acids) occur in small quantities and do not significantly influence daily lipid intake.

Medical applications (traditional and scientific interest)

Note: medical uses are primarily traditional or experimental and do not replace pharmacological treatments.

Cosmetic applications

Main INCI functions:

• Skin conditioning

• Soothing

• Astringent

• Protecting

Industrial applications

Studies

Ajuga reptans has been studied in the medical field for about fifteen years, mostly on guinea pigs, and scientific publications are not numerous.

We start from 1992 with an Italian study which found vasoconstrictor characteristics (1), then a 1996 study which discovered four anthocyanins (flavonoid family) in flowers (2) confirmed by a subsequent work by the same authors in 2001 (3), then a 2004 study finding out the effectiveness of Ajuga against mosquito-like insects (4) and another 2009 publication on the discovery of new steroids from the seedling (5). For those who would like to delve deeper, I suggest these two recent studies (6).

References__________________________________________________________________________

(1) Breschi, M. C., Martinotti, E., Catalano, S., Flamini, G., Morelli, I., & Pagni, A. M. (1992). Vasoconstrictor activity of 8-O-acetylharpagide from Ajuga reptans. Journal of natural products, 55(8), 1145-1148.

Abstract. The traditional therapeutic indications for the use of Ajuga reptans (Labiatae) have been investigated. The H20-soluble part of a crude and partially purified MeOH extract and two isolated iridoids (8-Q-acetylharpagide and harpagide), were tested for a biological activity on isolated smooth muscle preparations from guinea pig.

 (2) Terahara N, Callebaut A, Ohba R, Nagata T, Ohnishi-Kameyama M, Suzuki M. Triacylated anthocyanins from Ajuga reptans flowers and cell cultures. Phytochemistry. 1996 May;42(1):199-203. doi: 10.1016/0031-9422(95)00838-1. 

Abstract. Four anthocyanins were isolated from Ajuga reptans flowers and one from the cell cultures. By FAB mass spectrometry measurements, the structures of these pigments were determined as delphinidin and cyanidin glucosides acylated with two cinnamic acids, while three of them were also malonylated. A delphinidin-based pigment in the crude extract from cell cultures was identical to the major flower pigment as shown by HPLC co-chromatography. Moreover, by application of 1H and 13C NMR consisting of DQF-COSY, NOESY, ROESY, 2D-HOHAHA, HSQC and HMBC methods, the structures of two new anthocyanins were identified as delphinidin and cyanidin 3-O-(2-O-(6-O-(E)-p-coumaryl-beta-D-glucopyranosyl)-(6-O-(E)-p- coumaryl)-beta-D-glucopyranosyl)-5-O-(6-O-malonyl-beta-D-glucopyranoside ). The deacylated anthocyanins were confirmed as delphinidin and cyanidin 3-sophoroside-5-glucosides.

(3) Terahara N, Callebaut A, Ohba R, Nagata T, Ohnishi-Kameyama M, Suzuki M. Acylated anthocyanidin 3-sophoroside-5-glucosides from Ajuga reptans flowers and the corresponding cell cultures. Phytochemistry. 2001 Oct;58(3):493-500. doi: 10.1016/s0031-9422(01)00172-8. 

Abstract. Four anthocyanins from Ajuga reptans flowers and its cell cultures were isolated, and a fifth was also characterized by HPLC-mass spectrometry. By means of chemical and spectroscopic analyses, their structures were identified as delphinidin 3-(p-coumaroyl-feruloyl)sophoroside-5-malonylglucoside, delphinidin 3-(diferuloyl)sophoroside-5-malonylglucoside, and cyanidin 3-(di-p-coumaroyl)sophoroside-5-glucoside, respectively. The other two were tentatively identified as delphinidin 3-(diferuloyl)sophoroside-5-glucoside and cyanidin 3-(feruloyl-p-coumaroyl)sophoroside-5-malonylglucoside. In neutral aqueous solution, the crude extract from A. reptans flower cell cultures and the major anthocyanin cyanidin 3-(di-p-coumaroyl)sophoroside-5-malonylglucoside were more stable than cyanidin 3-glucoside, and also prevented more efficiently peroxidation than did the latter. A. reptans flower cell culture anthocyanins may have a potential as natural colorants for food utilities or other purposes.

(4) Fekete G, Polgár lL, Báthori M, Col J, Darvas B. Per os efficacy of Ajuga extracts against sucking insects. Pest Manag Sci. 2004 Nov;60(11):1099-104. doi: 10.1002/ps.928. PMID: 15532684.

(5) Ványolós A, Simon A, Tóth G, Polgár L, Kele Z, Ilku A, Mátyus P, Báthori M. C-29 ecdysteroids from Ajuga reptans var. reptans. J Nat Prod. 2009 May 22;72(5):929-32. doi: 10.1021/np800708g. 

Abstract. Investigation of the ecdysteroid constituents of the herb Ajuga reptans var. reptans resulted in the isolation of three new ecdysteroids, named reptanslactone A (2), reptanslactone B (3), and sendreisterone (5), and the known 24-dehydroprecyasterone (1) and breviflorasterone (4). The structures of compounds 1-5 were determined by spectroscopic methods including one- and two-dimensional NMR measurements.

(6) Fujimoto Y, Maeda I, Ohyama K, Hikiba J, Kataoka H. Biosynthesis of 20-hydroxyecdysone in plants: 3β-hydroxy-5β-cholestan-6-one as an intermediate immediately after cholesterol in Ajuga hairy roots. Phytochemistry. 2015 Mar;111:59-64. doi: 10.1016/j.phytochem.2014.12.019. Epub 2015 Jan 12. PMID: 25593010.

Findling S, Zanger K, Krueger S, Lohaus G. Subcellular distribution of raffinose oligosaccharides and other metabolites in summer and winter leaves of Ajuga reptans (Lamiaceae). Planta. 2015 Jan;241(1):229-41. doi: 10.1007/s00425-014-2183-2. 

Abstract. In Ajuga reptans, raffinose oligosaccharides accumulated during winter. Stachyose, verbascose, and higher RFO oligomers were exclusively found in the vacuole whereas one-fourth of raffinose was localized in the stroma. The evergreen labiate Ajuga reptans L. can grow at low temperature. The carbohydrate metabolism changes during the cold phase, e.g., raffinose family oligosaccharides (RFOs) accumulate. Additionally, A. reptans translocates RFOs in the phloem. In the present study, subcellular concentrations of metabolites were studied in summer and winter leaves of A. reptans to gain further insight into regulatory instances involved in the cold acclimation process and into the function of RFOs. Subcellular metabolite concentrations were determined by non-aqueous fractionation. Volumes of the subcellular compartments of summer and winter leaves were analyzed by morphometric measurements. The metabolite content varied strongly between summer and winter leaves. Soluble metabolites increased up to tenfold during winter whereas the starch content was decreased. In winter leaves, the subcellular distribution showed a shift of carbohydrates from cytoplasm to vacuole and chloroplast. Despite this, the metabolite concentration was higher in all compartments in winter leaves compared to summer leaves because of the much higher total metabolite content in winter leaves. The different oligosaccharides did show different compartmentations. Stachyose, verbascose, and higher RFO oligomers were almost exclusively found in the vacuole whereas one-fourth of raffinose was localized in the stroma. Apparently, the subcellular distribution of the RFOs differs because they fulfill different functions in plant metabolism during winter. Raffinose might function in protecting chloroplast membranes during freezing, whereas higher RFO oligomers may exert protective effects on vacuolar membranes. In addition, the high content of RFOs in winter leaves may also result from reduced consumption of assimilates.