Dill (Anethum graveolens), an aromatic perennial herb often used as a culinary spice, has been utilized for medical purposes for hundreds of years, at least since medieval times (Wurzbg. Medizinhist. Forsch. 1982;24:411-24). A member of the Umbelliferae (carrot or parsley) family, dill is used in traditional Chinese medicine, and its use in cooking and Uygur medicine is believed to date back to ancient times in China (Evid. Based Complement. Alternat. Med. 2011;2011:659-704).
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Dill is known for having demonstrated anti-inflammatory, antispasmodic, carminative, aromatic, and galactagogue activity.
Based on such past uses, as well as modern research, dill is known for having demonstrated anti-inflammatory, antispasmodic, carminative, aromatic, and galactagogue activity (Medical Herbalism: The Science and Practice of Herbal Medicine. Rochester, Vt.: Healing Arts Press, 2003).
Antimicrobial Activity
In a 2003 study of the essential oil of seeds of dill stored for more than 35 years, Bulgarian researchers tested its antimicrobial activity using various microorganisms. They noted high activity of the essential A. graveolens oil against the mold Aspergillus niger and the yeasts Saccharomyces cerevisiae and Candida albicans (J. Agric. Food. Chem. 2003;51:3854-7). Worth noting from this study is not only the anticandidal properties of dill but its potency even after a long time in storage.
In 2009, Kaur and Arora examined the spices dill, fennel (Foeniculum vulgare), and ajwain (Trachyspermum ammi) for their antibacterial activity. The investigators ascertained antibacterial activity by using agar diffusion assay, minimum inhibitory concentration, and viable cell count studies, and compared effects with those of some standard antibiotics. All three spices in the study exhibited significant activity against a wide range of bacteria, with the exception of Klebsiella pneumoniae and a strain of Pseudomonas aeruginosa. The researchers concluded that the results reveal a scientific basis for the reputed antibacterial effects of these plants and lend credence to their traditional medicinal applications. Further, they suggested that future work may lead to viable antibacterial agents based on these ingredients (BMC Complement. Altern. Med. 2009;9:30).
In 2011, Zeng et al. found that the essential oil produced from dill displays properties effective against vulvovaginal candidiasis in immunosuppressed mice (Evid. Based Complement. Alternat. Med. 2011;659704).
In addition, dill has been found to play an adjuvant role in augmenting the antibacterial activity of nitrofurantoin, which is used to treat urinary tract infections. Researchers used disk-diffusion and agar-dilution methods to determine the effects of essential oils of spearmint (Mentha spicata), dill (A. graveolens), and peppermint (Mentha piperita) and their components on the antibacterial activity of nitrofurantoin against Enterobacter cloacae. They used gas chromatography-mass spectrometry to examine essential oil composition. Dill and spearmint were found to exhibit the most significant effects, with pure carvone and piperitone identified as the most active constituents (Chemotherapy 2007;53:21-5).
Elastogenesis Promotion
In 2006, Cenizo et al. set out to induce elastogenesis in adult dermal fibroblasts by targeting lysyl oxidase (LOX) and lysyl oxidase–like (LOXL) enzymes, which are responsible for elastin cross-linking. LOX and LOXL have been identified as the rate-limiting step in synthesizing mature elastin in adult skin. The expression of LOXL in particular decreases with age. Copious amounts of LOX and LOXL allow the catalysis of immature elastin into desmosine and isodesmosine.
In studying these enzymes, Cenizo and colleagues screened more than 1,000 active ingredients to identify agents that could spur LOXL gene expression in adult dermal fibroblasts. They found that a dill extract was capable of penetrating into the epidermis and dermis in skin engineering and in vitro models, significantly stimulating LOXL gene expression in dermal equivalents (an increase of 64% in mRNA level compared with controls). The researchers also noted increases in elastin detection in dermal equivalents under the dermal-epidermal junction without a corresponding elevation in elastin mRNA. They concluded that LOXL is a suitable target for stimulating elastogenesis, and that dill extract appears to foster such activity (Exp. Dermatol. 2006;15:574-81).
Having shown that dill increases LOX and LOXL expression, along with their respective mRNAs, in 2011, some of the same investigators, this time led by Sohm, assessed the capacity of dill extract to enhance skin elasticity in vitro and in vivo. They reported that skin firmness and elasticity did indeed improve significantly in subjects treated for 56 days with a 1% topical application of dill extract, compared with subjects treated with placebo, based on cutometer measurements, biotribometer measurements, investigator evaluations, subject assessments, and photography. Most volunteers treated with dill extract identified marked enhancements in elasticity, firmness, and jaw line slackness. After 84 days, subjects treated with dill also exhibited significantly reduced mean wrinkle area and length compared with those taking the placebo formulation (Int. J. Cosmet. Sci. 2011;33:157-63). This greater elasticity might be attributed to increased LOX expression stimulated by dill extract application, though this study did not measure LOX or LOXL.