The anti-H. pylori properties of 26 different commercial essential oils were examined in vitro by MIC (minimal inhibitory concentration) determination for the reference strain H. pylori ATCC 43504. We selected 9 essential oils with different anti-Helicobacter activities and established their phytochemical composition and urease inhibition activities. Phytochemical analysis of the selected essential oils by GC-MS method and antioxidant activity were performed. The phenol red method was used to screen the effect of essential oils on urease activity expressed as IC₅₀ (the half of maximal inhibitory concentration). The most active essential oils, with MIC = 15.6 mg/L, were thyme, lemongrass, cedarwood and lemon balm oils; MIC = 31.3 mg/L—oregano oil; MIC = 62.5 mg/L—tea tree oil; MIC = 125 mg/L—pine needle, lemon and silver fir oils with bactericidal effect. Urease activity was inhibited by these oils with IC₅₀ ranged from 5.3 to > 1049.9 mg/L. The most active was cedarwood oil (IC₅₀ = 5.3 mg/L), inhibiting urease at sub-MIC concentrations (MIC = 15.6 mg/L). The statistical principal component analysis allowed for the division of the oils into three phytochemical groups differing in their anti-H. pylori activity. To summarize, the activity in vitro of the five essential oils silver fir, pine needle, tea tree, lemongrass, and cedarwood oils against H. pylori was found in this paper for the first time. The most active against clinical strains of H. pylori were cedar wood and oregano oils. Moreover, cedarwood oil inhibited the urease activity at subinhibitory concentrations. This essential oil can be regarded as a useful component of the plant preparations supporting the eradication H. pylori therapy.

The occurrence of candidiasis, including superficial infections, has recently increased dramatically, especially in immunocompromised patients. Their treatment is often ineffective due to the resistance of yeasts to antimycotics. Therefore, there is a need to search for new antifungals. The aim of this study was to determine the antifungal effect of clove essential oil (CEO) and eugenol (EUG) towards both reference and clinical Candida spp. strains isolated from the oral cavity of patients with hematological malignancies, and to investigate their mode of action and the interactions in combination with the selected antimycotics. These studies were performed using the broth microdilution method, tests with sorbitol and ergosterol, and a checkerboard technique, respectively. The CEO and EUG showed activity against all Candida strains with a minimal inhibitory concentration (MIC) in the range of 0.25–2 mg/mL. It was also found that both natural products bind to ergosterol in the yeast cell membrane. Moreover, the interactions between CEO and EUG with several antimycotics—cetylpyridinium chloride, chlorhexidine, silver nitrate and triclosan—showed synergistic or additive effects in combination, except nystatin. This study confirms that the studied compounds appear to be a very promising group of phytopharmaceuticals used topically in the treatment of superficial candidiasis. However, this requires further studies in vivo.

The purpose of this research was to investigate the chemical composition of essential oils (EOs) from:Origanum vulgareL.,Satureja hortensisL.,Thymus serpyllumL. andThymus vulgarisL. (Lamiaceae) cultivated in Poland, and to study their antifungal activity towards clinical isolates of oralCandidaspp. The hydrodistilled essential oils were analyzed using the GC-MS method. The antifungal activity was evaluatedin vitroagainst oral isolates and reference strains ofCandida albicansandC. glabrata, using the broth microdilution method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Clinical and Laboratory Standards Institute (CLSI) guidelines, allowing for estimation of minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC). GC-MS analysis revealed that carvacrol was the main EO compound in oregano and summer savory, while thymol and linalool were the major ingredients of thyme and wild thyme oils, respectively. The EOs possessed fungicidal activity againstC. albicansandC. glabrata, including oral isolates, with MIC = 125 – 2000 mg/L, MFC = 250 – 4000 mg/L and MFC/MIC = 1 – 4, depending on the yeast and plant species. The most active was thyme oil – with MIC = 125 – 500 mg/L, MFC = 250 – 500 mg/L and MFC/MIC = 1 – 2.

Over the past five years, phytochemical and pharmacological studies have been conducted on material extracted from members of the Rutaceae family. In such work, new furochinoline-structured alkaloids were isolated from Ruta sp. and Dictamnus sp. Beyond the aforementioned, other substances with promising activity were isolated from the less-known species of Zanthoxylum, Evodia, Lonchocarpus, Myrthopsis and Teclea. Currently used forms of extraction, as well as methods of isolation and detection, allow the obtaining of pure, biologically active compounds. Many of these have antifungal, anti-bacterial and anti-plasmodial properties. Others are still being researched as potential drugs, which, in future, may be used in treating those afflicted with HIV and cancer. This article is designed to give the readers a thorough review of the active natural products from the Rutaceae family.