Bryophytes are close extant relatives of the ancestral land plant. As such, they have retained many innovations that had enabled the adaptation of early land plants to the terrestrial environment. One of such important innovations is the elaboration of an enormously diverse array of secondary metabolites. This article reviews current knowledge of terpenoid secondary metabolites, which constitute the largest family of plant metabolites, in bryophytes from three perspectives: chemical diversity, biosynthesis, and biological functions. The diversity of terpenoids in bryophytes, particularly in liverworts, is enormously rich. More than 1600 terpenoids have been reported from this plant group. While many terpenoids are observed in both bryophytes and seed plants, some are unique to bryophytes. It is just the beginning for us to understand the molecular and biochemical basis underlying terpenoid biosynthesis in bryophytes. Compared to seed plants, which have only one type of terpene synthase genes, so-called typical plant terpene synthase genes, bryophytes employ not only typical plant terpene synthase genes but also another class of terpene synthase genes called microbial-terpene synthase-like (MTPSL) genes for terpenoid biosynthesis. Biochemical studies suggest the MTPSLs are largely responsible for the terpenoid diversity in bryophytes, particularly sesquiterpenes and monoterpenes. Existing literature indicates that terpenoids made by bryophytes have important functions in diverse biological and ecological processes, particularly as defenses against biotic and abiotic stresses. The continued development of genomic resources and molecular tool kit for bryophytes will accelerate characterization of terpenoids biosynthesis and their biological functions in this important lineage of plants.

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.