Micropropagation of Plantago media L. and the presence of phenolic compounds in organs of multiplied plants were investigated for the first time. Multiplication of plant material was achieved in shoot-tip cultures and via direct organogenesis on Murashige and Skoog (MS) medium with four variants of plant growth regulators (M1–M4). The best multiplication coefficient – 9.2 was obtained in seedling shoot-tip cultures on MS medium M3 with BA 0.2 mg/L and IAA 1.0 mg/L. Methanol extracts prepared separately from shoots and roots of in vitroderived plantlets were found to contain typical of the genus Plantago L. phenylethanoid glycosides as the only phenolics. Acteoside and plantamajoside were the major compounds – both known to possess a wide range of promising biological activities applicable for medicinal (therapeutic) and cosmetic uses. Martynoside, as a trace constituent, was also found for the first time in the studied species. The quantitative screening of the extracts by TLC video densitometric method showed a higher content of acteoside in shoots (range 62.43–93.03 mg/g, dry weight) and plantamajoside in roots (range 22.45–44.08 mg/g); the highest recorded values – 93.03 mg/g and 44.08 mg/g, respectively, were found in the organs obtained on MS medium M4 with BA 2.0 mg/L.
The free-living Acanthamoeba sp. causes various diseases. Treatment of them is very difficult and not always effective because of encystation, making it highly resistant to antiamoebic drugs. Gram-positive bacteria Staphylococcus aureus, Gram-negative bacteria Escherichia coli, and an yeast Candida albicans also exhibit outstanding resistance to antimicrobial substances. The search for new natural amoebicidal and antimicrobial agents of plant origin is still of current interest. The aim of the study was to investigate the amoebicidal activity of the extracts obtained from tissue culture and a field-grown plant of Chaenomeles japonica against pathogenic trophozoites of Acanthamoeba spp. and antimicrobial effect against S. aureus, E. coli, and C. albicans. The extracts of C. japonica had an inhibitory effect on the proliferation of Acanthamoeba trophozoites as compared to the non-treated control. Among the crude extracts tested, the extract of leaves, from both shoot culture and the field-grown plant had remarkable amoebicidal action against the trophozoites but also antibacterial activity against Gram-positive bacteria Staphylococcus aureus. The extract from leaves from shoot culture, already on the second and third days of treatment, showed an antiamoebicidal effect at a concentration of 1 mg mL-1 (inhibition of trophozoites 87.5% and 91.8%, respectively). In addition to leaves from shoot culture (a conc. 5 mg mL-1, 2nd day inhibition of trophozoites 85.7% and 3rd day 97.2%), leaves from a field-grown plant (a conc. 5 mg mL-1, 2nd day 91.0% and 3rd day 94.4%) and callus (a conc. 5 mg mL-1, 2nd day 90.0% and 3rd day – 95.4%) also exhibited a good antiamoebicidal activity. Out of the four extracts, the extracts from leaves from both shoot culture and a field-grown plant were reported to be the most active against Gram-positive S. aureus, which was determined by the values of MIC = 5.0 mg mL-1 and MIC = 2.5 mg mL-1, respectively. The inhibitory potential depends on the yield and composition of mainly bioactive compounds: pentacyclic terpenoids (mainly betulinic, ursolic, and oleanolic acids) and polyphenols (mainly chlorogenic acid and its isomers, epicatechin, dimeric, and trimeric proanthocyanidins, quercetin and kaempferol derivatives).