Methanolic extracts from the aerial parts and roots of two Scutellaria species, S. alpina and S. altissima, and five polyphenols from these plants demonstrated a significant ability to inhibit the formation of advanced glycation end-products (AGE) in vitro. S. alpina, which is richer in polyphenolic compounds, had strong antiglycation properties. These extracts demonstrated also high activity in the FRAP (ferric-reducing antioxidant power), antiradical (DPPH) and lipid peroxidation inhibition assays. Among the pure compounds, baicalin was the strongest glycation inhibitor (90.4% inhibition at 100 μg/mL), followed by luteolin (85.4%). Two other flavone glycosides had about half of this activity. Verbascoside was similar to the reference drug aminoguanidine (71.2% and 75.9%, respectively). The strong correlation observed between AGE inhibition and total flavonoid content indicated that flavonoids contribute significantly to antiglycation properties. A positive correlation was also observed between antiglycative and antioxidant activities. The studied skullcap species can be considered as a potential source of therapeutic agents for hyperglycemia-related disorders.

The present study evaluates the effects of various cytokinins on Scutellaria alpina shoot proliferation and production of polyphenolic metabolites (baicalin, wogonoside, luteolin, luteolin 7-O-glucoside, verbascoside). The shoots were induced from shoot tips on MS medium supplemented with IAA (indole-3-acetic acid, 0.57 µM) and various concentrations of 6-benzylaminopurine (BAP), kinetin, zeatin (1, 2, 4, 8 µM) or tidiazuron (TDZ) (0.2, 0.5, 1 µM). Among the cytokinins tested, BAP was the most effective for shoot induction, and the highest number of shoots (25 per explant) was achieved with 2 and 4 µM BAP. Maximum biomass production was also achieved on these media. Significantly higher baicalin, wogonoside and verbascoside contents were recorded in treatments containing cytokinins combined with 0.57 µM IAA, when compared to cytokinin-free medium. TDZ at a concentration of 0.5 µM was the most effective for polyphenol production. However, supplementation with cytokinins often results in the reduction of luteolin and its 7-O-glucoside production in the shoot culture of S. alpina. ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)] and ferric reducing antioxidant power assays were used to identify the antioxidant potential of methanolic extracts from shoots cultured in the presence of different types and concentrations of cytokinins. In both tests, the shoots from medium supplemented with 0.5 µM TDZ demonstrated the strongest antioxidant activity. The results indicate that higher polyphenolic content correlated with greater reducing power and antiradical efficiency.

Hairy roots of Dracocephalum moldavica L. were induced using Agrobacterium rhizogenes strain A4. Transformed roots were obtained from shoot explants with low transformation frequency of up to 3 %. The effects of different liquid media: Murashige and Skoog (MS), Gamborg et al. (B5) and Woody Plant (WP) with full- and half-strength (½MS, ½B5, ½WP), on biomass accumulation and rosmarinic acid (RA) content were investigated. The hairy roots were cultured in photoperiod (16 h light/8 h dark) and darkness. Biomass of D. moldavica hairy roots was the highest (7.23 g flask⁻¹ of fresh weight and 0.89 g flask⁻¹ of dry weight) in the cultures grown in WP medium under periodic light. Ultra performance liquid chromatography analysis revealed the highest RA content (78 mg g⁻¹ dry wt) in roots cultured in ½B5 medium under photoperiod conditions. It was about tenfold higher compared to roots of field-grown mother plants. Antioxidant activities and total phenolic contents of methanolic extracts of D. moldavica hairy roots cultured in ½B5 and WP media under photoperiod and darkness and roots of field grown plants were compared. All extracts were investigated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging and phosphomolybdenum reduction assays. Total phenolic contents were estimated by the Folin–Ciocalteu method. The methanolic extract of D. moldavica hairy roots grown in ½B5 medium under photoperiod possessed the strongest effects on reducing Mo and DPPH radical scavenging. The activities were significantly higher (p ≤ 0.05) than those of methanolic extract of roots of intact plants grown in the field. The most active methanolic extract of hairy roots was characterized by the highest level of rosmarinic acid and total content of phenolic compounds.

The ability to restore or replace injured tissues can be undoubtedly named among the most spectacular achievements of plant organisms. One of such regeneration pathways is organogenesis, the formation of individual organs from nonmeristematic tissue sections. The process can be triggered in vitro by incubation on medium supplemented with phytohormones. Cytokinins are a class of phytohormones demonstrating pleiotropic effects and a powerful network of molecular interactions. The present study reviews existing knowledge on the possible sequence of molecular and genetic events behind de novo shoot organogenesis initiated by cytokinins. Overall, the review aims to collect reactions encompassed by cytokinin primary responses, starting from phytohormone perception by the dedicated receptors, to transcriptional reprogramming of cell fate by the last module of multistep-phosphorelays. It also includes a brief reminder of other control mechanisms, such as epigenetic reprogramming.

Shoots of Salvia officinalis, a medicinally important plant, were infected with Agrobacterium rhizogenes strains ATCC 15834 and A4 which led to the induction of hairy roots in 57% and 37% of the explants, respectively. Seven lines of hairy roots were established in WP liquid medium under light and dark conditions. The transformed nature of the root lines was confirmed by polymerase chain reaction using rolB and rolC specific primers. Transformed root cultures of Salvia officinalis showed variations in biomass and rosmarinic acid production depending on the bacterial strain used for transformation and the root line analyzed. Both parameters (growth and rosmarinic acid content) of ATCC 15834-induced lines were significantly higher than the A4-induced lines. The maximum accumulation of rosmarinic acid (about 45 mg g^-1 of dry weight) was achieved by hairy root line 1 (HR-1) at the end of the culture period (45D50 days). The level was significantly higher than that found in untransformed root culture (19 mg g^-1 of dry wt).