A Simple Isocratic High-perfomance Liquid Chromatography Method for the Simultaneous Determination of Shikonin Derivatives in Some Echium Species Growing Wild in Turkey

Component Composition and Biological Activity of Various Extracts of Onosma gmelinii (Boraginaceae)

Onosma roots are widely used in traditional medicine to treat various diseases throughout the world. In this study, for the first time, we investigated the component composition and biological activity of various extracts from the roots of Onosma gmelinii collected in the highlands of the Kakpakty Mountains of the Almaty region (Republic of Kazakhstan). Extracts were obtained by three different methods: percolation extraction, ultrasound-assisted extraction, and supercritical carbon dioxide extraction. The component composition of the extracts was determined by gas chromatography/mass spectrometry (GC/MS), naphthoquinones by thin-layer chromatography (TLC), and spectrophotometric method. In this study, the presence of shikonin and its derivatives in the extracts was confirmed. The concentration of naphthoquinones during CO₂ extraction was about 40%, during ultrasonic extraction about 3%, and during percolation extraction about 1.3%. The GC-MS method identified 69 chemical compounds in the ultrasonic extract, 46 compounds in the CO₂ extract, and 51 compounds in the percolation extract. The extracts were tested on a panel of bacteria and viruses: two Gram-negative bacteria (Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027); nine Gram-positive bacteria (Staphylococcus aureus ATCC 6538-P, Staphylococcus aureus ATCC BAA-39, Staphylococcus epidermidis ATCC 51625, Staphylococcus epidermidis ATCC 12228, Streptococcus pyogenes ATCC 19615, Streptococcus pneumoniae ATCC BAA-660, Enterococcus hirae ATCC 10541, Enterococcus faecalis ATCC 51575, Enterococcus faecium ATCC 700221); and two fungal species (Candida albicans ATCC 10231, Candida albicans ATCC 2091); five subtypes of influenza virus A (A/FPV/Weybridge/78 (H7N7), A/Swine/Iowa/15/30 (H1N1), A/black-headed gull/Atyrau/743/04 (H13N6), A/FPV/Rostock/1934 (H7N1), A/Almaty/8/98 (H3N2)). The root extracts of Onosma gmelinii showed antibacterial activity in different degrees against all tested Gram-positive bacterial strains, while no inhibitory effect on Gram-negative bacteria was observed. The results indicated that the ultrasonic extract effectively inhibits the growth of the majority of tested Gram-positive bacteria (MBC from 18.3 to 293.0 µg/mL). CO₂ extract had the greatest bactericidal activity (MBC from 0.1 to 24.4 µg/mL). Percolation extract insignificantly inhibited bacterial growth (MBC from 2343.8 to 4687.5 µg/mL). CO₂ extract and ultrasonic extract significantly reduced the activity of C. albicans. The results of the antiviral action showed that the ultrasonic extract has the greatest effectiveness against different subtypes of the influenza virus A, while other extracts did not show significant activity.

Establishment of the hairy root culture of Echium plantagineum L. and its shikonin production

Echium plantagineum L. (Boraginaceae) is an invasive species in Australia and contains medicinal shikonins in its roots. In this study, the hairy root lines of E. plantagineum were established using Agrobacterium rhizogenes strain ATCC15834 and confirmed by the amplification of the rolB gene. Results showed significant difference in shikonin production between the hairy root lines in the ¹/₂B5 and M9 media. The biomass of the lines in the ¹/₂B5 medium was fivefold of that in the M9 medium. However, the components of detected shikonins were similar in these two liquid media. By contrast, different accumulation profiles appeared in the hairy root lines. HPLC analysis revealed the presence of nine possible related compounds, including shikonins, and acetylshikonin was the most abundant shikonin derivative. The content of acetylshikonin in the ¹/₂B5 medium (36.25 mg/L on average) was twofold of that in the M9 medium. Our results showed that the hairy root cultures of E. plantagineum can be used in enhancing the production of potential pharmaceutical compounds, such as acetylshikonin.

Antioxidant Properties and Reported Ethnomedicinal Use of the Genus Echium (Boraginaceae)

The genus Echium L. from the Boraginaceae family consists of 67 recognised species. The genus is widely distributed in the Mediterranean, having been documented in the traditional medicine of the area since 300 B.C. Current pharmacological studies have validated early ethnomedicinal properties showing that Echium spp. possesses antioxidant, analgesic, anxiolytic, anti-inflammatory, antibacterial, and antiviral effects. Nevertheless, only limited papers report specifically on the phytochemistry of this genus. Furthermore, the potential of utilising extracts from Echium species as natural antioxidant preparations has been significantly neglected. For the first time, this review comprehensively describes and discusses the presence of recorded Echium species with ethnomedicinal uses, their antioxidative properties in vitro and in vivo when available, and major phytochemical components recognised as potent antioxidants, as well as the possibilities and opportunities for future research.