Bio-Active Compounds from Teucrium Plants Used in the Traditional Medicine of Kurdistan Region, Iraq

Identification of Flavonoids, Antioxidant and Antiproliferative Activity of Aqueous Infusions of Calendula officinalis L., Chelidonium majus L., Teucrium chamaedrys L. and Alchemilla vulgaris L

Research background

The current changes in the global economy, characterised by the climate crisis and the economic and health impact of the COVID-19 pandemic, have led to a significant demand for medicinal herbs. This trend is expected to increase significantly by 2050. In this study, we investigated the biopotential of aqueous infusions of four medicinal plants: Calendula officinalis, Chelidonium majus, Teucrium chamaedrys and Alchemilla vulgaris.

Experimental approach

The flavonoid analysis of the aqueous infusions of the selected plants was carried out using the RP-HPLC technique. The antiproliferative activity of the prepared aqueous plant infusions was analysed against three human cancer cell lines (MDA-MD-231, T24 and A549), while the antioxidant potential was measured using three antioxidant methods (DPPH, FRAP and Rancimat assay).

Results and conclusions

T. chamaedrys had the highest total phenolics (expressed as GAE (2061±42) mg/L), free radical scavenging activity (IC50=1.9 mg/mL) and Fe(III) reducing antioxidant power (expressed as FeCl2 (9798±27) mg/L). At a concentration of 1 mg/mL, the antiproliferation of T24 by C. majus was 96 % and of MDA-MD-231 cells by A. vulgaris was 75 % after 72 h. After principal component analysis, T. chamaedrys and C. majus were grouped together. Quercetin glucoside and antioxidant capacity (DPPH) contributed the most to differentiate these infusions from the other two.

Novelty and scientific contribution

This study represents a comparative analysis of the biopotential of four medicinal plants. A new RP-HPLC method was developed to separate the flavonoids in the herbal infusions. This is the first report on the presence of kaempferol-3-O-rutinoside in C. officinalis and isorhamnetin-3-O-rutinoside in A. vulgaris aqueous infusion. For the first time, C. majus has been shown to contribute to the oxidative stability of edible oil. Furthermore, this is the first comparative study on the antiproliferative activity of selected medicinal plants against the cell lines MDA-MD-231, T24 and A549.

Screening of Volatile Compounds, Traditional and Modern Phytotherapy Approaches of Selected Non-Aromatic Medicinal Plants (Lamiaceae, Lamioideae) from Rtanj Mountain, Eastern Serbia

Ironwort (Sideritis montana L.), mountain germander (Teucrium montanum L.), wall germander (Teucrium chamaedrys L.), and horehound (Marrubium peregrinum L.) are species widely distributed across Europe and are also found in North Africa and West Asia. Because of their wide distribution they express significant chemical diversity. For generations, these plants have been used as medical herbs for treating different aliments. The aim of this paper is to analyze volatile compounds of four selected species that belong to the subfamily Lamioideae, family Lamiaceae, and inspect scientifically proven biological activities and potential uses in modern phytotherapy in relation to traditional medicine. Therefore, in this research, we analyze the volatile compounds from this plants, obtained in laboratory by a Clevenger-type apparatus, followed by liquid-liquid extraction with hexane as the solvent. The identification of volatile compounds is conducted by GC-FID and GC-MS. Although these plants are poor in essential oil, the most abundant class of volatile components are mainly sesquiterpenes: germacrene D (22.6%) in ironwort, 7-epi-trans-sesquisabinene hydrate (15.8%) in mountain germander, germacrene D (31.8%) and trans-caryophyllene (19.7%) in wall germander, and trans-caryophyllene (32.4%) and trans-thujone (25.1%) in horehound. Furthermore, many studies show that, in addition to the essential oil, these plants contain phenols, flavonoids, diterpenes and diterpenoids, iridoids and their glycosides, coumarins, terpenes, and sterols, among other active compounds, which affect biological activities. The other goal of this study is to review the literature that describes the traditional use of these plants in folk medicine in regions where they grow spontaneously and compare them with scientifically confirmed activities. Therefore, a bibliographic search is conducted on Science Direct, PubMed, and Google Scholar to gather information related to the topic and recommend potential applications in modern phytotherapy. In conclusion, we can say that selected plants could be used as natural agents for promoting health, as a source of raw material in the food industry, and as supplements, as well as in the pharmaceutical industry for developing plant-based remedies for prevention and treatment of many diseases, especially cancer.

Special Issue-"Bioactive Compounds from Natural Sources II"

In recent decades, there has been a great interest in bioactive compounds from natural sources [...].

Iridoids Isolation from a Phytochemical Study of the Medicinal Plant Teucrium parviflorum Collected in Iraqi Kurdistan

Herbal medicines are still widely practiced in Kurdistan Region-Iraq, especially by people living in villages on mountainous regions. Among plants belonging to the genus Teucrium (family Lamiaceae), which are commonly employed in the Kurdish traditional medicine, we have analyzed, for the first time, the methanol and aqueous methanol extracts of T. parviflorum aerial parts. The plant is mainly used by Kurds to treat jaundice, liver disorders and stomachache. We aimed to determine the phytochemical profile of the extracts and the structures of the main components, so to provide a scientific rationale for the ancient use of the plant in the ethno-pharmacological field. TLC analysis of the two extracts on silica gel and reversed phase TLC plates, using different visualization systems, indicated similar contents and the presence of phenolics, flavonoids, terpenoids and sugars. The chlorophyll-free extracts exhibited weak/no antimicrobial activities against a panel of bacteria (MICs = 800–1600 µg/mL) and fungal strains (MICs ≥ 5 mg/mL). At the concentration of 600 µg/mL, the methanol extract showed moderate antiproliferative effects against A549 and MCF-7 cancer cell lines in the MTS assay. Moreover, both extracts exhibited a significant dose-dependent free radical scavenging action against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical (EC₅₀ = 62.11 and 44.25 μg/mL, respectively). In a phytochemical study, a high phenolic content (77.08 and 81.47 mg GAE/g dry extract, respectively) was found in both extracts by the Folin–Ciocalteu assay. Medium pressure liquid chromatographic (MPLC) separation of the methanol extract on a reversed phase cartridge eluted with a gradient of MeOH in H₂O, afforded two bioactive iridoid glucosides, harpagide (1) and 8-O-acetylharpagide (2). The structures of 1 and 2 were established by spectral data, chemical reactions, and comparison with the literature. Interestingly, significant amounts of hepatotoxic furano neo-clerodane diterpenoids, commonly occurring in Teucrium species, were not detected in the extract. The wide range of biological activities reported in the literature for compounds 1 and 2 and the significant antiradical effects of the extracts give scientific support to the traditional use in Iraqi Kurdistan of T. parviflorum aerial parts for the preparation of herbal remedies.