Cytotoxicity of white birch bud extracts: Perspectives for therapy of tumours.

Birch buds (Gemmae Betulae) are widely used in Russian and Chinese traditional medicine mainly as a diuretic and diaphoretic agent but also as an antiseptic, anti-inflammatory and analgesic. Despite the long history of therapeutic use of birch buds in folk medicine, the existing information on their chemical composition and pharmacological effects is insufficient. This circumstance warrants further study of the chemistry and pharmacology of birch buds. The present study was designed to investigate (a) the chemical composition of buds from two species of white birch and (b) the in vitro cytotoxic effect of extracts from these sources on selected tumour cells. Extracts from Betula pubescens Ehrh. and Betula pendula Roth. buds were obtained using three different methods: carbon dioxide supercritical fluid extraction (SFE), washing of exudate covering whole buds, and extraction of milled buds with diethyl ether. The chemical composition of extracts was investigated by GC-MS. Cytotoxicity was determined by MTT assay, and cell proliferation was determined by [3H]thymidine uptake in cancer cells and normal skin fibroblasts. The GC-MS investigation identified a total of 150 substances of different classes. The chemical composition of B. pubescens and B. pendula buds differed, with bud extracts from the former containing a relatively high quantity of sesquiterpenoids and flavonoids, while the main components of extracts from the latter were triterpenoids. The results of the biological assay indicated that birch bud extracts demonstrated time- and concentration-dependent and differential cytotoxicity. The highest cytotoxic activity demonstrated bud exudates and SFE extracts obtained from both Betula species. The rich chemical composition of birch buds suggests the possibility of a wider spectrum of biological activity than previously thought. Birch bud extracts could be a promising source of compounds with cytotoxic activity against various cancers

Cytotoxicity of Triterpene Seco-Acids from Betula pubescens Buds

The present study investigated the magnitude and mechanism of the cytotoxic effect on selected cancer cell lines of 3,4-seco-urs-4(23),20(30)-dien-3-oic acid (1), 3,4-seco-olean-4(24)-en-19-oxo-3-oic acid (2), and 3,4-seco-urs-4(23),20(30)-dien-19-ol-3-oic acid (3) isolated from downy birch (Betula pubescens) buds by carbon dioxide supercritical fluid extraction and gradient column chromatography. Cell viability in six human cancer lines exposed to these compounds was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was quantified by annexin V/propidium iodide staining of gastric cancer AGS and colorectal cancer DLD-1 cells. To evaluate the mechanism of apoptosis, the expression of apoptosis-related proteins was analyzed by Western blot. Compound 1 exhibited non-specific toxicity, while compounds 2 and 3 were specifically toxic to colon and stomach cancer cells. The toxicity of compounds 2 and 3 against these two cell lines was greater than for compound 1. Cleavage of caspase-8, -9, and -3 was found in AGS and DLD-1 cells treated with all three seco-acids, indicating the induction of apoptosis via extrinsic and intrinsic pathways. Therefore, triterpene seco-acids (1–3) decreased cell viability by apoptosis induction. AGS and DLD-1 cells were more susceptible to seco-acids with an oxidized C19 than normal fibroblasts. Hence, it made them a new group of triterpenes with potential anticancer activity

Abies Concolor Seeds and Cones as New Source of Essential Oils—Composition and Biological Activity

The chemical composition, including the enantiomeric excess of the main terpenes, of essential oils from seeds and cones of Abies concolor was studied by chromatographic (GC) and spectroscopic methods (mass spectrometry, nuclear magnetic resonance), leading to the determination of 98 compounds. Essential oils were mainly composed of monoterpene hydrocarbons. The dominant volatiles of seed essential oil were: limonene (47 g/100 g, almost pure levorotary form) and α-pinene (40 g/100 g), while α-pinene (58 g/100 g), sabinene (11 g/100 g), and β-pinene (4.5 g/100 g) were the predominant components of the cone oil. The seed and cone essential oils exhibited mild antibacterial activity, and the MIC ranged from 26 to 30 μL/mL against all of the tested bacterial standard strains: Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Escherichia coli, and Klebsiella pneumoniae. The cytotoxic studies have demonstrated that tested essential oils were cytotoxic to human skin fibroblasts and human microvascular endothelial cells at concentrations much lower than the MIC. The essential oils from A. concolor seeds and cones had no toxic effect on human skin fibroblasts and human microvascular endothelial cells, when added to the cells at a low concentration (0–0.075 μL/mL) and (0–1.0 μL/mL), respectively, and cultured for 24 h

Bioprospecting of the <i>Telekia speciosa</i>: Uncovering the Composition and Biological Properties of Its Essential Oils

The essential oils (EOs) of Telekia speciosa, a perennial plant native to southeastern Europe and Asia Minor, were analyzed for their composition and biological properties. T. speciosa is an invasive plant in Poland; however, its beauty prompts gardeners to cultivate the plants. T. speciosa serves as a valuable source of nectar and pollen for honey bees. Our results revealed more than 150 compounds in the flower, leaf, and root EOs. Major constituents found in the essential oils from the roots included isoalantolacton (46.2%) and from the flowers nerol (11.9%), while from the leaves, they included (E)-nerolidol (10.1%). T. speciosa flower EO showed significant cytotoxicity against A375 cells, with IC50 values of 7.2, 5.1, and 3.4 μg/mL referring to 24, 48, and 72 h, respectively, indicating its potential as a natural cytotoxic agent. The antimicrobial activity of the essential oils against Staphylococcus aureus ATCC 29213 and Escherichia coli ATCC 25922 was also investigated. The essential oils from the flowers and leaves of T. speciosa demonstrated higher inhibitory activity against S. aureus (MIC: 5.9–7.8 μL/mL) and E. coli (MIC: 7.8–11.7 μL/mL) than the essential oil isolated from the roots of the plant (MICs 31.3 and 62.5 μL/mL against S. aureus and E. coli, respectively)

New Polymethoxyflavones from Hottonia palustris Evoke DNA Biosynthesis-Inhibitory Activity in An Oral Squamous Carcinoma (SCC-25) Cell Line

Four new compounds, 5-hydroxy-2&prime;,6&prime;-dimethoxyflavone (4), 5-hydroxy-2&prime;,3&prime;,6&prime;-trimethoxyflavone (5), 5-dihydroxy-6-methoxyflavone (6), and 5,6&prime;-dihydroxy-2&prime;,3&prime;-dimethoxyflavone (7), and three known compounds, 1,3-diphenylpropane-1,3-dione (1), 5-hydroxyflavone (2), and 5-hydroxy-2&prime;-methoxyflavone (3), were isolated from the aerial parts of Hottonia palustris. Their chemical structures were determined through the use of spectral, spectroscopic and crystallographic methods. The quantitative analysis of the compounds (1&ndash;7) and the zapotin (ZAP) in methanol (HP1), petroleum (HP6), and two chloroform extracts (HP7 and HP8) were also determined using HPLC-PDA. The biological activity of these compounds and extracts on the oral squamous carcinoma cell (SCC-25) line was investigated by considering their cytotoxic effects using the MTT assay. Subsequently, the most active compounds and extracts were assessed for their effect on DNA biosynthesis. It was found that all tested samples during 48 h treatment of SCC-25 cells induced the DNA biosynthesis-inhibitory activity: compound 1 (IC50, 29.10 &plusmn; 1.45 &micro;M), compound 7 (IC50, 40.60 &plusmn; 1.65 &micro;M) and extracts ZAP (IC50, 20.33 &plusmn; 1.01 &micro;M), HP6 (IC50, 14.90 &plusmn; 0.74 &micro;g), HP7 (IC50, 16.70 &plusmn; 0.83 &micro;g), and HP1 (IC50, 30.30 &plusmn; 1.15 &micro;g). The data suggest that the novel polymethoxyflavones isolated from Hottonia palustris evoke potent DNA biosynthesis inhibitory activity that may be considered in further studies on experimental pharmacotherapy of oral squamous cell carcinoma