Chromatographic analyses of Lavandula angustifolia and Rosmarinus officinalis extracts and their biological effects in mammalian cells and cell-free systems.

Knowledge of biological properties of natural compounds allows to understand their therapeutic value, efficacy and security. We investigated: composition of Lavandula angustifolia (LA) and Rosmarinus officinalis (RO) extracts, their antioxidant capacity, cytotoxicity and genotoxicity, their DNA-protective potential against DNA damage induced in hamster V79 cells by several genotoxins or in plasmid DNA by Fe2+ ions and activity of antioxidant enzymes in cells treated with these extracts. Higher cytotoxicity, observed at higher concentrations of extracts, was accompanied by the increased level of single-strand (ss) DNA breaks as well as formamidopyrimidine DNA glycosylase (Fpg) sensitive sites. LA and RO extracts were able to protect DNA of hamster cells as well as plasmid DNA against ss DNA breaks induced by genotoxins and Fe2+. LA extract mildly increased the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT), while RO extract decreased the activity of SOD, but increased the activity of CAT and GPx. Cell-free tests confirmed antioxidant activity of both extracts. The biological properties of LA and RO extracts showed that they could have a positive impact on human health.

Antioxidant potential of essential oil from Lavandula angustifolia in in vitro and ex vivo cultured liver cells.

Lavender is a commonly used herb in traditional medicine in Asia and Europe. It has been reported to be an effective medical plant in treating inflammation, depression and stress, thanks to its sedative and anxiolytic action, thrombotic, and antimicrobial properties. In the present study we investigated the protective effects of essential oil from Lavandula angustifolia (LO) against hydrogen peroxide and tert-butyl hydroperoxide -induced DNA damage. Also the effects of LO on the levels of enzymatic and non-enzymatic antioxidants (SOD-superoxide dismutase, GPx-glutathione peroxidase, GSH-glutathione) were evaluated in in vitro (human hepatoma cell line HepG2) and in ex vivo (freshly isolated rat hepatocytes) systems. The results showed that the oxidant-induced DNA lesions were significantly reduced in both systems pre-treated with the Lavandula angustifolia. The observed DNA-protective activity could be explained by both elevation of GPx activity in cells pre-treated with LO and antioxidant activity of LO.

Influence of different chemical agents (H2O2, t-BHP and MMS) on the activity of antioxidant enzymes in human HepG2 and hamster V79 cells; relationship to cytotoxicity and genotoxicity.

We investigated activities of antioxidant enzymes (AEs), superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) in human HepG2 and hamster V79 cells treated with a scale of concentrations of hydrogen peroxide (H2O2), tert-butyl hydroperoxide (t-BHP) and methyl methanesulfonate (MMS). Cytotoxicity and genotoxicity of these substances were evaluated simultaneously. We have found out that H2O2, t-BHP and MMS predictably induce significant concentration-dependent increase of DNA lesions in both cell lines. Cytotoxicity detected in V79 cells with help of PE test was in a good conformity with the level of DNA damage. MTT test has proved unsuitable, except for MMS-treated V79 cells. Compared with human cells HepG2, hamster cells V79 manifested approximately similar levels of SOD and CAT but ten times higher activity of GPx. Across all concentrations tested the most significant increase of activity of the enzyme CAT was found in H2O2- and t-BHP-treated HepG2 cells, of the enzyme SOD in t-BHP- and MMS-treated V79 cells, and of the enzyme GPx in H2O2-treated V79 cells. We suggest that stimulation of enzyme activity by the relevant chemical compounds may result from transcriptional or post-transcriptional regulation of the expression of the genes CAT, SOD and GPx. Several authors suggest that moderate levels of toxic reactants can induce increase of AEs activities, while very high levels of reactants can induce their decrease, as a consequence of damage of the molecular machinery required to induce AEs. Based on a great amount of experiments, which were done and described within this paper, we can say that the above mentioned principle does not apply in general. Only the reactions of t-BHP affected HepG2 cells were consistent with this idea.

Carvacrol and rosemary essential oil manifest cytotoxic, DNA-protective and pro-apoptotic effect having no effect on DNA repair.

For several thousand years natural products were successfully used to treat a variety of diseases and to maintain health in humans, but until now it is not fully known what causes these medicinal effects. In our study we assessed the cytotoxic, DNA-protective and pro-apoptotic effect of two frequently occurring natural compounds, carvacrol and rosemary essential oil, on human hepatoma HepG2 cells. In addition we examined the in vitro incision repair activity of liver cell extracts prepared from hepatocytes isolated from Sprague-Dawley (SD) rats fed with water containing carvacrol or rosemary oil. Using conventional and modified single cell gel electrophoresis we proved that incubation of HepG2 cells with selected concentrations of carvacrol and rosemary oil significantly protected cellular DNA against two dangerous oxidative agents, hydrogen peroxide (H(2)O(2)) and 2,3-dimethoxy-1,4-naphthoquinone (DMNQ). It is interesting that despite this DNA protection, the addition of both volatiles to the drinking water of SD rats had no effect on incision repair capacity of hepatocyte extracts. In this paper we also showed that carvacrol and rosemary oil can trigger apoptotic cell death pathways in HepG2 cells, which is probably connected with their cytotoxicity.

Biological effects of four frequently used medicinal plants of Lamiaceae.

Cancer is one of the leading causes of death characterized by uncontrolled growth and spread of cancer cells. There are several hundred thousands of new cases of cancer worldwide. Clinical oncology is still challenged by toxicity and side effects of multimodal therapy strategies in which it is associated with poor prognosis for patients. There is an urgent necessity to develop novel therapy strategies and to utilize preventive potential of natural compounds. As the majority of anticancer drugs are of natural origin, natural products represent a valuable source for the identification and development of novel treatment options and chemopreventive mechanisms for cancer. This review is focused on the summary of published knowledges on the antioxidant and potential chemopreventive effects of biologically active substances present in the extracts of four plants of the family Lamiaceae (sage, thyme, rosemary and lavander) in different animal and in vitro systems. It is assumed that the chemopreventive and chemotherapeutic potential of natural compounds is the result of a combined action of several mechanisms.

The intensity of internalization and cytotoxicity of superparamagnetic iron oxide nanoparticles with different surface modifications in human tumor and diploid lung cells.

The human lung adenocarcinoma epithelial (A549) cells and the human embryo lung (HEL 12469) cells were used to investigate the uptake and cytotoxicity of magnetite nanoparticles (MNPs) with different chemically modified surfaces. MNPs uptake was an energy-dependent process substantially affected by the serum concentration in the culture medium. Internalized MNPs localized in vesicle-bound aggregates were observed in the cytoplasm, none in the nucleus or in mitochondria. All MNPs induced a dose- and time-dependent increase in cytotoxicity in both human lung cell lines. The cytotoxicity of MNPs increased proportionally with the particle size. Since the cytotoxicity of MNPs was nearly identical when the doses were equalized based on particle surface area, we suppose that the particle surface area rather than the surface modifications per se underlay the cytotoxicity of MNPs. In general, higher internalized amount of MNPs was found in HEL 12469 cells compared with A549 cells. Accordingly, the viability of the human embryo lung cells was reduced more substantially than that of the adenocarcinoma lung cells. The weak MNPs uptake into A549 cells might be of biomedical relevance in cases where MNPs should be used as nanocarriers for targeted drug delivery in tumor tissue derived from alveolar epithelial cells.

Structure of flavonoids influences the degree inhibition of Benzo(a)pyrene - induced DNA damage and micronuclei in HepG2 cells.

Flavonoids are plant derivatives of flavone of which chemical structure is characterized by various degrees of hydroxylation and glycosidic substitution. In the present study we investigated the protective effect of two structurally different groups of flavonoids against-benzo[a]pyrene (B(a)P)-induced genotoxic effects on human hepatocellular carcinoma (HepG2) cells. The first group of flavonoids: fisetin, kaempferol, galangin, quercetin, and luteolin, hydroxylated at the 3´,4´-position on the B ring, 3 - position of C ring and on the A ring was able to inhibit significantly B(a)P-induced genotoxic effects in a greater degree than the second group of flavonoids: chrysin, 7-hydroxyflavone, 7,8-dihydroxyflavone and baicalein (hydroxylated on the A ring) which showed a statistically significant inhibition of genotoxicity mainly at higher concentrations (10 and 25 µM). The tenth flavonoid tested rutin, which contains hydroxyl group at the position 3 of C ring, substituted by the sugar rutinose, was not able to inhibit effectively genotoxic changes induced by B(a)P. Our results, obtained with help of micronucleus test and single cell gel electrophoresis (comet assay) suggest that inhibition of B(a)P-induced DNA lesions and micronuclei correlates with the structural arrangement and organization of the hydroxyl groups in the molecular structure of the flavonoids tested.

Electrochemical behavior and determination of tumor inhibiting or promoting activities of flavonoids.

This paper deals with determination of the tumor inhibiting or promoting activities of 11 flavonoids performed by DC polarography. Flavonoids were tested in the presence of polyaromatic carcinogen 7,12-dimethylbenz(a)anthracene (DMBA) or in combination with DMBA and 12-O-tetradecanoylphorbol-13-acetate (TPA), which is known as a specific tumor promoter for epidermal carcinogenesis. We found that in this experimental system the promotory or inhibitory activities of studied flavonoids depend on the number and position of hydroxyl groups in their chemical structures and are related to the polarographic behavior of these compounds. Flavonoids, which are hydroxylated at the ring B, are reduced in anhydrous DMF on a mercury dropping electrode in two one-electron steps. Absence of the hydroxyl groups in these positions caused their reduction in three one-electron steps. Similarly, flavonoids with hydroxyl groups at the ring B have been shown to inhibit the activities of DMBA (2.7-45.9%) and of DMBA + TPA (47.2-78.2%). Missing hydroxyl groups caused weaker inhibitory activity against DMBA + TPA (19.01-38.74%) and the enhancement of DMBA activity (31.08-66.21%). Presented data demonstrated that the electrochemical method--DC polarography is very sensitive, simple technique for determination of the tumor inhibiting or promoting activities of the studied compounds.

Structure-activity relationship of trans-resveratrol and its analogues.

Cancer is one of the main causes of death in both men and women, claiming over 6 million people each year worldwide. Chemoprevention in combination with anti-cancer treatment is therefore important to reduce morbidity and mortality. Stilbene-based compounds have over the years attracted attention of many researchers due to their wide ranging biological activities. One of the most relevant and extensively studied stilbenes is trans-resveratrol, a phytoalexin present in grapes and other foods. One of the most striking biological activities of trans-resveratrol soundly investigated during recent years has been its cancer-chemopreventive potential. It has been found that the biological activity of trans-resveratrol and its analogues depends significantly on the structural determinants, which are (i) number and position of hydroxyl groups, (ii) intramolecular hydrogen bonding, (iii) stereoisomery and (iv) double bond. The observation that trans-stilbene compounds having 4 -hydroxy group, double bond and bearing ortho-diphenoxyl or para-diphenoxyl functionalities possess remarkably higher chemopreventive activity than trans-resveratrol gives us useful information for further chemopreventive drug design.