Influence of In Vitro Human Digestion Simulation on the Phenolics Contents and Biological Activities of the Aqueous Extracts from Turkish Cistus Species.

Oxidative stress is one of the significant precursors of various metabolic diseases such as diabetes, Parkinson's disease, cardiovascular diseases, cancer, etc. Various scientific reports have indicated that secondary plant metabolites play an important role in preventing oxidative stress and its harmful effects. In this respect, this study was planned to investigate the phenolic profile and antioxidant and antidiabetic potentials of the aqueous extracts from Turkish Cistus species by employing in vitro methods. In vitro digestion simulation procedure was applied to all extracts to estimate the bioavailability of their phenolic contents. Total phenolic, flavonoid, phenolic acid and proanthocyanidin contents were determined for all phases of digestion. In addition, changes in the quantity of the assigned marker flavonoids (tiliroside, hyperoside and quercitrin) were monitored by High-Performance Thin Layer Chromatography (HPTLC) analysis. The antioxidant activity potentials of the extracts were studied by various methods to reveal their detailed activity profiles. On the other hand, in vitro α-amylase and α-glucosidase enzymes and advanced-glycation end product (AGE) inhibitory activities of the extracts were determined to evaluate the antidiabetic potentials of extracts. The results showed that aqueous extracts obtained from the aerial parts of Turkish Cistus species have rich phenolic contents and potential antioxidant and antidiabetic activities; however, their bioactivity profiles and marker flavonoid concentrations might significantly be affected by human digestion. The results exhibited that total phenolic contents, antioxidant activities and diabetes-related enzyme inhibitions of the bioavailable samples were lower than non-digested samples in all extracts.

Hypericum olympicum L. recovers DNA damage and prevents MMP-9 activation induced by UVB in human dermal fibroblasts.

ETHNOPHARMACOLOGICAL RELEVANCE: Hypericum olympicum L. (Hypericaceae) flowering aerial parts has been utilized in Turkish folk medicine as a remedy against inflamed skin problems. AIM OF THE STUDY: This study was designed to state the effect of H. olympicum on dermatological problems. For this purpose effect of the plant extract on the DNA strand break and matrix metalloproteinase (MMP)-9 activity of human dermal fibroblast (HDFs) cells irradiated with UVB as well as antioxidant activity potential were studied. MATERIALS AND METHODS: The methanolic extract of Hypericum olympicum (HOM) was prepared by maceration at room temperature. DNA damage and increased MMP-9 activity in HDFs were induced by UVB irradiation. The cell viability was measured by water-soluble tetrazolium salt (WST)-1 assay. The effects on DNA strand break was investigated by single gel electrophoresis (commonly known as Comet assay), while MMP-9 activity was observed by gelatin zymography assay. In vitro antioxidant tests were performed to indicate the effect on reactive oxygen species (ROS). The major metabolites were identified and their concentrations were measured by high performance thin layer chromatography (HPTLC). RESULTS: HOM was found to recover DNA damage dose-dependently. The enzymatic activity of MMP-9 was inhibited almost 100% by the treatment of 1.5 mg/mL of the extract. It also enhanced cell proliferation in those cells, and also it was shown to possess antioxidant activity. The major metabolites of HOM were identified as chlorogenic acid and quercetin glycosides (rutin, hyperoside, isoquercitrin). CONCLUSION: Experimental studies have proven the traditional use of Hypericum olympicum in inflamed skin problems acting by inhibition of the inflammatory pathway and recovery of DNA damage induced experimentally.

The fruit extract of Berberis crataegina DC: exerts potent antioxidant activity and protects DNA integrity.

BACKGROUND: Dried fruits of Berberis crataegina (Berberidaceae) have been frequently consumed as food garniture in Turkish cuisine, while its fruit paste has been used to increase stamina and in particular to prevent from cardiovascular dysfunctions in Northeastern Black Sea region of Turkey. This study investigated this folkloric information in order to explain the claimed healing effects as well as to evaluate possible risks. METHODS: Total phenolic, flavonoid and proanthocyanidin contents and antioxidant capacity of the methanolic fruit extract were evaluated through several in vitro assays. The cytotoxic and genotoxic effects of B. crataegina fruit extract were also assessed in both cervical cancer cell line (HeLa) and human peripheral blood lymphocytes. RESULTS: The extract showed protective effects against ferric-induced oxidative stress and had a relatively good antioxidant activity. It also ameliorated the H2O2 mediated DNA damage in lymphocytes, suggesting the protective effect against oxidative DNA damage. CONCLUSION: The methanolic extract of B. crataegina fruits may be a potential antioxidant nutrient and also may exert a protective role against lipid peroxidation as well as oxidative DNA damage.

Appraisal of in vitro and in vivo antioxidant activity potential of cornelian cherry leaves.

The antioxidant activity of the 80% methanolic extract of Cornus mas L. leaves (CMM) was evaluated by various methods both in vitro and in vivo. In vitro screening tests indicated that CMM had high antioxidant activity in terms of free radical scavenging and metal reducing activity. In vivo antioxidant activity studies in normal healthy rats demonstrated that the total antioxidant capacity of liver homogenates were increased, although no changes were observed in the activities of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase or in the level of lipid peroxidation. Studies on CCl4-treated rats also showed that CMM restored the activities of antioxidant enzymes, lowered the level of lipid peroxidation and elevated the total antioxidant capacities of both the total blood and liver homogenates of the animals. Further activity-guided fractionation studies led to the isolation of gallic acid, a well-known antioxidant, as one of the active components.

Phenolic compounds from Hypericum calycinum and their antioxidant activity.

From the MeOH extract of Hypericum calycinum, two caffeoylquinic acid derivatives, butyl chlorogenate (1), and chlorogenic acid (2), seven flavonoids, quercetin (3), quercitrin (4), hyperoside (5), isoquercitrin (6), miquelianin (7), rutin (8) and I3,II8-biapigenin (9) and two flavanols, (+)-catechin (10) and (-)-epicatechin (11) were isolated. Identification of the isolates was carried out by spectroscopic analysis including 1D and 2D NMR experiments as well as mass spectrometry. Free radical scavenging activities of the isolated compounds were determined in in-vitro 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide (NO) scavenging models. The compounds showed strong DPPH and moderate NO scavenging activities in a concentration dependent manner. (+)-Catechin and (-)-epicatechin were found to be the most active compounds with IC50 values of 4.16 and 4.67 microM for DPPH and 190 and 170 microM for NO scavenging activities, respectively.