Identification of molecular pathways affected by pterostilbene, a natural dimethylether analog of resveratrol

<p>Abstract</p> <p>Background</p> <p>Pterostilbene, a naturally occurring phenolic compound produced by agronomically important plant genera such as <it>Vitis </it>and <it>Vacciunium</it>, is a phytoalexin exhibiting potent antifungal activity. Additionally, recent studies have demonstrated several important pharmacological properties associated with pterostilbene. Despite this, a systematic study of the effects of pterostilbene on eukaryotic cells at the molecular level has not been previously reported. Thus, the aim of the present study was to identify the cellular pathways affected by pterostilbene by performing transcript profiling studies, employing the model yeast <it>Saccharomyces cerevisiae</it>.</p> <p>Methods</p> <p><it>S. cerevisiae </it>strain S288C was exposed to pterostilbene at the IC₅₀concentration (70 μM) for one generation (3 h). Transcript profiling experiments were performed on three biological replicate samples using the Affymetrix GeneChip Yeast Genome S98 Array. The data were analyzed using the statistical methods available in the GeneSifter microarray data analysis system. To validate the results, eleven differentially expressed genes were further examined by quantitative real-time RT-PCR, and <it>S. cerevisiae </it>mutant strains with deletions in these genes were analyzed for altered sensitivity to pterostilbene.</p> <p>Results</p> <p>Transcript profiling studies revealed that pterostilbene exposure significantly down-regulated the expression of genes involved in methionine metabolism, while the expression of genes involved in mitochondrial functions, drug detoxification, and transcription factor activity were significantly up-regulated. Additional analyses revealed that a large number of genes involved in lipid metabolism were also affected by pterostilbene treatment.</p> <p>Conclusion</p> <p>Using transcript profiling, we have identified the cellular pathways targeted by pterostilbene, an analog of resveratrol. The observed response in lipid metabolism genes is consistent with its known hypolipidemic properties, and the induction of mitochondrial genes is consistent with its demonstrated role in apoptosis in human cancer cell lines. Furthermore, our data show that pterostilbene has a significant effect on methionine metabolism, a previously unreported effect for this compound.</p

Stilbene derivatives promote Ago2-dependent tumour-suppressive microRNA activity

It is well known that natural products are a rich source of compounds for applications in medicine, pharmacy, and biology. However, the exact molecular mechanisms of natural agents in human health have not been clearly defined. Here, we demonstrate for the first time that the polyphenolic phytoalexin resveratrol promotes expression and activity of Argonaute2 (Ago2), a central RNA interference (RNAi) component, which thereby inhibits breast cancer stem-like cell characteristics by increasing the expression of a number of tumour-suppressive miRNAs, including miR-16, -141, -143, and -200c. Most importantly, resveratrol-induced Ago2 resulted in a long-term gene silencing response. We also found that pterostilbene, which is a natural dimethylated resveratrol analogue, is capable of mediating Ago2-dependent anti-cancer activity in a manner mechanistically similar to that of resveratrol. These findings suggest that the dietary intake of natural products contributes to the prevention and treatment of diseases by regulating the RNAi pathway

PERENCANAAN KEBUTUHAN MATERIAL (PKM) PADA PRODUKSI KINCIR ANGIN KAPASITAS 100 WATT

Banda Ace

Wild species of vaccinium composition, nutritional value and utilization

There are still, in many parts of the globe, some edible fruit collects from the wild for human feeding and other uses. These fruits are utilised either in their raw nature or after some form of processing. One of these wild fruits are Vaccinium species such as Vaccinium myrtoides (Blume) Miq., Vaccinium cylindraceum, Vaccinium padifolium, Vaccinium corymbosum, Vaccinium myrtillus and others from the plant family Ericaceae. The term wild infers non-cultivated plants found in plantation felids or the forest. The species Vaccinium myrtoides and the others are small trees (shrubs) that are well known in Southeast Asian countries such as Philippines, Indonesia and other neighbouring islands. The plants classified as wild growing shrubs. However, the locals have made it be fully utilized in some areas as the wood that are used in grafting utensils and cutleries, or as fuel and fruits. The small-sized berry-like fruits with an average diameter of about 4–5 mm turn black when ripe. They have a delicious flavour that makes it edible and used in the making of other delicacies such as tart and pies to add flavour and as preservatives as well. A few published researches were done on Vaccinium myrtoides showing that it is still used in folkloric medicine. Leaves and fruits extracts showed strong antioxidant activity when tested in-vitro using DPPH (2, 2-diphenyl-1-picrylhydrazyl) free radical scavenging activity as part of a preliminary phytochemical screening for V. myrtoides. The study revealed that the antioxidant activity is due to the presence of flavonoids and other phenolic compounds in the plant leaves and fruit extracts