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Anthocyanins of the proanthocyanidin-type glucosides in flavonoids are contained as functional constituents of fruits such as cranberry, blueberry, orange and apple and vegetables such as tomato, sweet pepper, spinach and radishes, and have been eaten as part of daily diets from the primitive era of human history. When anthocyanins are coupled with some water-soluble sugar molecules, they produce red, yellow, violet or blue colors. This explains why anthocyanins give a colorful variety of pigments for pansies, petunias, plums and other flowers. Interestingly, chlorophyll in various fruits and vegetables is the main green component, while anthocyanins are probably the most important visible plant pigments having specific colors. Anthocyanins have been clinically used in many folklore medicines worldwide that provide health benefits. Anthocyanins display antioxidant capacity against superoxide radicals, hydrogen peroxide, and other oxidants, and thus are expected to protect us from oxidative injury. In this review, the antioxidant mechanism of anthocyanidins present in common foods is discussed. [ABSTRACT FROM AUTHOR]

Anthocyanins are the largest group of naturally occurring phytochemicals, and impart the rich colors ranging from red to violet and blue to fruits, vegetables and other plants. These are the glycosides of polyhydroxy and polymethoxy derivatives of 2-phenylbenzopyrylium or flavylium salts. The interest in anthocyanins has increased immensely during the past decade due to their array of healthily beneficial phytochemicals. Anthocyanins can protect against health damage by some types of harmful oxidants through different mechanisms. The purpose of this article is to review the biological activities of anthocyanins and the interactions of anthocyanins with DNA and protein. [ABSTRACT FROM AUTHOR]

The multidrug resistance (MDR) proteins which belong to the ATP-binding cassette superfamily are present in a majority of human tumors and are an important final cause of therapeutic failure. Therefore, some compounds which inhibit the function of the MDR-efflux proteins may improve the cytotoxic action in cancer chemotherapy. The mechanism of action was believed to be a competition between their resistance modifiers and the cytotoxic agents for the same binding site of MDR P-glycoprotein (P-gp) due to a complementarity with a hypothetic receptor site with unknown structure. In the absence of the crystal structures of the P-gp, a receptor fitting was not available. Therefore, we tried to indirectly define the receptor structure or mapping of human MDR1-encoded P-gp in the presence of the structurally unrelated carotenoids, flavonoids, isoflavones and terpenoids. The inhibition of the efflux activity was measured by the increase of rhodamine 123 (R123) uptake by cancer cells. The effects of flavonoids, carotenoids and anthocyanins were studied on the activity of the MDR-1 gene-encoded efflux pump system. The effective flavonoids were rotenone, chrysin, phloretin and sakuranetin, which could inhibit the MDR efflux pump in the mouse lymphoma and colon cancer cells. The carotenoids isolated from paprika and other vegetables were tested on the increase of R123 accumulation of human MDR-1 gene-transfected L1210 mouse lymphoma cells and human breast cancer cells MDA-MB-231 (HTB-26). Capsanthin and capsorubin enhanced the R123 accumulation 30-fold relative to the nontreated lymphoma cells. Lycopene, lutein, antheraxanthin and violaxanthin had moderate effects, whereas α- and β-carotene had no effect on the reversal of MDR in the cancer cells. The MDR reversal of anthocyanins such as callistephin chloride, pelargonin chloride, ideaninchloride and pelargonidin chloride were studied. Cyanin chloride slightly increased the activity of P-gp; however, all other flavonoids were ineffective as resistance modifiers. Their biological ineffectivity is possibly related to the differences on the polarities of their compounds and permanent positive charge. [ABSTRACT FROM AUTHOR]

Significant antimicrobial action was detected in vitro and in vivo in phenothiazines that are applied to humans as neuroleptics or antihistamines. Both Gram-positive and Gram-negative bacteria were equally sensitive, with the MIC varying between 25 and 100 μg/ml with most agents. Some phenothiazines were bactericidal, while others were bacteriostatic in action. Similar activity could be observed in isoflavonones obtained from the plants Sophora spp. Trifluoperazine and methdilazine exhibited antimycobacterial properties as well, and in experimental animals the latter showed definite healing properties. Chlorpromazine and thioridazine were able to eliminate R-plasmids in drug-resistant bacteria. Artificially synthesized Benzo[α]phenothiazines could effectively suppress adenovirus oncogene expression. Phenothiazines have now been shown to inhibit efflux pumps in multidrug-resistant bacteria. [ABSTRACT FROM AUTHOR]

Considering the presence of multiple types of cell death induced by chemicals, it is important to determine a definitive strategy for the exploration of new highly tumor-selective compounds. The screening of highly selective compounds should be performed before the identification of the type of cell death (either apoptosis, autophagy, or necrosis) and the cell death induction mechanism. The tumor specificities of heterocyclic compounds and the type of cell death induced by them are summarized. [ABSTRACT FROM AUTHOR]

Dihydropyridines (DHPs) are recognized as one of the Ca+2 channel-blockers as a number of clinically used drugs are derivatives of various DHPs. Despite this, these DHPs are significantly potent in cancer chemotherapy along with clinically used drugs. This family of compounds is potent inhibitors of P-glycoprotein (Pgp), which are the main cause of the efflux of toxins the cells. This review mainly focuses on the Pgp inhibitory property of DHPs. The literature collection includes the latest developments in this area. This comprehensive review could also encompass their synthetic methodology for the preparation of the most active Pgp inhibitor DHPs. This article specifically covers the MDR reversal activity. However, this article does not cover their cardiovascular or rest of the pharmacological activities shown of DHPs. [ABSTRACT FROM AUTHOR]

Natural polyamines (putrescine, spermidine, spermine) are aliphatic amines containing 2 or more amino groups, and play an important role in regulating cell growth and differentiation. Depletion of polyamine in cells has been known to inhibit cell proliferation or induce cell death. This review summarizes changes in polyamine levels during cell death induced by the selective properties of various heterocycles. [ABSTRACT FROM AUTHOR]