Complexes involving quercetin, DNA and Cu(II)

Rahman, Arshad; Shahabuddin,; Hadi, S. M.; Parish, J.H.

doi:10.1093/carcin/11.11.2001

Cited by 112 publications

(58 citation statements)

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“…Similar pro-oxidant effects have been reported for other antioxidant phytochemicals including flavonoids, [33] tannins [34] and curcumin. [35] Previous studies have shown that transition metal ions, such as copper or iron, can enhance the conversion of the anti-oxidant to the pro-oxidant state.…”

Section: Other Phenolic Aloe Vera Constituentssupporting

confidence: 80%

Problems of Reproducibility and Efficacy of Bioassays Using Crude Extracts, with reference to Aloe vera

Cock¹

2011

Phcog Commn.

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Aloe vera has a long history of medicinal usage and its biological activities have been well documented in a variety of bioassays. However, isolated Aloe vera leaf components generally do not display the same bioactivities, or have lower efficacies than crude juice/extracts. It is likely that several components work in a synergistic manner in the crude mixture, resulting in increased bioactivities. Furthermore, different laboratories often report varying bioactivities using the same extraction procedure on plant material from the same species. Individual Aloe vera cultivars may have widely varying levels of the bioactive phytochemicals. Due to the structure and chemical nature of many of the Aloe vera phytochemicals, it is likely that many of its reported medicinal properties are due to anti-oxidant or pro-oxidant effects. The anti-oxidant/prooxidant activities of many of Aloe vera's phytochemicals is dependent not only on their individual levels, but also on the ratios of various components, and on their individual redox states. Therefore, discrepancies between bioactivity studies are likely when using different crude mixtures. The potential differences between these crude mixtures need to be taken into account when analysing the reproducibility and efficacy of bioassays of crude extracts.

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Section: Other Phenolic Aloe Vera Constituentssupporting

confidence: 80%

Problems of Reproducibility and Efficacy of Bioassays Using Crude Extracts, with reference to Aloe vera

Cock¹

2011

Phcog Commn.

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“…Thus, although many plant species have very high antioxidant contents, it is possible that the individual components may act as either antioxidants or as pro-oxidants and thus may also be effective in the treatment of cancer, as well as in its prevention at different concentrations. Similar pro-oxidant effects have been reported for other antioxidant phytochemicals including flavonoids 11 and tannins. 12 Furthermore, the presence of transition metal ions such as copper or iron in an extract can further enhance the conversion of the antioxidant to the prooxidant state.…”

Section: Introductionsupporting

confidence: 81%

Anti-Proliferative Properties of Terminalia sericea Burch. Ex Dc Leaf Extracts Against Caco2 and HeLa Cancer Cell Lines

Gu¹,

Shalom²,

Cock³

2018

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Introduction: Terminalia spp. are characterised by their high levels of antioxidant phytochemicals and several species have anticancer activity. This study examines the anti-proliferative activity of T. sericea leaf extracts against Caco2 and HeLa carcinoma cell proliferation. Methods: Solvent extracts were prepared from T. sericea leaves and their antioxidant capacities were determined by the DPPH free radical scavenging assay. Anti-proliferative activities against Caco2 and HeLa cancer cells were determined by an MTS based cell proliferation assay. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: The methanolic and aqueous T. sericea leaf extracts displayed high antioxidant capacities (equivalent to 150 and 340 mg of ascorbic acid per gram of plant material extracted respectively). In contrast, the ethyl acetate, chloroform and hexane extracts had relatively low antioxidant contents (≤5 mg of ascorbic acid equivalents per gram of plant material extracted). The antioxidant contents of the T. sericea leaf extracts correlated with the ability of the extracts to inhibit proliferation of Caco2 and HeLa cancer cell lines. The high antioxidant methanolic and aqueous extracts were potent inhibitors of cell proliferation, with IC 50 values 120-1400 µg/mL. The aqueous T. sericea leaf extract was particularly effective, with IC 50 values of 528 and 120 µg/mL against Caco2 and HeLa cells respectively. The methanolic extract also displayed good, albeit substantially less potent, antiproliferative activity against HeLa cells, with an IC 50 of 1358 µg/mL. In contrast, the lower antioxidant content extracts generally did not inhibit cancer cell proliferation. Cell imaging studies detected morphological features consistent with apoptosis in Caco2 cells exposed to sub-lethal concentrations of the methanolic and aqueous T. sericea leaf extracts, indicating that these extracts are functioning by cytotoxic mechanisms. The aqueous T. sericea leaf extract displayed low to moderate toxicity in the Artemia franciscana bioassay, with an LC 50 value of 737 µg/mL. All other extracts were nontoxic. Conclusion: The antiproliferative activity and low toxicity of the T. sericea methanolic and aqueous leaf extracts extracts against HeLa and Caco2 cancer cell lines indicates their potential in the treatment and prevention of some cancers.

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“…Thus, although many plant species have very high antioxidant contents, it is possible that the individual components may act as either antioxidants or as oxidants and thus may also be effective in the treatment of cancer, as well as in its prevention at different concentrations. Similar pro-oxidant effects have been reported for other antioxidant phytochemicals including flavonoids 10 and tannins. 11 The pro-oxidant/antioxidant effect of plant extracts is due to a balance between the free radical scavenging activities and reducing power of their phytochemical components.…”

Section: Introductionsupporting

confidence: 81%

Acai, cacao and maca extracts: Anticancer activity and growth inhibition of microbial triggers of selected autoimmune inflammatory diseases

Wang¹,

Zhang²,

Cock³

2016

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Background: The consumption of high antioxidant foods has been linked with a decreased incidence of some cancers and inflammatory diseases. Some high antioxidant foods also inhibit the growth of a variety of bacterial pathogens. Despite this, the high antioxidant 'superfoods' acai, cacao and maca are yet to be adequately tested for anticancer activity or the ability to inhibit the growth of bacterial triggers of autoimmune inflammatory diseases. Materials and Methods: Freeze dried acai, cacao and maca powders were extracted and tested for antimicrobial activity using a modified disc diffusion assay and the MICs were determined. Inhibitory activity against CaCo2 and HeLa cancer cell lines was evaluated using colorimetric cell proliferation assays. Toxicity was evaluated using an Artemia franciscana nauplii bioassay. Results: The acai, cacao and maca extracts displayed broad spectrum antibacterial activity, inhibiting the growth of all of the bacteria screened, although generally with only low efficacy. The ethyl acetate extracts were more potent bacterial growth inhibitors than were the corresponding methanolic and aqueous extracts. The inhibitory activity of the acai and maca ethyl acetate extracts against P. mirabilis was particularly noteworthy, with MIC values <1000 µg/mL. The aqueous and methanolic extracts of all fruits had only low bacterial growth inhibitory activity. In contrast, the aqueous extracts of cacao and maca were the most effective at inhibiting proliferation of the colorectal cancer cell line CaCo2 (aqueous maca extract IC 50 =1800 µg/mL) and HeLa cervical cancer cell growth, (aqueous cacao extract IC 50 values 1810 µg/mL). All extracts were non-toxic, with LC 50 values substantially > 1000 µg/mL. Conclusion: These studies demonstrate that the aqueous cacao and maca extracts have appreciable inhibitory activity against some cancer cell lines and that the acai and maca ethyl acetate extracts were moderate inhibitors of the growth of bacteria associated with selected autoimmune inflammatory disorders. Furthermore, the toxicity studies indicate that they are safe for therapeutic usage. All other extracts were inactive or of low activity towards the cancer and bacterial cells.

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Complexes involving quercetin, DNA and Cu(II)

Cited by 112 publications

References 0 publications

Problems of Reproducibility and Efficacy of Bioassays Using Crude Extracts, with reference to Aloe vera

Problems of Reproducibility and Efficacy of Bioassays Using Crude Extracts, with reference to Aloe vera

Anti-Proliferative Properties of Terminalia sericea Burch. Ex Dc Leaf Extracts Against Caco2 and HeLa Cancer Cell Lines

Acai, cacao and maca extracts: Anticancer activity and growth inhibition of microbial triggers of selected autoimmune inflammatory diseases

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