Profiling oxidative DNA damage: effects of antioxidants

The Southern European Atlantic Diet and Its Supplements: The Chemical Bases of Its Anticancer Properties

Scientific evidence increasingly supports the strong link between diet and health, acknowledging that a well-balanced diet plays a crucial role in preventing chronic diseases such as obesity, diabetes, cardiovascular issues, and certain types of cancer. This perspective opens the door to developing precision diets, particularly tailored for individuals at risk of developing cancer. It encompasses a vast research area and involves the study of an expanding array of compounds with multilevel "omics" compositions, including genomics, transcriptomics, proteomics, epigenomics, miRNomics, and metabolomics. We review here the components of the Southern European Atlantic Diet (SEAD) from both a chemical and pharmacological standpoint. The information sources consulted, complemented by crystallographic data from the Protein Data Bank, establish a direct link between the SEAD and its anticancer properties. The data collected strongly suggest that SEAD offers an exceptionally healthy profile, particularly due to the presence of beneficial biomolecules in its foods. The inclusion of olive oil and paprika in this diet provides numerous health benefits, and scientific evidence supports the anticancer properties of dietary supplements with biomolecules sourced from vegetables of the brassica genus. Nonetheless, further research is warranted in this field to gain deeper insights into the potential benefits of the SEAD's bioactive compounds against cancer.

Elucidation of chemical profiles and molecular targets of Mondia whitei leave fractions bioactive as novel therapeutics: an in vitro and in silico assay

BACKGROUND

Mondia whitei root is often used in Africa as a local therapeutic agent for libido enhancement. The fractions of the M. whitei leaves (MWL) lack chemical characterization of their bioactive components and possible molecular targets. We characterized and investigated its molecular target as therapeutic agents in an in vitro and in silico assay. Mineral compositions, antioxidant, and GC-MS characterization were studied. The cytotoxicity effect was measured on HeLa and HT-29 cells by MTT assay. In silico potential inhibitors of Cathepsin B (CathB) as a cancer biomarker were determined.

RESULTS

The flame photometry produced marked Na⁺ and K⁺. GC-MS revealed eighteen bioactive components. The fractions (chloroformic 47.00, ethanolic 45.52, and aqueous 40.13) of MWL caused a higher inhibition ratio compared to standards. The MWL showed a significant cytotoxic effect on the treated cell lines at concentrations of 150 and 200 μg/ml and 100, 150, and 200 μg/ml for HT-29 and HeLa cells, respectively. Ten bioactives (MWL 4, 5, 6, 8, 9, 10, 14, 15, 17, and 18) showed potential inhibition of CathB with binding affinities of -4.40 to -8.3 Kcal/Mol. However, MWL 4, 9, 14, and 17 which have higher binding affinities (-6.7, -7.1, -8.2, and -8.3, respectively) than the standard inhibitor (-6.5) were the lead molecules.

CONCLUSION

These chemical profiles and potential molecular targets unraveled in this study propose that MWL has a promising anticancer activity.

Occurrence, Biological Consequences, and Human Health Relevance of Oxidative Stress-Induced DNA Damage

A variety of endogenous and exogenous agents can induce DNA damage and lead to genomic instability. Reactive oxygen species (ROS), an important class of DNA damaging agents, are constantly generated in cells as a consequence of endogenous metabolism, infection/inflammation, and/or exposure to environmental toxicants. A wide array of DNA lesions can be induced by ROS directly, including single-nucleobase lesions, tandem lesions, and hypochlorous acid (HOCl)/hypobromous acid (HOBr)-derived DNA adducts. ROS can also lead to lipid peroxidation, whose byproducts can also react with DNA to produce exocyclic DNA lesions. A combination of bioanalytical chemistry, synthetic organic chemistry, and molecular biology approaches have provided significant insights into the occurrence, repair, and biological consequences of oxidatively induced DNA lesions. The involvement of these lesions in the etiology of human diseases and aging was also investigated in the past several decades, suggesting that the oxidatively induced DNA adducts, especially bulky DNA lesions, may serve as biomarkers for exploring the role of oxidative stress in human diseases. The continuing development and improvement of LC-MS/MS coupled with the stable isotope-dilution method for DNA adduct quantification will further promote research about the clinical implications and diagnostic applications of oxidatively induced DNA adducts.

Phytoagents for cancer management: regulation of nucleic acid oxidation, ROS, and related mechanisms

Accumulation of oxidized nucleic acids causes genomic instability leading to senescence, apoptosis, and tumorigenesis. Phytoagents are known to reduce the risk of cancer development; whether such effects are through regulating the extent of nucleic acid oxidation remains unclear. Here, we outlined the role of reactive oxygen species in nucleic acid oxidation as a driving force in cancer progression. The consequential relationship between genome instability and cancer progression highlights the importance of modulation of cellular redox level in cancer management. Current epidemiological and experimental evidence demonstrate the effects and modes of action of phytoagents in nucleic acid oxidation and provide rationales for the use of phytoagents as chemopreventive or therapeutic agents. Vitamins and various phytoagents antagonize carcinogen-triggered oxidative stress by scavenging free radicals and/or activating endogenous defence systems such as Nrf2-regulated antioxidant genes or pathways. Moreover, metal ion chelation by phytoagents helps to attenuate oxidative DNA damage caused by transition metal ions. Besides, the prooxidant effects of some phytoagents pose selective cytotoxicity on cancer cells and shed light on a new strategy of cancer therapy. The “double-edged sword” role of phytoagents as redox regulators in nucleic acid oxidation and their possible roles in cancer prevention or therapy are discussed in this review.

Phytochemical analysis and free radical scavenging activity of medicinal plants Gnidia glauca and Dioscorea bulbifera

Gnidia glauca and Dioscorea bulbifera are traditional medicinal plants that can be considered as sources of natural antioxidants. Herein we report the phytochemical analysis and free radical scavenging activity of their sequential extracts. Phenolic and flavonoid content were determined. Scavenging activity was checked against pulse radiolysis generated ABTS^•+ and OH radical, in addition to DPPH, superoxide and hydroxyl radicals by biochemical methods followed by principal component analysis. G. glauca leaf extracts were rich in phenolic and flavonoid content. Ethyl acetate extract of D. bulbifera bulbs and methanol extract of G. glauca stem exhibited excellent scavenging of pulse radiolysis generated ABTS^•+ radical with a second order rate constant of 2.33×10⁶ and 1.72×10⁶, respectively. Similarly, methanol extract of G. glauca flower and ethyl acetate extract of D. bulbifera bulb with second order rate constants of 4.48×10⁶ and 4.46×10⁶ were found to be potent scavengers of pulse radiolysis generated OH radical. G. glauca leaf and stem showed excellent reducing activity and free radical scavenging activity. HPTLC fingerprinting, carried out in mobile phase, chloroform: toluene: ethanol (4: 4: 1, v/v) showed presence of florescent compound at 366 nm as well as UV active compound at 254 nm. GC-TOF-MS analysis revealed the predominance of diphenyl sulfone as major compound in G. glauca. Significant levels of n-hexadecanoic acid and octadecanoic acid were also present. Diosgenin (C₂₇H₄₂O₃) and diosgenin (3á,25R) acetate were present as major phytoconstituents in the extracts of D. bulbifera. G. glauca and D. bulbifera contain significant amounts of phytochemicals with antioxidative properties that can be exploited as a potential source for herbal remedy for oxidative stress induced diseases. These results rationalize further investigation in the potential discovery of new natural bioactive principles from these two important medicinal plants.

Pyrimidine base damage is increased in women with BRCA mutations

Oxidatively-induced DNA damage was measured in the DNA of WBC from two groups of women: carriers of a BRCA mutation, but asymptomatic for disease, and healthy controls. Two oxidatively induced lesions were measured: a formamide remnant of pyrimidine base and the glycol modification of thymine. These lesions, employed previously in studies of the effects of smoking, antioxidant usage and ovarian cancer, are proving valuable indicators of oxidative stress. The BRCA carriers of mutations, with no overt sign of cancer, nevertheless had significantly higher levels of DNA damage than the controls. The level measured for the formamide lesion was 5.9 ± 1.0 (femtomoles/μg of DNA ± SEM) compared with 2.4 ± 0.3 in controls. The level of the glycol lesion was 2.9 ± 0.4 compared with 1.8 ± 0.2 in controls. The experimental design utilized DNA from WBC and employed LC-MS/MS to detect the lesions.

Profiling oxidative DNA damage: effects of antioxidants

The goal of this research was to determine whether antioxidant usage could be correlated with changes in DNA damage levels. Liquid Chromatography-tandem Mass Spectrometry (LC-MS/MS) was used to simultaneously measure five different oxidatively-induced base modifications in the DNA of WBC. Measurements of the five modifications were made before and after an 8-week trial during which participants took the SU.VI.MAX supplement. Levels of the five DNA modifications were compared among different groupings: users versus non-users of antioxidant supplements, before versus after the supplement intervention and men versus women. The statistical significance of differences between groups was most significant for pyrimidine base modifications and the observed trends reflect trends reported in epidemiological studies of antioxidant usage. A combination of modifications derived from pyrimidine bases is suggested as a superior indicator of oxidative stress.