Black Raspberry Extract Enhances Glutathione Conjugation of the Fjord-Region Diol Epoxide Derived from the Tobacco Carcinogen Dibenzo[def,p]chrysene in Human Oral Cells

Explainable no-code OECD-compliant machine learning models to predict the mutagenic activity of polycyclic aromatic hydrocarbons and their radical cation metabolites

Polycyclic aromatic hydrocarbons (PAHs) are persistent pollutants with well-known genotoxic and mutagenic effects, posing risks to ecosystems and human health. Their hydrophobic nature promotes accumulation in soils and aquatic environments, increasing exposure risks. Upon metabolic activation, PAHs generate reactive species that form DNA adducts, driving their mutagenic potential. This study presents an OECD-compliant methodology that integrates conceptual density functional theory (CDFT) calculations at the GFN2-xTB level with machine learning models to predict PAH mutagenicity. Using quantum chemical descriptors of procarcinogens and radical cation metabolites alongside Ames test data, key electronic properties linked to mutagenicity were identified. Feature selection consistently highlighted radical cation descriptors as key indicators of metabolic activation pathways. Machine learning models - including SPAARC, Random Tree, and JCHAID - achieved validation accuracies exceeding 89 %, with minimal false-negative rates, ensuring conservative predictions for environmental risk assessment. The PSL and CDP electrophilicity frameworks proved particularly effective in modeling DNA damage-related processes. This no-code, freeware-based methodology provides a scalable and cost-effective tool for assessing mutagenic risks in environmentally relevant conditions. The findings reinforce the importance of metabolic activation, validate the radical cation as a reliable proxy for this process, and demonstrate the predictive value of electronic properties in QSAR modeling. These insights support advances in environmental toxicology and contribute to improved strategies for regulatory risk assessment.

Inhibition of benzo[a]pyrene-induced DNA adduct in buccal cells of smokers by black raspberry lozenges

Using LC-MS/MS analysis we previously showed for the first time (Carcinogenesis 43:746-753, 2022) that levels of DNA damage induced by benzo[a]pyrene (B[a]P), an oral carcinogen and tobacco smoke (TS) constituent, were significantly higher in buccal cells of smokers than those in nonsmokers; these results suggest the potential contribution of B[a]P in the development of oral squamous cell carcinoma (OSCC) in humans. Treating cancers, including OSCC, at late stages, even with improved targeted therapies, continues to be a major challenge. Thus interception/prevention remains a preferable approach for OSCC management and control. In previous preclinical studies, we and others demonstrated the protective effects of black raspberry (BRB) against carcinogen-induced DNA damage and OSCC. Thus, to translate preclinical findings, we tested the hypothesis in a Phase 0 clinical study that BRB administration reduces DNA damage induced by B[a]P in the buccal cells of smokers. After enrolling 27 smokers, baseline buccal cells were collected before the administration of BRB lozenges (5/day for 8 weeks, 1 gm BRB powder/lozenge) at baseline, at the middle and the end of BRB administration. The last samples were collected 4 weeks after BRB cessation (washout period). B[a]P-induced DNA damage (BPDE-N2-dG) was evaluated by LC-MS/MS. BRB administration resulted in a significant reduction in DNA damage: 26.3% at the midpoint (P = .01506) compared to baseline, 36.1% at the end of BRB administration (P = .00355), and 16.6% after BRB cessation (P = .007586). Our results suggest the potential benefits of BRB as a chemopreventive agent against the development of TS-initiated OSCC.

The Effects of Black Raspberry as a Whole Food-Based Approach on Biomarkers of Oxidative Stress in Buccal Cells and Urine of Smokers

Cigarette smoke is a rich source of free radicals that can promote oxidative stress and carcinogenesis, including head and neck squamous cell carcinoma (HNSCC) development; importantly, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-iso-prostaglandin F2α (8-isoprostane) are biomarkers of oxidative stress. Several mechanisms, including the antioxidant properties of black raspberry (BRB), account for their chemopreventive effects. In the present clinical trial, we tested the hypothesis that BRB administration reduces biomarkers levels of oxidative stress in buccal cells and urine of smokers. One week after enrolling 21 smokers, baseline buccal cells and urine samples were collected before the administration of BRB lozenges for 8 weeks (5/day, 1 gm BRB/lozenge). Buccal cells and urine samples were collected at the middle and the end of BRB administration. The last samples were collected after the BRB cessation (washout period). We analyzed levels of 8-oxodG and 8-isoprostane (LC/MS-MS), urinary cotinine (ELISA), and creatinine (spectrophotometry). BRB significantly reduced the levels of 8-oxodG by 17.08% (P = 0.00079) in buccal cells and 12.44% (P = 0.034) in urine at the middle of BRB administration as compared with baseline; the corresponding values at the end of BRB administration were 16.46% (P = 0.026) in buccal cells and 25.72% (P = 0.202) in urine. BRB had no significant effect on the levels of urinary 8-isoprostane. BRB's capacity to inhibit 8-oxodG formation of smokers' buccal cells and urine is clearly evident and the reduction in 8-oxodG suggests that antioxidant abilities are central to BRB's HNSCC chemopreventive properties.

PREVENTION RELEVANCE

Cigarette smoke contains highly active components namely free radicals that can promote oxidative stress and oral cancer. We found that black raspberry (BRB) inhibited the formation of oxidative stress markers in the oral cavity and urine of smokers suggesting the antioxidant abilities of BRB in preventing oral cancer.

Rubus Occidentalis and its bioactive compounds against cancer: From molecular mechanisms to translational advances

BACKGROUND

Cancer ranks as the second leading cause of death globally, imposing a significant public health burden. The rise in cancer resistance to current therapeutic agents underscores the potential role of phytotherapy. Black raspberry (BRB, Rubus Occidentalis) is a fruit rich in anthocyanins, ellagic acid, and ellagitannins. Accumulating evidence suggests that BRB exhibits promising anticancer effects, positioning it as a viable candidate for phytotherapy.

PURPOSE

This article aims to review the existing research on BRB regarding its role in cancer prevention and treatment. It further analyzes the effective components of BRB, their metabolic pathways, and the potential mechanisms underlying the fruit's anticancer effects.

METHODS

Ovid MEDLINE, EMBASE, Web of Science, and CENTRAL were searched through the terms of Black Raspberry, Raspberry, and Rubus Occidentali up to January 2023. Two reviewers performed the study selection by screening the title and abstract. Full texts of potentially eligible studies were retrieved to access the details.

RESULTS

Out of the 767 articles assessed, 73 papers met the inclusion criteria. Among them, 63 papers investigated the anticancer mechanisms, while 10 conducted clinical trials focusing on cancer treatment or prevention. BRB was found to influence multiple cancer hallmarks by targeting various pathways. Decomposition of free radicals and regulation of estrogen metabolism, BRB can reduce DNA damage caused by reactive oxygen species. BRB can also enhance the function of nucleotide excision repair to repair DNA lesions. Through regulation of epigenetics, BRB can enhance the expression of tumor suppressor genes, inducing cell cycle arrest, and promoting apoptosis and pyroptosis. BRB can reduce the energy and nutrients supply to the cancer nest by inhibiting glycolysis and reducing angiogenesis. The immune and inflammatory microenvironment surrounding cancer cells can also be ameliorated by BRB, inhibiting cancer initiation and progression. However, the limited bioavailability of BRB diminishes its anticancer efficacy. Notably, topical applications of BRB, such as gels and suppositories, have demonstrated significant clinical benefits.

CONCLUSION

BRB inhibits cancer initiation, progression, and metastasis through diverse anticancer mechanisms while exhibiting minimal side effects. Given its potential, BRB emerges as a promising phototherapeutic agent for cancer treatment.