Ethanol and aloe emodin alter the p53 mutational spectrum in ultraviolet radiation-induced murine skin tumors

Aloe veraat the frontier of glycobiology and integrative medicine: Health implications of an ancient plant

Aloe vera plant extracts are ubiquitous in foods, cosmetics, and medicine. Like all plants, these extracts contain an array of potential bioactives or glycans, which may contribute to health when applied or consumed. In the Aloe vera plant, these bioactives are dominated by acemannan, a type of carbohydrate, and related complexes of saccharides, proteins, and lipids. Clinical data suggest aloe extracts may be beneficial in the management of cutaneous and some systemic conditions, such as some forms of immune dysfunction, atherogenesis, malignancy, and numerous cell functions. These extracts also contain an entourage of bioactive substances that may be allergenic and potentially toxic as well as salutary. These substances include aloin and a variety of anthracenes. The concentrations of potential allergens, aloin, and related compounds are markedly reduced through controlled decolorization processes that are utilized by leading Aloe products manufacturers. The entourage effects of contemporary Aloe vera when consumed or applied topically represent opportunities for clinical investigation which may be applied to commercial consumer products and therapeutic indications. Future research should fully explore the range of bioactive glycan components and their respective safety and efficacy. The history and ongoing popularity of Aloe vera products represent a pragmatic mandate for well-designed investigation into the diverse functional roles of glycans.

p53 pathway determines the cellular response to alcohol-induced DNA damage in MCF-7 breast cancer cells

Alcohol consumption is associated with increased breast cancer risk; however, the underlying mechanisms that contribute to mammary tumor initiation and progression are unclear. Alcohol is known to induce oxidative stress and DNA damage; likewise, p53 is a critical modulator of the DNA repair pathway and ensures genomic integrity. p53 mutations are frequently detected in breast and other tumors. The impact of alcohol on p53 is recognized, yet the role of p53 in alcohol-induced mammary carcinogenesis remains poorly defined. In our study, we measured alcohol-mediated oxidative DNA damage in MCF-7 cells using 8-OHdG and p-H2AX foci formation assays. p53 activity and target gene expression after alcohol exposure were determined using p53 luciferase reporter assay, qPCR, and Western blotting. A mechanistic study delineating the role of p53 in DNA damage response and cell cycle arrest was based on isogenic MCF-7 cells stably transfected with control (MCF-7/Con) or p53-targeting siRNA (MCF-7/sip53), and MCF-7 cells that were pretreated with Nutlin-3 (Mdm2 inhibitor) to stabilize p53. Alcohol treatment resulted in significant DNA damage in MCF-7 cells, as indicated by increased levels of 8-OHdG and p-H2AX foci number. A p53-dependent signaling cascade was stimulated by alcohol-induced DNA damage. Moderate to high concentrations of alcohol (0.1-0.8% v/v) induced p53 activation, as indicated by increased p53 phosphorylation, reporter gene activity, and p21/Bax gene expression, which led to G0/G1 cell cycle arrest. Importantly, compared to MCF-7/Con cells, alcohol-induced DNA damage was significantly enhanced, while alcohol-induced p21/Bax expression and cell cycle arrest were attenuated in MCF-7/sip53 cells. In contrast, inhibition of p53 degradation via Nutlin-3 reinforced G0/G1 cell cycle arrest in MCF-7 control cells. Our study suggests that functional p53 plays a critical role in cellular responses to alcohol-induced DNA damage, which protects the cells from DNA damage associated with breast cancer risk.

Alcohol consumption and risk of cutaneous basal cell carcinoma in women and men: 3 prospective cohort studies

BACKGROUND

Alcohol consumption has been associated with an increased prevalence of sunburn, which is an established skin cancer risk factor.

OBJECTIVE

We investigated whether alcohol consumption is associated with risk of cutaneous basal cell carcinoma (BCC).

DESIGN

We conducted a prospective analysis on alcohol consumption and risk of BCC on the basis of data from 167,765 women in the NHS (Nurses' Health Study) (1984-2010) and NHS II (1991-2011) and 43,697 men in the Health Professionals Follow-Up Study (1986-2010). Alcohol intake was repeatedly assessed every 2-4 y over the follow-up period. HRs and 95% CIs for BCC in association with alcohol intake were computed with the use of Cox proportional hazards models with adjustment for sun exposure and other skin cancer risk factors.

RESULTS

A total of 28,951 incident BCC cases were documented over 3.74 million person-years of follow-up. Increased alcohol intake was associated with increased BCC risk in both women and men (both P-trend < 0.0001). Pooled multivariable-adjusted HRs over increasing cumulative averaged alcohol intake categories were 1.00 (reference) for nondrinkers, 1.13 (95% CI: 1.06, 1.20) for 0.1-9.9 g/d, 1.24 (95% CI: 1.14, 1.35) for 10.0-19.9 g/d, 1.27 (95% CI: 1.20, 1.35) for 20.0-29.9 g/d, and 1.22 (95% CI: 1.15, 1.30) for ≥30.0 g/d (P-trend < 0.0001, P-heterogeneity by study = 0.10 ). The association remained consistent when we used alcohol intakes over different latency periods (0-4, 4-8, 8-12, and 12-16 y) as exposures and over categories of sun exposure-related factors. In the individual alcoholic beverages, white wine and liquor were positively associated with BCC risk.

CONCLUSION

Alcohol consumption is associated with increased risk of cutaneous BCC in both women and men.

Potential antineoplastic effects of Aloe-emodin: a comprehensive review

Aloe-emodin (AE), a bioactive anthraquinone derived from both Aloe vera and Rheum officinale, has recently been demonstrated to have various pharmacological activities. With the widespread popularity of natural products, such as antineoplastic drugs, AE has attracted much attention due to its remarkable antineoplastic activity on multiple tumor cells involving multi-channel mechanisms, including the disruption of cell cycle, induction of apoptosis, anti-metastasis, antiangiogenic, and strengthening of immune function. Experimental data have revealed AE as a potentially potent anti-cancer candidate. Despite this, the pharmaceutical application of AE is still in a fledging period as most research has concentrated on the elucidation of the molecular mechanism of action of existing treatments, rather than the development of novel formulations. Therefore, the present review summarizes the potential toxicity, molecular mechanism, pharmacokinetic characteristics, and pharmaceutical development of AE as an antineoplastic agent. This is based on its physicochemical properties, in an attempt to encourage further research on AE as a potential anti-cancer agent.

Safety evaluation of topical applications of ethanol on the skin and inside the oral cavity

Ethanol is widely used in all kinds of products with direct exposure to the human skin (e.g. medicinal products like hand disinfectants in occupational settings, cosmetics like hairsprays or mouthwashes, pharmaceutical preparations, and many household products). Contradictory evidence about the safety of such topical applications of the alcohol can be found in the scientific literature, yet an up-to-date risk assessment of ethanol application on the skin and inside the oral cavity is currently lacking.The first and foremost concerns of topical ethanol applications for public health are its carcinogenic effects, as there is unambiguous evidence for the carcinogenicity of ethanol orally consumed in the form of alcoholic beverages. So far there is a lack of evidence to associate topical ethanol use with an increased risk of skin cancer. Limited and conflicting epidemiological evidence is available on the link between the use of ethanol in the oral cavity in the form of mouthwashes or mouthrinses and oral cancer. Some studies pointed to an increased risk of oral cancer due to locally produced acetaldehyde, operating via a similar mechanism to that found after alcoholic beverage ingestion.In addition, topically applied ethanol acts as a skin penetration enhancer and may facilitate the transdermal absorption of xenobiotics (e.g. carcinogenic contaminants in cosmetic formulations). Ethanol use is associated with skin irritation or contact dermatitis, especially in humans with an aldehyde dehydrogenase (ALDH) deficiency.After regular application of ethanol on the skin (e.g. in the form of hand disinfectants) relatively low but measurable blood concentrations of ethanol and its metabolite acetaldehyde may occur, which are, however, below acute toxic levels. Only in children, especially through lacerated skin, can percutaneous toxicity occur.As there might be industry bias in many studies about the safety of topical ethanol applications, as well as a general lack of scientific research on the long-term effects, there is a requirement for independent studies on this topic. The research focus should be set on the chronic toxic effects of ethanol and acetaldehyde at the point of impact, with special regard to children and individuals with genetic deficiencies in ethanol metabolism.

Anti-cancer properties of anthraquinones from rhubarb

Rhubarb has been used as a traditional Chinese medicine since ancient times and today it is still present in various herbal preparations. In this review the toxicological and anti-neoplastic potentials of the main anthraquinones from Rhubarb, Rheum palmatum, will be highlighted. It is interesting to note that although the chemical structures of various anthraquinones in this plant are similar, their bioactivities are rather different. The most abundant anthraquinone of rhubarb, emodin, was capable of inhibiting cellular proliferation, induction of apoptosis, and prevention of metastasis. These capabilities are reported to act through tyrosine kinases, phosphoinositol 3-kinase (PI3K), protein kinase C (PKC), NF-kappa B (NF-kappaB), and mitogen-activated protein kinase (MAPK) signaling cascades. Aloe-emodin is another major component in rhubarb found to have anti-tumor properties. Its anti-proliferative property has been demonstrated to be through the p53 and its downstream p21 pathway. Our recent proteomic study also suggests that the molecular targets of these two anthraquinones are different. However, both components were found to be able to potentiate the anti-proliferation of various chemotherapeutic agents. Rhein is the other major rhubarb anthraquinone, although less well studied. This compound could effectively inhibit the uptake of glucose in tumor cells, caused changes in membrane-associated functions and led to cell death. Interestingly, all three major rhubarb anthraquinones were reported to have in vitro phototoxic. This re-evaluation of an old remedy suggests that several bioactive anthraquinones of rhubarb possess promising anti-cancer properties and could have a broad therapeutic potential.

An evaluation of the biological and toxicological properties of Aloe barbadensis (miller), Aloe vera

Aloe barbadensis (Miller), Aloe vera, has a long history of use as a topical and oral therapeutic. The plant is the source of two products, gel and latex, which are obtained from its fleshy leaves. Aloe vera products contain multiple constituents with potential biological and toxicological activities, yet the active components elude definition. Ingestion of Aloe vera is associated with diarrhea, electrolyte imbalance, kidney dysfunction, and conventional drug interactions; episodes of contact dermatitis, erythema, and phototoxicity have been reported from topical applications. This review examines the botany, physical and chemical properties, and biological activities of the Aloe vera plant.