Protective Effects of Pinus halepensis Bark Extract and Nicotine on Cigarette Smoke-induced Oxidative Stress in Keratinocytes

The protective effects of medicinal plants against cigarette smoking: A comprehensive review

BACKGROUNDS

Cigarette smoking remains a pervasive and harmful habit, and it poses a significant public health concern globally. Tobacco smoke contains numerous toxicants and carcinogens that contribute to the incidence of various diseases, including respiratory ailments, cancer, and cardiovascular disorders. Over the past decade, there has been a growing interest in exploring natural remedies to mitigate the harmful effects of cigarette smoke (CS). Medicinal plants, with their rich phytochemical compositions, have emerged as potential sources of protective agents against CS-induced damage.

OBJECTIVES

The current review attempts to comprehensively review and provide a thorough analysis of the protective effects of medicinal plants, including ginseng, Aloe vera, Olea europaea, Zea mays, green tea, etc. against CS-related toxicities.

MATERIALS AND METHODS

A comprehensive research and compilation of existing literature were conducted. We conducted a literature search using the Web of Science, PubMed, Scopus, and Google Scholar. We selected articles published in English between 1987 and 2025. The search was performed using keywords including cigarette smoking, cigarette smokers, second-hand smokers, natural compounds, plant extracts, naturally derived products, natural resources, phytochemicals, and medicinal plants.

RESULTS

This review critically investigated recent literature focusing on the effects of medicinal plant extracts, essential oils, and isolated compounds on reducing the adverse consequences of CS exposure. These investigations encompassed several in vivo, in vitro, and clinical trials, clarifying the mechanisms underlying the protective effects of these plants. The notable antioxidant, anti-inflammatory, and detoxifying properties of these botanical interventions were also highlighted.

CONCLUSION

Collectively, this review emphasizes the potential of medicinal plants in alleviating the harmful effects of CS. The rich active constituents present in these plants offer various mechanisms that counteract oxidative stress, inflammation, and carcinogenesis induced by CS exposure. Further research is warranted to reveal the precise molecular mechanisms, derive dosing recommendations, and explore the efficacy of botanical interventions in large-scale clinical trials, ultimately improving public health outcomes and providing valuable insights for the smoking population worldwide.

Cigarette smoke extract induces ferroptosis in human retinal pigment epithelial cells

Background

Age-related macular degeneration (AMD) is a common blindness diseases. Retinal pigment epithelium (RPE) dysfunction due to smoking is an essential environmental factor in the pathogenesis of AMD. Ferroptosis is a novel type of iron-dependent programmed cell death (PCD). However, the relationship between cigarette smoke extract (CSE)-induced RPE damage and ferroptosis remains unclear.

Methods

In our study, we extracted CSE using a modified device to explore the optimal concentration of CSE, and observed the expression of proteins and molecules after CSE exposure for ARPE-19 cells by protein immunoblotting and assay kits for iron ions and mitochondrial membrane potential (MMP). At the same time, CSE was injected into the vitreous cavity of mice with a microsyringe for AMD modeling to observe the morphology of the retina-RPE-choroid complex and the differences expression of proteins. In addition, the protective effects of ferroptosis inhibitors on CSE-induced RPE cell damage were also investigated by in vivo and in vitro experiments.

Results

In this study, we observed that CSE induced cellular damage in a human retinal pigment epithelial cell line (ARPE-19), resulting in ferrous ion (Fe2+) accumulation, an increas in reactive oxygen species (ROS) and lipid peroxidation (LP), a reduction in GSH levels, and the inhibition of Gpx4 expression. In addition, transmission electron microscopy (TEM) of in vivo and in vitro samples showed that after exposure to CSE, the mitochondria of RPE cells were wrinkled, the membrane density was increased, and the number of cristae decreased or cristae were not observed.

Conclusions

The results of this study indicate that the ferroptosis inhibitors ferrostatin-1 (Fer-1) and liproxstatin-1 (Lip-1) protect RPE cells from CSE-induced ferroptosis, and this evidence paves the way for AMD studies.

Assessment of natural antioxidants' effect on PDT cytotoxicity through fluorescence microscopy image analysis

BACKGROUND AND OBJECTIVES

Photodynamic therapy (PDT) is a cancer treatment modality mediated by reactive oxygen species (ROS). However, the intracellular antioxidant defense system antagonizes PDT-generated ROS, impeding PDT efficacy. This study aimed to evaluate the enhancement of PDT cytotoxicity by its combination with natural antioxidants in pro-oxidant concentrations.

METHODS

A rich natural antioxidant mixture originating from Pinus halepensis bark extract was studied for its potential to enhance the efficacy of m-tetrahydroxyphenylchlorin (m-THPC)-PDT on LNCaP prostate cancer cells, in vitro. Various P. halepensis concentrations, at two different incubation times, were used in combination with m-THPC-PDT. Assessment of cellular viability and intracellular ROS levels evaluated the treatments' outcome. A novel method was developed for the assessment of the intracellular ROS levels, based on image analysis and data extraction from fluorescence microscopy images.

RESULTS

P. halepensis bark extract increased the intracellular ROS levels in a concentration-dependent but not in an incubation-dependent manner. The higher concentrations used (≥50 μg/ml) reduced cellular viability even by 50%. One hour pretreatment with 30 μg/ml P. halepensis before m-THPC-PDT exceeded the levels of cellular death by approximately 15%.

CONCLUSIONS

The results provided evidence of the cytotoxic effect of P. halepensis bark extract on LNCaP cells, showing the potential of P. halepensis to be used as an anticancer agent in prostate cancer treatment. The results also provided evidence of enhancement of m-THPC-PDT by P. halepensis bark extract showed the potential to be used as a supplementary agent to improve prostate cancer PDT treatment.

Pinus thunbergii bark extract rich in flavonoids promotes hair growth in dorsal skin by regulating inflammatory cytokines and increasing growth factors in mice

Korean maritime pine bark (Pinus thunbergii) has been used as an alternative medicine due to its beneficial properties, including anti-inflammatory effects. To date, the anti-inflammatory and hair growth-promoting effects of Pinus densiflora bark extract have remained elusive. Therefore, in the present study, Pinus thunbergii bark was extracted with pure water (100°C) and the extract was examined to determine its polyphenol and flavonoid content. C57BL/6 mice were used to assess the effects of the extract to promote hair growth. The extract (1, 2 and 4%) was topically applied onto shaved dorsal skin and hair growth was observed for 17 days. A significant increase in hair growth was observed with 2 and 4% extract. Based on this finding, the optimal dose of the extract for effective hair growth promotion was determined to be 2%. The mechanisms of hair growth promotion were investigated via immunohistochemical analysis of changes in inflammatory cytokines and growth factors in the hair follicles following treatment with 2% extract. The treatment reduced the levels of TNF-α and IL-1β, which are pro-inflammatory cytokines, while it enhanced the levels of IL-4 and IL-13, which are anti-inflammatory cytokines, in the hair follicles. In addition, elevated insulin-like growth factor I and vascular epidermal growth factor were detected in hair follicles following treatment. Based on these findings, it was suggested that the extract of Pinus thunbergii bark may be utilized for hair loss prevention and/or hair growth promotion.