α-Bisabolol improves 5-aminolevulinic acid retention in buccal tissues: Potential application in the photodynamic therapy of oral cancer

Assessing α-Bisabolol as a Transmucosal Permeation Enhancer of Buccal Local Anesthetics

Needle-free buccal anesthesia improves dental treatment outcomes for both patients and dentists. In this study, we report on an assessment of the enhancement effects of α-bisabolol on the in vitro transmucosal permeation of prilocaine hydrochloride (PCl) and lidocaine hydrochloride (LCl) from needleless buccal films. We also evaluated the mechanical properties of the film, which consisted of Methocel™ K100 LV as the film-forming polymer (3% m·m-1), PEG 400 as a cosolvent (15% m·m-1 based on drug loading), α-bisabolol (15 and 30% m·m-1 based on drug loading), and the drugs combined at a 1:1 ratio (15 mg·unit-1). The porcine esophageal epithelium was used as a membrane barrier, and artificial saliva was the release medium. After a 1 h experiment at 25 ± 2 °C, α-bisabolol significantly decreased, rather than enhanced, the permeation fluxes (five-fold), permeability coefficients (seven-fold), and retentions (two-fold) of both PCl and LCl through the epithelium, regardless of the concentration. Moreover, the resistance and flexibility of the films markedly decreased compared to those without α-bisabolol. Therefore, under the experimental conditions, using α-bisabolol as a buccal permeation enhancer for the hydrophilic local anesthetics PCl and LCl from buccal films is not feasible.

Effectiveness of photodynamic therapy on treatment response and survival in patients with recurrent oral squamous cell carcinoma: A systematic review

BACKGROUND

This systematic review assessed the effectiveness of photodynamic therapy (PDT) in patients with recurrent oral squamous cell carcinoma (OSCC).

METHODS

Clinical studies on recurrent OSCC treated with PDT alone were included. Combined treatment strategies were excluded. The search was performed on Medline/Pubmed, Cochrane Library, Embase, Web of Science and ClinicalTrials.gov, manual search, and grey literature.

RESULTS

The eleven included studies were observational. The risk of bias and methodological quality were evaluated using the Newcastle-Ottawa Quality Assessment Scale. The studies reported the use of hematoporphyrin derivative, PhotofrinⓇ, FoscanⓇ and 5-aminolevulinic acid. Data on treatment response and survival was collected. Secondarily, postoperative courses and patient's quality of life/acceptance were reported whenever available. PhotofrinⓇ and FoscanⓇ were the most used photosensitisers, with more complete responses. Lesions responding less favourably were on posterior regions or deep-seated in the tissue.

CONCLUSIONS

Although treatment response differs between treatment protocols, PDT stands as a viable treatment option to be considered, as it can achieve therapeutic results and disease-free, long-lasting periods. Partial treatment responses may be of interest when achieving eligibility for other treatment strategies. Despite this study's limitations, which considered four photosensitisers, PhotofrinⓇ was the most used but more recent photosensitisers like FoscanⓇ have greater chemical stability, tissue penetration, and may be more efficacious on recurrent OSCC.

Evaluation of the potential of Delta-aminolevulinic acid for simultaneous detection of bioburden and anti-microbial photodynamic therapy of MRSA infected wounds in Swiss albino mice

BACKGROUND

The dramatic increase of drug-resistant bacteria necessitates urgent development of platforms to simultaneously detect and inactivate bacteria causing wound infections, but are confronted with various challenges. Delta amino levulinic acid (ALA) induced protoporphyrin IX (PpIX) can be a promising modality for simultaneous bioburden diagnostics and therapeutics. Herein, we report utility of ALA induced protoporphyrin (PpIX) based simultaneous bioburden detection, photoinactivation and therapeutic outcome assessment in methicillin resistant Staphylococcus aureus (MRSA) infected wounds of mice.

METHODS

MRSA infected wounds treated with 10% ALA were imaged with help of a blue LED (∼405 nm) based, USB powered, hand held device integrated with a modular graphic user interface (GUI). Effect of ALA application time, bacteria load, post bacteria application time points on wound fluorescence studied. PpIX fluorescence observed after excitation with blue LEDs was used to detect bioburden, start red light mediated antimicrobial photodynamic therapy (aPDT), determine aPDT effectiveness and assess selectivity of the approach.

RESULTS

ALA-PpIX fluorescence of wound bed discriminates infected from uninfected wounds and detects clinically relevant load. While wound fluorescence pattern changes as a function of ALA incubation and post infection time, intra-wound inhomogeneity in fluorescence correlates with the Gram staining data on presence of biofilms foci. Lack of red fluorescence from wound granulation tissue treated with ALA suggests selectivity of the approach. Further, significant reduction (∼50%) in red fluorescence, quantified using the GUI, relates well with bacteria load reduction observed post topical aPDT.

CONCLUSION

The potential of ALA induced PpIX for simultaneous detection of bioburden, photodynamic inactivation and "florescence-guided aPDT assessment" is demonstrated in MRSA infected wounds of mice.

Bioactive phytocompounds for oral cancer prevention and treatment: A comprehensive and critical evaluation

The high incidence of oral cancer combined with excessive treatment cost underscores the need for novel oral cancer preventive and therapeutic options. The value of natural agents, including plant secondary metabolites (phytochemicals), in preventing carcinogenesis and representing expansive source of anticancer drugs have been established. While fragmentary research data are available on antioral cancer effects of phytochemicals, a comprehensive and critical evaluation of the potential of these agents for the prevention and intervention of human oral malignancies has not been conducted according to our knowledge. This study presents a complete and critical analysis of current preclinical and clinical results on the prevention and treatment of oral cancer using phytochemicals. Our in-depth analysis highlights anticancer effects of various phytochemicals, such as phenolics, terpenoids, alkaloids, and sulfur-containing compounds, against numerous oral cancer cells and/or in vivo oral cancer models by antiproliferative, proapoptotic, cell cycle-regulatory, antiinvasive, antiangiogenic, and antimetastatic effects. Bioactive phytochemicals exert their antineoplastic effects by modulating various signaling pathways, specifically involving the epidermal growth factor receptor, cytokine receptors, toll-like receptors, and tumor necrosis factor receptor and consequently alter the expression of downstream genes and proteins. Interestingly, phytochemicals demonstrate encouraging effects in clinical trials, such as reduction of oral lesion size, cell growth, pain score, and development of new lesions. While most phytochemicals displayed minimal toxicity, concerns with bioavailability may limit their clinical application. Future directions for research include more in-depth mechanistic in vivo studies, administration of phytochemicals using novel formulations, investigation of phytocompounds as adjuvants to conventional treatment, and randomized clinical trials.

Oral Mucosa Models to Evaluate Drug Permeability

Due to its numerous advantages, such as excellent drug accessibility, rapid absorption, and bypass of first-pass metabolism, the route of drug administration that involves crossing the oral mucosa is highly favored. As a result, there is significant interest in investigating the permeability of drugs through this region. The purpose of this review is to describe the various ex vivo and in vitro models used to study the permeability of conveyed and non-conveyed drugs through the oral mucosa, with a focus on the most effective models. Currently, there is a growing need for standardized models of this mucosa that can be used for developing new drug delivery systems. Oral Mucosa Equivalents (OMEs) may provide a promising future perspective as they are capable of overcoming limitations present in many existing models.

Pharmacological and biological effects of alpha-bisabolol: An updated review of the molecular mechanisms

Alpha-bisabolol (α-bisabolol), an unsaturated monocyclic sesquiterpene alcohol, is known as one of the "most-used herbal constituents" in the world. Various therapeutic and biological properties of α-bisabolol in preventing oxidative stress, inflammatory disorders, infections, neurodegenerative diseases, cancers, and metabolic disorders have been reported. In this review, we evaluated new findings regarding the molecular mechanisms of α-bisabolol published from 2010 until 2021 in PubMed, Science Direct, and Scopus. The antioxidant mechanism of α-bisabolol is mainly associated with the reduction of ROS/RNS, MDA, and GSH depletion, MPO activity, and augmentation of SOD and CAT. Additionally, upregulating the expression of bcl-2 and suppression of bax, P53, APAF-1, caspase-3, and caspase-9 activity indicates the anti-apoptotic effects of α- bisabolol. It possesses anti-inflammatory effects via reduction of TNF-α, IL-1β, IL-6, iNOS, and COX-2 and suppresses the activation of ERK1/2, JNK, NF-κB, and p38. The antimicrobial effect is mediated by inhibiting the viability of infected cells and improves cognitive function via downregulation of bax, cleaved caspases-3 and 9 levels, β-secretase, cholinesterase activities, and upregulation of bcl-2 levels. Finally, due to multiple biological activities, α-bisabolol is worthy to be subjected to clinical trials to achieve new insights into its beneficial effects on human health.

Effectiveness of photodynamic therapy on treatment response and survival of patients with recurrent oral squamous cell carcinoma: a systematic review protocol

OBJECTIVE

This review aims to systematically examine the effectiveness of photodynamic therapy for the treatment of patients with recurrent oral squamous cell carcinoma.

INTRODUCTION

Oral squamous cell carcinoma is a significant public health problem, and is the seventh most common cancer. Its incidence is mainly due to tobacco use, alcohol consumption, and HPV infection. The survival rates are poor due to diagnosis at advanced stages, with high recurrence rates. Although current evidence does not point to photodynamic therapy as a first-line option, this treatment might be suitable for treating recurrent stages of the cancer where conventional treatments were ineffective. Despite the potential of photodynamic therapy, there is a need to verify the scientific evidence to support its indication for the treatment of recurrent oral squamous cell carcinoma.

INCLUSION CRITERIA

This review will consider studies on any stage of recurrent oral squamous cell carcinoma treated with photodynamic therapy after receiving first-line conventional treatments. Patients of any age, gender, and geographic location will be included. The primary outcomes will be to evaluate response to treatment, focusing on remission, recurrence, change in size of the lesion, alleviation of symptoms, and survival. Secondary outcomes will be postoperative complications, presence of necrosis, patient quality of life after treatment, and patient satisfaction.

METHODS

Studies will be searched using a combination of index terms and keywords in MEDLINE, Cochrane Central, Web of Science, Embase, and ClinicalTrials.gov. No date limits will be applied. Articles written in English, French, Spanish, or Portuguese will be considered. Findings will be provided as a narrative synthesis, structured around the photodynamic therapy protocol used. A meta-analysis is planned and subgroup analysis will be conducted if possible. The certainty of findings will be assessed.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42020141075.

Anti-Cancer Potential of Cannabinoids, Terpenes, and Flavonoids Present in Cannabis

In recent years, and even more since its legalization in several jurisdictions, cannabis and the endocannabinoid system have received an increasing amount of interest related to their potential exploitation in clinical settings. Cannabinoids have been suggested and shown to be effective in the treatment of various conditions. In cancer, the endocannabinoid system is altered in numerous types of tumours and can relate to cancer prognosis and disease outcome. Additionally, cannabinoids display anticancer effects in several models by suppressing the proliferation, migration and/or invasion of cancer cells, as well as tumour angiogenesis. However, the therapeutic use of cannabinoids is currently limited to the treatment of symptoms and pain associated with chemotherapy, while their potential use as cytotoxic drugs in chemotherapy still requires validation in patients. Along with cannabinoids, cannabis contains several other compounds that have also been shown to exert anti-tumorigenic actions. The potential anti-cancer effects of cannabinoids, terpenes and flavonoids, present in cannabis, are explored in this literature review.

Possible involvement of Fas/FasL-dependent apoptotic pathway in α-bisabolol induced cardiotoxicity in zebrafish embryos

α-Bisabolol, an unsaturated monocyclic sesquiterpene alcohol, is a common ingredient in many pharmaceuticals and personal care products (PPCPs). Despite being widely used, little is known about its toxic effects on organisms and aquatic environment. In this study, we investigated the developmental toxicity of α-Bisabolol, especially its effects on the cardiac development using zebrafish embryos as a model. Embryos at 4 h post-fertilization (hpf) were exposed to 10, 30, 50, 70, 90, and 100 μM α-Bisabolol until 144 hpf. α-Bisabolol caused phenotypic defects and the most striking one is the heart malformation. Treatment of α-Bisabolol significantly increased the cardiac malformation rate, the SV-BA distance, as well as the pericardial edema area, and reduced heart rate in a concentration-dependent manner. Notably, considerable numbers of apoptotic cells were mainly observed in the heart region of zebrafish treated with α-Bisabolol. Further study on α-Bisabolol induced apoptosis in the zebrafsh heart suggested that an activation of Fas/FasL-dependent apoptotic pathway. Taken together, our study investigated the cardiotoxicity of α-Bisabolol on zebrafish embryonic development and its underlying molecular mechanism, shedding light on the full understanding of α-Bisabolol toxicity on living organisms and its environmental impact.

Medicinal properties of terpenes found in Cannabis sativa and Humulus lupulus

Cannabaceae plants Cannabis sativa L. and Humulus lupulus L. are rich in terpenes - both are typically comprised of terpenes as up to 3-5% of the dry-mass of the female inflorescence. Terpenes of cannabis and hops are typically simple mono- and sesquiterpenes derived from two and three isoprene units, respectively. Some terpenes are relatively well known for their potential in biomedicine and have been used in traditional medicine for centuries, while others are yet to be studied in detail. The current, comprehensive review presents terpenes found in cannabis and hops. Terpenes' medicinal properties are supported by numerous in vitro, animal and clinical trials and show anti-inflammatory, antioxidant, analgesic, anticonvulsive, antidepressant, anxiolytic, anticancer, antitumor, neuroprotective, anti-mutagenic, anti-allergic, antibiotic and anti-diabetic attributes, among others. Because of the very low toxicity, these terpenes are already widely used as food additives and in cosmetic products. Thus, they have been proven safe and well-tolerated.

Photodynamic therapy with topical photosensitizers in mucosal and semimucosal areas: Review from a dermatologic perspective

Photodynamic Therapy is a procedure based on the interaction between a Photosensitizer, a light source with a specific wavelength and oxygen. The aim of this review is to provide a brief and updated analysis of scientific reports on the use of PDT with topical PS in the management of oncological, infectious, and inflammatory disorders involving mucosal and semimucosal areas, with a specific focus on diseases of dermatologic interest.

A novel sorbent based on carbon nanotube/amino-functionalized sol-gel for the headspace solid-phase microextraction of α-bisabolol from medicinal plant samples using experimental design

A novel sol-gel coating on a stainless-steel fiber was developed for the first time for the headspace solid-phase microextraction and determination of α-bisabolol with gas chromatography and flame ionization detection. The parameters influencing the efficiency of solid-phase microextraction process, such as extraction time and temperature, pH, and ionic strength, were optimized by the experimental design method. Under optimized conditions, the linear range was between 0.0027 and 100 μg/mL. The relative standard deviations determined at 0.01 and 1.0 μg/mL concentration levels (n = 3), respectively, were as follows: intraday relative standard deviations 3.4 and 3.3%; interday relative standard deviations 5.0 and 4.3%; and fiber-to-fiber relative standard deviations 6.0 and 3.5%. The relative recovery values were 90.3 and 101.4% at 0.01 and 1.0 μg/mL spiking levels, respectively. The proposed method was successfully applied to various real samples containing α-bisabolol.