Theses (MSc. Molecular Medicine)

INTRODUCTION: Quebrachitol, an optically active cyclitol derived from plants, has attracted interest as a possible natural product inspiration for pharmaceuticals due to its potential medicinal therapeutic qualities in diabetes, cancer, and drug production. However, the antimicrobial properties of quebrachitol were indefinite. This is the first systematic review to specifically determine, appraise, and consolidate the antimicrobial effects of quebrachitol. METHODS: A comprehensive database search from PubMed, Scopus, and Google Scholar from January 2000 to February 2024 was conducted. All English, full-text, original articles involving experimental, in vivo, or in vitro research were included. Data pertaining to quebrachitol’s effectiveness (nil, partial, or total inhibition) against microorganisms was extracted. In the presence of antimicrobial effects, the minimum effective dosage or duration and mechanism of action were determined. The quality assessments of the articles were performed with QUIN (in vitro) and SYRCLE RoB (in vivo). RESULTS: The research yielded 866 studies, but only 11 met the inclusion criteria, comprising 7 in vitro, 1 in vivo, 1 in ovo, and 2 papers, which combined both in vitro and in vivo trials. Quebrachitol was found to have an anti-infectious effect against Salmonella sp., Candida albicans, infectious bursal disease virus, Newcastle disease virus, and Plasmodium sp. Additionally, there was significant evidence of inhibitions against biofilm in Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus (MRSA). QUIN tool revealed that 60% of in vitro studies had a low risk of bias, with overall scores ranging from 56.25 to 87.5%. SYRCLE, however, showed that none of the studies contained more than 50% of the studies exhibited low-risk bias. The allocation sequence demonstrated high-risk bias due to a lack of random sequence generation and reliance on non-random approaches like availability or predetermined rules. CONCLUSION: Quebrachitol had demonstrated significant and promising antimicrobial potential in the in vitro studies, showing efficacy against pathogens associated with typhoid, malaria, avian flu disease, and biofilm-related diseases. However, the in vivo findings were inconclusive due to high-risk bias. Thus, further well-designed in vivo research is required to establish the antimicrobial efficacy and safety of quebrachitol and to assess its potential role in developing alternative treatments to address current antimicrobial resistance and pharmacovigilance concerns. Keywords: Quebrachitol, antimicrobial, antibacterial, antifungal, antiviral, antiparasitic, antibiofilm

Chronic wounds represent a significant healthcare challenge, often leading to prolonged patient suffering, bacterial infections, and impaired tissue regeneration, causing untreated and long-lasting scars formation. This study explores the potential of curcumin and quercetin-loaded chitosan-pectin scaffolds as a novel solution for enhancing wound healing. Curcumin and quercetin, both are well-known for their antioxidant, anti-inflammatory, and antibacterial properties, were incorporated into chitosan-pectin scaffolds via a lyophilization method. Different ratios of curcumin and quercetin were being explored and tested for their biocompatibility, antioxidant capacity, antibacterial and antibiofilm capacities, drug release profiles as well as physicochemical tests to assess their suitability for wound healing applications. The surface morphology and pore sizes and distributions were assessed with scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy. Besides that, the antioxidant activity of the resulting scaffolds was tested using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, while their anti-inflammatory effects were evaluated in vitro through a bovine serum albumin (BSA) denaturation assay. Moreover, the antibacterial efficacy as well as antibiofilm affinity of the scaffolds were tested against Staphylococcus aureus and Pseudomonas aeruginosa. Biocompatibility of the scaffolds was tested via cell viability MTT assay while in-vitro wound healing was assessed using scratch assay. All of the curcumin-quercetin loaded scaffolds demonstrated strong antioxidant activity, ranging from 83 – 90%, and exhibited comparable anti-inflammatory activity, with values between 83 – 91%. They also showed impressive wound healing potential in vitro, with rates ranging from 85 - 100% at the 48-hour. Additionally, the antibiofilm activity against Staphylococcus aureus was notably high, achieving a 75 – 85% biofilm reduction. In comparison, the reduction in biofilm formation for Pseudomonas aeruginosa was moderate, ranging from 45 – 59%. The curcumin-quercetin loaded scaffolds, particularly the scaffold containing curcumin and quercetin at ratio 1:3 demonstrated the most promising results. These findings highlight the potential application of curcumin and quercetin-loaded chitosan-pectin scaffolds in promoting wound healing, addressing bacterial biofilms and supporting tissue regeneration. The results contribute to advancing biomimetic scaffolds as innovative solutions for managing chronic wounds and improving patient outcomes.