Wound healing properties of acid condensate from oil palm kernel shell

Abstract
Wound healing is a complex and highly regulated process for structural and functional maintenance of skin barrier where any changes to the process can hinder the healing process thus leading to delayed wound healing. The use of commercial silver sulfadiazine and non-steroidal anti-inflammatory drugs may impair skin re-epithelialisation. Acid condensate (AC) is reported to exhibit various biological activities including antioxidant, antimicrobial and anti-inflammatory that are valuable in assisting wound healing process. AC is a product of biomass pyrolysis where Malaysia produced huge amount of oil palm biomass but is underutilised. The aim of this study is to evaluate the potential of AC for wound healing activity and its wound healing mechanism. In this study, concentrated AC extract (CACE) obtained from microwave-assisted pyrolysis of palm kernel shells was fractionated using column chromatography with n-hexane-ethyl acetate-methanol solvent system and pooled into combined fractions of AC (CFACs) based on similarity of their thin layer chromatography (TLC) profiles. A total of 134 fractions were obtained and pooled into 9 combined fractions (CFAC1-CFAC9). CACE and CFAC1-3 exhibited the highest antioxidant activities. GC-MS revealed phenol and derivatives as their major compounds. CFAC3 showed the highest antibacterial activity against all pathogenic bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis) with 0.10 mg/mL of minimum inhibitory concentration and 0.33 ± 0.11 mg/mL of minimum bactericidal concentration against S. aureus. Effect on cell viability of human skin fibroblast cells (HSF 1184) was determined using (3-4,5-dimethylthiazol2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assay. The non-toxic concentrations of 1.25 and 12.5 μg/mL (10-fold difference) were selected for scratch wound assay of HSF 1184. CFAC3 was further evaluated for wound healing mechanism via phosphoinositide 3-kinase / protein kinase B (PI3K/AKT) signalling pathway using western blot. The antibacterial mode of action and wound healing mechanism were evaluated using molecular docking study. The cytotoxicity study showed that CFAC2 and CFAC3 were non-cytotoxic at concentration ≤ 50 μg/mL while CACE and CFAC1 at ≤ 100 μg/mL. CFAC3 at 1.25 μg/mL showed the fastest wound healing (82.41 ± 7.57 % wound closed) compared to control (62.65 ± 5.14 %) after 30 h. The western blot showed significant upregulation of phosphorylation of PI3K and AKT throughout 24 h. Molecular docking showed that CFAC3 compounds were able to bind the target enzymes involved in antibacterial mode of action and wound healing activity. As a conclusion, phenolic-rich fraction (CFAC3) of acid condensate obtained from pyrolysis of palm kernel shell has demonstrated potential medical application with high antioxidant, antibacterial and wound healing activity. This was the first study to report on wound healing activity of AC and its wound healing mechanism.
Description
Thesis (PhD. (Bioprocess Engineering))
Keywords
Wound healing, Palm oil--Therapeutic use, Wound healing--Research
Citation