Acute Wound Healing Potential of Marine Worm, Diopatra claparedii Grube, 1878 Aqueous Extract on Sprague Dawley Rats

Diopatra claparedii which is colloquially known as Ruat Sarung can be found along the west coast of Peninsular Malaysia. The species has a unique ability to regenerate anterior and posterior segments upon self-amputation or injury, thus having potential as a wound healing promoter. In this study, the wound healing potential of D. claparedii aqueous extract on acute wound model in rats was revealed for the first time. Various concentrations (0.1%, 0.5%, and 1.0% w/w) of D. claparedii ointment were formulated and tested on Sprague Dawley rats through topical application on full-thickness skin wounds for 14 days. The wound healing effects were investigated via behaviour observation, wound contraction, and histopathological analysis. Quality assessment was performed via skin irritation test, microbial contamination test (MCT), and heavy metal detection. The study also included test for antibacterial activities and detection of bioactive compounds in D. claparedii. One percent of D. claparedii ointment showed rapid wound healing potential with good soothing effects and more collagen deposition in comparison to the commercial wound healing ointments such as acriflavine (0.1% w/v) and traditional ointment gamat (sea cucumber extract) (15.0% w/v). No local skin irritation, microbial contamination, and insignificant concentration of heavy metals were observed, which indicate its safe application. Moreover, the aqueous extract of D. claparedii exhibited antibacterial activities against Escherichia coli and Pseudomonas aeruginosa with minimum inhibitory concentration (MIC) value at 0.4 g/ml. ¹H NMR analysis of the aqueous extract of D. claparedii revealed some metabolites that might be responsible for its wound healing properties such as amino acids, halogenated aromatics, organic acids, vitamins, and others. Altogether, these results suggested that the aqueous extract of D. claparedii could be utilised as an alternative natural wound healing promoter.