Evaluation of antibacterial potential of Pandanus kaida inflorescence crude extracts and formulation of a transparent antibacterial soap

Abstract

Pandanus kaida, also known as "Wetakeiya" in Sinhala, is a coastal plant native to Sri Lanka and India, yet the antibacterial properties of inflorescence remain unexplored. This study aims to introduce a transparent antibacterial soap incorporating different solvent extracts obtained from Pandanus kaida male inflorescence to combat bacterial skin infections. The extraction process yielded 262 mg, 195 mg and 520 mg of hexane (HE), dichloromethane (DE), and ethyl acetate (EE) extracts, respectively from 1.3 kg of ground male inflorescence. These crude extracts (100mg/mL in DMSO) were tested against Staphylococcus aureus (SA), methicillin resistant Staphylococcus aureus (MRSA), Escherichia coli (EC), Pseudomonas aeruginosa (PA), and Proteus sp. using an agar well diffusion assay. Transparent soap formulations were formulated with 2%, 5%, and 10% of crude extract mixtures (HE:DE:EE 1:1:1). Crude extracts demonstrated inhibitory effects against SA, MRSA and PA with a zone of inhibition ranging from 7-13 mm while the ciprofloxacin, the positive control exhibited a zone of inhibition more than 33 mm against all the tested pathogens and DMSO, the negative control showed no inhibition. Soap formulations (500 mg/mL) with crude extracts exhibited antibacterial properties against SA, MRSA and PA and inhibition zone diameters were ranging from 13-18 mm while commercial antibacterial soap and the soap base (500 mg/mL) showed 7-8 mm of inhibition zone. Tests for pH (8-9), fatty acid content (50-55%), and water content (31-38%) of the developed soap formulation were aligned with the SNI06-3532-1994 reference standards. In conclusion, this study successfully formulated an antibacterial transparent herbal soap infused with Pandanus kaida flower extract, demonstrating promising antibacterial effects to the tested bacterial species.