ANTIBACTERIAL AND CYTOTOXICITY STUDIES OF GOSSYPOL ISOLATED FROM FRUITS OF THESPESIA POPULNEA (L.) SOL. EX CORREA- A REMEDY FOR SKIN DISEASES

Abstract

Skin infections caused by Staphylococcus aureus and Streptococcus pyogenes and dermatophytoses are becoming severe nowadays. In a previous study, gossypol from fruits of Thespesia populnea (L.) Sol. ex Correa was found to possess growth-inhibiting activity against dermatophytes, causing dermatophytoses, the major fungal disease of the skin (Anuthara et al., 2021). There may be a chance of secondary bacterial infection in the case of dermatophytoses. Hence the present study was designed to evaluate the activity of gossypol against Staphylococcus aureus and Streptococcus pyogenes, the major bacterial pathogens of the skin. Gossypol (GP) was isolated from the fruits of T. populnea and was identified and characterised by HPLC, HPTLC, FTIR, LCMS and NMR spectroscopy in a previous study (Anuthara et al., 2021). Then checked its antibacterial activity against Staphylococcus aureus and Streptococcus pyogenes. The MIC and MBC of gossypol were 31.25 µg/mL and 62.50 µg/mL for Staphylococcus aureus. The MIC of gossypol against Streptococcus pyogenes was 125 µg/mL. It was not bactericidal at the tested concentration. The antibacterial study was done by the disc diffusion method, and it showed inhibition against the growth of two pathogens tested. The minimum inhibitory concentration (MIC) was determined according to the CLSI (clinical and laboratory standards Institute) method- M07-A9 with slight modification (CLSI, 2012b). Since GP showed good inhibition activity against bacterial pathogens, the cytotoxicity of the compound was also tested towards the goal of developing a new antibacterial preparation. Cytotoxicity of gossypol has been evaluated by direct microscopic observation and MTT assay. The apoptosis was detected by acridine orange (AO) and ethidium bromide (EtBr) double staining method.