Development of roselle ointment with antibacterial effects

Abstract

Hibiscus sabdariffa (roselle or krachiap daeng in Thai) is a plant commonly used as a beverage and herbal medicine for diuretic purposes. There is no previous development of topical formulation from quality-controlled roselle extract. To develop an ointment containing the roselle extract and investigate for the physical, chemical, and biological stabilities. The ointment was developed from roselle extract. Physical properties including organoleptic characteristics, viscosity, pH and microbial contamination were investigated. Phytochemical characteristics were investigated by thin layer chromatographic technique. Total anthocyanin contents were analyzed by pH differential methods. In vitro antibacterial activities against clinical isolated bacteria were evaluated by agar well diffusion method. The stability test of the ointment was conducted according to ASEAN guideline on stability study and shelf-life of traditional medicine (2013). Roselle ointment appeared as dark red semi-solid with unique odor, smooth texture, pH 3.81 ± 0.02 and no microbial contamination. Thin layer chromatography showed the major bands corresponded to delphinidin-3-sambubioside, cyanidin-3- sambubioside, delphinidin-3-glucoside, and cyanidin-3-glucoside. The ointment kept in the refrigerator (2 – 8 °C) showed the highest remaining total anthocyanin content (1.50 ± 0.00 mg% cyanidin-3-glucoside equivalent (mg% C3GE) of the ointment) after 4 weeks. Roselle ointment in all storage conditions still promoted inhibitory effects against Staphylococcus aureus and Staphylococcus intermedius with the inhibition zone ranging from 9.61 ± 0.10 to 11.97 ± 0.05 mm at the end of stability test. Roselle ointment was developed with good physical, chemical, and biological activities. The refrigerator was recommended as storage condition to prolong chemical stability of the ointment.