Antimicrobial investigation, Formulation and Evaluation of Andrographis paniculata aqueous herbal cream for topical application

Abstract

Herbal plants contain substances of medicinal values or precursors for synthesis of important drugs, however, not much have been done in terms of standardization and effective delivery system. Various routes can be employed to deliver herbs, but the topical route is the safest. In this study, aqueous and ethanolic extractions of Andrographis paniculata were carried out. Antimicrobial screening of the extract before and after incorporation into cream base was carried out using standard antimicrobial agents as positive control. Formulated creams were evaluated for organoleptic properties, pH, spreadability, viscosity and stability. Staphylococcus aureus and Candida albicans were used for the sensitivity studies. Percentage yield for ethanolic and aqueous extracts were 17.5%w/w and 13.33%w/w respectively. Both microbes were sensitive to pure ethanolic extract and creams formulated from ethanolic extract, but resistant to aqueous extract. Zones of inhibition for the ethanolic extract ranged from 7.33 ± 0.58 mm to 14.00 ± 0.00 mm (Candida albicans) and 6.00 ± 1.00 mm to 12.33 ± 0.58 mm (Staphylococcus aureus). Minimum Inhibitory Concentrations, MICs, were 25 mg/mL and 200 mg/mL for Candida albicans and Staphylococcus aureus respectively. The MIC for the formulated cream (15% w/w) was 150 mg/mL for both organisms. The pH of formulated creams ranged from 5.54 to 6.84; the viscosity, 18,800 to 60,500 mPas. The spreadability values were between 37.5 ± 0 and 75.0 ± 0.2 g.cm/s. All formulated creams were stable. Thus herbal creams formulated from Andrographis paniculata ethanolic extract retained the antimicrobial properties of the extract and as such can be applied topically for the treatment of skin diseases involving these microorganisms.