Topical green tea formulation with anti-hemorrhagic and antibacterial effects

Abstract

Objectives: Potentially preventable death from uncontrolled hemorrhage clearly indicates the importance of simple, fast and efficient ways to achieving hemostasis. The aim of this study was to develop a topical formulation of green tea extract for reducing bleeding that can be helpful in hemorrhage control.

Materials and methods: Hydroalcoholic extract of green tea was isolated from Camellia sinensis and formulated in polyvinyl alcohol (PVA) to achieve two concentrations of 2% and 4% v/v. Folin-Ciocalteau assay was used to determine the total amount of tannins in extract. Rheological behavior of solutions was investigated by measuring viscosity at shear rates of 0-200 sec^-1. Quantitative and qualitative microbial limit tests and minimum inhibitory concentration (MIC) assay were done. The effect of formulations on bleeding time was evaluated in an animal model.

Results: The total amount of tannin in green tea extract was 3.8% w/w and addition of green tea significantly increased the viscosity of PVA. The results of MIC assay showed that PVA could not inhibit the growth of bacteria, while, 716 µg/ml of green tea and 2860 µg/ml of green tea/PVA 4% inhibited the growth of Staphylococcus aureus and Pseudomonas aeruginosa. In an animal study both 2% and 4% formulations were able to stop hemorrhage approximately at an equal time compared with tranexamic acid (TXA) 50 mg/ml as a control and the lowest bleeding time was 6.4±0.51 sec for green tea/PVA 4%.

Conclusion: Based on our results, the topical formulation of green tea extract in PVA has a great potential for anti-hemorrhage applications.

Keywords: Bleeding; Green tea; Hemostasis; Polyvinyl alcohol; Tannin; Topical formulation.

Figure 1

Standard calibration curve of tannic acid

Figure 2

A: Viscosity as a function of shear rate (sec^-1) for Polyvinyl alcohol (PVA) solution and PVA+ green tea extract (GT) solutions with different GT concentrations. B: Apparent viscosity of PVA solution and PVA+ green tea (GT) solutions with different GT concentrations. Data represent the average of all 3 experimental replicates and the error bars represent SD. (Pa.S: The SI derived unit for dynamic viscosity is the pascal-second. 1 pascal/second is equal to 1000 centipoise)

Figure 3

Comparison of time to achieve hemostasis after cutting off rat tail in different concentrations of tranexamic acid (TXA) and direct finger pressure (direct pressure) as a positive control and phosphate buffered saline (PBS) as negative control groups. In each group, 5 mice were evaluated and the results were reported based on mean±SEM. ***: P-value <0.001 vs PBS group

Figure 4

The effect of different concentrations of green tea extract (extract) alone or in combination with PVA to stop bleeding in rat tail. In each group, 5 mice were evaluated and the results were reported based on mean±SEM. ***: P-value <0.001 vs tranexamic acid (TXA) 50 mg/ml group