Anti-inflammatory, Antibacterial Properties and Tannin Contents of Thai Spice Water Extracts

The objective of this research was to develop water-based extracts of Thai spices, prepared using traditional decoction techniques, to assess their potential medicinal properties. These extracts provide a foundation for developing a Thai spice-based oral spray. To achieve this, the study investigated the in vitro anti-inflammatory activity which was assessed using the albumin denaturation inhibition method with egg albumin, and compared that to the standard drug Diclofenac diethylammonium. The antibacterial properties against the oral pathogenic bacterium Streptococcus mutans (S. mutans) were tested using the disc diffusion method and compared with the standard antibiotic Erythromycin, and total tannin content using the Folin-Ciocalteu colorimetric technique. The extraction process was enhanced through the application of the reflux method to optimize the development of the extracts. Three types of Thai spices; Chinese cinnamon (Cinnamomum cassia L.), clove (Syzygium aromaticum), and star anise (Illicium verum), were extracted using water as a solvent, with a ratio of 1:10 (w/v). The extraction process was conducted for two different durations, resulting in six extract samples as 1-hour extractions; Chinese cinnamon extract (E1A), clove extract (E1B), and star anise extract (E1C), and 3-hour extractions; Chinese cinnamon extract (E3A), clove extract (E3B), and star anise extract (E3C). These six extracts were tested for their in vitro anti-inflammatory activity, antibacterial activity against S. mutans, and total tannin content. The results showed that E1B exhibited the strongest in vitro anti-inflammatory activity, with an IC50 value of 1.17±0.05 mg/ml, which was significantly higher than that of the other extracts (p<0.05). Additionally, extracts obtained from 1-hour extraction demonstrated higher anti-inflammatory effects than 3-hour extraction. Furthermore, E1B contained the highest total tannin content (87.89±2.51 mg TAE/g extract). However, when tested for antibacterial activity against S. mutans, none of the six extracts showed any inhibitory effects compared to the standard antibiotic Erythromycin (23.23±0.17 mm). This finding is crucial for future studies exploring these Thai spices for many medicinal uses, particularly their potential as natural anti-inflammatory agents in various products."