Introduction
This study aimed to evaluate the combinative in vitro antacid activity of two terrestrial medicinal plants; Desmodium triflorum and Pogostemon heyneanus, and to subsequently formulate an antacid dosage form using their extracts.
Methods
The gastric acid-neutralising activity of crude aqueous extract combinations of D. triflorum whole plant and P. heyneanus leaves was evaluated using different in vitro assays, against distilled water. Then, the 3:1 concentration combination of D. triflorum and P. heyneanus was membrane dialysed and the resulting fractions were assayed in Vatier’s artificial stomach model. The same extract combination was characterised by high-performance liquid chromatography (HPLC) and fourier transform infrared (FTIR) analyses and then used in the formulation of herbal antacid tablets.
Results
The combination ratio of 3:1 (D. triflorum: P. heyneanus) demonstrated a significant activity (P < 0.05) in acid-neutralising effect assay (4.94 ± 0.00 end pH) and acid neutralisation duration assay (403.4 ± 4.6 seconds). The 3:1 combination further resulted in synergistic antacid activity, evidenced by the combinative index analysis. Membrane dialysed high- and low-molecular fractions of the same extract demonstrated bioactivities comparable to each other (P > 0.05) in antacid duration assay (182.78 ± 3.66 seconds and 218.18 ± 2.34 seconds respectively). The herbal tablet formulated using the 3:1 combination of the test plants showed pharmaceutically acceptable physical characteristics along with a significant acid-neutralisation (P < 0.05).
Conclusions
The 3:1 concentration combination of D. triflorum and P. heyneanus extracts resulted in synergistic gastric acid-neutralising effects, possibly with the aid of phytochemicals with various molecular weights. The combination can be further used in an antacid tablet formulation with sufficient in vitro activity.