Exploiting in vitro gastric acid-neutralising synergy between Desmodium triflorum (L.) DC. and Pogostemon heyneanus Benth. in an antacid tablet formulation

Abstract

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.