Evaluation of Synergistic Gastroprotective Activity of Desmodium triflorum Linn. and Pogostemon heyneanus Benth. Using In-Vitro Methods
Abstract
Desmodium triflorum Linn. and Pogostemon heyneanus Benth. are common
terrestrial plants found in tropical countries. The gastroprotective activities of these
individual plants have been investigated separately in previous studies. This study
aimed to evaluate the synergistic in-vitro gastroprotective activity of ‘combinations’
of aqueous extracts (AEs) of D. triflorum whole plant and P. heyneanus leaves. AEs of
the plants were prepared by refluxing. Thin layer chromatograms for individual
plant extracts and combined extracts were obtained after solvent-extracting the AE
with dichloromethane. Gastroprotective activities of different combination ratios of
the combined extract and the large and small molecular fractions (10000 Da
molecular weight cut-off) of the best combination were evaluated in-vitro. A
commercially available antacid formulation was used as the positive control,
whereas distilled water was used as the negative control. Thin Layer
Chromatograms of different combinations of AEs resulted in dissimilar profiles due
to the spots with dissimilar Rf values. Different ratios of the combined AEs and, both
small (<10000 Da MWC) and large molecular fractions exerted significant (p<0.05)
gastroprotection compared to the negative control, based on in-vitro assays of; acidneutralising
effect, neutralising capacity by Fordtran’s method and duration of
consistent neutralisation by Vatier’s artificial stomach (modified) model. The
combination ratio of 3:1 (D. triflorum: P. heyneanus) demonstrated the best activity
with acid-neutralising effect assay (4.94±0.00 end pH) and duration of consistent
neutralisation (403.43±4.63 s), whereas the positive control resulted in 6.51±0.01
end pH and 450.78±2.87 s in respective assays. Hence, the study concludes that
combined AE of D. triflorum whole plant and P. heyneanus leaves exhibit synergistic
gastroprotection where the molecules with different molecular weights are
responsible for the activity.