Medicinal plants are in practice for the management of various ailments from ancient times. The mode and use of medicinal plants as medicaments for many diseases change day by day with new research and scientific approaches. Inflammation and its associated nociceptive pain are among the vital health challenges to the current researchers. In this research, we have used four genetic variants of Mirabilis jalapa for the possible management of inflammatory processes and associated nociceptive pain. The crude extract, chloroform and EtOAc fractions of the four variants (MJ-1, MJ-2, MJ-3, and MJ-4) have been used in this study. In the in vitro enzyme inhibition studies, all samples were evaluated against COX-2 (cyclooxygenase) and 5-LOX (lipoxygenase). The activity profile of the crude extract samples was encouraging and gave mediocre inhibitions against both COX-2 and 5-LOX. Among the crude samples, we noticed that Pink and light pink variants were comparatively more active against COX-2 and 5-LOX. In chloroform fractions, all four variants were poorly active. Similarly, the highest in vitro activity was shown by the ethyl acetate fraction of the pink variant giving IC₅₀ values of 260 and 360.47 μg/ml against COX-2 and 5-LOX respectively. All selected variants were also tested safe in experimental animals for in vivo studies. In the carrageenan-induced method of inflammation, the pink variant was most active showing 56.7% inhibition during 3 h of observation. Similarly, in hot plate and tail immersion in vivo experiments, the ethyl acetate fractions of all four variants showed encouraging inhibitions. In the acetic acid writhing model, we also found ethyl acetate fractions more active. Furthermore, both MJ-4 and MJ-3 were more active compared to other variants selected. It can be concluded from our current findings that among the four genetic variants, the pink variant was most potent on all the tested in vitro and in vivo targets of inflammation and nociception, which may be associated with relatively rich phenolic and flavonoid content of the variant. Furthermore, it was also obvious from our results that the ethyl acetate fraction was the most active and can be used as a targeted sample for further extended studies.

Keywords: Mirabilis jalapa; Inflammation; Nociception; COX; LOX; Carrageenan and Hot plate method