Immunomodulatory and anti-inflammatory potential of myrmecodia platytyrea tuber aqueous extract: in vivo and in vitro approaches / Maisarah Mohd Zin

Myrmecodia sp. had been traditionally used as a remedy by local people of Papua Island to treat severe diseases such as tuberculosis, hyperuricemia and cancer. Several studies on pharmacological effects of this plant revealed that Myrmecodia sp. have potent antioxidant activities, anticancer and antiproliferative activities with immunomodulatory effects. Myrmecodia platytyrea was chosen in this study as this plant exhibit a special feature, red hypocotyl, which makes it different from other Myrmecodia species. Moreover, very few literatures on this species were found. The main objective of this study was to prove scientifically the effectiveness of this plant in treating diseases as claimed by the ancestors. M. platytyrea was extracted using decoction method and phytochemicals in the extract were analysed. In vitro toxicity test using MTT assay and in vivo oral toxicity test, acute and 28-days repeated dose toxicity test, were done to determine the safety profile of this extract. Further evaluation of Myrmecodia platytyrea tuber aqueous extract (MPAE) effects towards immune system and global metabolomics using healthy rats and validated through in vitro and in vivo study of anti- inflammation of LPS-induced macrophage and carrageenan-induced rat paw oedema. After screening for the phytochemicals in MPAE, the results revealed that MPAE contained flavonoids, phenolics, free-radical scavenging activity and chelating properties. For the cytotoxicity test, MPAE showed IC50>1000 μg/mL on normal cell lines after 24 h incubation, which was considered non-toxic. Acute oral toxicity study and 28-days repeated dose toxicity study of MPAE (p.o.), did not cause any toxic effect, physical and behavioral changes to the mice. Immunomodulatory study revealed, MPAE may act as an adjuvant, that signals the immune system to respond to the antigen as it would to an active infection. Next, metabolomics analysis on sub-chronic administration of 400 mg/kg MPAE (p.o.) revealed that MPAE might involve in regulation of fatty acid metabolism, precursors of inflammation, endogenous antioxidant system (GSH) and exogenous metabolites. The results also showed MPAE exhibited anti-inflammatory properties, in vitro and in vivo by inhibiting the inflammatory biomarkers. Conclusively, MPAE is not toxic, can boost the immune system and inhibit inflammation, may be due to the presence of high phenols and flavonoids content in the extract.