Gynura procumbens is a medicinal plant, traditionally used to treat inflammation and fever. A yeast-based assay detected GSK3β-inhibitory activity in the aqueous extract of G. procumbens. GSK3β is now known to have a central role in the modulation of host inflammatory response during bacterial infections. In this study, we investigated the involvement of GSK3β in the anti-malarial and anti-inflammatory effects of an aqueous extract of G. procumbens. Our results showed that G. procumbens inhibited growth of P. falciparum 3D7. Consecutive four-day administration of 250 mg/kg body weight (b.w.) G. procumbens resulted in strong chemosuppression and improved survivability in P. berghei-infected mice. B. pseudomallei-infected mice treated with G. procumbens (50 mg/kg b.w.) showed increased survivability. TNF-α and IFN-γ levels in liver and serum of B. pseudomallei-infected mice were lowered by G. procumbens treatment. IL-10 level was higher in serum of G. procumbens-administered infected mice. G. procumbens treatment of P. berghei- and B. pseudomallei-infected animals each resulted in increased hepatic GSK3β (Ser9) phosphorylation. It is noteworthy that kaempferol (one of the compounds in G. procumbens) also inhibited the growth of P. falciparum 3D7; showed strong chemosuppression and improved survivability in P. berghei-infected mice at 5 mg/kg b.w. B. pseudomallei-infected mice treated with kaempferol (10 mg/kg b.w.) showed improved survivability. Concomitantly, the described effects due to kaempferol also involved enhanced GSK3β (Ser9) phosphorylation as observed with G. procumbens. In summary, the observed anti-malarial and anti-inflammatory effects of G. procumbens involved inhibition of GSK3β and kaempferol may in part be responsible for the pharmacological effects.
The potential of secondary metabolites extracted from Streptomyces sp. to treat bacterial infections including infections with Staphylococcus aureus is previously documented. The current study showed significant antimicrobial activities associated with endophytic Streptomyces sp. isolated from medicinal plants in Peninsular Malaysia.