Immunological activity evaluation of Alchornea spp in vitro on the production of hydrogen peroxide, nitric oxide and tumor necrosis factor-α by murine macrophages

Resumo

The use of natural resources as treatment and healingfor diseases is as old as the human species. However, most ofall plant species were not investigated chemistry or biologically.Many plants used in the traditional medicine modulate theimmunological response. The immune system is a remarkablyadaptive defense system that has evolved in vertebrates toprotect them from invading pathogenic microorganisms andcancer. Macrophages play an important role in this systembecause they are cells capable to secrete many biological activeproducts such as reactive nitrogen and oxygen species and cytokines. In this work, methanolic extract and ethyl acetatefraction obtained from Alchornea triplinervia and Alchorneaglandulosa were studied in the murine immune system usingperitoneal macrophages cultures from Swiss mice. Cell viabilityassays were realized to assure the experimental development.Hydrogen peroxide (H2O2) and nitric oxide (NO) were determinedby espectrophotometric procedures and enzyme-linkedimmunosorbent assay (ELISA) was used to detect tumornecrosis factor (TNF-α). The ability of methanolic extract andethyl acetate fraction to stimulate or inhibit the murine immunesystem was evaluated. These plants didn’t showimmunostimulating properties, once liberation of H2O2, NO andTNF-α were not observed. However, extracts and fractions fromboth plants, strongly inhibited NO and H2O2 production inducedby LPS and PMA, respectively. Production of TNF-α by LPSstimulated macrophages was partially inhibited. Theconcentration of 15,62 μg/mL from A. triplinervia methanolicextract (cellular viability > 95%) showed to inhibit 88,35% ofH2O2, 52,54% of NO and 10,41% of TNF-α production. Theethyl acetate fraction of the same plant and concentration(cellular viability > 90%), inhibited 72,25% of H2O2, 47,80% ofNO and 16,41% of TNF-α production. Regarding theA. glandulosa methanolic extract in the concentration of15,62μg/mL (cellular viability > 91%), there was a productioninhibition of 88,62% of H2O2, 32,40% of NO and 11,61% of TNF-α. The ethyl acetate fraction of the same plant and concentration(cellular viability > 92%), inhibited 70,56% of H2O2, 21,67% ofNO and 12,21% of TNF -α production. In the NO and TNF-αassays, the inhibition percentage grows according to increasingconcentrations, but this fact was not noticed in H2O2determination. According to these results, it is suggested thatmethanolic extracts and ethyl acetate fractions fromA. triplinervia and A. glandulosa can present anti-inflammatoryactivity, confirming their traditional use.