Objective: To evaluate the anti-inflammatory activity of a tropical African medicinal plant,
Costus afer (C. afer) Ker Gawl. in vitro and identify the chemical constituents in the most
Methods: Hexane, ethyl acetate, n-butanol and aqueous fractions obtained through successive
solvent partitioning of 70% methanolic leaf or stem extracts of C. afer were subjected to
in vitro anti-inflammatory screening assays viz. anti-denaturation of protein, stabilization
of human red blood cell (HRBC) membrane against hypotonicity-induced hemolysis and
anti-proteinase activities. Diclofenac sodium was used as a standard drug. The chemical
compounds in the most active fraction were determined using quantitative phytochemical and
gas chromatography-mass spectrometry (GC/MS) analytical methods, comparing the mass
spectra of the GC/MS identified compounds with those of the National Institute of Standards
and Technology (NIST) database library.
Results: The hexane fraction of C. afer leaf (HFCAL) with an IC50 of 33.36 ?g/mL, 33 ?g/mL
and 212.77 ?g/mL exhibited the highest anti-denaturation of protein, stabilization of HRBC
membrane and anti-proteinase activities respectively when compared with other test fractions.
The GC/MS identified compounds in HFCAL known to possess anti-inflammatory property
were terpenoids (naphthalene 1,6-dimethyl-; naphthalene 2,3-dimethyl-; phytol), phenol
[phenol 2,4-bis(1,1-dimethylethyl)], coumaran [2(4H)-benzofuranone, 5,6,7,7a-tetrahydro-4,
4,7atrimethyl and fatty acids (pentadecanoic acid; hexadecanoic acid; n-hexadecanoic acid;
9,12-octadecanoic acid-methyl ester; 9,12,15 octadecatrienoic acid and cis-vaccenic acid)].
Conclusion: Therefore, HFCAL could be considered as a potential source of antiinflammatory
agents for herbal formulation or pharmaceutical drug production.