Abstract:
Background: Traditional medicinal plants have been widely used to treat or manage various
ailments for centuries in Lesotho. With an increase in multi drug resistance and undesired
adverse events to current drugs challenges, there is a need for alternative drugs. Aim: In
this study we aimed at the investigation of antibacterial, antioxidant and anti-inflammatory
effects of Senecio asperulus and Gunnera perpensa roots extracted in three solvents of
different polarities. Materials and Methods: Antibacterial activity was determined using
the disc diffusion method, while antioxidant activity was determined using free radical
scavenging of 2,2-diphenyl-1-picrylhydrazyl and the ferric reducing antioxidant power assay.
The Lipopolysaccharide (LPS) stimulated RAW 264.7 mouse macrophage in vitro model was
used to evaluate the anti-inflammatory activity of both plants. Resveratrol was used as a
positive control. Results: Methanol extracts of Senecio asperulus inhibited microbial growth
even at the lowest concentration of 50 μg/ml. Senecio asperulus dichloromethane extract was
active on most bacteria with MIC’s between 50 μg/ml and 500 μg/ml. However, the water and
methanol extracts of Gunnera perpensa had no activity against all organisms tested. Aqueous
extracts of Senecio asperulus and Gunnera perpensa showed free radical scavenging activity
yielding EC50 values of 100 μg/ml and 25 μg/ml, respectively. The aqueous extracts of Senecio
asperulus showed moderate anti-inflammatory activity from 50 to 200 μg/ml. while the
methanol extract was at 200 μg/ml and with no cytotoxicity. No anti-inflammatory activity was
observed from all Gunnera perpensa extracts using LPS-induced macrophages, this suggests
that this species may be using other mechanisms for anti-inflammatory activity. Conclusion:
The antibacterial, antioxidant and anti-inflammatory activities observed from water extracts
of Senecio asperulus support its ethnomedicinal use for the management of inflammation
related diseases.
