Abstract:
The present study was carried out to compare the antioxidant activity, antibacterial
activity, and total phenolic content of the leaf extracts of Solanum torvum, Solanum
incanum, and Solanum violaceum and to identify the effect of geographical area on the
selected chemical properties to utilize them in medicinal purposes effectively. Three
mature leaf samples for each variety were taken from three different locations of Badulla
and Puttalam district and Methanolic extracts of shade-dried leaf powder were prepared.
The antioxidant activity was determined using DPPH spectrometric assay. The
antibacterial activity was investigated using agar disk diffusion assay against Escherichia
coli and Staphylococcus aureus with Gentamicin as positive control and Methanol as the
negative control. Folin Ceocalteu method was used to determine the total phenolic content
of selected plants. S. torvum growing in Badulla district has shown the highest total
phenolic content (163.4 GAE/g) and highest antioxidant activity (IC 50 value, 0.72 ppm).
All the extracts tested were not active against E. coli. However, extracts of S. torvum in
Badulla district were active against S. aureas (Average Inhibition Diameter, 7.33 mm;
Positive Control, 24 mm; Negative control, 0 mm). According to statistical analysis, there
is no significant difference in antioxidant activity and total phenolic content of the studied
varieties and no significant effect from geological area to any of the studied properties
(Two-way ANOVA, p >0.05). Since S. torvum of Badulla district has shown
comparatively higher antioxidant activity, antibacterial activity, and total phenolic
content, it could be more effective in the production of various medical commodities.
However, further studies should be done for S. torvum growing in other areas as well.
Keywords: Solanum sp., Antioxidant activity, Anti-bacterial activity, Total phenolic
content, Geographical area
