Abstract:
ommon mullein, also known as Wooly Mullein (Verbascum thapsus L., Scrophulariaceae)
has been used as a medicinal herb since ancient times. The aim of the present study was to
investigate qualitative screening of major phytochemicals and antimicrobial activity of
common mullein (Verbascum thapsus L.) root, leaf and fruit methanolic extracts. The
qualitative analyses of major phytochemicals were tested for tannins, phlobatannins,
saponins, flavonoids, steroids, termenoids and alkaloids. The antimicrobial experiment was
arranged as 3 x 1 x 4 (3 source extracts: root, leaf and fruits of common mullein at three
concentration levels; 1 solvent system i.e. methanol, 4 test organisms (2 bacteria: Escherichia
coli (gram negative), Staphylococcus aureus (gram positive), two fungi (Aspergillus
versicolor and A. Niger)) factorial design in three replications. The result indicated that
phytochemical substances of the methanolic extract of V. thapsus (L) were screening by
qualitative chemical analysis which revealed the presence of tannins, flavonoids, steroids,
terpenoids and alkaloids as bioactive compounds in the leaf methanolic extracts. While the
methanolic fruit extract of V. thapsus revealed the presence of tannins, saponins, flavonoids,
terpenoids and alkaloids. Contrastingly, the methanolic root extract indicated the presence of
tannins, phlobatannins, saponins, flavonoids, steroids, terpenoids and alkaloids. The
antibacterial activity of methanolic extracts of V. thapsus (L) root, leaf and fruit at highest
concentration of the extracts has recorded mean zone of inhibition ranging from 12.00±0.55
to 16.07±0.40mm While the antifungal activity of the methanolic extract with growth
inhibitory effect at the highest dose recorded a mean zone of inhibition ranged
from13.50±0.50 to 16.03±0.90mm. The methanolic root extract of V. thapsus
(L.)demonstrated strong bactericidal activity with minimum inhibitory concentration MIC
(6.25mg/ml) and corresponding minimum bactericidal concentration MBC (12.50mg/ml)
against S.aureus. The strongest antifungal activity with MIC (4.70mg/ml) and corresponding
minimum fungicidal concentration MFC (6.25mg/ml) was recorded for methanolic fruit
extract of V. thapsus (L) against Aspergillus versicolor. It can be concluded from the result of
antimicrobial activities that the methanolic root extract of V. thasus (L) had exhibited the
strongest antibacterial potential while the methanolic fruit extract presented strongest
antifungal potential