Purpose: To evaluate the antimicrobial, cytotoxic and phytotoxic activities of the organic extract of
Rhizopus stolonifer
whole cell static culture in order to determine the presence of potentially bioactive compounds in the culture.
Methods: The organic extract was obtained by extracting the whole cell culture of
R. stolonifer with Ethyl Acetate (EtOAc). The antifungal activity was determined by inhibitory effect on the growth of
Alternaria alternata
,
Aspergillus flavus
,
Curvularia protuberata
and
Fusarium oxysporum
, cytotoxic activity by brine shrimp lethality test, antibacterial activity against
Ervinia carotovora
and
Xanthomonas campestris
by disc diffusion technique, and phytotoxic activity by testing the crude extract against the Lemna minor frond.
Results: The extract showed phytotoxic activity (at 95% level of significance) against
Lemna minor (67.7 % lethality) with Fronds Inhibition (FI
50) of 167.85 µg mL
-1. The extract exhibited a significant (at 95% level of significance) cytotoxic activity (LC
50 of 115.71 µg mL
-1) against brine shrimp. Maximum mortality (56.7 %) was obtained at a concentration of 200 µg mL
-1 concentration after 48 h. In the antifungal test, the highest inhibitory effect was observed against
Fusarium oxysporum (88.8 %) followed by
Alternaria alternata (81.5 %),
Aspergillus flavus (70.5 %) and
Curvularia protuberata (37.5 %) at 1000 µg. mL
-1 when compared to negative reference. Antibacterial activity against
Ervinia carotovora and
Xanthomonas campestris was minimal even at extract level of 2000 µg mL
-1.
Conclusion: The ethyl acetate extract of
R. stolonifer possesses significant herbicidal, cytotoxic and antifungal properties. Isolation and characterization is required for structural elucidation of its bioactive compounds.
