Antibacterial effects were tested using medicinal crude extracts (for example, natural occurring phenolic substances, flavonoids, terpenes and alkaloids) from local medicinal plants such as Guizotia scabra and Maesa lanceolata in order to determine the minimum inhibitory concentration (minimum lethal dose of studied plant) that could stop the growth of Erwinia carotovora inoculated on culture medium in Petri dishes.
Figure 1 shows higher production of dried crude extracts from roots and leaves of Maesa lanceolata L.
Yield of dried crude extracts from different parts of Guizotia scabra and Maesa lanceolata were utilized in order to evaluate their anti-microbial activity on isolated and cultivated Erwinia carotovora causing potato soft rot as shown in Table 2.
The Maesa lanceolata extract had a higher anti-bacterial activity on potato bacterium at initial dose of 5 microliters while Guizotia scabra demonstrated an antimicrobial effect at 10 microliters as shown in Figure 2.
Figure 2 shows that the minimum volume for Erwinia carotovora inhibition was 1 ml considered as minimum dose for Maesa lanceolata roots extract having an inhibition zone of 3 mm, while at the same dose Guitia scabra has 0 mm.
Maesa lanceolata roots and leaves extracts were more active than those of Guizotia scabra roots and leaves.