Discussion

The first objective of this study, which was to extract the antimicrobial compounds from Ficus deltoidea was achieved. Bioactive compounds were effectively obtained from plant extraction and this was depended on the type of solvent used in the extraction procedure. To choose which type of solvent to use to get a good extraction, the solvent must be easy to evaporate at low toxicity, easy to evaporate at low heat, have preservative action and the inability to cause the extract to complex or dissociate (Tiwari et al, 2011).

In this experiment, methanol was used as the solvent for the extraction process because it has characteristic of all good solvent. Since all identified compounds from plant against microorganisms are aromatic or saturated organic compounds, they are most easily obtained through methanol extraction
(Cowan, 1999) 

Then the second objective was to determine the effect of F.deltoidea leaf extract on mycelial growth of selected plant pathogenic fungi. The extract from F.deltoidea leaves showed antifungal activity against the two tested fungal pathogens. The leaf extract inhibited the mycelial growth of Ganoderma boninense at 55.9% compared to Rhizoctonia solani inhibited at 53.67% at 5% concentration. Statistical analysis of percent of inhibition of Ganoderma boninense and Rhizoctonia solani showed no significant difference. 

Different concentrations of F.deltoidea leaf extract used in this experiment also influenced the mycelial growth of the pathogens. During the tests, the leaf extract of F.deltoidea was observed to inhibit the mycelial growth for both fungal pathogens at the minimum concentration of 5%. It shows that even at 5% concentration of F.deltoidea leaf extract could inhibit the mycelial growth of both fungal pathogens even though the percentage of inhibition is different. Besides, the other reasons are related to the types of secondary metabolites existing and the composition of these secondary metabolites differs in plants from species to species. However, the other concentrations for both fungal pathogens showed a good percentage of inhibition. 

Most of the studies of the Ficus species revealed the presence of phenolic compounds as major components from different parts (leaves, stem wood, branches, stem bark, roots, root bark, fruits, and seeds)
(Abdel-Hameed, 2009). 

Besides, the other reasons are related to the types of secondary metabolites existing and the composition of these secondary metabolites differs in plants from species to species. The methanol leaf extract of F.deltoidea exhibited good antibacterial and antifungal activities against the test organisms.
(Salem et.al., 2013).

The presence of alkaloids, flavonoids and cardiac glycosides in the leaves of these Ficus species may have conferred the antimicrobial properties on these species. (Salem et.al., 2013). 

Thus additional study is recommended to classify the chemical constituents in F.deltoidea leaf extract that inhibit the growth of fungi and to study concentrations of leaf extract below 10% as this study showed that 10% concentration of the leaf extract could fully inhibit the two tested plant pathogenic fungi. 

In addition, more study should be done to test more on plant pathogenic fungi. Moreover, other parts of F.deltoidea plant could be tested to determine their effectiveness on plant pathogenic fungi.