Chemical identification and evaluation of the antimicrobial activity of fixed oil extracted from Rhinella jimi

Figures & data

Figure 1. The municipality of Exu (7°30′S × 39°43′W), Pernambuco State in Brazil.

Table 1. Methyl esters and fatty acids identified in the fixed oil extracted from Rhinella jimi specimens collected in Exu – PE (ORJ) using a gas chromatograph coupled to a mass spectrometer (CG/MS), in increasing order of retention/min (RT).

Constituents	RT (min)	(%)	Equivalent fatty acid
Saturated
Methyl dodecanoate	17.5	0.6	Lauric acid
Methyl tetradecanoate	21.9	2.4	Myristic acid
Methyl pentadecanoate	23.2	1.9	Pentadecanoic acid
Methyl eicosanoate	33.9	0.4	araquídico acid
Methyl octadecanoate	30.6	8.1	Steric acid^a
Methyl hexadecanoate	25.9	26.8	Palmitic acid^a
Methyl heptadecanoate	27.8	1.6	Heptadecanoic acid
Unsaturated
Methyl (Z,Z)-octadeca-9, 12-dienoate	29.5	6.2	Linoleic acid^a
Methyl (E)-octadec-10-enoate	29.8	38.0	Oleic acid^a
Methyl (Z)-octadec-13-enoate	29.9	1.4	Oleic acid^a
Methyl hexadec-11-enoate	25.3	1.4	Palmitoleic acid
Methyl (Z)-hexadec-9-enoate	25.4	4.9	Palmitoleic acid
Total		93.7

^aPrincipal fatty acids.

Table 2. Test results of ORJ concentrations as effective modulators of micro-diluted antibiotics. Control = without ORJ. All results in µg/mL.

	S. aureus 358		P. aeruginosa 24		E. coli 27
Antibiotics	ORJ	Control	ORJ	Control	ORJ	Control
Amikacin	78.12	39.06	39.06	312.50^a	39.06	156.25^a
Neomycin	9.76	9.76	39.06	156.25^a	39.06	78.12
Gentamicin	2.44	4.88	9.76	39.06^a	9.76	19.53

^aMost expressive results.

Table 3. Test results of the use of ORJ concentrations as effective modulators of the actions of micro-diluted anti-fungal agents. Control = without ORJ.

	C. albicans ICB 12		C. krusei ATCC6258
Anti-fungal agent	ORJ	Control	ORJ	Control
Mebendazol	≥1024	≥1024	≥1024	≥1024
Amphotericin B	≥1024	≥1024	64^a	512^a
Nystatin	≥1024	≥1024	≥1024	≥1024
Benzoilmetronidazole	≥1024	≥1024	≥1024	≥1024

All results in µg/mL.

^aSignificant results.

Table 4. Results of the checkerboard experiments using ORJ with amikacin, gentamicin, and neomycin against the multi-resistant bacteria Escherichia coli 27 and Pseudomonas aeruginosa 24, and the types of interactions of ORJ with aminoglycosides.

	E. coli 27		P. aeruginosa 24
	MIC	MIC combined	MIC	MIC combined
ORJE	1024	4	1024	64
Amikacin	78.12	19.53	39.06	78,12
CIF and type of interaction	0.25 – synergistic		2.06 – indifferent
ORJE			1024	8
Gentamicin			39.06	19,53
CIF and type of interaction			0.51 – additive
ORJE			1024	16
Neomycin			39.06	39,06
CIF and type of interaction			1.01 – indifferent

MIC, minimum inhibitory concentration; ORJ_E, Rhinella jimi oil collected in Exu – PE; FIC, fractionated inhibitory concentration.