Synergistic combinations of various antimicrobial agents are considered ideal strategies in combating clinical and multidrug resistant (MDR) infections. In this study, antibacterial potential of
Jatropha curcas
crude seed extracts, seed oil, commercially available antibiotics, and their combinations were investigated for their synergistic effect against clinical, MDR and ATCC bacterial strains by agar well diffusion assay. Methanolic extracts remained more active against
Staphylococcus aureus
(ATCC), with zone of inhibition (ZOI) of 21 mm, than clinical and methicillin-resistant
S. aureus
(MRSA) strains (ZOI range ~ 15.0–17.0 mm). Molecular docking demonstrated that beta-monolaurin from methanolic extract exhibited greater affinity conformation for UDP-
N
-acetylmuramoyl-tripeptide–
d
-alanyl-
d
-alanine (MurF) ligase’s active pocket with binding energy of -7.3 kcal/mol. Moxifloxacin exhibited greater activity against
Escherichia coli
(ATCC) (ZOI ~ 50.0 mm), followed by ofloxacin against
Pseudomonas chlororaphis
(47.3 mm), moxifloxacin against
P. monteilii
(47 mm)
, P. aeruginosa
(46.3 mm) and MRSA2 (46 mm) and ofloxacin against
S. aureus
(ATCC) strains (45.7 mm). Methanolic extract in combination with rifampicin showed the highest synergism against MRSA strains,
A. baumannii
,
E. coli, E. faecalis, S. aureus,
and
P. aeruginosa
,
A. baumannii
(MDR strain),
P. chlororaphis
,
E. coli
ATCC25922 and
S. aureus
ATCC25923. In combinations, moxifloxacin exhibited the highest antagonism. The methanolic,
n
-hexane, aqueous extracts and seed oil in various combinations with antibiotics showed 44.71, 32.94, 9.41 and 25.88% synergism, respectively. The current study showed that potency of antibiotics was improved when screened in combination with
J. curcas
seed’s components, supporting the drug combination strategy to combat antibacterial resistance.
Electronic supplementary material
The online version of this article (10.1186/s13568-019-0793-6) contains supplementary material, which is available to authorized users.