Abstract
•Composition of two medicinal plants essential oils (EO) was authenticated by GC–MS.•EO effectively protected jack fruit from spoilage fungi.•EO from Ocimum basilicum and Vetiveria zizanioides revealed increased synergistic activity.•EO vapours predominantly reduced the growth of P. notatum and R. microspores.•EO from V. zizanioides and O. basilicum documented good antioxidant activities.
The essential oil (EO) composition of Vetiveria zizanioides and Ocimum basilicum were analysed and its post-harvest protective properties of jack fruits (Artocarpus heterophyllus Lam.) against the spoilage bacteria and fungi were investigated. Hydrodistillation and GC–MS analysis documented the presence of various components, including, hexamethyl-cycloocta-1,3,6-triene, d-Cadinene, Cedren-8-en-15-ol, 2-Isopropenyl-1,3,5-trimethylbenzene, metylchavico and trans-sabinene in V. zizanioides and O. basilicum, respectively. V. zizanioides EO showed potent activity against Staphylococcus aureus and Proteus mirabilis and the zone of inhibition was 32 ± 2, 26 ± 0 mm, respectively. Whereas, O. basilicum oil showed potential activity against Streptococcus mutans (28 ± 3 mm) and Rhizopus microsporus (28 ± 3 mm). EO of V. zizanioides exhibited high activity against S. aureus (MIC = 50 ± 0 μg/ml), followed by P. mirabilis (MIC = 75 ± 5 μg/ml). The EO from O. basilicum displayed high activity against S. mutans (MIC = 50 ± 0 μg/ml). The EOs from these two sources showed synergistic effect on S. mutans (29 ± 2 mm), P. mirabilis (27 ± 2 mm), Enterobacter aerogenes (13 ± 3 mm), S. aureus (34 ± 3 mm), Penicillium notatum (22 ± 3 mm) and R. microsporus (33 ± 3 mm). In addition, the EO at 100 μg/ml concentration V. zizanioides (79 %) and O. basilicum (83 %) documented significant antioxidant activity. The mixture of Vetiver roots and Ocimum oil suppressed the growth of P. notatum. The colony area was 32 ± 3.5 cm2 after incorporation of 5 μl EO concentration. However, at 25 μl concentration, colony area decreased as 4.2 ± 1 cm2 after 7 days of incubation and spore germination was completely suppressed. R. microsporus growth was decreased at 100 μl concentration. EO significantly reduced the spreading of rot causing P. notatum on the surface of jack fruit is an additional advantage. Overall, the results concluded that the obtained EO counter the severity of P. notatum and R. microsporus on the surface of jack fruit and protect from spoilage and deterioration.