Anticancer and antibacterial effects of a clove bud essential oil-based nanoscale emulsion system

Figures & data

Table 1 Clove bud oil formulations with Tween 20 (CB) and Tween 80 (CBO) surfactant, respectively, reported against their visual appearance

Formulation code	Oil	Surfactant	Water	Appearance
CB-1, CBO -1 (1:1)	5	5	90	Milky white
CB-2, CBO - 2 (1:2)	5	10	85	Cloudy
CB-3, CBO - 3 (1:3)	5	15	80	Cloudy
CB-4, CBO - 4 (1:4)	5	20	75	Clear and transparent
CB-5, CBO - 5 (1:5)	5	25	70	Clear and transparent
CB-6, CBO - 6 (1:6)	5	30	65	Clear and transparent
CB-7, CBO - 7 (1:7)	5	35	60	Clear and transparent
CB-8, CBO - 8 (1:8)	5	40	55	Clear and transparent
CB-9, CBO - 9 (1:9)	5	45	50	Clear and transparent
CB-10, CBO - 10 (2:8)	10	40	50	Clear and transparent
CB-11, CBO - 11 (3:7)	15	35	50	Clear and transparent
CB-12, CBO - 12 (4:6)	20	30	50	Milky white
CB-13, CBO - 13 (5:5)	25	25	50	Milky white
CB-14, CBO - 14 (6:4)	30	20	50	Milky white
CB-15, CBO - 15(7:3)	35	15	50	Milky white
CB-16, CBO - 16 (8:2)	40	10	50	Milky white
CB-17, CBO - 17(9:1)	45	5	50	Milky white

Figure 1 Images of formulations from 1:1 to 1:9 and 1:9 to 9:1, respectively, of the nanoscale emulsion of clove bud oil in Tween 20 and Tween 80 surfactant.

Figure 2 Ternary phase diagram constructed using clove bud oil, Tween 20, and 80, respectively, and water showing oil/water microemulsion region varying oil:surfactant ratio from 1:1 to 1:9 (left), and from 1:9 to 9:1 (right) for both Tween 20 and Tween 80.

Figure 3 Droplet size distribution of the optimized formulation CB-4 (clove bud microemulsion formulation with oil: surfactant [Tween 20] ratio of 1:4) showing the particle size in the nanometer range using dynamic light scattering technique.

Figure 4 Variation of pH with oil:surfactant ratio (1:1 to 1:9) for the oil-based nanoscale emulsion in Tween 20 surfactant.

Figure 5 Variation of absorbance measured by the UV-Spectrophotometer with oil:surfactant ratio (1:1 to 1:9) for the oil-based nanoscale emulsion in Tween 20 surfactant.

Figure 6 Variation of viscosity measured by the Brookfield viscometer with oil:surfactant ratio (1:1 to 1:4) for the oil-based nanoscale emulsion in Tween 20 surfactant.

Figure 7 Effect of treatment with clove bud microemulsion on cell viability of Hek 293 (A) and HTh-7 (B) after 48 hrs incubation by MTT assay. (*P<0.05 compared with respective control).

Figure 8 (A and B) Colony formation assay showing significant decrease of HTh-7 cells on treatment with microemulsion CB-4 (clove bud oil: Tween 20 ratio of 1:4; right), as compared to untreated control (left) indicating antiproliferative effect. (*P<0.05 compared with respective control).

Figure 9 Effect of treatment with clove bud microemulsion at 0.7 µL/mL, 48 hrs against HTh-7 cells, in comparison with control using Annexin V-FITC/PI assay showing later stage apoptosis and early necrosis.

Figure 10 Well diffusion assay of Staphylococcus aureus treated with clove bud emulsion (top) and clove bud oil (bottom).

Figure 11 Membrane permeability study showing significant increase in the cytoplasmic leakage from Staphylococcus aureus on interaction with clove bud oil nanoscale emulsion (CB-4), as compared to untreated control cells.