Nanostructured lipid system as a strategy to improve the anti-Candida albicans activity of Astronium sp.

Figures & data

Table 1 Experimental groups and treatments used in the study

Experimental groups	Specification	Treatment
1	Non-infected control	–
2	Infected control	–
3	Positive control (antimicrobial treatment)	0.1 mL of antifungal cream (tetracycline + amphotericin B)
4	Solvent control	0.1 mL of a solution (20% DMSO)
5	Treatment 1	0.1 mL of pure extract (250 µg/mL)
6	Vehicle control for microemulsion	0.1 mL of microemulsion
7	Treatment 2	0.1 mL of extract-loaded nanostructured lipid system (250 µg/mL)

Abbreviation: DMSO, dimethyl sulfoxide.

Table 2 Results of biological assessments (MIC and IC₅₀) and determination of the SI of extracts of Astronium sp. alone (unincorporated) or incorporated into the nanostructured lipid system for Candida albicans

Extracts	Parameters
	Unincorporated			Incorporated
	IC50(µg/mL)	MIC (µg/mL)	SI	IC50(µg/mL)	MIC (µg/mL)	SI
AFs	767.20	>1,000.00	<0.76	>1,000.00	62.50	>16.00
AFl	950.00	>1,000.00	<0.95	>1,000.00	250.00	>4.00
AGs	>1,000.00	>1,000.00	<1.00	>1,000.00	62.50	>16.00
AGl	833.00	>1,000.00	<0.83	>1,000.00	125.00	>8.00
AUs	900.00	>1,000.00	<0.90	>1,000.00	62.50	>16.00
AUl	536.10	125.00	4.28	>1,000.00	15.62	>64.02
Positive controls	MIC (µg/mL)
Amphotericin B	0.06
Fluconazole	8.00

Abbreviations: MIC, minimal inhibitory concentration; IC₅₀, half maximal inhibitory concentration; AFs, Astronium fraxinifolium stem; AFl, A. fraxinifolium leaves; AGs, A. graveolens stem; AGl, A. graveolens leaves; AUs, A. urundeuva stem; AUl, A. urundeuva leaves; SI, selectivity index.

Figure 1 Pseudoternary phase diagram for the system containing SPC/Brij^® 58 (S), CHO (O), and aqueous buffer (W).

Abbreviations: TLS, transparent liquid system; VOS, viscous and opaque system; PS, phase separation; TVS, transparent viscous system; VSTS, viscous semitransparent system.

Table 3 Determination of the droplet size and polydispersity of the ME by light scattering

Formulation	Mean diameter ± SD (nm)*	Mean PDI ± SD*
ME	117.200±1.966	0.245±0.006
AFs	123.600±0.252	0.222±0.003
AFl	133.100±0.551	0.276±0.008
AGs	126.700±0.702	0.249±0.007
AGl	135.400±0.551	0.237±0.002
AUs	141.900±1.137	0.268±0.000
AUl	146.700±1.825	0.255±0.010

Note:

* SD, PDI.

Abbreviations: ME, microemulsion; SD, standard deviation; PDI, polydispersity index; AFs, Astronium fraxinifolium stem; AFl, A. fraxinifolium leaves; AGs, A. graveolens stem; AGl, A. graveolens leaves; AUs, A. urundeuva stem; AUl, A. urundeuva leaves.

Figure 2 Transmission electron micrographs of ME at a magnification of 400,000× (A) and 800,000× (B), respectively.

Abbreviation: ME, microemulsion.

Figure 3 X-ray scattering curves for ME and ME + AUl.

Abbreviations: ME, microemulsion; AUl, A. urundeuva leaves.

Figure 4 Peak of bioadhesion (N) of AUl-unloaded microemulsion and AUl-loaded microemulsion.

Note: Each value represents the mean (± standard deviation) of at least seven replicates.

Abbreviation: AUl, A. urundeuva leaves.

Table 4 Fungal loads (CFUs) obtained from the culture of vaginal fluid collected during the treatment period

Groups	Treatment
	Day 2	Day 4	Day 6
Positive control (infection)	1,585.0±13.0	1,692.0±37.0	986.8±11.0
Positive control (tetracycline + amphotericin B)	1,600.0±9.0	836.0±33.0	264.6±23.0
Solvent control (DMSO)	1,608.0±8.0	1,641.0±65.0	982.8±18.0
Treatment 1	1,553.0±27.0a,*	776.0±73.0b,*	195.6±50.0b,*
Microemulsion	1,590.0±13.0	1,657.0±17.0	932.8±21.0
Treatment 2	1,589.0±47.0a	349.0±31.0b,*	0.0±27.0b,*

Notes:

a Non-significant and

b significant differences between treatments 1 and 2 according to parametric post-hoc test (P<0.05 – Tukey’s test).

* Significant difference (P<0.05) when compared with the positive control group (tetracycline + amphotericin B – Dunnett’s test).

Abbreviations: CFU, colony-forming unit; DMSO, dimethyl sulfoxide.