Chitosan-tripolyphosphate nanoparticles as Arrabidaea chica standardized extract carrier: synthesis, characterization, biocompatibility, and antiulcerogenic activity

Abstract

Natural products using plants have received considerable attention because of their potential to treat various diseases. Arrabidaea chica (Humb. & Bonpl.) B. Verlot is a native tropical American vine with healing properties employed in folk medicine for wound healing, inflammation, and gastrointestinal colic. Applying nanotechnology to plant extracts has revealed an advantageous strategy for herbal drugs considering the numerous features that nanostructured systems offer, including solubility, bioavailability, and pharmacological activity enhancement. The present study reports the preparation and characterization of chitosan-sodium tripolyphosphate nanoparticles (NPs) charged with A. chica standardized extract (AcE). Particle size and zeta potential were measured using a Zetasizer Nano ZS. The NP morphological characteristics were observed using scanning electron microscopy. Our studies indicated that the chitosan/sodium tripolyphosphate mass ratio of 5 and volume ratio of 10 were found to be the best condition to achieve the lowest NP sizes, with an average hydrodynamic diameter of 150±13 nm and a zeta potential of +45±2 mV. Particle size decreased with AcE addition (60±10.2 nm), suggesting an interaction between the extract's composition and polymers. The NP biocompatibility was evaluated using human skin fibroblasts. AcE-NP demonstrated capability of maintaining cell viability at the lowest concentrations tested, stimulating cell proliferation at higher concentrations. Antiulcerogenic activity of AcE-NP was also evaluated with an acute gastric ulcer experimental model induced by ethanol and indomethacin. NPs loaded with A. chica extract reduced the ulcerative lesion index using lower doses compared with the free extract, suggesting that extract encapsulation in chitosan NPs allowed for a dose reduction for a gastroprotective effect. The AcE encapsulation offers an approach for further application of the A. chica extract that could be considered a potential candidate for ulcer-healing pharmaceutical systems.

Keywords: Arrabidaea chica; chitosan; herbal drug; nanoparticle; natural product; plant extract; ulcer healing.

Figure 1

Chemical structure of 3-deoxyanthocyanidins: pigment 1 (6,7,3′,4′-tetrahydroxy-5-methoxyflavylium), pigment 2 (6,7,4′-trihydroxy-5-methoxyflavylium), and pigment 3 (carajurin).

Figure 2

Images of Arrabidaea chica nanoparticles obtained by scanning electron microscopy.

Figure 3

Scanning electron micrograph of freeze-dried Arrabidaea chica nanoparticles (sponge).

Figure 4

Fibroblast viability in the presence of chitosan NPs, AcE, or AcE-NP at 0.5 mg·mL⁻¹. Notes: Data are presented as the mean ± standard deviation (n=8). Statistical analysis was performed using a one-way ANOVA followed by a Student’s t-test. *Significant difference between the AcE-NP and the control was P<0.05. Abbreviations: NP, nanoparticle; AcE, Arrabidaea chica extract; AcE-NP, Arrabidaea chica extract nanoparticle; n, number; ANOVA, analysis of variance.

Figure 5

Fibroblast viability in relation to 24-hour, 48-hour, or 72-hour exposure to chitosan NPs, AcE, or AcE-NPs. Notes: (A) 24 hours; (B) 48 hours; (C) 72 hours. Data are shown as the mean ± standard deviation (n=8). Statistical analysis was performed using a one-way ANOVA followed by a Student’s t-test. *P<0.01; **P<0.001. Abbreviations: NP, nanoparticle; AcE-NP, Arrabidaea chica extract nanoparticle; AcE, Arrabidaea chica extract; n, number; ANOVA, analysis of variance.

Figure 6

Ulcerative lesion index of nonloaded NPs and AcE-NP on ethanol-induced gastric ulceration in rats. Notes: Data are shown as the mean ± standard error (n=6). Statistical analysis was performed using a one-way ANOVA followed by Tukey’s test. ***P<0.001 compared with negative control (saline). Carbenoxolone was used as a positive control. Abbreviations: NP, nanoparticle; AcE-NP, Arrabidaea chica extract nanoparticle; n, number; ANOVA, analysis of variance.

Figure 7

Ulcerative lesion index of AcE-NP on indomethacin-induced gastric ulceration in rats. Notes: Data are shown as the mean ± standard error (n=6). Statistical analysis was performed using a one-way ANOVA followed by Tukey’s test. *P<0.001; **P<0.01 compared with negative control (saline). Ranitidine was used as a positive control. Abbreviations: AcE-NP, Arrabidaea chica extract nanoparticle; n, number; ANOVA, analysis of variance.