Enhancement of epimedium fried with suet oil based on in vivo formation of self-assembled flavonoid compound nanomicelles

Abstract

The purpose of this work was to research the enhancement of Epimedium fried with suet oil based on the in vivo formation self-assembled flavonoid nanomicelles. Taking icariin as the representative, under the action of suet oil, self-assembled nanomicelles were prepared under simulated gastrointestinal tract conditions and were characterized by dynamic light scattering and transmission electron microscopy (TEM). The experiments with icariin self-assembled nanomicelles without suet oil were done according to the above. The influence of suet oil on the transportation of icariin across Caco-2 cell monolayers and the absorption in rat intestine of self-assembled nanomicelles were evaluated. The particle size of icariin self-assembled nanomicelles with suet oil was smaller than without suet oil. The nanomicelles seemed to be monodisperse spherical particle with smooth surfaces. The icariin entrapment efficiency of self-assembled nanomicelles with suet oil was increased from 43.1% to 89.7%. In Caco-2 cell monolayers, the absorptive permeability, secretory permeability and efflux ratio of icariin self-assembled nanomicelles with suet oil was 1.26 × 10−6 cm/s, 5.91 × 10−6 cm/s and 4.69, respectively, while that of icariin self-assembled nanomicelles without suet oil was 0.62 × 10−6 cm/s, 3.00 × 10−6 cm/s, and 4.84, respectively. In rat intestinal perfusion experiments, the permeability coefficient of icariin self-assembled nanomicelles with suet oil in duodenum was higher than the value of icariin self-assembled nanomicelles without suet oil (p < 0.05). With the action of suet oil, icariin self-assembled nanomicelles were more stable and the entrapment efficiency was higher than that without suet oil, which could increase the solubility of icariin and improve its intestinal absorption. Therefore, suet oil plays a role in its enhancement.

Figure 1

Chemical structure of icariin.

Figure 2

TEM figures of the self-assembled nanomicelles: (A) icariin + DOC (A1: ×5.0 K; A2: ×20.0 K); (B) icariin + DOC + suet oil (B1: ×7.0 K; B2: ×12.0 K).

Figure 3

The transportation of icariin as time changes. Cumulative amounts of icariin transported across Caco-2 cell monolayers. The cumulative amount transported at each time point using the Kruskal–Wallis test followed by Tamhane’s post hoc was used to analyze the data statistically, n = 3. (a: 20 μM icariin + DOC A-B; b: 20 μM icariin + DOC B-A; c: 20 μM icariin + DOC + suet oil A-B; d: 20 μM icariin + DOC + suet oil B-A).

Figure 4

Permeabilities of icariin + DOC and icariin + DOC + suet oil. The experiments were performed at 37°C. Each bar represents the average of three determinations and the error bars are the standard deviation of the means. One-way ANOVA with Tamhane’s post hoc test was used to analyze the data statistically, ** p < 0.01 and * p < 0.05. (a: 20 μM icariin + DOC; b: 20 μM icariin + DOC + suet oil).

Figure 5

The cellular accumulation of the icariin + DOC and icariin + DOC + suet oil. The accumulation was measured after 4 h incubation of cell monolayers with the icariin + DOC and icariin + DOC + suet oil. Each data point is the average of three determinations, and the error bars represent the standard deviation of the mean. One-way ANOVA with Tamhane’s post hoc test was used to analyze the data statistically, *** p < 0.001. (a: 20 μM icariin + DOC; b: 20 μM icariin + DOC + suet oil).

Figure 6

Comparison of permeability coefficient between four different intestinal segments. Data are expressed as mean ± S.D. (n = 4). The statistically significant differences are shown by the asterisk symbol, * p < 0.05 (a: 20 μM icariin + DOC, b: 20 μM icariin + DOC + suet oil).