Hepatoprotective and antidiabetic effects of Pistacia lentiscus leaf and fruit extracts

Abstract

Pistacia lentiscus (Anacardiaceae) is commonly used in folk medicine to treat various diseases. The aim of the present study was to evaluate the hepatoprotective and antioxidant activities of extracts of P. lentiscus leaves (PL) and fruits (PF) against experimentally induced liver damage. Furthermore, characterization of extracts was attempted by a spectroscopic methodology (Fourier transform infrared spectroscopy) and high-performance liquid chromatography with diode array detection analysis. A hepatoprotective potential against paracetamol [165 mg/kg body weight (b.w.)] toxicity was noticed in mice pretreated with the same dose of PL or PF extract (125 mg/kg b.w.) or a combination of both (PL/PF 63/63 mg/kg b.w.), as revealed by an analysis of biochemical parameters (alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase activities and total bilirubin). These results were confirmed by histological examination of the liver, which revealed significant protection against paracetamol-induced hepatic necrosis. Furthermore, PF extract exhibited a promising antidiabetic activity in streptozotocin-induced diabetic rats, similar to the reference drug glibenclamide (0.91 g/L), a result confirmed by in vitro inhibition of α-amylase. We demonstrated that the leaf crude extract showed the best effect in all tested methods, compared to its fruit counterpart, probably due to the presence of higher amounts of phenolic compounds, as determined by phytochemical and Fourier transform infrared spectroscopy analyses. Moreover, high-performance liquid chromatography with diode array detection led to the identification of six compounds for each part of the plant. Gallic acid, a characteristic compound of Pistacia species, was most abundant in leaves and fruits, while luteolin was detected for the first time in fruits. Obtained activities of P. lentiscus extracts may well be due, at least in part, to the presence of the above compounds.

Keywords: Fourier transform infrared spectroscopy; Pistacia lentiscus; antidiabetic; antioxidant; hepatoprotective; high-performance liquid chromatography; α-amylase.

Figure 1

FTIR spectra of the crude extracts of (A) Pistacia lentiscus leaves and (B) fruits. FTIR = Fourier transform infrared spectroscopy.

Figure 2

Oxygen uptake during the autoxidation of methyl linoleate induced by AIBN in the presence of different Pistacia lentiscus leaf extracts and the reference (catechin). AIBN = 2,2′-azodiisobutyronitrile.

Figure 3

Oxygen uptake during the autoxidation of methyl linoleate induced by AIBN in the presence of different Pistacia lentiscus fruit extracts and the reference (catechin). AIBN = 2,2′-azodiisobutyronitrile.

Figure 4

Rat weight versus time. All values are expressed as mean ± SEM, n = 5. Group A is the normal control group; Group B, 50 mg/kg b.w. Pistacia lentiscus leaf crude extract-treated group; Group C, 250 mg/kg b.w. P. lentiscus leaf crude extract-treated group; Group D, 50 mg/kg b.w. P. lentiscus fruit crude extract-treated group; and Group E, 250 mg/kg b.w. P. lentiscus fruit crude extract-treated group. b.w. = body weight; SEM = standard error of the mean.

Figure 5

Effect of PL and PF crude extracts on rat livers after treatment for 28 days. Histological changes in rat liver after treatment with Pistacia lentiscus leaf and fruit crude extracts are shown. Rats were administered orally 50 mg/kg b.w. and 250 mg/kg b.w. of leaf and fruit crude extracts. The liver was stained with hematoxylin and eosin method: (A) control group (normal central vein and hepatocytes); (B) 50 mg/kg b.w. PL-treated group (light steatosis); (C) 250 mg/kg b.w. PL-treated group (steatosis); (D) 50 mg/kg b.w. PF-treated group (sub-normal structure); and (E) 250 mg/kg b.w. PF-treated group (light necrosis) (magnification 200×). Each arrow indicates an adipocyte linked to a lateral nucleus membrane. cv = central vein; d = degenerated hepatocytes; h = surrounding hepatocytes; m = infiltration of inflammatory cells; n = focal necrosis; PF = P. lentiscus fruits; PL = P. lentiscus leaves; s = dilated hepatic sinusoids.

Figure 6

Effect of PL and PF crude extracts on rat kidneys after treatment for 28 days. Histological changes in kidneys of rats treated with Pistacia lentiscus leaf and fruit crude extracts are shown. Rats were administered orally 50 mg/kg b.w. and 250 mg/kg b.w. of plant extracts. Kidney tissue was stained with hematoxylin and eosin: (A) control rats group (normal kidney structure); (B) 50 mg/kg b.w. PL-treated group (minor necrosis); (C) 250 mg/kg b.w. PL-treated group (distension of the renal tubules); (D) 50 mg/kg b.w. PF-treated group (subnormal kidney structure); and (E) 250 mg/kg b.w. PF-treated group (light necrosis) (magnification 250×). Arrows indicate coagulate necrosis of tubular epithelial cells and arrow heads dilated hypocellular tubules. D = intratubular debris; G = glomeruli; PF = P. lentiscus fruits; PL = P. lentiscus leaves.

Figure 7

MDA levels in different treated groups. All values are expressed as mean ± SEM, n = 7. One-way ANOVA followed by Dunnett multiple comparison test was used for statistical significance. The animal groups are as follows: GI, normal control group; GII, 165 mg/kg b.w. paracetamol-treated group; GIII, 125 mg/kg b.w. Pistacia lentiscus leaves crude extract-treated group; GIV, 125 mg/kg b.w. P. lentiscus fruits crude extract-treated group; and GV, 63/63 mg/kg b.w. P. lentiscus leaves/fruits crude extract-treated group. * p < 0.05, when compared with normal control values. ** p < 0.01, when compared with normal control values. *** p < 0.001, when compared with normal control values. ANOVA = analysis of variance; b.w. = body weight; MDA = malondialdehyde; SEM = standard error of the mean.

Figure 8

Effect of PL and PF crude extracts on liver pathologic analysis after paracetamol treatment in mice. Histological changes in the livers of paracetamol-treated rats that received orally PL (125 mg/kgb.w.), PF (125 mg/kg b.w.), or a mixture (PL/PF; 63 + 63 mg/kg b.w.) plant crude extracts are shown. Livers were stained with hematoxylin–eosin method. The animal groups are as follows: GI, normal control group (normal central vein and architecture); GII, paracetamol group (completely necrosed); GIII, PL-treated group (a very light necrosis); (GIV, PF-treated group [showing central vein containing blood (CV) and necrosis around the central vein] (200×); and GV, PL/PF-treated group (light necrosis, which occupies a tiny surface of the organ, but the rest of the organ is intact from both) (250×). b.w. = body weight; CV = central vein; FN = focal necrosis; PF = P. lentiscus fruits crude extract; PL = P. lentiscus leaves crude extract; PL/PF = P. lentiscus leaves/fruits crude extracts; S = dilated hepatic sinusoids.

Figure 9

Glucose levels in treated groups. All values are expressed as mean ± SEM, n = 6. One-way ANOVA followed by Dunnett multiple comparison test was used for statistical significance. The animal groups are as follows: GI, diabetic control; GII, glibenclamide-treated group; GIII, 50 mg/kg b.w. PL-treated group; GIV, 125 mg/kg b.w. PL-treated group; GV, 50 mg/kg b.w. PF-treated group; and GVI, 125 mg/kg b.w. PF-treated group. * Values deviate significantly (p < 0.05) from diabetic control. *** Values deviate very significantly (p < 0.001) when compared with diabetic control values. ANOVA = analysis of variance; b.w. = body weight; PF = Pistacia lentiscus fruits; PL = P. lentiscus leaves; SEM = standard error of the mean.

Figure 10

Comparison of α-amylase inhibitory effect of Pistacia lentiscus ethanolic leaf and fruit extracts at different concentrations. All values are expressed as mean ± SD, n = 3. One-way ANOVA followed by Dunnett multiple comparison test was used for statistical significance, when compared with acarbose. * p < 0.05. ** p < 0.01. *** p < 0.001. ANOVA = analysis of variance; SD = standard deviation.