Preclinical Research on Cinnamic Acid Derivatives for the Prevention of Liver Damage: Promising Therapies for Liver Diseases

Abstract

Background: Liver diseases are a global health issue with an annual mortality of 80,000 patients, mainly due to complications that arise during disease progression, as effective treatments are lacking. Objectives: This study evaluated the hepatoprotective effects of two derivatives of cinnamic acid, LQM717 and LQM755, in a murine model of acute liver damage induced by carbon tetrachloride (CCl_4, 4 g/kg, single dose p.o.). Methods: Male Wistar rats were pretreated with five doses of LQM717 (20 mg/kg i.p.) or LQM755 (equimolar dose), starting 2 days before inducing hepatotoxic damage with CCl₄. Results: The key parameters of hepatocellular function and damage showed significant increases in ALT, ALP, GGT, and total and direct bilirubin in rats intoxicated with CCl₄, with decreased liver glycogen and serum albumin. Macroscopic and microscopic liver examinations revealed reduced inflammation, necrosis, and steatosis in animals pretreated with LQM717 or LQM755. Hepatomegaly was observed only in the LQM717 + CCl₄ group. LQM755 statistically provided partial protection against increases in ALT and ALP and completely prevented elevations in GGT and total and direct bilirubin. LQM755 completely prevented albumin reduction, while LQM717 only partially prevented it. Both compounds partially prevented glycogen depletion. Bioinformatic analysis identified 32 potential liver protein targets for LQM717 and 36 for LQM755. Conclusions: These findings suggest that LQM717 and LQM755 have significant hepatoprotective effects against CCl₄-induced acute liver injury, providing information for future studies in other acute and chronic models, as well as to elucidate their mechanisms of action.

Keywords: CCl4; LQM717; LQM755; cinnamic acid derivatives; liver damage.

Figure 1

Chemical structure of CAPE.

Figure 2

3-(4-Phenoxyphenyl)-2-propenoic acid. Yield: 85%; mp 156–157 °C. IR (diamond, cm⁻¹): νmax 1588, 3031, 3200–2200. ¹H NMR (300 MHz, CDCl₃): δ 6.30 (1H, d), 6.90 (5H, m), 7.24 (4H, m), 7.64 (1H, d, J = 15.6 Hz), 8.95 (1H, s). ¹³C NMR (75 MHz, CDCl₃): δ 116.02, 117.02, 117.32, 121.61, 125.69, 128.21, 128.91, 144.64, 155.32, 156.13, 169.64.

Figure 3

LQM717—N-(2-Chlorobenzyl)-2-phenylacetamide (11). Yield: 3.9 g (79.83%); mp 118–120 °C. IR (diamond, cm⁻¹): νmax 1546, 2923, 3274. ¹H NMR (300 MHz, CDCl₃, Me₄Si): δ 3.63 (2H, s), 4.46 (2H, d, J = 4.0 Hz), 5.90 (1H, br s, NH), 7.29 (9H, m). ¹³C NMR (75 MHz, CDCl₃, Me₄Si): δ 42.05, 44.18, 127.44, 127.85, 129.28, 129.48, 129.88, 129.89, 130.32, 133.91, 135.05, 135.86, 171.29. Elemental analysis calcd. for C₁₅H₁₄ClNO: C, 69.33; H, 5.43; Cl, 13.64; N, 5.39; O, 6.16. Found: C, 69.44; H, 5.05; Cl, 13.50; N, 5.71; O, 6.22.

Figure 4

LQM755.—3-(4-Phenoxy)phenyl-N-[(3,4-dichlorophenyl)methyl]prop-2-enamide. Yield: 41.98%; mp 136 °C; white solid. IR (diamond, cm⁻¹): νmax 3400–3100 (N–H), 3043.48 (C–H sp²), 2921.22 (C–H sp³), 2478.05, 2401.64, 2328.29, 1606.98 (C=O), 1495 (C=C). ¹H NMR (300 MHz, CDCl₃, Me₄Si): δ 8.67 (1H, t, NH), 7.57–7.56 (1H, m), 7.55–7.54 (2H, m), 7.50 (2H, d), 7.42 (1H, d, =CH), 7.40–7.37 (1H, m), 7.26–7.24 (1H, m), 7.16–7.13 (1H, m), 7.04–7.02 (2H, m), 6.96 (2H, d), 6.55 (1H, d, =CH), 4.36 (2H, d, CH₂). ¹³C NMR (75 MHz, CDCl₃, Me₄Si): δ 165.79, 158.60, 156.38, 141.37, 139.13, 131.42, 131.04, 130.71, 129.79, 128.22, 130.36, 130.03, 124.60, 129.86, 121.10, 118.92, 119.82, 41.79. Elemental analysis calcd. for C₂₂H₁₇Cl₂NO₂: C, 66.30; H, 4.30; Cl, 17.80; N, 3.52; O, 8.04. Found: C, 69.35; H, 5.05; Cl, 17.60; N, 3.49; O, 8.01.

Figure 5

Experimental groups and dosing schedule.

Figure 6

Synthesis of 4-phenoxy cinnamic acid.

Figure 7

Preparation of LQM717 and LQM755. (a) LQM717: N-(2-Chlorobenzyl)-2-phenylacetamide, yield (3.9 g, 79.83%); mp 118 –120 °C. IR (Diamond, cm⁻¹): ν max 1546, 2923, 3274. ¹H NMR (300 MHz; CDCl₃; Me₄Si) δ (ppm)3.63 (2H, s), 4.46 (2H, d, J = 4.0), 5.90 (1H, br, s, NH), 7.29 (9H, m); ¹³C NMR (75 MHz; CDCl₃; Me₄Si) δ (ppm) 42.05 (CH₂), 44.18 (CH₂), 127.44, 127.85, 129.28, 129.48, 129.88, 129.89, 130.32, 133.91, 135.05, 135.86 (Ph), 171.29 (-CO-). Analysis Calc. For C₁₅H₁₄ClNO: C, 69.3; H, 5.4; N, 5.3. Found C, 69.35; H, 5.05; N, 5.71. (b) LQM755: Yield (42%), mp 135–136 °C. IR (Diamond, cm⁻¹): ν max 1495, 1606, 2478, 2401, 2328, 2921, 3043, 3100–3400. ¹H NMR (500 MHz; DMSO-D₆; Me₄Si) δ (ppm) 4.35 (2H, d), 6.55 (1H, d), 6.96 (2H, d), 7.03 (2H, m), 7.14 (1H, m), 7.24 (1H, m), 7.38 (1H, m), 7.42 (1H, d), 7.50 (2H, d), 7.54 (2H, m), 7.56 (1H, m), 8.66 (1H, t). ¹³C NMR (125 MHz DMSO-D₆; Me₄Si) δ (ppm) 41.78 (-CH₂-), 119.82 (-CH=), 118.92, 121.09, 124.60, 128.21, 129.85, 129.79, 130.36, 130.71, 131.04, 131.42, 139.13 (Ph), 141.36 (-CH=), 15637, 158.59 (Ph), 165.79 (C=O).

Figure 8

Analysis of body and liver weights. (a) Body weights at the beginning of the experiment. (b) Body weights on the day of sacrifice. (c) Liver Weights after sacrifice. (d) Ratio between liver weight and body weight. Results show the average of each group ± SD. Statistically significant differences using a one-way ANOVA with a Tukey–Kramer post hoc test (* p < 0.05, ** p < 0.01, *** p < 0.001).

Figure 9

Representative images of livers in situ. (a) Healthy controls. (b) Group intoxicated with only hepatotoxic CCl₄ and groups pretreated with LQM717 or LQM755 and intoxicated with CCl₄.

Figure 10

Representative images of histological liver sections stained with H&E. CV = central vein; H = hepatocytes; white arrow = steatosis; black arrow = ballooning necrosis; asterisk = sinusoid.

Figure 11

Representative images of histological liver sections stained with PAS. CV = central vein; H = hepatocytes; asterisk = sinusoid.