Cytoprotective Potential of Aged Garlic Extract (AGE) and Its Active Constituent, S-allyl-l-cysteine, in Presence of Carvedilol during Isoproterenol-Induced Myocardial Disturbance and Metabolic Derangements in Rats

Abstract

This study was conducted to determine the potential interaction of aged garlic extract (AGE) with carvedilol (CAR), as well as to investigate the role of S-allyl-l-cysteine (SAC), an active constituent of AGE, in rats with isoproterenol (ISO)-induced myocardial dysfunction. At the end of three weeks of treatment with AGE (2 and 5 mL/kg) or SAC (13.1 and 32.76 mg/kg), either alone or along with CAR (10 mg/kg) in the respective groups of animals, ISO was administered subcutaneously to induce myocardial damage. Myocardial infarction (MI) diagnostic predictor enzymes, lactate dehydrogenase (LDH) and creatinine kinase (CK-MB), were measured in both serum and heart tissue homogenates (HTH). Superoxide dismutase (SOD), catalase, and thiobarbituric acid reactive species (TBARS) were estimated in HTH. When compared with other groups, the combined therapy of high doses of AGE and SAC given alone or together with CAR caused a significant decrease in serum LDH and CK-MB activities. Further, significant rise in the LDH and CK-MB activities in HTH was noticed in the combined groups of AGE and SAC with CAR. It was also observed that both doses of AGE and SAC significantly increased endogenous antioxidants in HTH. Furthermore, histopathological observations corroborated the biochemical findings. The cytoprotective potential of SAC and AGE were dose-dependent, and SAC was more potent than AGE. The protection offered by aged garlic may be attributed to SAC. Overall, the results indicated that a high dose of AGE and its constituent SAC, when combined with carvedilol, has a synergistic effect in preventing morphological and physiological changes in the myocardium during ISO-induced myocardial damage.

Keywords: S-allyl cysteine; aged garlic extract; carvedilol; cytoprotection; isoproterenol; metabolic derangements; myocardial disturbance.

Figure 1

Typical chromatogram of standard S-allyl cysteine (SAC) and aged garlic extract.

Figure 2

Effect on serum LDH activities. The data are given as mean ± SEM; *** p < 0.001 compared with normal control; ^†† p < 0.01, ^††† p < 0.001 in comparison with ISO control; ^● p < 0.05, ^●● p < 0.01, ^●●● p < 0.001 in comparison with carvedilol; ^◊◊ p < 0.01, when compared with respective AGE dose; ^□□ p < 0.01 when compared with respective SAC dose; ISO (isoproterenol, 150 mg/kg); CAR (carvedilol 10 mg/kg); AGELD (aged garlic extract low dose 2 mL/kg); AGEHD (aged garlic extract high dose 5 mL/kg); SACLD (S-allyl cysteine low dose 13.1 mg/kg); SACHD (S-allyl cysteine high dose 32.76 mg/kg).

Figure 3

Effect on LDH activities in heart tissue homogenate. The data are presented as mean ± SEM; *** p < 0.001 compared with normal control; ^†† p < 0.01, ^††† p < 0.001 in comparison with ISO control; ^●● p < 0.01, ^●●● p < 0.001 in comparison with carvedilol; ^◊◊ p < 0.01 when compared with respective AGE dose; ^□ p < 0.05 when compared with respective SAC dose.

Figure 4

Effect on serum CK-MB activities. The data are presented as mean ± SEM; *** p <0.001 compared with normal control; ^††† p < 0.001 in comparison with ISO control; ^● p < 0.05, ^●● p < 0.01 in comparison with carvedilol; ^◊ p < 0.05, ^◊◊ p < 0.01 when compared with respective AGE dose; ^□□ p < 0.01 when compared with respective SAC dose.

Figure 5

Effect on CK-MB activities in heart tissue homogenate. The data are given as mean ± SEM; *** p < 0.001 compared with normal control; ^†† p < 0.01, ^††† p < 0.001 in comparison with ISO control; ^● p < 0.05, ^●● p < 0.01, ^●●● p < 0.001 in comparison with carvedilol; ^◊◊ p < 0.01 when compared with respective AGE dose; ^□ p < 0.05 when compared with respective SAC dose.

Figure 6

Effect on superoxide dismutase activities. The data are given as mean ± SEM; *** p < 0.001 compared with normal control; ^† p < 0.05, ^†† p < 0.01, ^††† p < 0.001 in comparison with ISO control; ^● p < 0.05, ^●● p < 0.01 in comparison with carvedilol; ^◊ p < 0.05 when compared with respective AGE dose; ^□ p < 0.05 when compared with respective SAC dose.

Figure 7

Effect on catalase activities. The data are given as mean ± SEM; *** p < 0.001 compared with normal control; ^† p < 0.05, ^†† p < 0.01, ^††† p < 0.001 in comparison with ISO control; ^● p < 0.05, ^●● p < 0.01, ^●●● p < 0.001 in comparison with carvedilol; ^◊◊ p < 0.01, ^◊◊◊ p < 0.001 when compared with respective AGE dose; ^□□ p < 0.01 when compared with respective SAC dose.

Figure 8

Effect on thiobarbituric acid reactive species. The data are given as mean ± SEM; *** p < 0.001 compared with normal control; ^††† p < 0.001 in comparison with ISO control; ^● p < 0.05, ^●● p < 0.01, ^●● p < 0.001 in comparison with carvedilol; ^◊ p < 0.05, ^◊◊ p < 0.01 when compared with respective AGE dose; ^□□ p < 0.01 when compared with respective SAC dose.

Figure 9

Effect on histopathological score.

Figure 10

Hematoxylin and eosin (H&E) stained section of hearts of different study groups. Photographed at magnification 400×. (A) Normal control group shows normal myocardial structure with intact cell membrane without necrosis, (B) ISO control shows vacuolar change and necrosis with focal cell infiltration with inflammatory patches, (C) carvedilol-treated groups (10 mg/kg) with intact architecture, (D) AGE low-dose-treated group (2 mL/kg) with slight increase in the intercellular space and decrease in the size of the cardiocytes in some areas, (E) AGE high dose (5 mL/kg) with some areas showing haphazardly arranged cardiocytes, (F) SAC low dose (13.1 mg/kg) shows patchy areas of mild necrosis, (G) SAC high dose (32.76 mg/kg) shows mild decreased size of some cardiocytes, (H) AGE low dose + CAR shows moderately diffused necrosis, (I) AGE high dose + CAR, (J) SAC low dose + CAR with moderately diffused necrosis and inflammatory patches, and (K) SAC high dose + CAR shows almost normal cardiac musculature.