Effects of Black Garlic Extract and Nanoemulsion on the Deoxy Corticosterone Acetate-Salt Induced Hypertension and Its Associated Mild Cognitive Impairment in Rats

Abstract

Organosulfur compounds, phenolic acids and flavonoids in raw and black garlic were determined, and followed by preparation of black garlic nanoemulsion for studying their effects on deoxycorticosterone acetate-salt-induced hypertension and associated mild cognitive impairment in rats. Three organosulfur compounds, including diallyl sulfide (87.8 μg/g), diallyl disulfide (203.9 μg/g) and diallyl trisulfide (282.6 μg/g) were detected in black garlic by GC-MS, while gallic acid (19.19 μg/g), p-coumaric acid (27.03 μg/g) and quercetin (22.77 μg/g) were detected by UPLC-MS/MS. High doses of both black garlic extract and nanoemulsion prepared using Tween-80, glycerol, grapeseed oil and water could decrease systolic blood pressure through the elevation of bradykinin and nitric oxide levels as well as diminish aldosterone and angiotensin II levels in rats. In Morris water maze test, they could significantly decrease escape latency and swimming distance and increase the time spent in the target quadrant, accompanied by a decline of acetylcholinesterase activity and malondialdehyde level in the hippocampus as well as a rise in glutathione level and activities of superoxide dismutase, catalase and glutathione peroxidase. In addition, the levels of tumor necrosis factor, interleukin-6 and interleukin-1β were reduced. Effects of lowering blood pressure and improving learning/memory ability in rats followed the order: lisinopril > black garlic nanoemulsion > black garlic extract.

Keywords: Morris water maze test; black garlic nanoemulsion; organosulfur compounds; phenolic acids and flavonoids; rats; systolic blood pressure.

Figure 1

GC-MS chromatogram of black garlic extract using a DB-5MS column (A) and UPLC-MS/MS chromatograms of phenolic acid and flavonoids in black garlic with total ion chromatogram shown on the top and the other three being SRM chromatograms (B) as well as the particle size distribution of black garlic nanoemulsion by a dynamic light scattering method along with an inset showing its appearance (C) and transmission electron microscopic image (D). Peaks: 1, diallyl sulfide (DAS); 2, isopropyl disulfide (internal standard); 3, diallyl disulfide (DADS); 4, diallyl trisulfide (DATS).

Figure 1

GC-MS chromatogram of black garlic extract using a DB-5MS column (A) and UPLC-MS/MS chromatograms of phenolic acid and flavonoids in black garlic with total ion chromatogram shown on the top and the other three being SRM chromatograms (B) as well as the particle size distribution of black garlic nanoemulsion by a dynamic light scattering method along with an inset showing its appearance (C) and transmission electron microscopic image (D). Peaks: 1, diallyl sulfide (DAS); 2, isopropyl disulfide (internal standard); 3, diallyl disulfide (DADS); 4, diallyl trisulfide (DATS).

Figure 2

Effect of the administration of black garlic extract and nanoemulsion onkidney weight (A), kidney volume (B), bradykinin (C), angiotensin II (D) and aldosterone (E) in DOCA-salt-induced hypertension and its associated mild cognitive impairment in rats. Data are presented as means ± standard deviation (n = 6); C, control; D, DOCA-salt at a dose 25 mg/kg BW; PC, DOCA-salt with the administration of lisinopril at a dose 15 mg/kg BW; HE, DOCA-salt with the administration of black garlic extract at a dose of 100 mg/kg BW; HN, DOCA-salt with the administration of black garlic nanoemulsion at a dose of 100 mg/kg BW; LE, DOCA-salt with the administration of black garlic extract at a dose of 50 mg/kg BW; LN, DOCA-salt with the administration of black garlic nanoemulsion at a dose of 50 mg/kg BW. Values with different small letters (a–c) are significantly different (p < 0.05).