The antioxidant, aged garlic extract, exerts cytotoxic effects on wild-type and multidrug-resistant human cancer cells by altering mitochondrial permeability

Abstract

Aged garlic extract (AGE) has been shown to possess therapeutic properties in cancer; however its mechanisms of action are unclear. In this study, we demonstrate by MTT assay that AGE exerts an anti-proliferative effect on a panel of both sensitive and multidrug-resistant (MDR) human cancer cell lines and enhances the effects of hyperthermia (42˚C) on M14 melanoma cells. The evaluation of the mitochondrial activity in whole cancer cells treated with AGE, performed by cytofluorimetric analysis in the presence of the lipophilic cationic fluorochrome JC-1, revealed the occurrence of dose-dependent mitochondrial membrane depolarization. Membrane potential was measured by the TPP+ selective electrode. In order to shed light on its mechanisms of action, the effects of AGE on isolated rat liver mitochondria were also examined. In this regard, AGE induced a mitochondrial membrane hyperpolarization of approximately 15 mV through a mechanism that was similar to that observed with the ionophores, nigericin or salinomycin, by activating an exchange between endogenous K+ with exogenous H+. The prolonged incubation of the mitochondria with AGE induced depolarization and matrix swelling, indicative of mitochondrial permeability transition induction that, however, occurs through a different mechanism from the well-known one. In particular, the transition pore opening induced by AGE was due to the rearrangement of the mitochondrial membranes following the increased activity of the K+/H+ exchanger. On the whole, the findings of this study indicate that AGE exerts cytotoxic effects on cancer cells by altering mitochondrial permeability. In particular, AGE in the mitochondria activates K+/H+ exchanger, causes oxidative stress and induces mitochondrial permeability transition (MPT).

Allium vegetable consumption and health: An umbrella review of meta‐analyses of multiple health outcomes

“…Basic experiments have indicated that both aged garlic extract and fresh garlic extract had anticancer effects. The aged garlic extract had cytotoxic effects on cancer cells by activating K+/H+ exchange, causing oxidative stress in the mitochondria and inducing mitochondrial permeability transition (Ohkubo et al, ). Fresh garlic extract was suggested to suppress cancer cell proliferation, which was related to increased endoplasmic reticulum stress (Petrovic et al, ).…”

“…Moreover, basic studies showed that aged garlic extract could suppress collagen-induced platelet aggregation via the inhibition of the P2X1 receptor, thromboxane receptor, and MAP kinase phosphorylation by acting on newly formed platelets from bone marrow megakaryocytes (Morihara & Hino, 2017), and it was also suggested that the aged garlic extract might inhibit platelet aggregation by increasing cyclic nucleotides and inhibiting fibrinogen binding and platelet shape change (Rahman, Lowe, & Smith, 2016). Although it was suggested that the aged garlic extract might influence the function of platelets, the results from animal studies indicated that the aged garlic extract was not associated with serious hemorrhagic risk (Morihara & Hino, 2017), and a randomized placebo-controlled study also showed that the daily consumption of 4.2 g raw garlic did not impair the platelet function of healthy participants (Scharbert, Kalb, Duris, Marschalek, & Kozek-Langenecker, 2007 (Ohkubo et al, 2018). Fresh garlic extract was suggested to suppress cancer cell proliferation, which was related to increased endoplasmic reticulum stress (Petrovic et al, 2018).…”

Aged garlic extract and its constituent, S‑allyl‑L‑cysteine, induce the apoptosis of neuroblastoma cancer cells due to mitochondrial membrane depolarization

“…human cancer cells (1). Following treatment of the cells with AGE, cytofluorimetric analysis revealed the occurrence of dose-dependent mitochondrial membrane depolarization (MMD) (1).…”

“…human cancer cells (1). Following treatment of the cells with AGE, cytofluorimetric analysis revealed the occurrence of dose-dependent mitochondrial membrane depolarization (MMD) (1). A large number of epidemiological investigations have suggested that garlic is active in the prevention and treatment of various diseases with multiple pharmacological functions, such as anticarcinogenic (2), antithrombotic (3), hypolipidemic (4) and hepatoprotective (5) activities.…”

“…It has been reported that garlic is able to suppress carcinogenesis and to inhibit the proliferation of cancer cells (e.g., esophageal, gastric, colorectal, lung, skin and prostate cancer cells) in vivo and in vitro (6). These studies have yielded significant findings, since the number of cancer patients worldwide has recently increased (1). Moreover, garlic has been reported to be beneficial in preventing neurodegeneration due to its antioxidant and amyloid β (Aβ)-lowering properties (7).…”