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Citric acid is the acid form, and citrate is the salt or conjugate base form. The two terms are often used interchangeably in casual conversation, but chemically they refer to different states depending on the pH of the environment.
Citrate is a naturally occurring compound found in various forms in nature. It is a conjugate base of citric acid, a weak organic acid that is commonly found in citrus fruits, such as lemons and oranges.
Citrate plays a crucial role in the production of energy in cells. It is a key intermediate in the citric acid cycle (also known as the Krebs cycle or tricarboxylic acid cycle), which is a series of chemical reactions that occur in the mitochondria of cells.
Naturally found in citrus fruits and many other plants.
Citric acid is a key metabolic intermediate in the tricarboxylic acid (TCA) cycle.
• Citric acid is central to cellular energy metabolism as part of the TCA cycle. Changes in its concentration can affect the flux through the cycle and the overall cellular redox state.
• Enhanced TCA activity may lead to increased production of reducing equivalents (NADH, FADH₂) and subsequent electron transport chain (ETC) activity. If the ETC becomes overloaded or dysfunctional, it can lead to electron leakage and increased ROS production.
• Although citric acid itself is not a classical antioxidant, it can act as a chelating agent for certain metal ions. By binding transition metals (such as iron and copper), citrate can potentially reduce metal-catalyzed ROS formation.
• This chelating property can indirectly protect cells from oxidative damage, especially under conditions where free metal ions might otherwise catalyze ROS-generating reactions.
-Crucial role of citrate to supply the acetyl-CoA pool for fatty acid synthesis and histone acetylation in tumors
-Citrate is a major product of mitochondria, the engine of the cell.
-The more Citrate builds up in the cell, the more the cell will think it has enough of what it needs and will reduce or even shut down the glycolisis process.
Citrate is produced inside the mitochondria within the Krebs cycle. When the cell has excess energy, citrate is transported out of the mitochondrial matrix across the inner membrane via the mitochondrial citrate transport protein (CTP). In the cytoplasm, is then broken down by the ACLY (ACL) enzyme into
acetyl-CoA: for fatty acid synthesis and cholesterol production
oxaloacetate: to be converted back to pyruvate and enter mitochondria again
(might be desirable to inhibit ACYL with HCA) and maybe Statins.
-May also synergize with Metformin?
Sodium citrate is the sodium salt of citric acid, used as a buffer and food additive, while citric acid is a weak organic acid, naturally found in citrus fruits.
Summary:
-Citrate is considered to play a crucial role in cancer metabolism by virtue of its production in the reverse Krebs cycle from glutamine
-Chelation of Ca2+ by sodium citrate resulted in inactivation of CAMKK2 and AMPK (inhibited the Ca2+/CAMKK2/AKT/mTOR signaling)
-”promoter of cell proliferation (at lower concentrations) and as an anticancer agent (at higher concentrations)”
-”ACLY, which has been found to be overexpressed in many cancers, converts citrate into acetyl-CoA and OAA.“
-”administration of citrate at high level mimics a strong inhibition of ACLY” (HCA is a known natural ACLY inhibitor)
-Citrate is a well-known physiological inhibitor of PFK1.
-Some reduction in Mcl-1 expression
-May low ROS by decreasing oxygen consumption (ie not compatible with proxidant treatment?)
-Deactivation of the NF-κB signaling ?
-Lemons: 5–8% citric acid by weight
-Limes: 4–7% citric acid.
-Grapefruits: 2–5% in the juice
-Oranges (and Tangerines/Mandarins): 1–2% in the juice
Many commercially prepared beverages (like some soft drinks, citrus-based jams, and preserves) and sour candies have citric acid added as a flavoring agent or preservative. In these products, the citric acid concentration can sometimes be higher than that in the unprocessed fruit juice.
Acid Reflux & Dental Health: Increasing citric acid, especially from highly concentrated sources (like pure citric acid or very sour juices), may exacerbate symptoms in individuals with acid reflux or cause enamel erosion on teeth. Drinking water after consuming citrus products or using a straw (when drinking acidic beverages) can help reduce the direct contact of acid with your teeth.
• Low/Moderate Doses: In some models, low to moderate citrate supplementation can actually help cells maintain redox balance.
• High Doses: At higher concentrations, citrate can overload certain metabolic pathways. An excess supply of citrate may drive the TCA cycle at a rate that overwhelms the electron transport chain, potentially increasing the leakage of electrons and therefore raising ROS production.
• Cancer vs. Non-Cancer Cells: Cancer cells frequently have reprogrammed metabolism. In some cases, citrate supplementation in cancer cells can have different effects compared to healthy cells. For instance, due to the metabolic alterations in cancer cells, a high dose of citrate might exacerbate mitochondrial dysfunction, leading to higher ROS levels. Conversely, in a non-cancer context or cells with robust metabolic flexibility, the same dose might be better tolerated or even beneficial for redox balance.
ROS:
Antioxidant Role:
• In some contexts, citrate can act as an antioxidant. It has the capacity to chelate metal ions (like iron and copper), which can catalyze ROS formation via reactions such as the Fenton reaction.
• Moreover, as a key intermediate in the tricarboxylic acid (TCA) cycle, citrate contributes to cellular energy metabolism, which, when properly balanced, may help maintain homeostasis and limit excessive ROS production.
Potential Pro-Oxidant Effects:
• At high doses or under certain conditions, an overload of citrate might alter normal cellular metabolic pathways. For example, excess citrate can affect mitochondrial function and the TCA cycle’s balance, potentially leading to metabolic disturbances that contribute to increased ROS formation in some in vitro models or under pathological conditions.
• In certain experimental settings, drastic changes in cellular intermediate concentrations can trigger compensatory mechanisms that might inadvertently lead to oxidative stress.
Context Matters:
• The net effect of high-dose citrate on ROS largely depends on the experimental model and the presence of additional factors (such as the concentration of available metal ions, the oxidative state of the cell, and the cell’s overall metabolic status).
• In a well-regulated physiological environment, moderate levels of citrate may support antioxidant defenses, whereas in stress or disease states, high doses might tip the balance toward increased ROS production.
-High doses of citric acid/citrate in cancer cells are generally associated with an increase in ROS due to metabolic and mitochondrial stress. However, because the effect is highly context-specific, the overall outcome may depend on multiple factors related to the cancer cell type and its existing metabolic state. (Note this statement might not be supported by research papers-but rather chat ai)
DoseCitric acid: 4g-30g/day. 4g-8g/day most common? split 3-4 times/day? with meals