Storage conditions：Short-term storage at 2~8℃, long-term storage at -20 ~ -80℃
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Gamma linolenic acid (GLA) is a highly active polyunsaturated fatty acid belonging to the omega-6 fatty acid family, with the molecular formula C18H30O2 and CAS number 506-26-3. As a naturally occurring fatty acid, GLA is metabolized and converted into linoleic acid in the human body, and is widely present in various vegetable oils. In recent years, with the deepening of research on the mechanism of action of fatty acids in physiological and pathological processes, GLA has gradually become a research hotspot in the field of natural product pharmacology due to its unique multiple pharmacological activities such as anti-inflammatory, antioxidant, anti-tumor, and neuroprotective effects. It exerts a wide range of biological effects by regulating multiple cellular signaling pathways, particularly key molecules such as NF - κ B and MAPK (including ERK1/2 and JNK), demonstrating potential application value in the treatment of inflammatory diseases, neurodegenerative diseases, and tumors.
This article aims to systematically review the chemical structure and physicochemical properties, plant sources, and extraction methods of gamma linolenic acid, explore its pharmacological activity and mechanism of action, analyze its pharmacokinetic characteristics based on drug parameters, and finally look forward to its clinical application prospects, providing theoretical support and reference for subsequent basic and clinical research.
Gamma linolenic acid (GLA) is a long-chain fatty acid composed of 18 carbon atoms, containing three cis double bonds located at the 6th, 9th, and 12th carbon atoms. It is a typical polyunsaturated fatty acid. Its molecular weight is 278.43 and its molecular formula is C18H30O2. The structural formula of GLA can be summarized as 18:3 (ω -6), which means that starting from the methyl end of the fatty acid, the first double bond is located at the 6th carbon atom.
In terms of physical and chemical properties, GLA is a colorless to light yellow oily liquid with high hydrophobicity. Its LogP value is about 6.7, indicating strong lipid solubility. The polar surface area (TPSA) is 37.3 Å ², and the number of hydrogen bond acceptors is 2, indicating a low molecular polarity. GLA is not easily able to pass through the blood-brain barrier (BBB), indicating that its direct action in the central nervous system may be limited. Its LD50 value is about 2000 mg/kg, indicating low acute toxicity. In vitro toxicological evaluation showed that GLA has no hepatotoxicity, cardiotoxicity, or hERG channel inhibition effect, and the Ames mutagenicity test was also negative, indicating its good safety and suitability for further development as a drug.
GLA is widely present in various plant oils, with borago oil, Oenothera biennis oil, blackcurrant seed oil (Ribes nigrum), and borage seed oil being the main sources. The GLA content in these plant seed oils can reach up to 15% -25%, making them the main raw material for industrial extraction of GLA.
The extraction methods mainly include solvent extraction, cold pressing, and supercritical CO2 extraction techniques. Traditional solvent extraction usually uses organic solvents such as hexane and ethanol, combined with refining processes such as degumming, decolorization, and deodorization, to obtain high-purity GLA oil. The cold pressing method has gradually gained popularity due to its ability to avoid high-temperature damage to the structure of unsaturated fatty acids, but its extraction efficiency is relatively low. Supercritical CO2 extraction technology has become a research hotspot in recent years due to its environmental friendliness, residue free nature, and good selectivity. It can effectively protect the active ingredients of GLA, improve extraction purity and yield.
In addition, with the development of biotechnology, research on the fermentation production of GLA by genetically engineered microorganisms has gradually begun, providing a new approach for large-scale and controllable production.
The anti-inflammatory effect of GLA is one of its most widely studied pharmacological effects. GLA and its metabolites (such as docosahexaenoic acid, DGLA) can regulate the synthesis of inflammatory mediators and inhibit the expression of pro-inflammatory cytokines such as TNF - α, IL-1 β, and IL-6. Mechanistically, GLA inhibits the activation of the nuclear factor kappa B (NF - κ B) signaling pathway, reduces the transcription of inflammatory genes, and lowers the cascade amplification of inflammatory responses. In addition, GLA can inhibit the phosphorylation of ERK1/2 and JNK, members of the mitogen activated protein kinase (MAPK) family, further suppressing inflammatory signaling.
Multiple studies both in vitro and in vivo have confirmed that GLA has a good relieving effect on chronic inflammatory diseases such as rheumatoid arthritis, atopic dermatitis, and inflammatory bowel disease. Its safety and oral activity make it an ideal candidate for natural anti-inflammatory agents.
The mechanism of GLA in tumor cells mainly involves inducing apoptosis and inhibiting tumor cell proliferation. Research has found that GLA can regulate intracellular redox status, activate mitochondrial pathways, promote cytochrome C release, activate the caspase family, and ultimately induce cancer cell apoptosis. In addition, GLA inhibits the NF - κ B signaling pathway, reduces the expression of anti apoptotic proteins, and enhances the sensitivity of tumor cells to chemotherapy drugs.
In a variety of cancer models, GLA shows the potential to inhibit the growth of breast cancer, colon cancer, prostate cancer and other tumors, and its side effects are significantly reduced compared with traditional chemotherapy drugs, showing a good prospect of adjuvant treatment.
GLA has significant antioxidant activity, which can eliminate free radicals, reduce lipid peroxidation, and protect the integrity of cell membrane structure. Its antioxidant effect is mainly achieved by regulating the activity of intracellular antioxidant enzymes such as glutathione peroxidase (GPx) and superoxide dismutase (SOD). This effect is of great significance in preventing oxidative stress related diseases, such as atherosclerosis, diabetes and neurodegenerative diseases.
Although GLA is not easily able to pass through the blood-brain barrier, its metabolites and indirect regulatory effects have attracted much attention for its application in neurological diseases. GLA can regulate neuroinflammatory responses, reduce nerve cell damage, and promote nerve regeneration. Animal experiments have shown that GLA supplementation can improve cognitive function, enhance learning and memory abilities, suggesting its potential in adjuvant therapy for Alzheimer's disease and other neurodegenerative diseases.
The biological effects of GLA are mainly achieved through multiple signaling pathways:
NF - κ B signaling pathway
NF - κ B is a core transcription factor that regulates inflammation and immune responses. GLA exerts anti-inflammatory effects by inhibiting the activity of I κ B kinase (IKK), preventing I κ B degradation, inhibiting NF - κ B nuclear translocation, reducing the expression of pro-inflammatory genes.
MAPK signaling pathway (ERK1/2 and JNK)
Members of the MAPK family, ERK1/2 and JNK, are involved in cell proliferation, differentiation, and stress response. GLA inhibits its phosphorylation, blocks downstream signaling, suppresses inflammatory response and tumor cell proliferation.
Mitochondrial apoptosis pathway
GLA induces the loss of mitochondrial membrane potential in cancer cells, promotes the release of cytochrome C, activates caspase-9 and -3, and initiates the apoptosis program.
Regulation of antioxidant enzymes
GLA regulates the Nrf2 ARE signaling pathway, promotes the expression of antioxidant enzymes, enhances cellular antioxidant capacity, and reduces oxidative stress damage.
In addition, GLA metabolites such as DGLA can be converted into anti-inflammatory prostaglandin E1, further enhancing its anti-inflammatory and immune regulatory effects.
The pharmacological parameters of GLA show that it has good safety and drug compatibility. Its high LogP value indicates that GLA has good lipid solubility, which is beneficial for cell membrane penetration, but may also limit its water solubility and bioavailability. GLA has a low polar surface area and a limited number of hydrogen bond acceptors, which is consistent with the characteristics of lipophilic molecules.
Toxicological evaluation shows that GLA has no significant hepatotoxicity, cardiotoxicity, or mutagenicity, with a high LD50 value, indicating low acute toxicity and suitability for long-term oral use. GLA does not inhibit hERG ion channels, reducing the risk of arrhythmia.
In terms of pharmacokinetics, GLA is mainly absorbed in the intestine after oral administration, metabolized by the liver into DGLA and other metabolites, and then distributed in plasma and tissues. It is not easy to cross the blood-brain barrier, which limits its direct action in the central nervous system. GLA has a moderate half-life and is suitable for daily supplementation and therapeutic applications.
To improve the bioavailability and targeting of GLA, research on new drug delivery systems such as nanocarriers, liposomes, and eutectic formulations is underway.
GLA has shown broad application prospects in clinical research of various diseases due to its multiple pharmacological activities and good safety.
Inflammatory diseases
Including rheumatoid arthritis, atopic dermatitis, asthma, and inflammatory bowel disease, GLA regulates inflammatory mediators, reduces symptoms, and improves quality of life. Partial clinical trials have confirmed that GLA supplements have a positive effect on relieving joint pain and skin inflammation.
neoadjuvant therapy
As a natural anti-cancer agent, GLA can enhance the efficacy of chemotherapy drugs, reduce side effects, and improve patient prognosis. More randomized controlled trials are needed in the future to verify its safety and efficacy.
Neurological disorders
Although GLA is not easily able to cross the blood-brain barrier, its anti-inflammatory and antioxidant effects have the potential to assist in the treatment of neurodegenerative diseases. The combination therapy strategy with other neuroprotective agents deserves further research.
Metabolic diseases
GLA can regulate inflammation and oxidative stress in diabetes and cardiovascular disease, and may become a part of comprehensive treatment plan in the future.
Looking ahead, with the development of molecular biology and drug delivery technology, targeted therapy and personalized medication of GLA will become a research focus. The design of GLA based derivatives and their synergistic effects with other drugs will also promote their clinical translation process.
Gamma linolenic acid, as an important natural polyunsaturated fatty acid, has shown broad application prospects in anti-inflammatory, anticancer, antioxidant, and neuroprotective fields due to its unique chemical structure and diverse biological activities. Its mechanism of action involves the regulation of multiple signaling pathways and has good safety and pharmacological characteristics. In the future, by combining modern drug development technology, in-depth exploration of the pharmacokinetic characteristics and clinical efficacy of GLA will provide a solid foundation for its application in fields such as inflammation, tumors, and neurological diseases, and promote it as an important drug candidate molecule in natural product pharmacology.
