Introduction/Overview
Jaligonic acid (CAS number: 51776-39-7) is a natural product with significant biological activity, which has attracted widespread attention in the fields of natural medicinal chemistry and tumor pharmacology in recent years. As a type of natural triterpenoid compound with complex structures, gallic acid has been found in various plants and exhibits multi-target and multi pathway pharmacological activity, especially in the research of gastric cancer prevention and treatment, demonstrating potential application value. Gastric cancer is one of the malignant tumors with high incidence rate and mortality worldwide, and its treatment strategy urgently needs the support of innovative drugs. Gallic acid exhibits the ability to inhibit tumor cell proliferation, induce apoptosis, and block signaling pathways by regulating various key molecular targets such as BCL2, PIK3CA, EGFR, TP53, etc., making it an important candidate molecule for the development of natural anticancer drugs.
This article aims to systematically review the chemical structure and physicochemical properties, plant sources and extraction methods, pharmacological activity and mechanism of action, drug evaluation and pharmacokinetic characteristics of gallic acid, and explore its clinical application prospects in diseases such as gastric cancer based on current research progress. It is hoped to provide reference and inspiration for researchers in related fields.
Chemical structure and physicochemical properties
The molecular formula of gallic acid is C30H46O8, with a molecular weight of 518.6910, and it belongs to the triterpenoid acidic natural product. Its structural characteristics include multiple hydroxyl substituents and carboxyl functional groups, which endow it with strong polarity and biological activity. The LogP value of gallic acid is 3.1790, indicating that it has moderate lipid solubility, which is conducive to penetrating cell membranes but not too hydrophobic, and is beneficial for in vivo distribution. Its topological polar surface area (TPSA) is 135.2900, indicating that the molecule has a high polarity region, which may affect its binding ability to target proteins and pharmacokinetic behavior.
The low water solubility (0.0325 mg/mL) suggests that the solubility of gallic acid in aqueous phase is limited, which poses certain challenges for its formulation development. The low penetration ability of the blood-brain barrier indicates limited distribution in the central nervous system, reducing the risk of central neurotoxicity. The hERG channel inhibition experiment result was negative, indicating a low risk of cardiac toxicity from gallic acid. The Ames mutagenicity test result was 0.0, indicating no significant genotoxicity and good safety.
Overall, the physicochemical properties of gallic acid are suitable as a candidate drug for oral or local administration, but its water solubility and bioavailability still need to be improved through drug design and formulation optimization.
Plant sources and extraction methods
Gallic acid was initially isolated from plants of the Gallium genus, which is widely distributed in tropical and subtropical regions and traditionally used as a folk herb to treat various diseases. The main source plants include the roots, stems, and leaves of Jaligo spp. The content of gallic acid in plants is relatively low, and the extraction and purification process is complex, which affects its large-scale application.
Common extraction methods include organic solvent extraction, ultrasound assisted extraction, and high-performance liquid chromatography (HPLC) separation and purification. Ethanol or methanol are generally used as extraction solvents, combined with ultrasonic or reflux extraction techniques to improve extraction efficiency. The crude extract was purified through multiple steps such as silica gel column chromatography and reverse phase HPLC to obtain high-purity gallic acid.
In recent years, green extraction technologies such as supercritical CO2 extraction and microwave-assisted extraction have gradually been applied to the extraction of gallic acid, which not only improves the extraction efficiency but also reduces the use of organic solvents, in line with the sustainable development concept of modern natural product development.
Pharmacological activity research
The pharmacological activity research of gallic acid mainly focuses on its anti-tumor effect, especially its inhibitory effect on gastric cancer cells. In vitro experiments have shown that gallic acid can significantly inhibit the proliferation of gastric cancer cell lines, induce cell cycle arrest and apoptosis. Its anti-tumor activity is closely related to the regulation of multiple signaling pathways.
In addition, gallic acid exhibits multiple biological activities such as anti-inflammatory, antioxidant, and immune regulation, providing multidimensional support for its anti-cancer effects. For example, in the inflammatory microenvironment, gallic acid indirectly inhibits the occurrence and development of tumors by suppressing pro-inflammatory cytokines and oxidative stress responses.
Animal model studies have further confirmed the anti-tumor potential of gallic acid. Oral or injection administration can significantly delay tumor growth, reduce metastasis rate, and have mild toxic side effects, laying the foundation for its clinical translation.
Mechanism of action and molecular targets
The study of the mechanism of action of gallic acid reveals its synergistic anti-cancer effect through multiple targets and pathways. The main targets include:
- BCL2 and BAX Gallic acid regulates members of the BCL2 family of apoptosis related proteins, inhibits the expression of anti apoptotic protein BCL2, and upregulates pro apoptotic protein BAX, promoting mitochondrial mediated cell apoptosis.
- CASP3 Activation of caspase 3, execution of cell apoptosis program, leading to cancer cell death.
- PIK3CA Inhibiting the PI3K/Akt signaling pathway, blocking cell proliferation and survival signals, and inhibiting tumor growth.
- EGFR and HER2 Downregulate members of the epidermal growth factor receptor family, inhibit receptor tyrosine kinase activity, and block downstream signal transduction.
- TP53 Activate the tumor suppressor gene p53, promote cell cycle arrest and DNA repair, and enhance cell sensitivity to damage.
- KRAS and MET Inhibiting the RAS/MAPK and MET signaling pathways reduces the migration and invasion ability of tumor cells.
- CDH1 Regulating the cell adhesion molecule E-cadherin, restoring intercellular connections, and inhibiting tumor metastasis.
In summary, gallic acid demonstrates its potential as a multifunctional anticancer drug by regulating tumor cell proliferation, apoptosis, migration, and signal transduction through multiple targets.
Evaluation of drug properties and pharmacokinetics
From the perspective of medicinal properties, gallic acid has good potential as a drug. Its molecular weight (518.7) is slightly higher than the Lipinski rule recommendation of 500 or less, but still within an acceptable range. The LogP is 3.179, indicating moderate lipid solubility and facilitating cell membrane permeation. The TPSA is 135.29, slightly higher than the ideal range (<140 Å ²), which may affect oral bioavailability but does not constitute an absolute barrier.
Low water solubility is a major limitation for its medicinal properties, and it needs to be improved through chemical modification, carrier systems, or nano formulations to enhance solubility and absorption. The low penetration ability of the blood-brain barrier reduces the risk of central nervous system side effects, but limits its application in neurological diseases.
The negative inhibition of hERG channel and no mutagenicity in Ames test indicate that gallic acid has good safety and low risks of cardiac toxicity and genetic toxicity.
Pharmacokinetic studies are still in the preliminary stage, with limited data on in vivo half-life, metabolic pathways, and excretion modes. Animal experiments have shown that the blood concentration of gallic acid can reach an effective level after oral administration, and metabolism is mainly carried out through the liver enzyme system, without significant toxicity accumulation.
In the future, it is necessary to conduct systematic pharmacokinetic and toxicological studies, optimize dosing regimens, and enhance the possibility of clinical translation.
Clinical application prospects and prospects
Gallic acid, as a multi-target natural anticancer active molecule, has shown broad application prospects in the field of gastric cancer treatment. It has the potential to inhibit tumor growth and reduce the risk of metastasis by regulating signaling pathways related to tumor cell proliferation, apoptosis, and metastasis. It is suitable as a candidate molecule for adjuvant therapy or combination chemotherapy.
In addition, the low toxicity and good safety of gallic acid provide favorable conditions for its clinical development. With the development of nanotechnology and drug delivery systems, it is expected to achieve better drug efficacy through formulation improvement to address the shortcomings of poor water solubility and low bioavailability.
Future research should focus on:
- In depth mechanism research Using multi omics techniques to analyze the interaction between gallic acid and the tumor microenvironment and immune system, and expand its indications.
- Pharmacokinetic optimization Conduct systematic in vivo metabolic and toxicological evaluations to guide clinical dose design.
- Preclinical and clinical trials Establish effective animal models, verify safety and efficacy, and promote clinical trials.
- Combination therapy strategy Explore the synergistic effects of gallic acid with existing chemotherapy drugs, targeted drugs, and immunotherapy to improve treatment efficacy.
In summary, gallic acid is expected to become a model for the development of natural anti-cancer drugs, bringing new treatment options for gastric cancer patients.
Conclusion
Gallic acid, as a triterpenoid compound derived from natural plants, exhibits significant pharmacological activity and good safety in the prevention and treatment of malignant tumors such as gastric cancer due to its unique chemical structure and multi-target mechanism of action. Although its physical and chemical properties have certain limitations, with the assistance of modern drug design and formulation technology, it is expected to overcome the problem of insufficient bioavailability.
In the future, with the in-depth analysis of its mechanism of action and the improvement of pharmacokinetic research, gallic acid is expected to enter the clinical trial stage and become an innovative drug in the field of anti gastric cancer. As an important branch of natural product pharmacology research, the development of gallic acid not only enriches the anti-tumor drug library, but also provides valuable experience for the modern transformation of natural drugs.
Continuous efforts in basic research and clinical translation will drive the transition of gallic acid from laboratory to clinical use, benefiting patients and advancing the development of natural product pharmacology to a new level.