Amentoflavone: A Comprehensive Reference
1. Identity and Chemical Characterization
Chemical Names and Formula
Amentoflavone (C30H18O10) is a common biflavonoid chemically named as 8-[5-(5,7-dihydroxy-4-oxo-4H-chromen-2-yl)-2-hydroxyphenyl]-5,7-dihydroxy-2-(4-hydroxyphenyl)-4H-chromen-4-one, which naturally occurs in many plants. It is also considered as an apigenin dimer linked by a C3′–C8″ covalent bond. Its systematic name in PubChem (CID 5281600) is sometimes rendered as 4′,5,7-trihydroxyflavone-(3′→8)-(4′,5,7-trihydroxyflavone); it is also known as 3′,8″-bis-apigenin, or didemethyl-ginkgetin.
Amentoflavone is a hydrophobic molecule and practically insoluble in water. This physical property has major implications for its oral bioavailability and pharmaceutical development, discussed further below.
Discovery and First Isolation
This compound was first isolated by Okigawa and his colleagues in 1971 from three plants of the Selaginella species: Selaginella tamariscina (Beauv.) Spring, Selaginella nipponica, and Selaginella pachystachys. From then on, phytochemical researchers have isolated and identified this biflavonoid from more than 120 plants, some of which have been used as traditional folk medicines in many regions of the world for even thousands of years.
Botanical Sources
Over 120 plants have been found to contain this bioactive component, spanning Selaginellaceae, Cupressaceae, Euphorbiaceae, Podocarpaceae, and Calophyllaceae plant families. The Selaginella genus, comprising 21 species, is the most prevalent source of amentoflavone. Other significant botanical families containing this compound include Cupressaceae, Euphorbiaceae, and Clusiaceae.
Among the most pharmacologically studied source plants are:
- Selaginella tamariscina (tamarisk spike-moss, "Juanbai" in Chinese) — the primary source plant and the one from which amentoflavone was originally isolated.
- Ginkgo biloba — a well-known medicinal tree. However, some studies suggest that the amentoflavone in Ginkgo biloba leaf extracts exhibits no biological activity and amentoflavone has been removed from the listing of the active components of such extracts.
- Hypericum perforatum (St. John's Wort), Chamaecyparis obtusa (hinoki), and Xerophyta plicata are among the other prominent sources of this phytochemical.
- Calophyllum spp. and Garcinia spp. (family Calophyllaceae/Clusiaceae), Torreya nucifera, Cnestis ferruginea, and Biophytum sensitivum are additional documented sources.
Typically, amentoflavone is extracted from the leaves, aerial parts, and whole plants. The most well-known extraction technique is central composite design (CCD), which uses supercritical-CO2 fluid extraction (SFE-CO2) with methanol as a co-solvent.
Pharmacopeial Status
With its good pharmacological performance and high content, amentoflavone is even listed as the chemical marker of Selaginellae Herba ("Juanbai" in Chinese, which represents the whole plants of Selaginella tamariscina or Selaginella pulvinata) for quality evaluation in the Chinese Pharmacopoeia.
2. Traditional and Historical Use
Traditional Chinese Medicine (TCM)
Extracts of Selaginella tamariscina have been used for a long time in traditional medicine in Asia. Selaginella tamariscina has long been used to treat blood stagnation in traditional Chinese medicine, and many previous studies have focused on its effect on the cardiovascular system and metabolic syndrome. In China, S. tamariscina is listed in the Chinese Pharmacopoeia and used as a traditional medicine for promoting blood circulation.
The treatment of inflammatory diseases and cancers can benefit from the use of standard alcoholic extracts of native S. tamariscina, whereas extracts of the carbonized plant (S. tamariscina carbonisatus) are adapted to treat bleedings. Several biflavonoids (chiefly amentoflavone) and phenolic compounds (selaginellin derivatives) are primarily responsible for the observed pharmacological properties.
Among the plants used as folk phytomedicines for a very long time, those employed in traditional Chinese medicine (TCMs) include Ginkgo biloba, Lobelia chinensis, Polygala sibirica, Ranunculus ternatus, Selaginella pulvinata, and Selaginella tamariscina.
Traditional Indian Medicine
Calophyllum inophyllum and Selaginella bryopteris have been used in traditional Indian medicines. Calophyllum tomentosum, belonging to the Clusiaceae family, is an Indian medicinal plant used as folklore medicine to cure various kinds of diseases reported in Ayurveda, and the leaves of the plant are also used as an active ingredient for the preparation of a botanical medicine known as "Punnaga," "Surapunnaga," and "Tamoil" among other common names.
Traditional African Medicine
Amentoflavone is found in Cnestis ferruginea, which is used in traditional African medicine in the management of psychiatric disorders. Cnestis ferruginea and Drypetes gerrardii have been used in traditional African medicines.
Traditional American Uses
Byrsonima intermedia has been used in traditional American medicine.
Common Preparation Methods in Traditional Contexts
Even before amentoflavone was isolated from Selaginella, extracts of this plant were used extensively in traditional medicine for the treatment of various health problems. Traditional preparations took the form of decoctions, whole-plant preparations, and alcoholic extracts of the aerial plant parts. Such extracts display a range of pharmacological effects useful for treating metabolic disorders, several inflammatory diseases, and various cancers; a specific carbonized extract (S. tamariscina carbonisatus) has shown hemostatic effects, whereas standard extracts can promote blood circulation.
3. Chemical Classification and Key Constituents
Structural Classification
Amentoflavone is a biflavonoid — a class of dimeric flavonoids formed by the coupling of two flavone units. It is also known as 3′,8″-biapigenin, indicating that the two apigenin subunits are connected at the C-3′ position of one ring and the C-8 position of the other. Its molecular weight is 538.46 g/mol. The compound belongs to the polyphenol superfamily and carries six phenolic hydroxyl groups, which underlie much of its antioxidant and receptor-binding chemistry.
Natural Derivatives
Amentoflavone occurs in nature alongside numerous methylated derivatives. Known natural isolates structurally related to amentoflavone include sequoiaflavone, sotetsuflavone, 7,7″-dimethoxyamentoflavone, and other dimethoxy variants. These derivatives differ in the degree and position of methoxylation on the flavone skeleton and may exhibit distinct pharmacological profiles from the parent compound.
4. Mechanisms of Action
Anti-Inflammatory Mechanisms
Amentoflavone dose-dependently suppresses the production of nitric oxide (NO) and prostaglandin E2 (PGE2) in RAW264.7 cells stimulated with the TLR4 ligand lipopolysaccharide (LPS). Amentoflavone suppresses the nuclear translocation of c-Fos, a subunit of activator protein (AP)-1, at 60 min after LPS stimulation and inhibits the activity of purified and immunoprecipitated extracellular signal-regulated kinase (ERK), which mediates c-Fos translocation. In agreement with these results, amentoflavone also suppresses the formation of a molecular complex including ERK and c-Fos.
Recent studies have shown that amentoflavone treatment can decrease the production of cytokines such as tumor necrosis factor (TNF)-α and inflammatory mediators such as nitric oxide (NO) and arachidonate by tumor-associated macrophages, peritoneal macrophages, and RAW264.7 cells. Additionally, amentoflavone inhibits the NF-κB signaling pathway. It significantly suppresses lipopolysaccharide-induced NO, reactive oxygen species (ROS), and malondialdehyde (MDA) in a rat astrocytoma cell line, as well as NO, PGE2, and the nuclear translocation of c-Fos in RAW 264.7 cells, and TNF-α in a human monocytic leukemia cell line.
Antioxidant Mechanisms
Scavenging effects measured with DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), superoxide, and hydroxyl radicals have shown amentoflavone to have high antioxidant capacity in the range of 19.2%–75.5%. Amentoflavone inhibited the oxidative burst of neutrophils and damage to human erythrocyte membranes induced in human peripheral blood mononuclear cells.
Anticancer Signaling Pathways
Amentoflavone is involved in anti-cancer activity by mediating various signaling pathways such as extracellular signal-regulated kinase (ERK), nuclear factor kappa-B (NF-κB), and phosphoinositide 3-kinase/protein kinase B (PI3K/Akt). Amentoflavone, isolated from Selaginella tamariscina, is able to cross the blood–brain barrier and afford neuroprotection against neonatal hypoxic-ischemic brain injury. In prior studies, amentoflavone-induced apoptosis and reduced NF-κB activation were demonstrated in MCF-7 breast cancer cells. Amentoflavone significantly induced expression of active caspase-3 and -8 and induced loss of mitochondrial membrane potential, all associated with apoptosis.
Amentoflavone can synergistically increase the cytotoxic effects of carboplatin in A549 cells and may be a potential chemosensitizer to carboplatin for non-small cell lung cancer (NSCLC) through PARP-1, in vitro and in vivo.
Antiviral Mechanisms
Amentoflavone is one of the flavonoids known for antiviral effects; it is predicted to have inhibitory effects against severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) enzymes 3-chymotrypsin-like protease (3CLpro) and papain-like protease (PLpro). Using a fluorogenic peptide assay, amentoflavone was shown to inhibit SARS-CoV 3CLpro proteolytic activity in vitro at an IC50 = 8.3 μM and Ki = 13.8 ± 1.5 μM. This IC50 is lower than that for the antiviral flavones such as its parent molecule apigenin (280.8 μM), luteolin (20.2 μM), and quercetin (280.8 μM). Amentoflavone has also been reported to bind to the receptor binding site of the spike glycoprotein of SARS-CoV-2 with a binding energy of −8.5 kcal/mol.
Neuropharmacological Mechanisms
Amentoflavone is a negative modulator of GABAA receptors in vitro, which binds to the benzodiazepine site with an affinity similar to diazepam. It can act via classical flumazenil-sensitive benzodiazepine binding sites, as well as independently of flumazenil. This effect is dependent not only on subunit composition but also on amentoflavone doses.
Amentoflavone, the biflavonoid identified in over 120 natural plants, exhibited agonistic activity at 5-HT1Dα and 5-HT2C receptor subtypes. Amentoflavone produces its antidepressant effect through interaction with 5-HT2 receptor and α1- and α2-adrenoceptors, while the anxiolytic effect involves the ionotropic GABA receptor.
CYP Enzyme Inhibition
Compared with herbal extracts that induce cytochrome P450 (CYP) and UDP-glucuronosyltransferases (UGT) activity, amentoflavone is a potent inhibitor of CYP3A4, CYP2C9, and UGT. Among constituents of Selaginella doederleinii extract, amentoflavone had the highest content (13.65%) and the strongest inhibitory effect (IC50 < 5 μM) on cytochrome P450 enzymes, especially for CYP2C9, CYP2C8, and CYP3A. Amentoflavone also showed time-dependent inhibition on CYP2C19 and CYP2D6.
CYP3A4 participates in the metabolic clearance of more than 50% of commonly used clinical drugs, including tyrosine kinase inhibitors, dihydropyridine calcium antagonists, benzodiazepine sedative-hypnotics, and statins (HMG-CoA reductase inhibitors). Amentoflavone's strong inhibitory activity against this enzyme is accordingly a clinically significant pharmacokinetic concern.
5. Scientific Evidence by Area of Use
5.1 Anti-Inflammatory Activity
The anti-inflammatory evidence for amentoflavone is extensive but derives almost exclusively from in vitro cell culture experiments and animal models. In vivo studies have demonstrated the efficacy of amentoflavone as an anti-inflammatory agent for various conditions such as ulcers, psoriasis, arthritis, and other inflammatory diseases. A 2013 animal study demonstrated that amentoflavone inhibits iNOS and COX-2 expression and modulates cytokine profile and NF-κB signal transduction pathways in rats with ulcerative colitis.
Evidence strength: Predominantly preclinical (in vitro and animal). No randomized controlled trials (RCTs) in humans have been identified in the peer-reviewed literature examining isolated amentoflavone as an anti-inflammatory agent. The mechanistic data are robust, but translation to human outcomes remains undemonstrated.
5.2 Anticancer Activity
Amentoflavone has been studied across multiple cancer types in cell lines and animal models. Current reviews comprehensively discuss its diverse biological activities, with a special focus on its role against various types of cancers. Key mechanistic findings include apoptosis induction, NF-κB inhibition, PI3K/Akt pathway suppression, and effects on tumor metastasis.
In glioblastoma research, amentoflavone significantly induced expression of active caspase-3 and -8, while inducing loss of mitochondrial membrane potential, all associated with apoptosis in glioblastoma cell studies. In non-small cell lung cancer (NSCLC), amentoflavone can synergistically increase the cytotoxic effects of carboplatin in A549 cells and may be a potential chemosensitizer to carboplatin through PARP-1, demonstrated both in vitro and in vivo.
In hepatocellular carcinoma research, inactivation of AKT/ERK signaling and induction of apoptosis have been associated with amentoflavone sensitization of hepatocellular carcinoma to lenvatinib. Additionally, endometrial carcinoma studies found that amentoflavone promotes ferroptosis by regulating the ROS/AMPK/mTOR signaling axis to inhibit the malignant progression of endometrial carcinoma cells.
Evidence strength: Exclusively preclinical (in vitro cell lines and rodent xenograft models). No human clinical trials of isolated amentoflavone as an anticancer agent have been published. The compound is regarded as a promising candidate and chemosensitizer, but remains investigational.
5.3 Antiviral Activity
A PubMed and PubFacts search shows that amentoflavone has broad-spectrum antiviral activity in addition to its anti-inflammatory and antioxidant effects, and is a naturally occurring human thrombin inhibitor. Its antiviral activity has been documented against herpes simplex virus (HSV), influenza, and in particular against coronaviruses.
Regarding SARS-CoV-2: Molecular docking studies have found that amentoflavone binds strongly to the active site of the main protease (Mpro) of SARS-CoV-2. Computational screening of over 224 natural compounds to identify effective SARS-CoV-2 inhibitors found amentoflavone as the lead candidate, exhibiting a strong binding affinity to 3CLpro (−10.7 kcal/mol). Amentoflavone also demonstrates anti-SARS-CoV-2 effect via binding towards the main protease (Mpro/3CLpro), spike protein receptor binding domain (RBD), and RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2.
Evidence strength: Antiviral data are predominantly from in vitro enzyme inhibition assays and computational (in silico) molecular docking studies. No human clinical trials of isolated amentoflavone as an antiviral have been completed. Clinical studies with Hypericum and Ginkgo extract as additional or alternative drugs/supplements are registered, but these involve complex plant extracts, not pure amentoflavone.
5.4 Neuroprotective Activity and CNS Effects
In vivo studies have demonstrated the efficacy of amentoflavone as a neuroprotective agent to improve cognitive function and eliminate toxic oligomers in tests associated with the onset of Alzheimer's and Parkinson's diseases.
Regarding mood disorders, this biflavonoid has antidepressant and anxiolytic-like effects in mice. The anxiolytic effects appear to have been due to action at benzodiazepine receptors, as they were reversed by the benzodiazepine antagonist flumazenil. In fact, amentoflavone displaced [3H]flumazenil from rat brain benzodiazepine binding sites with a potent IC50 of 14.9 nM.
In a study using mice in which amentoflavone was isolated from Cnestis ferruginea: amentoflavone reduced time of immobility in forced swim and tail suspension tests, increased the number of head-dips and time spent in open arms (behavioral anxiety markers), and the anti-immobility effect was reversed by 5-HT2, α1- and α2-adrenoceptor antagonist pretreatment. The anxiolytic effect was reversed by flumazenil pretreatment.
In zebrafish models of alcohol withdrawal-induced anxiety: the reversal of anxiety by pretreatment with granisetron suggested that the anxiolytic effect of amentoflavone is dependent on serotonergic 5-HT3A/3B receptors. Furthermore, amentoflavone reversed anxiety via flumazenil pretreatment, suggesting dependence on the GABAA receptor.
The neuroprotective effect of amentoflavone is also evident in its ability to reduce cell death induced by staurosporine, etoposide, and sodium nitroprusside in neuroblastoma SH-SY5Y cells.
Evidence strength: Preclinical (animal models — mice and zebrafish, and in vitro cell models). No human clinical trials of isolated amentoflavone for anxiety, depression, or neurodegeneration have been published. The mechanistic profile (GABAA modulation, serotonergic activity) is pharmacologically interesting and consistent with behavioral outcomes in rodent models.
5.5 Cardiovascular and Cerebrovascular Effects
Amentoflavone is a flavonoid compound found in over 120 plants. Its extensive pharmacological activity for treating cardiocerebrovascular diseases and neurological disorders has attracted the attention of researchers in recent years. Research in this area has focused on antithrombotic, vasoprotective, and anti-ischemic properties in preclinical models. Studies of the pharmacological functions of amentoflavone suggest it to be anti-inflammatory, antioxidative, and vasoprotective.
However, owing to the poor solubility and low bioavailability of amentoflavone, it has not been developed as a drug for treating these diseases.
Evidence strength: Preclinical. Cardiovascular effects are established in cell and animal models, but no published human clinical trials on isolated amentoflavone in this domain have been identified.
5.6 Antidiabetic and Metabolic Effects
The main component of total flavonoids from Selaginella tamariscina is amentoflavone, which has various functions, including regulation of glycolipid metabolism, improvement of insulin resistance and liver steatosis, anti-oxidative, and anti-inflammatory effects. These effects have been studied in diabetic mouse models (db/db mice), though these represent complex mixture exposures, not isolated amentoflavone.
Evidence strength: Preclinical (animal and cell models). No human clinical trials evaluating isolated amentoflavone for glycemic control have been published.
5.7 Antimicrobial Effects
Amentoflavone plays various pharmacological roles including anti-microorganism activity, with documented effects against bacteria and fungi in vitro. Amentoflavone is a biflavonoid compound with antioxidant, anticancer, antibacterial, antiviral, anti-inflammatory, and UV-blocking activities.
Evidence strength: Preliminary, in vitro only. No controlled clinical studies on antimicrobial applications have been identified.
5.8 Musculoskeletal and Bone Effects
Current reviews discuss amentoflavone's diverse biological activities, including musculoskeletal protection, encompassing data on bone density, osteoporosis, and joint inflammatory models in rodents. Related amentoflavone-type biflavonoid structures exhibit interesting biological functions including anticancer, antioxidant, osteoporosis treatment, and diabetic osteopathy properties.
Evidence strength: Preclinical. No human clinical trials on bone or musculoskeletal outcomes with isolated amentoflavone have been identified.
6. Pharmacokinetics and Bioavailability
Absorption
Amentoflavone's poor water solubility constrains its release within the body, resulting in incomplete gastrointestinal absorption and low oral bioavailability, thereby limiting its pharmacological efficacy. Experimental assessment of absorption risks suggested that amentoflavone is a compound with moderate intestinal absorption and that poor solubility is the key rate-limiting step for its oral absorption.
It has been demonstrated that amentoflavone is absorbed via passive diffusion in rats. A study employing the Caco-2 cell model indicated that amentoflavone exhibits intestinal absorption, possibly involving paracellular passive diffusion and clathrin-mediated endocytosis, while the efflux transporter appears to be uninvolved.
Distribution
Following oral administration in rats, amentoflavone is dominantly distributed in the small intestine, stomach, liver, and large intestine, with minimal distribution to other tissues. However, amentoflavone is able to cross the blood–brain barrier and afford neuroprotection against neonatal hypoxic-ischemic brain injury — a finding consistent with its documented CNS pharmacology.
Metabolism and Excretion
Studies on pharmacokinetics and biliary excretion found that the percentage of amentoflavone conjugates in bile was determined to be up to 96.73%, and no amentoflavone conjugates were detected in rat plasma, indicating extensive first-pass conjugation and biliary elimination. This profile further constrains systemic exposure after oral dosing.
Efforts to Improve Bioavailability
To overcome the water insolubility and low bioavailability of amentoflavone, drug delivery carriers have been developed, including N-vinyl pyrrolidone-maleate-guerbet alcohol monoester polymer [P(NVP-MGAM)] micelles, amorphous solid dispersion (ASD) with polyvinylpyrrolidone K-30 (PVP K-30), and amentoflavone-loaded vitamin E polyethylene glycol succinate (TPGS)/soluplus mixed micelles. These drug delivery carriers have effectively improved the solubility and bioavailability of amentoflavone in animal studies. Trials using an oral delivery system with micelles have proven to be more effective, but further research is needed to optimize the use of amentoflavone for higher bioavailability.
Nano-encapsulation is an additional strategy: amentoflavone's clinical application is limited by poor solubility and low bioavailability. To address these limitations, amentoflavone has been encapsulated in nano-zeolite, enhancing its stability and therapeutic potential.
7. Dosage Forms and Reported Dosages
Amentoflavone is available commercially as a dietary supplement, typically as a standardized extract of Selaginella tamariscina or in combined botanical formulas. It is also present as a minor constituent in standardized Ginkgo biloba and Hypericum perforatum extracts, though, as noted above, its activity in Ginkgo extracts has been questioned. Amentoflavone is an active ingredient found in extracts from Ginkgo biloba, St. John's Wort (Hypericum perforatum), Selaginella tamariscina, Torreya nucifera, and many other plants, which have been used as dietary supplements in many countries.
With respect to dosages used in the scientific literature: the overwhelming majority of pharmacological studies have been conducted in vitro (cell cultures) or in rodents, and no dose-ranging clinical studies of isolated amentoflavone in humans appear in the peer-reviewed literature. Preclinical in vitro studies have typically employed concentrations in the range of 1–100 μM; animal in vivo studies have administered the compound at doses ranging from approximately 10 to 100 mg/kg in rodent models, though specific reported values vary widely across studies and targets. No validated human clinical dosage for amentoflavone as a purified supplement has been established in published research.
The challenge of establishing a meaningful dose is compounded by the bioavailability limitations described above: owing to the poor solubility and low bioavailability of amentoflavone, it has not been developed as a drug for treating any of the investigated diseases.
8. Safety, Toxicity, and Drug Interactions
CYP450 Enzyme Inhibition and Drug Interactions
The most pharmacologically significant and evidence-based safety concern for amentoflavone is its inhibition of hepatic drug-metabolizing enzymes. Amentoflavone can interact with many medications by being a potent inhibitor of CYP3A4 and CYP2C9, which are enzymes responsible for the metabolism of some drugs in the body. Studies found strong inhibitory effect on CYP2C9 and CYP2C8, with IC50 values approximately 1 μg/ml, and moderate inhibitory effect against CYP2C19, CYP2E1, and CYP3A. Among the constituents examined, amentoflavone had the strongest inhibitory effect (IC50 < 5 μM), especially for CYP2C9, CYP2C8, and CYP3A.
Amentoflavone may be one of the main reasons for the inhibition of Selaginella doederleinii extract on CYP450 enzymes, and the potential for herb-drug interactions should be considered when this extract or amentoflavone is used with other clinical drugs.
CYP3A4 participates in the metabolic clearance of more than 50% of commonly used clinical drugs, including tyrosine kinase inhibitors, dihydropyridine calcium antagonists, benzodiazepine sedative-hypnotics, and HMG-CoA reductase inhibitors (statins). Inhibition of this enzyme by amentoflavone therefore carries theoretical risk of increasing plasma concentrations of co-administered drugs metabolized by this pathway.
Amentoflavone is also an inhibitor of human cathepsin B.
Unlike some herbal extracts that induce CYP and UGT activity (which can reduce drug effectiveness), amentoflavone acts as a potent inhibitor of CYP3A4, CYP2C9, and UGT, potentially increasing the exposure of co-administered drugs rather than reducing them — a pharmacokinetically distinct and clinically relevant risk profile.
GABAA Receptor Modulation: Implications for CNS Drug Interactions
Amentoflavone is a negative modulator of GABAA receptors in vitro, binding to the benzodiazepine site with affinity similar to diazepam. It can act via classical flumazenil-sensitive benzodiazepine binding sites, as well as independently of flumazenil. This binding profile raises theoretical concerns about potential interactions with benzodiazepines, other GABAA-active drugs, alcohol, and anxiolytics, though the clinical magnitude of this interaction in humans has not been established.
Toxicity Data
Formal toxicological profiling in humans is absent from the published literature. In vitro and animal studies have largely been conducted at pharmacologically relevant concentrations without reporting significant cytotoxic effects on normal (non-cancer) cells. Amentoflavone has not been developed as a pharmaceutical drug, and systematic human safety data (including standardized adverse event reporting, long-term safety studies, or reproductive toxicology evaluations) are not available in the peer-reviewed literature.
Source-Plant Context: St. John's Wort and Ginkgo
Amentoflavone occurs in medicinal plants including Ginkgo biloba and Hypericum perforatum. Both of these source plants are associated with well-documented herb-drug interactions (notably Hypericum as an inducer of CYP3A4 and P-glycoprotein, and Ginkgo with anticoagulant-related concerns), but these interactions are attributable to other constituents, not to amentoflavone specifically. The CYP inhibitory activity described above is distinct and specific to amentoflavone itself, not to the crude plant extracts in which it is embedded.
9. Current Research Status and Limitations
With the development of modern pharmacology, more and more evidence has proved many bioactivities of amentoflavone, including anti-oxidant, anti-inflammatory, anti-senescence, anti-tumor, anti-virus, and anti-fungal effects. Despite this growing preclinical evidence base, several fundamental obstacles limit translation to clinical use.
First, the bioavailability problem: owing to the poor solubility and low bioavailability of amentoflavone, it has not been developed as a drug for treating cardiocerebrovascular diseases or neurological disorders. Second, the cost of sourcing: most sources of amentoflavone are perennial plants whose recovery or reproduction takes considerable time, making plant-derived preparation expensive. This is another reason for fewer animal model experiments, which would require much higher amounts of the biflavonoid than cell experiments.
Despite these challenges, amentoflavone is considered to be a promising therapeutic agent for clinical research. The development of nanoformulations, micelles, and amorphous solid dispersions represents the current focus of pharmaceutical research aimed at making the compound viable for clinical investigation.
References
Volver