Elaeagnus glabra

Elaeagnus glabra: A Comprehensive Reference

1. Identity and Botanical Classification

1.1 Taxonomy and Nomenclature

Elaeagnus glabra is an evergreen vine or climbing shrub reaching up to 5 m in height. It belongs to the genus Elaeagnus, which encompasses about 90 species of flowering plants in the family Elaeagnaceae. The species was formally described by the Swedish botanist Carl Peter Thunberg, and its accepted full binomial name is Elaeagnus glabra Thunb. The specific epithet glabra (Latin: "smooth" or "hairless") distinguishes it from many closely related species. In Chinese botanical literature, it is recorded under the Chinese name man hu tui zi (蔓胡颓子).

Several synonyms and infraspecific taxa have been recorded in the botanical literature, including Elaeagnus buisanensis Hayata, E. erosifolia Hayata, E. glabra subsp. oxyphylla Servettaz, E. glabra subsp. tenuiflora (Bentham) Servettaz, E. longidrupa Hayata, E. paucilepidota Hayata, and E. tenuiflora Bentham. The form Elaeagnus glabra f. oxyphylla (Servett.) W.T. Lee has been the subject of its own pharmacological investigations and is sometimes treated as a distinct entity in Korean botanical and phytochemical studies.

1.2 Morphology and Distribution

E. glabra is widespread in southern China, growing in sunny forests or forest margins below 1000 m above sea level. Its range in China includes the provinces of Jiangsu, Zhejiang, Fujian, Taiwan, Anhui, Jiangxi, Hubei, Hunan, Sichuan, Guizhou, Guangdong, and Guangxi, as well as Japan. E. glabra is an evergreen shrub native to China, the Ryukyus in Japan, Korea, and Taiwan.

Elaeagnus plants are deciduous or evergreen shrubs or small trees. The alternate leaves and the shoots are usually covered with tiny silvery to brownish scales, giving the plants a whitish to grey-brown colour from a distance. The flowers are small, with a four-lobed calyx and no petals; they are often fragrant. The fruit is a fleshy drupe containing a single seed; it is edible in many species.

1.3 Phylogenetics and Genomic Characterisation

The complete plastome of E. glabra is 152,555 bp with a typical quadripartite structure of angiosperms. It contains two Inverted Repeats (IRs) of 25,918 bp, a large single-copy (LSC) of 82,408 bp, and a small single-copy (SSC) region of 18,311 bp. The complete plastome contains 129 genes, including 83 protein-coding genes, 38 tRNA genes, and eight rRNA genes. Phylogenetic analysis indicated that E. glabra is close to E. loureirii within Elaeagnaceae.

1.4 Common Preparations and Forms

Research studies have employed several parts of the plant, including leaves, branches, bark, and aerial parts, formulated as crude methanol extracts, ethanol extracts, and ethyl-acetate-layer fractions. Many Elaeagnus species are used in health food and folk medicine; among these, E. umbellata, E. multiflora, E. macrophylla, and E. glabra are widely distributed in Korea and commonly consumed as food and herbal medicine. In scientific studies reviewed below, preparations have included dried, powdered plant material extracted with methanol or ethanol, as well as bioassay-guided fractions separated by column chromatography.

2. Traditional and Historical Use

2.1 East Asian Folk Medicine

Elaeagnus glabra (Thunb.), an evergreen shrub with alternate leaves, has been used as a medicinal plant in Korea. It is a native medicinal plant to Korea, South China, Japan, and Taiwan.

The leaves of Elaeagnus species are traditionally used as a restorative drink or decoction for intestinal disorders in China and Japan. Across the broader genus, many Elaeagnus species are used in health food and folk medicine. The contextual record for E. glabra specifically centres on Korea and southern China, where it has been incorporated into local herbalist traditions.

In the broader Elaeagnaceae tradition relevant to understanding how E. glabra has been contextualised by practitioners, ellagitannins and their derivatives in the leaves of Elaeagnus species possess clinically valuable activities, chemopreventive effects, and have nutraceutical applications. E. glabra has been attributed with anticancer, antiasthmatic, antibacterial, and antidiarrhoeal properties in the traditional medicine literature.

2.2 Uses Attributed in Traditional Contexts

Traditional and ethnobotanical sources attribute to E. glabra and closely related species a range of preparations and purposes:

• Intestinal and digestive complaints: Leaf decoctions used for intestinal disorders, including diarrhoea, across Chinese and Japanese folk traditions.
• Respiratory support: Within the genus, bark and leaf preparations have been used in a manner paralleling related species, where antiasthmatic and antitussive applications are recorded.
• Antibacterial and antimicrobial applications: Folk use of various plant parts against infections.
• Anticancer applications: Traditional attributions recorded in the ethnobotanical literature cite the plant in the context of cancer-related complaints, though no clinical evidence from pre-modern practice has been formally documented for E. glabra specifically.

It is important to note that many of these traditional uses are documented at the genus level or for closely allied species (E. pungens, E. umbellata, E. angustifolia). Specific historical records uniquely attributing particular preparations to E. glabra alone are sparse in the peer-reviewed ethnobotanical literature.

3. Key Chemical Constituents and Active Compounds

3.1 General Phytochemical Profile of the Genus

Phytochemical and biological evaluation studies have revealed the presence of essential chemical constituents like flavonoids, phenolic acids, carotenoids, terpenoids, lignanoids, organic acids, coumarins, alkaloids, steroids, vitamin C, lycopene, and polyphenols in Elaeagnus species that are responsible for their remarkable observed biological activities.

3.2 Compounds Isolated Specifically from E. glabra

Until the comprehensive 2023 phytochemical study, only one antibacterial flavonoid, namely (−)-epigallocatechin; two steroids; and three triterpenes had been identified from E. glabra.

The landmark 2023 investigation by Cheng et al., published in Plants (MDPI), substantially expanded the known chemical landscape: one new flavonoid, two new triterpenoids, and 35 known compounds were isolated from the ethyl acetate layer of aerial parts of E. glabra via a bioassay-guided fractionation process. Their structures were characterised by 1D and 2D NMR, UV, IR, and MS data. In total, the study found 13 triterpenoids and 10 flavonoids in the aerial parts of E. glabra.

Key compounds of bioactivity interest isolated from E. glabra aerial parts in this study include:

• 3-O-(E)-Caffeoyloleanolic acid (compound 13): A triterpenoid ester identified as a key anti-inflammatory agent.
• Methyl pheophorbide a (compound 37): A chlorophyll derivative demonstrating potent anti-lipid droplet accumulation activity.

The study uncovered three new compounds and 35 known compounds from aerial parts of E. glabra. The skeletons of triterpenoids and flavonoids were a major part of this study, consistent with the chemotaxonomy of Elaeagnaceae.

3.3 Compounds Isolated from E. glabra f. oxyphylla (Branches)

A 2020 study by Kim et al., published in Molecules (MDPI/PMC), focused on the branches of E. glabra f. oxyphylla: sixteen compounds were isolated from the branches of E. glabra f. oxyphylla (EGFOB). The key bioactive flavonoids identified were:

• Procyanidin B3
• Procyanidin B4
• Helichrysoside

These compounds are catechol-type flavonoids (procyanidins), a class noted for antioxidant and neuroprotective properties. The broader genus also yields lignanoids, benzoids, and polyphenolic ellagitannins.

3.4 Mechanisms of Action of Key Constituent Classes

Several Elaeagnus species, including E. glabra, are known for their cytotoxic activities against cancer cells. Bioactive components such as triterpenoids, flavonoids, lignanoids, and benzenoids isolated from these species may be responsible for their antitumour activities.

Based on the available in vitro and animal literature, the following mechanisms have been proposed for the active constituents:

• Matrix metalloproteinase (MMP) suppression: Extract-mediated suppression of MMP-2 and MMP-9 gelatinolytic activity and gene expression, leading to inhibition of tumour cell invasion.
• Anti-lipid droplet accumulation: Reduction of hepatic lipid accumulation via metabolic effects in liver cell lines.
• Neutrophil inhibition: Suppression of superoxide anion generation and elastase release from human neutrophils (relevant to inflammatory processes).
• Cholinergic modulation: Enhancement of acetylcholine levels and inhibition of acetylcholinesterase (AChE), with downstream activation of CREB/NGF signalling in the brain.
• MAPK pathway modulation: Suppression of p38 and JNK phosphorylation in activated microglia, reducing neuroinflammatory cytokine output.
• Amyloid-β aggregation inhibition: Direct in vitro inhibition of amyloid-β (Aβ) fibrillation, a key pathological process in Alzheimer's disease.
• Cyclin-CDK pathway interference: Suppression of cyclin D3/CDK11p58, a cell-cycle-related signalling axis in microglial inflammatory responses.
• Free radical scavenging: Antioxidant activity against ABTS and DPPH radicals demonstrated in multiple extract preparations.

4. Scientific Evidence by Area of Use

4.1 Anti-tumour and Anti-invasive Activity

The most directly studied pharmacological activity specific to E. glabra in the peer-reviewed literature is inhibition of tumour cell invasion.

Key study (in vitro / preclinical): A 2009 study published in Oncology Reports (PubMed PMID 19148535) investigated the methanol extract of E. glabra against HT1080 human fibrosarcoma cells. Since many plant-derived molecules have inhibitory effects on tumour cell invasion, primarily via suppression of the activity of matrix metalloproteinases (MMPs), researchers investigated the effect of the methanol extract of E. glabra on tumour cell invasion. The invasiveness of HT1080 human fibrosarcoma cells was reduced in a dose-dependent manner following 24-hour treatment of up to 200 µg/mL of the E. glabra extract, at which concentration no cytotoxicity occurred. Furthermore, gelatinolytic activities, and the protein and mRNA levels of MMP-2 and MMP-9 were also suppressed with increasing concentrations of the extract.

Another study demonstrated that the bark extract of Elaeagnus glabra has a dose-dependent inhibitory effect on the invasion of human fibrosarcoma cell lines HT1080.

Evidence strength: Preliminary. All anti-tumour evidence for E. glabra is confined to in vitro (cell culture) experiments. There are no animal tumour model studies or clinical trials specific to this species. The data support mechanistic hypotheses but cannot be extrapolated to human clinical outcomes.

4.2 Neurological: Cognition, Memory, and Cholinergic Function

The most detailed preclinical studies on E. glabra f. oxyphylla (EGFO) address neurological endpoints, particularly those relevant to Alzheimer's disease and cognitive decline.

Key study (animal model, 2019): Published in Nutrients (PMC6627942), this study from the Korea Institute of Oriental Medicine investigated the effects of EGFO ethanol extract in a scopolamine-induced amnesia mouse model. Researchers investigated the therapeutic effects of an EGFO ethanol extract in mice with scopolamine-induced memory dysfunction. Fifty male mice were randomly divided into a normal control group, a scopolamine-treated group, a scopolamine and EGFO extract-treated group, and a scopolamine and tacrine-treated group. EGFO (50 or 100 mg/kg/day) was administered for 21 days. Step-through passive avoidance and Y-maze tests were performed to examine the effects of treatment on learning and memory impairments.

Acetylcholine (ACh) levels and acetylcholinesterase (AChE) activity were measured via enzyme-linked immunosorbent assay (ELISA). Levels of choline acetyltransferase (ChAT), nerve growth factor (NGF), cAMP response element-binding protein (CREB), and apoptosis-related protein expression were determined via Western blot analysis. EGFO pretreatment significantly attenuated scopolamine-induced memory impairments, relative to findings observed in the scopolamine-treated group.

Evidence strength: Preclinical (animal model only). The study employed a standard pharmacological amnesia model using a muscarinic receptor antagonist, not a genetic or pathological model of neurodegeneration. Results are mechanistically suggestive, but no human or clinical data exist for this application.

4.3 Neuroinflammation

Key study (in vitro, 2022): A study published in Natural Product Communications (SAGE Journals, DOI 10.1177/1934578X221075079) explored the anti-neuroinflammatory activity of an ethanol extract of E. glabra f. oxyphylla branches. Neuroinflammation plays a pivotal role in the pathogenesis of neurodegenerative diseases and is characterised by microglial dysregulation. Researchers explored the beneficial effects of a leaf extract of Elaeagnus glabra f. oxyphylla (EGFO), a native medicinal plant to Korea, South China, Japan, and Taiwan, on neuroinflammation using lipopolysaccharide (LPS)-stimulated BV-2 microglia. The study documented suppression of cyclin D3/CDK11p58 as a mechanistic pathway for the observed anti-inflammatory effects.

Evidence strength: Preliminary, in vitro only. BV-2 cell results provide mechanistic hypotheses but cannot establish clinical efficacy in humans.

4.4 Amyloid-β Aggregation and Oxidative Stress (Alzheimer's Disease-Relevant Endpoints)

Key study (in vitro, 2020): Published in Molecules (PMC7660689), a study by Kim et al. characterised the chemical composition of E. glabra f. oxyphylla branches for the first time and evaluated anti-amyloid and antioxidant properties. Researchers evaluated the effects of the ethanol extract of EGFOB and each of its chemical components on key mediators of Alzheimer's disease (AD), namely amyloid-β (Aβ) aggregation and oxidative stress. The ethanol extract of EGFOB decreased Aβ aggregation (IC₅₀ = 32.01 µg/mL) and the levels of the oxidative free radicals ABTS and DPPH (IC₅₀ = 11.35 and 12.32 µg/mL, respectively).

Sixteen compounds were isolated from EGFOB. Among them, procyanidin B3 (compound 8), procyanidin B4 (compound 9), and helichrysoside (compound 13) significantly inhibited Aβ aggregation (IC₅₀ = 14.59, 32.64, and 44.45 μM, respectively), indicating their potential as bioactive compounds to control Aβ aggregation. Furthermore, these compounds markedly enhanced in vitro scavenging activity against ABTS (IC₅₀ = 3.21–4.61 µM).

Evidence strength: Preliminary, in vitro only. In vitro Aβ aggregation inhibition does not translate directly into demonstrated clinical benefit in Alzheimer's disease; no animal model studies or human data from E. glabra preparations for Alzheimer's disease are available in the peer-reviewed literature.

4.5 Hepatoprotective / Anti-NAFLD Activity

Key study (in vitro, 2023): The most recent comprehensive phytochemical and bioactivity study of E. glabra, published in Plants (MDPI/PMC, PMC10458971), was conducted at Kaohsiung Medical University and Chang Gung University in Taiwan. Researchers were motivated to investigate the bioactive components of Formosan plants that could attenuate lipid droplet (LD) accumulation. In a series of screenings of 3,000 methanolic extracts from the Formosan plant extract bank for anti-LD accumulation activity, the methanolic extract of aerial parts of Elaeagnus glabra Thunb. showed excellent anti-LD accumulation activity.

Among the isolated compounds, methyl pheophorbide a (compound 37) efficiently reduced the normalised LD content to 0.3% with a concentration of 20 µM in AML12 cell lines without significant cytotoxic effects. Furthermore, 3-O-(E)-caffeoyloleanolic acid (compound 13) and methyl pheophorbide a (compound 37) showed potent inhibitory activities on superoxide anion or elastase release in human neutrophils, displaying effects similar to those of the positive control, namely LY294002.

These findings indicate that E. glabra can be used for developing a new botanical drug for managing LD accumulation and against inflammation-related diseases.

Evidence strength: Preliminary, in vitro (cell line) only. AML12 is a murine hepatocyte cell line; no animal model or human study of E. glabra preparations in NAFLD has been published to date.

4.6 Anti-inflammatory Activity

Anti-inflammatory properties have been reported for multiple preparations of E. glabra across several studies:

• Inhibition of neutrophil superoxide anion generation and elastase release at IC₅₀ < 3.0 µM for caffeoyloleanolic acid and methyl pheophorbide a (human neutrophil cell model, in vitro).
• Suppression of p38 and JNK MAPK phosphorylation in LPS-stimulated BV-2 microglia (in vitro).

Levels of the inflammatory mediators were determined by enzyme-linked immunosorbent assays and reverse transcription–PCR. The phospho-levels of mitogen-activated protein kinases, which are key kinase molecules in the inflammatory signalling pathway in microglia, were analysed by Western blotting.

Evidence strength: Preclinical in vitro only. No randomised controlled trials or formal human studies on inflammation endpoints specific to E. glabra exist in the published literature.

4.7 Antioxidant Activity

Multiple extract preparations of E. glabra and its form oxyphylla have demonstrated in vitro antioxidant activity in standard radical-scavenging assays. The ethanol extract of EGFOB decreased levels of the oxidative free radicals ABTS and DPPH (IC₅₀ = 11.35 and 12.32 µg/mL, respectively).

Evidence strength: Preliminary, in vitro. In vitro DPPH and ABTS assays are widely used as proxies for antioxidant potential but do not directly establish in vivo or clinical antioxidant benefit.

5. Body Systems and Health Areas of Association

Based on the available preclinical and in vitro literature, E. glabra and its subspecific forms have been studied or attributed with relevance to the following body systems:

• Central nervous system / neurological: Cognitive function, cholinergic transmission, neuroinflammation, amyloid-β pathology (all preclinical).
• Hepatic / metabolic: Lipid metabolism and hepatic steatosis via anti-lipid-droplet accumulation activity (in vitro).
• Oncological / anti-invasive: Suppression of matrix metalloproteinase-mediated tumour cell invasion (in vitro).
• Immune and inflammatory: Neutrophil activity modulation, MAPK pathway inhibition in microglia, general anti-inflammatory properties (in vitro).
• Antioxidant / free radical: Radical scavenging in standard in vitro assays.
• Gastrointestinal: Traditional attribution to intestinal disorders; no controlled data specific to E. glabra are available.
• Respiratory: Traditional attribution at genus level; no controlled data specific to E. glabra are available.

6. Dosage Forms and Reported Dosages

No standardised or approved dosage for human therapeutic use of E. glabra exists. The following dosages have been reported exclusively in preclinical research settings:

• Animal (mouse) study — cognitive / cholinergic function: EGFO (50 or 100 mg/kg/day) was administered for 21 days by oral gavage to ICR mice in the scopolamine-induced memory impairment model.
• In vitro — anti-lipid droplet (hepatocyte cell line): Methyl pheophorbide a (compound 37) efficiently reduced the normalised LD content to 0.3% with a concentration of 20 µM in AML12 cell lines without significant cytotoxic effects.
• In vitro — anti-tumour invasion: The invasiveness of HT1080 human fibrosarcoma cells was reduced in a dose-dependent manner following 24-hour treatment of up to 200 µg/mL of the E. glabra extract, at which concentration no cytotoxicity occurred.
• In vitro — anti-inflammatory (neutrophils): 3-O-(E)-Caffeoyloleanolic acid and methyl pheophorbide a showed inhibitory effects on superoxide anion generation or elastase release in fMLP/CB-treated human neutrophils (IC₅₀ < 3.0 µM).
• In vitro — anti-amyloid (extract level): The ethanol extract of EGFOB decreased Aβ aggregation (IC₅₀ = 32.01 µg/mL) and ABTS and DPPH radical levels (IC₅₀ = 11.35 and 12.32 µg/mL, respectively).

These values represent experimental concentrations used in laboratory conditions and should not be construed as guidance for human use.

7. Safety Considerations and Interactions

7.1 Observed Safety in Published Studies

The cytotoxicity profile of E. glabra preparations has been evaluated only in in vitro cell models and in limited mouse studies. In the anti-invasive study, the invasiveness of HT1080 human fibrosarcoma cells was reduced in a dose-dependent manner following 24-hour treatment of up to 200 µg/mL of the E. glabra extract, at which concentration no cytotoxicity occurred. The 2023 anti-NAFLD study similarly noted that the methanolic extract of aerial parts of E. glabra stood out for potent inhibitory activity toward LD accumulation with little effect on cell viability.

7.2 Absence of Clinical Safety Data

E. glabra is an evergreen shrub on which only a few phytochemical and biological studies have been conducted. There are no published human clinical trials, phase I safety studies, or systematic toxicology studies (including genotoxicity, reproductive toxicity, or chronic dosing studies) for E. glabra or its extracts in the peer-reviewed literature. The plant is not currently listed in any major pharmacopoeia (e.g., European Pharmacopoeia, USP, or Japanese Pharmacopoeia) nor has it been formally assessed by the WHO, EMA, EFSA, or NIH Office of Dietary Supplements as of the time of writing.

7.3 Drug Interactions

No formal drug interaction studies for E. glabra extracts or isolated compounds have been identified in the peer-reviewed literature. The presence of catechol-type flavonoids (procyanidins), polyphenols, and triterpenoids suggests potential for interactions with cytochrome P450 enzyme systems, anticoagulant drugs, or other phenolic-sensitive pathways, as documented for these compound classes in the broader pharmacology literature — but no data specific to E. glabra have been published.

7.4 Ellagitannins and Genus-Level Context

Ellagitannins and their derivatives in the leaves of Elaeagnus species possess clinically valuable activities, chemopreventive effects, and have nutraceutical applications. Ellagitannins are generally considered safe in dietary quantities, but high-dose extracts may interact with gut microbiota and gut permeability; no such data specific to E. glabra have been reported.

8. Summary of Evidence Quality

The overall body of scientific evidence for E. glabra as a medicinal or dietary supplement ingredient is at an early, preliminary stage. The species has been the subject of a limited number of phytochemical and in vitro pharmacological studies, with one relevant animal (mouse) model study for cognitive endpoints. E. glabra is an evergreen shrub on which only a few phytochemical and biological studies have been conducted. Most research on Elaeagnus has focused on the aspects of commercial and industrial applications, such as their chemical and nutritional compositions. No randomised controlled trials, human clinical studies, or meta-analyses have been published. All mechanistic claims are based exclusively on in vitro or rodent data. The species remains a subject of academic phytochemical interest rather than an evidence-supported clinical intervention.

References

• Cheng J-H, Wu H-C, Yen C-H, et al. "Chemical Constituents with Anti-Lipid Droplet Accumulation and Anti-Inflammatory Activity from Elaeagnus glabra." Plants 2023; 12(16):2943. PMC10458971.
• Kim YJ, Sohn E, Kim J-H, Na M, Jeong S-J. "Catechol-Type Flavonoids from the Branches of Elaeagnus glabra f. oxyphylla Exert Antioxidant Activity and an Inhibitory Effect on Amyloid-β Aggregation." Molecules 2020; 25(21):4917. PMC7660689.
• Sohn E, Lim H-S, Kim YJ, Kim B-Y, Kim J-H, Jeong S-J. "Elaeagnus glabra f. oxyphylla Attenuates Scopolamine-Induced Learning and Memory Impairments in Mice by Improving Cholinergic Transmission via Activation of CREB/NGF Signaling." Nutrients 2019; 11(6):1205. PMC6627942.
• Lim H-S, Sohn E, Kim YJ, Kim B-Y, Kim J-H, Jeong S-J. "Ethanol Extract of Elaeagnus glabra f. oxyphylla Branches Alleviates the Inflammatory Response Through Suppression of Cyclin D3/Cyclin-Dependent Kinase 11p58 Coupled to Lipopolysaccharide-Activated BV-2 Microglia." Natural Product Communications 2022. DOI: 10.1177/1934578X221075079.
• PubMed: "Methanol extract of Elaeagnus glabra, a Korean medicinal plant, inhibits HT1080 tumor cell invasion." Oncology Reports 2009; 21:559–563. PMID 19148535.
• Zhao K-K, Wang J-H, Zhu Z-X, et al. "Complete plastome sequence of Elaeagnus glabra (Elaeagnaceae): an Asian endemic plant species." Mitochondrial DNA Part B: Resources 2019; 4(2). PMC7748609.
• PMC: "Complete chloroplast genomes of E. umbellata Thunb., E. multiflora Thunb., E. macrophylla Thunb., and E. glabra Thunb. (Elaeagnaceae)." PMC7782260.
• Botanical Review: "A Review on Traditional Uses and Pharmacological Importance of Genus Elaeagnus Species." The Botanical Review 2020. Springer Nature.
• Symbiosisonlinepublishing / ScienceDirect: "Russian olive (Elaeagnus angustifolia L.): From a variety of traditional medicinal applications to its novel roles as active antioxidant, anti-inflammatory, anti-mutagenic and analgesic agent." Journal of Traditional and Complementary Medicine 2016.
• Royal Botanic Gardens, Kew. "Elaeagnus glabra Thunb." Plants of the World Online. Accessed 2025.
• Missouri Botanical Garden. "Elaeagnus glabra." Flora of China @ eFloras.org.
• Symbiosis Online Publishing: "Chemistry, Pharmacology and Medicinal Property of Russian olive (Elaeagnus angustifolia L.)." 2019.