Verbascoside

Other Names

(2R,3R,4R,5R,6R)-6-[2-(3,4-dihydroxyphenyl)ethoxy]-5-hydroxy-2-(hydroxymethyl)-4-{[(2S,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxy}oxan-3-yl (2E)-3-(3,4-dihydroxyphenyl)prop-2-enoate2-(3,4-Dihydroxyphenyl)ethyl 3-O-(6-deoxy-α-L-mannopyranosyl)-4-O-[(2E)-3-(3,4-dihydroxyphenyl)-2-propenoyl]-β-D-glucopyranosideAcetosideActeosideKusagininNSC 603831Orobanchinβ-(3,4-dihydroxyphenylethyl)-O-α-L-rhamnopyranosyl-(1→3)-β-D-(4-O-caffeoyl)-glucopyranosideβ-D-Glucopyranoside, 2-(3,4-dihydroxyphenyl)ethyl 3-O-(6-deoxy-α-L-mannopyranosyl)-4-O-[(2E)-3-(3,4-dihydroxyphenyl)-1-oxo-2-propen-1-yl]-

Synopsis

Verbascoside (Acteoside): A Comprehensive Reference

1. Identity: Names, Chemical Structure, and Natural Sources

1.1 Nomenclature

Verbascoside is also known as acteoside, kusaginin, or orobanchin. In 1963, verbascoside was first isolated from the medicinal plant Verbascum sinuatum L., before a compound called acteoside was reported in 1968; it was later found to be the same compound. Both names, "verbascoside" and "acteoside," continue to be used in publications. Although it was proposed to accept only one name, both names remain in use in the literature, while the names kusaginin and orobanchin are less common.

1.2 Chemical Identity

Verbascoside (C₂₉H₃₆O₁₅, MW 624.6 g/mol) is a water-soluble disaccharide derivative related to trans-caffeic acid and hydroxytyrosol; it consists of four components: caffeic acid, glucose, rhamnose, and hydroxytyrosol.

Its CAS number is 61276-17-3, and its full chemical name is β-(3,4-dihydroxyphenylethyl)-O-α-L-rhamnopyranosyl-(1→3)-β-D-(4-O-caffeoyl)-glucopyranoside. Structurally, it consists of caffeic acid (3,4-dihydroxycinnamic acid) bound to glucose at the C4 position via an ester bond, while hydroxytyrosol (4,5-hydroxyphenylethanol) is bound to glucose at position C1 via an ether bond.

More precisely, verbascoside is a polyphenol glycoside in which the phenylpropanoid caffeic acid and the phenylethanoid hydroxytyrosol form an ester and an ether bond respectively, to the rhamnose part of a disaccharide.

Phenylethanoid glycosides are naturally occurring water-soluble compounds with remarkable biological properties that are widely distributed in the plant kingdom. Investigation of biosynthetic pathways revealed that the hydroxytyrosol moiety is synthesized from tyrosine by the shikimate pathway, while the caffeoyl moiety is derived from phenylalanine by the cinnamate pathway.

1.3 Natural Sources and Distribution

Verbascoside has been isolated from different parts of more than 200 plant species. It can be found in species in all families of the order Lamiales (syn. Scrophulariales). Only two examples are known from outside the order, in the clade Asterids.

Verbascoside can be isolated from medicinal plants commonly used in folk medicine, such as Verbascum thapsus (common mullein), Verbena officinalis (common vervain), Plantago lanceolata, and Olea europaea (olive).

Verbascoside is one of the major bioactive ingredients of medicinal plants such as the Echinacea and Plantago species historically used in North America and Europe, as well as "Roucongrong" (Cistanches Herba) and "Dihuang" (Rehmannia glutinosa) used in traditional Chinese medicine. Verbascoside is also the major bioactive compound of a dietary supplement popularly consumed in Japan produced from Sesamum indicum leaves, as well as "Kudingcha" (bitter tea), produced from the leaves of Ligustrum robustum in China.

Verbascum leaves and flowers are reported to have expectorant, mucolytic and demulcent properties and are used in traditional Turkish medicine to treat respiratory conditions such as bronchitis, dry coughs, tuberculosis, and asthma. Plants within this genus are also used to treat hemorrhoids, rheumatic pain, superficial fungal infections, wounds, and diarrhea.

Verbascoside is widely distributed within Lamiaceae and Plantaginaceae and is frequently used as a quantitative chemical marker in the standardization of herbal extracts due to its strong bioactivity and well-characterized pharmacological relevance.

1.4 Common Forms and Preparations

Verbascoside is encountered commercially and in research in several forms. It is available as a standardized plant extract (e.g., from Lippia citriodora, mullein, or Cistanche species), as a purified isolated compound, and as a component in whole herbal preparations such as teas, tinctures, and topical creams. It has also been produced using sustainable biotechnology platforms that employ in vitro plant cell culture technology. It has been produced by in vitro plant culture systems, including genetically transformed roots (so-called "hairy roots"). Topical formulations including creams and gels containing verbascoside have been investigated for dermatological applications.

Liposomal encapsulation of acteoside has been investigated to improve its stability and bioavailability; the average diameter, zeta potential, encapsulation efficiency, and relative bioavailability (Frel) of the acteoside liposome were 78.49 ± 1.44 nm, −4.93 ± 0.79 mV, 81.06 ± 3.48%, and 217.62%, respectively.

2. Traditional and Historical Use

Traditionally, plants with high concentrations of verbascoside have been used in folk medicine to treat inflammation and microbial infections. Due to its antimicrobial and anti-inflammatory properties, it has been traditionally used for the treatment of infections, wounds, and inflammatory conditions.

The most important verbascoside-bearing plants in traditional medicine are summarized below by tradition and context:

Mullein (Verbascum thapsus and related species) — Europe, Near East, Turkey: Verbascum leaves and flowers were used in traditional Turkish medicine to treat respiratory conditions such as bronchitis, dry coughs, tuberculosis, and asthma, as well as hemorrhoids, rheumatic pain, superficial fungal infections, wounds, and diarrhea. Infusions and teas made from the dried flowers were the primary preparation.
Plantain (Plantago species) — Europe and globally: Leaves of verbascoside-rich plants in the Lippia genus were utilized for the treatment of fever, neuropathic and stomach pains, dizziness, headaches, hypnotic conditions, anemia, migraine, and cold symptoms. Applied as poultices and infusions across European, Asian, and indigenous North American traditions.
Lemon verbena (Lippia citriodora / Aloysia citriodora) — South American and Mediterranean traditions: This plant has been widely used in food, cosmetic, and household product industries, and its leaves are used in foods as flavoring agents. Medicinally it was used for digestive and nervous conditions.
Cistanche (Cistanche deserticola, "Roucongrong") — Traditional Chinese Medicine (TCM): Cistanches Herba has been employed in traditional Chinese medicine as a tonic herb for conditions related to kidney deficiency, reproductive function, and age-related decline. Verbascoside is one of its bioactive markers.
Rehmannia (Rehmannia glutinosa, "Dihuang") — Traditional Chinese Medicine: Rehmannia glutinosa has been used in traditional Chinese medicine to nourish yin, replenish essence, and address conditions such as blood deficiency and weakness. Preparations include decoctions and prepared (steamed) root extracts.
Echinacea species — North America: Echinacea species, historically used in North America, contain verbascoside as one of their major bioactive constituents. Indigenous peoples and later European settlers used Echinacea-based preparations for infections and wound healing.
Sesame leaf (Sesamum indicum) — Japan: Verbascoside is the major bioactive compound of a dietary supplement popularly consumed in Japan produced from Sesamum indicum leaves.

The species with high content of verbascoside are used in folk medicine, and in modern phytotherapy, mostly based on their recognized anti-inflammatory and antimicrobial effects.

3. Key Constituents and Mechanisms of Action

3.1 Chemical Structure and Active Moieties

Verbascoside belongs to the phenylethanoid glycosides, which are made of monosaccharides, phenylethanol (C6–C2 skeleton with aldohexose/aldopentose attached by a glycosidic bond), and organic acids such as caffeic acid, ferulic acid, and coumaric acid. It is among the most widespread of the disaccharide caffeoyl esters and is also one of the best-known phenylethanoids because of its health benefits.

The structural combination of caffeic acid and hydroxytyrosol within the molecule is believed to underpin its multiple biological activities. Each moiety contributes individually to overall antioxidant capacity, and their combination yields synergistic radical-scavenging effects.

3.2 Antioxidant Mechanisms

Verbascoside, a polyphenol present in many plants used for food, flavouring, and medicines like olive and mullein, shows the highest scavenger activity among phenylethanoid glycosides tested, as well as a high antioxidant power, even in comparison with other natural phenolic compounds.

Verbascoside activates Nrf2, the nuclear factor regulating protective and antioxidant enzymes, while inhibiting BACH1, which is a repressor of the antioxidant response element, in addition to inducing phase II cytoprotective enzymes, the most prominent of which is heme oxygenase 1 (HO-1).

Verbascoside increases the activity of the antioxidant enzyme SOD, reduces the oxidative stress indicator 8-OHdG, and reduces apoptosis. Moreover, it upregulates PGC1-α and NRF1 expression and promotes mitochondrial biogenesis, mediated by suppression of PKC/HMGB1/RAGE/NFκB signaling.

3.3 Anti-Inflammatory Mechanisms

It has been conjectured that SHP-1 (Src homology region 2 domain-containing phosphatase-1) mediates the anti-inflammatory effect of verbascoside through the regulation of TAK-1/JNK/AP-1 signalling. Results demonstrate that verbascoside increased the phosphorylation of SHP-1 by attenuating the activation of TAK-1/JNK/AP-1 signalling, leading to a reduction in the expression and activity of both COX (cyclooxygenase) and NOS (nitric oxide synthase). Moreover, SHP-1 depletion deletes verbascoside's inhibitory effects on pro-inflammatory molecules induced by LPS.

The health-promoting characteristics of verbascoside (acteoside) can be attributed to its mediation in many signaling pathways, such as MAPK, NF-κB, PI3K/AKT, TGFβ/Smad, and AMPK/mTOR.

3.4 PKC Inhibition

Verbascoside is a documented inhibitor of protein kinase C (PKC). Suppression of PKC/HMGB1/RAGE/NFκB signaling has been demonstrated in experimental models, contributing to reduced oxidative stress and promotion of mitochondrial biogenesis. This PKC inhibitory action is considered one of the central mechanisms linking verbascoside to its anti-inflammatory and neuroprotective properties.

3.5 Neuroprotective Mechanisms

Proteomic analysis has demonstrated that the neuroprotection of verbascoside correlates closely to its anti-inflammatory effect. It significantly blocked microglia and astrocyte activation in the brains of APP/PS1 mice, suppressed the generation of IL-1β and IL-6, and boosted that of IL-4, IL-10, and TGF-β in vivo.

Verbascoside was reported to inhibit the NOD-like receptor family protein 3-mediated acute inflammatory injury in an intracerebral hemorrhage mouse model. Inhibition of acetylcholinesterase and β-secretase levels, and suppression of Aβ plaque accumulation in Aβ1-42-induced AD rats, suggests its neuroprotective role in Alzheimer's disease. In a previous study on APP/PS1 double transgenic male AD model mice, verbascoside inhibited the formation of Aβ deposits and neurofibrillary tangles (NFTs) partly through inhibiting endoplasmic reticulum stress.

3.6 Antimicrobial Mechanisms

The antistaphylococcal activity of verbascoside is based on the inhibition of leucine adsorption and the blocking of protein synthesis. It also inhibits sortase A in Staphylococcus aureus and thus reduces bacterial adhesion, invasion, and biofilm formation.

3.7 Anticancer / Cytotoxic Mechanisms

In addition to its antimicrobial activity, verbascoside shows cytotoxic effects against various cancer cell lines, suggesting its potential use in cancer therapy. Studies have shown that it is able to induce apoptosis and inhibit cell proliferation. Verbascoside's anticancer activity includes anti-proliferation, anti-angiogenesis, and pro-apoptotic effects in several types of cancer cell lines.

4. Scientific Evidence by Area of Use

Important caveat: The large majority of evidence for verbascoside is preclinical — derived from in vitro (cell culture) and in vivo (animal) studies. Human clinical trial evidence is sparse and where noted below, limited in scope and scale. All findings must be interpreted with this in mind.

4.1 Neuroprotection and Cognitive Function

Evidence level: Predominantly preclinical (in vitro and animal); systematic review with meta-analysis of animal studies available; no large-scale human RCTs.

Acteoside (verbascoside) is a phenylpropanoid glycoside widely distributed in medicinal plants that has been extensively investigated for its neuroprotective potential in preclinical models of neurological disorders; a systematic review and meta-analysis was published evaluating its neuroprotective effects across experimental models of neurodegeneration by synthesizing behavioral, biochemical, inflammatory, oxidative stress, and neurotrophic outcomes.

Pooled analyses demonstrated that acteoside significantly improved behavioral performance, including anxiety-related behavior and cognitive function, as assessed using the elevated plus maze and Morris water maze paradigms. Acteoside robustly enhanced endogenous antioxidant defenses by increasing superoxide dismutase, catalase, and reduced glutathione levels, while significantly reducing lipid peroxidation, indicating effective mitigation of oxidative stress.

Prior studies indicate that acteoside possesses anti-inflammatory and antioxidative properties in models of Parkinson's disease (PD) and Alzheimer's disease (AD), thereby alleviating neuronal damage. Furthermore, the suppression of ferroptosis by acteoside is achieved through the activation of the Nrf2-mitophagy signaling pathway, and results from animal studies show that acteoside is beneficial for both treating and preventing PD.

A systematic review was prepared according to PRISMA guidelines appraising preclinical and limited clinical evidence on the anti-depression capacity of verbascoside. A systematic review of 32 preclinical trials published up to April 2023, combined with comprehensive bioinformatics analysis of network pharmacology and molecular docking, was conducted to elucidate the antidepressant mechanism of action of verbascoside.

In the area of hypoxia-induced memory impairment, the effect and mechanism of verbascoside on hypoxic memory injury were studied in a low-pressure and low-oxygen chamber. Verbascoside (50, 150, and 300 mg/kg) was intragastrically administered once a day for 7 days to rats placed in a chamber simulating a 7,500 m high-altitude environment, with the eight-arm maze used to test memory ability. These findings are from rodent models and cannot yet be extrapolated to humans.

4.2 Anti-Inflammatory and Immunomodulatory Effects

Evidence level: Predominantly in vitro and animal; mechanistic data robust; clinical evidence very limited.

Analyses of total phenolic contents in verbascoside-rich plant extracts and evaluation of their associated bioactive activities, specifically antioxidant, anti-tyrosinase, and anti-inflammatory activities, have been reported.

In the U937 monocyte cell line model, verbascoside increased the phosphorylation of SHP-1 by attenuating the activation of TAK-1/JNK/AP-1 signalling, which leads to a reduction in the expression and activity of both COX and NOS. These are in vitro findings only.

Acteoside (verbascoside) exhibits inhibitory activity against inflammatory responses and oxidative stress. NF-κB signaling can be activated by upstream factors such as interleukins, TNFα, LPS, and p38 MAPK, with active NF-κB entering the nucleus to promote the transcriptional expression of inflammatory factors.

4.3 Antimicrobial Activity

Evidence level: In vitro antibacterial and antifungal studies; no clinical trials.

Traditionally, plants with high concentrations of verbascoside have been used in folk medicine to treat inflammation and microbial infections. Therefore, investigations into its antimicrobial and antifungal activities have been conducted over the course of many years. In general, these studies may be regarded as purely observational because they lack mechanistic approaches.

The antistaphylococcal activity of verbascoside is based on the inhibition of leucine adsorption and the blocking of protein synthesis. It also inhibits sortase A in Staphylococcus aureus and thus reduces bacterial adhesion, invasion, and biofilm formation.

The antiviral activity of verbascoside was investigated against Dengue virus-2 in Vero and LLCMK2 cells treated with verbascoside for 48 h, with an EC₅₀ of 3.4 ± 0.4 μg/mL. However, the mechanisms of the antiviral effect have not yet been clarified.

4.4 Antioxidant Effects

Evidence level: Robust in vitro data; some in vivo animal evidence; human data largely indirect (from verbascoside-containing plant foods/supplements).

Nektarios et al. (2003) investigated the free radical scavenging effect of verbascoside in vitro and found it was comparable to that of α-tocopherol. Verbascoside's antioxidant activity operates through direct radical scavenging, metal chelation, and induction of endogenous antioxidant enzymes via the Nrf2 pathway.

4.5 Anticancer / Cytotoxic Activity

Evidence level: In vitro studies across multiple cell lines; animal model data; no human clinical trials.

Several studies have shown that verbascoside was highly cytotoxic to a variety of tumor cell lines, such as the breast cancer cell lines MDA-MB-231 and MCF-7, the ovarian cancer cell line OVCAR-3, the glioblastoma cell line U138-MG, and the hepatocellular carcinoma cell line HepG2, whereas it was less toxic to non-tumor cell lines, such as the non-tumorigenic breast epithelial cell line MCF-12A.

Verbascoside even promoted the growth and proliferation of normal lymphocytes and normal human embryonic diploid lung fibroblasts and delayed senescence. This selective cytotoxicity toward tumor cells while sparing normal cells is of research interest but remains entirely preclinical.

4.6 Hepatoprotective and Renal Protective Effects

Evidence level: Animal and in vitro studies; no controlled human trials.

Acteoside has demonstrated various pharmacological activities including hepatoprotection in preclinical research. Verbascoside presents relevant biological activities including hepatoprotection and renal protection, and a neuroprotective role in Alzheimer's disease. All of these activities, tested in in vitro studies and in studies on mice and rats, are mainly linked with verbascoside's antioxidant and anti-inflammatory properties.

4.7 Antidiabetic Activity

Evidence level: In vitro enzyme inhibition studies and animal models; no human RCTs.

Verbascoside's antidiabetic activity is principally related to carbohydrate digestion, decreasing α-amylase activity and glucose adsorption, and negatively modulating the activity of the sodium-dependent glucose cotransporter 1, as observed in in vitro studies.

4.8 Bone Protection

Evidence level: Animal model data; no human clinical trials.

Acteoside, an active phenylethanoid glycoside compound isolated from herbs of Cistanche, was chosen for investigation of anti-osteoporotic effects on postmenopausal osteoporosis using an ovariectomized (OVX) mice model. Results from in vivo experiments showed that after daily oral administration of acteoside (20, 40, and 80 mg/kg body weight/day) for 12 weeks, bone mineral density and bone biomechanical properties of OVX mice were greatly enhanced, with significant improvement in bone microarchitecture.

4.9 Wound Healing and Skin Applications

Evidence level: In vitro, animal models, limited topical investigations; no large controlled clinical trials.

Studies have tested the effect of verbascoside on improvement of cell viability and wound healing capacity of gingival epithelial cells under high glucose conditions. Verbascoside attenuated the high glucose-induced cytotoxicity and impaired healing, potentially through downregulation of oxidative stress.

Verbascoside, a phenylpropanoid glycoside known for its antioxidant, anti-inflammatory, and photoprotective actions, was investigated to assess the behavior of the active ingredient in solution or in finished preparations, in view of its potential topical use, especially in skin protection.

4.10 Cardiovascular Effects

Evidence level: In vitro and animal model data; no human clinical trials.

Recent pharmacological studies in vitro or in vivo have demonstrated that verbascoside possesses cardiovascular protective activities. Verbascoside has been reported to possess antithrombotic and cardioprotective effects in preclinical literature, though controlled human evidence is absent.

5. Body Systems Associated with Verbascoside

Acteoside (verbascoside) has demonstrated pharmacological activities including anti-oxidation, anti-inflammation, anti-cancer, neuroprotection, cardiovascular protection, anti-diabetes, bone and cartilage protection, hepatoprotection, and anti-microorganism effects in preclinical studies. The body systems for which the most research data exist are:

Nervous system: Neuroprotection in models of Alzheimer's disease, Parkinson's disease, and depression; memory enhancement; anti-neuroinflammation.
Immune/inflammatory system: Modulation of macrophage and microglial activation; inhibition of NF-κB, MAPK, COX, and NOS pathways.
Integumentary system (skin): Wound healing, photoprotection, anti-inflammatory activity in skin cell models.
Metabolic/endocrine system: α-Amylase inhibition and glucose transporter modulation relevant to diabetes.
Skeletal system: Anti-osteoporotic effects in animal models.
Cardiovascular system: Antithrombotic and cardioprotective effects demonstrated preclinically.
Hepatic and renal systems: Hepato- and nephroprotective activity in animal models.
Antimicrobial (multi-system): Activity against bacteria, fungi, and certain viruses in vitro.

6. Pharmacokinetics and Dosage Forms

6.1 Pharmacokinetics

The kinetic properties and particularly the metabolism of a xenobiotic determine its internal dose and concentration in a specific target of the body. No extensive data are available on the pharmacokinetic properties of verbascoside. However, the pharmacokinetic properties of verbascoside, such as absorption and elimination rates, were previously studied in rats, with findings stating fast absorption and elimination.

The bioavailability of verbascoside is approximately 1%, which may be related to its highly hydrophilic nature and extensive metabolism of polyphenolic compounds.

Studies on the pharmacokinetics of dietary verbascoside showed that it is subject to modification during absorption via methylation, sulfation, and glucuronidation in the small intestine and later in the liver.

Verbascoside was metabolized efficiently to methyl and sulphate conjugates, but it was not hydrolyzed or oxidized by human liver subcellular fractions. Three recombinant UGTs (UDP-glucuronosyltransferases) had the ability to conjugate verbascoside to glucuronides. Through this in vitro study it can be summarized that verbascoside can undergo phase two metabolism in the liver and most probably also in the intestine, which may explain its low oral bioavailability as seen in previous studies.

This study also established that phenylethanoid glycosides were metabolized by both intestinal bacteria and enzymes, both in humans and rats. The low oral bioavailability in rats has been described as being due to the multiple routes of hydrolysis by the bacteria of the gastrointestinal ducts, with several degradation products as a result thereof.

The inhibition potency of verbascoside against human CYP enzymes was very weak, and therefore indicated low potential of verbascoside for clinical herb–drug interactions based on CYP-mediated metabolism.

6.2 Dosages Reported in Studies

Dosage data are derived exclusively from studies cited in the peer-reviewed literature:

Human maximum tolerance dose: The maximum tolerance dose of verbascoside reported in humans was 0.443 mg/kg/day.
Animal (rat) — hypoxic memory impairment: Verbascoside (50, 150, and 300 mg/kg) was intragastrically administered once a day for 7 days.
Animal (mouse) — anti-osteoporotic: Daily oral administration of acteoside at 20, 40, and 80 mg/kg body weight/day for 12 weeks.
Animal (mouse/rat) — acute toxicity: Verbascoside was evaluated in mice after a single intraperitoneal injection at the dose range of 0, 1, 2, and 5 g/kg body weight (acute model) and 21 days administration at the dose range of 0, 10, 30, and 60 mg/kg body weight (subacute model).

One method to improve the bioavailability of polyphenols is to dope them with nanoparticles. Research into liposomal, nanoparticulate, and enzymatically modified forms of verbascoside is ongoing with the aim of improving oral absorption.

7. Safety Considerations

7.1 Acute and Subacute Toxicity

According to animal research, the LD₅₀ value of verbascoside was found to be greater than 5 g/kg. In the subacute toxicity study, no statistically significant differences were observed in the values of hematological, biochemical, and pathological parameters in comparison with the control group.

In acute toxicity studies, a single dose of 5000 mg/kg verbascoside did not result in any toxic symptoms or death in male BALB/c mice (25–30 g) or Wistar rats (200–250 g).

No acute cytotoxicity was observed in Wistar rats after oral administration of verbascoside and a 14-day follow-up, and the median lethal dose (LD₅₀) was above 5000 mg/kg.

No pathological, hematological, or biochemical toxic effect was reported with a sub-acute dosage in a 21-day trial in rats. In an in vitro study on human fibroblasts, ethanolic extract of Lippia citriodora leaves (21% verbascoside) did not show any cytotoxic effects and to some extent exerted a cytoprotective effect against oxidative stress.

7.2 In Vitro Cytotoxicity to Normal Cells

In cell viability assays, 24- and 72-hour treatment with verbascoside had no cytotoxic effects at concentrations up to 400 μM on HepG2 and NIH cell lines in the non-cancerous populations. Selective cytotoxicity was observed in several cancer cell lines, whereas normal human cells showed no signs of cytotoxicity. Verbascoside even promoted the growth and proliferation of normal lymphocytes and normal human embryonic diploid lung fibroblasts and delayed senescence.

7.3 Drug Interactions: CYP Enzymes

The inhibition potency of verbascoside against human CYP enzymes was very weak, and therefore indicated low potential of verbascoside for clinical herb–drug interactions via CYP-mediated mechanisms. However, this was an in vitro study, and comprehensive human drug-interaction data are not yet available.

7.4 Bioavailability as a Safety-Relevant Factor

Verbascoside (acteoside) has poor bioavailability, which can potentially be improved by different strategies. The low systemic exposure after oral ingestion means that high in vitro activities may not translate directly to clinical effects or risks at typical intake levels. In summary, verbascoside showed significant toxicity in cellular experiments; however, in animal experiments, verbascoside was a relatively safe and reliable natural ingredient. Therefore, continued attention to the possible toxicity of verbascoside is required for subsequent clinical observations.

7.5 Human Tolerance

Few studies have reported toxicological data on verbascoside. The maximum tolerance dose of verbascoside reported in humans was 0.443 mg/kg/day. This figure represents the only formally documented human tolerance threshold identified in the peer-reviewed literature; more extensive human safety and dose-escalation data are lacking.

7.6 Overall Evidence Gaps

As of the available literature, there are no large-scale, long-term human clinical trials establishing safety at supplemental doses, no established pharmacopoeial monographs for isolated verbascoside as a standalone supplement (as distinct from monographs for the whole plants from which it derives), and no formal regulatory approval of verbascoside as a drug. Many clinical trials for acteoside have been investigated, and it shows great potential in drug development, but this prospective assessment has not yet translated into confirmed human efficacy data from Phase II or III trials. Human studies on verbascoside bioavailability, metabolism, and pharmacokinetics may shed light on the mechanisms underlying its systemic health effects.

References

Health Conditions

Health conditions that Verbascoside may help support.

No conditions available.

Body Systems

Body systems that Verbascoside may help support.

No body systems available.