Trial reportNeuropsychopharmacology : official publication of the American College of Neuropsychopharmacology2013
Acute effects of Sceletium tortuosum (Zembrin), a dual 5-HT reuptake and PDE4 inhibitor, in the human amygdala and its connection to the hypothalamus.
Trial report in Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 16 papers, 2 of them syntheses that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
16 citing papers in PubMed, 2 syntheses or guidelines pooled it, 64 citations in OpenAlex.
- Skeletons in the closet? Using a bibliometric lens to visualise phytochemical and pharmacological activities linked toFrontiers in plant science · 2024Pooled it
- Herbal medicine for depression and anxiety: A systematic review with assessment of potential psycho-oncologic relevance.Phytotherapy research : PTR · 2018Pooled it
- Mitigation of serotonin-caused suppression of osteoblast function by extracts of the psychoactive indigenous plant Sceletium tortuosum.BMC complementary medicine and therapies · 2026Article
- ZembrinMolecules (Basel, Switzerland) · 2026Article
- Cyclic nucleotide phosphodiesterases as drug targets.Pharmacological reviews · 2025Review
- Permeation of Phytochemicals of Selected Psychoactive Medicinal Plants across Excised Sheep Respiratory and Olfactory Epithelial Tissues.Pharmaceutics · 2023Article
- What is next in African neuroscience?eLife · 2022Article
- Depression in Sub-Saharan Africa.IBRO neuroscience reports · 2022Article
- Article
- A Chewable Cure "Kanna": Biological and Pharmaceutical Properties ofMolecules (Basel, Switzerland) · 2021Review
- Sceletium for Managing Anxiety, Depression and Cognitive Impairment: A Traditional Herbal Medicine in Modern-Day Regulatory Systems.Current neuropharmacology · 2021Article
- Pharmacology of Herbal Sexual Enhancers: A Review of Psychiatric and Neurological Adverse Effects.Pharmaceuticals (Basel, Switzerland) · 2020Review
- Therapeutic targeting of 3',5'-cyclic nucleotide phosphodiesterases: inhibition and beyond.Nature reviews. Drug discovery · 2019Review
- Leaf Spray Mass Spectrometry: A Rapid Ambient Ionization Technique to Directly Assess Metabolites from Plant Tissues.Journal of visualized experiments : JoVE · 2018Article
- cAMP/PKA/CREB/GLT1 signaling involved in the antidepressant-like effects of phosphodiesterase 4D inhibitor (GEBR-7b) in rats.Neuropsychiatric disease and treatment · 2016Article
- Proof-of-Concept Randomized Controlled Study of Cognition Effects of the Proprietary Extract Sceletium tortuosum (Zembrin) Targeting Phosphodiesterase-4 in Cognitively Healthy Subjects: Implications for Alzheimer's Dementia.Evidence-based complementary and alternative medicine : eCAM · 2014Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
8 authors at 2 institutions in 3 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The South African endemic plant Sceletium tortuosum has a long history of traditional use as a masticatory and medicine by San and Khoikhoi people and subsequently by European colonial farmers as a psychotropic in tincture form. Over the past decade, the plant has attracted increasing attention for its possible applications in promoting a sense of wellbeing and relieving stress in healthy individuals and for treating clinical anxiety and depression. The pharmacological actions of a standardized extract of the plant (Zembrin) have been reported to be dual PDE4 inhibition and 5-HT reuptake inhibition, a combination that has been argued to offer potential therapeutic advantages. Here we tested the acute effects of Zembrin administration in a pharmaco-fMRI study focused on anxiety-related activity in the amygdala and its connected neurocircuitry. In a double-blind, placebo-controlled, cross-over design, 16 healthy participants were scanned during performance in a perceptual-load and an emotion-matching task. Amygdala reactivity to fearful faces under low perceptual load conditions was attenuated after a single 25 mg dose of Zembrin. Follow-up connectivity analysis on the emotion-matching task showed that amygdala-hypothalamus coupling was also reduced. These results demonstrate, for the first time, the attenuating effects of S. tortuosum on the threat circuitry of the human brain and provide supporting evidence that the dual 5-HT reuptake inhibition and PDE4 inhibition of this extract might have anxiolytic potential by attenuating subcortical threat responsivity.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.