Vernonia glaberrima
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Gymnanthemum glaberrimum Common Names: Scientific
Classification Kingdom: Plantae Clade: Tracheophytes Clade: Angiosperms Clade: Eudicots Clade: Asterids Order: Asterales Family: Asteraceae Genus: Gymnanthemum Species: Gymnanthemum glaberrimum (Welw. ex
O.Hoffm.) H. Rob. Synonyms: Vernonia glaberrima Welw. ex O.Hoffm.; Vernonia hensii Klatt (treated as a synonym in some
African floras). Morphological Description Gymnanthemum glaberrimum is a much-branched, perennial subshrub or small shrub with a
woody base, usually 0.5–1 m tall but occasionally reaching about 2 m in
favourable sites. It often forms small, open tufts in grassland and savanna,
becoming conspicuous when in full flower. · Stems: Slender, erect to ascending, terete, glabrous to sparsely
pubescent. Plants are characteristically almost leafless at peak flowering,
with older leaves shed and new ones emerging shortly after, giving a delicate,
twiggy aspect to flowering stands (Isawumi, 1995; Hyde et al., 2025). · Leaves: Elliptic to oblanceolate, about 3–10 cm long and 1–3 cm
wide, with subentire to coarsely dentate-serrate margins. Apex acute to
acuminate, base cuneate; texture coriaceous and often somewhat shiny; surfaces
mostly glabrous and dark green. In some floristic treatments, leaves are
described as appearing shortly after flowering, suggesting adaptation to
seasonal climates ( Hyde et al., 2025). · Inflorescences: Numerous small capitula, usually 5–8 mm in
diameter, borne in open panicles or pseudumbels on short lateral branches.
Florets are white, tubular, sweetly scented and five-lobed; involucral bracts
are several-seriate and narrowly lanceolate. Flowering is commonly observed in
the dry season or at the end of the rains in many parts of its range. · Fruit: Cylindrical achenes, about 2–3 mm long, 10-ribbed, crowned
by a pappus of white bristles. The light achenes are wind-dispersed and can
rapidly colonise disturbed patches (Fern, 2024; Hyde et al., 2025). · Microscopic characters: Pharmacognostic studies on the leaf report
amphistomatic blades with anomocytic stomata, stomatal indices around 3–4%
(adaxial) and 11% (abaxial), and the presence of oil glands, starch grains,
tannins, cellulose, gum, calcium oxalate crystals, fibres and vessel elements. Distribution and Habitat Gymnanthemum glaberrimum is African in distribution and corresponds to Vernonia glaberrima in older floras. · Geographic range: West Africa (from Guinea through Togo and
Nigeria to Cameroon), Central Africa (Democratic Republic of Congo), and
Eastern to Southern Africa, including Tanzania, Malawi, Zambia and Zimbabwe
(Kew Science, n.d.; Hyde et al., 2025). · Altitude: Typically recorded between 600 and 1,600 m above sea level
in Flora of Tropical East Africa and Flora Zambesiaca accounts (Kew Science,
n.d.; Flora of Zambia, 2025). · Habitats: Open hillside grasslands, wooded grassland and
Brachystegia-dominated miombo woodland, forest margins, fallow fields and other
disturbed sites. Often locally frequent in well-drained, sandy or loamy soils
with moderate to high rainfall (c. 600–1,800 mm). · Regional notes: In Zimbabwe and Malawi it is described as
a frequent native shrub of grassland and woodland edges, sometimes forming
scattered clumps in open savanna (Hyde et al., 2025). In Nigeria it occurs
mainly in northern savanna zones and forest–savanna transition belts, often on
fallow land and roadsides. · Ecological role: A light-demanding pioneer species that
colonises disturbed ground, providing nectar and pollen for insects (bees,
butterflies and other pollinators). The root system helps stabilise soil on
slopes and contributes to herbaceous diversity in savannas and open woodland. Ethnopharmacology Under its synonym Vernonia glaberrima, this species is recognised in West and Central
African ethnomedicine. Ethnobotanical surveys and pharmacological introductions
consistently report its use for inflammatory and infectious conditions,
malaria, diabetes and skin-related disorders, particularly skin cancers and
chronic lesions (Alhassan et al., 2018; Abdullahi et al., 2015a; Gangas et al.,
2021; Onugwu et al., 2024). · Malaria and febrile illness: Decoctions of the leaves are taken orally
in northern Nigeria and neighbouring regions to treat malaria and fever, often
in combination with other antipyretic herbs. This use is explicitly mentioned
in several pharmacological papers and reviews of the species (Abdullahi et al.,
2015b; de Villiers et al., 2010; Gangas et al., 2021). · Skin cancer and chronic skin conditions: Leaf preparations, especially methanolic
or aqueous extracts and poultices, are used traditionally in West Africa for
the management of skin cancers, chronic skin ulcers and other skin-related
disorders (Alhassan et al., 2018; Abubakar et al., 2022). · Pain and inflammation: The plant is widely cited in local
practice as a remedy for body pains, headaches, arthritis and general
inflammatory complaints. Leaves may be taken as decoctions or used topically as
poultices (Abdullahi et al., 2016; Yusuf et al., 2020). · Infectious and gastrointestinal diseases: Traditional healers use leaf extracts for
diarrhoea, gastrointestinal discomfort and a range of microbial infections,
including wound and skin infections. These uses align with observed
antibacterial activity in vitro (Abdullahi et al., 2015c; Gangas et al., 2021). · Diabetes and metabolic disorders: In northern Nigeria, leaf infusions or
decoctions are administered to people with “sugar disease” (diabetes mellitus),
reflecting its hypoglycaemic potential demonstrated in experimental models
(Abdullahi et al., 2015a). · Mosquito-borne disease control: Recent ethnopharmacological-inspired work
has explored the plant as a larvicidal and mosquito-repellent agent
against Aedes mosquitoes,
supporting its emerging role in community-based vector control strategies
(Onugwu et al., 2024). A growing body of in
vitro and in vivo work substantiates many of the traditional uses of Gymnanthemum glaberrimum, especially under its synonym Vernonia glaberrima. Key activities are summarised below. Antimicrobial and Antibacterial Activity · Crude methanol leaf extract showed
broad-spectrum antimicrobial activity against clinically important pathogens,
including methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Listeria monocytogenes, Helicobacter pylori, various Gram-negative bacteria and pathogenic
yeasts, using agar diffusion and broth dilution methods (Abdullahi et al.,
2015c; Abdullahi et al., 2015d). · Hexane extracts of leaves and stems, alone and
in combination with standard antibiotics, displayed notable antibacterial
activity and synergistic effects against multidrug-resistant bacteria. These
findings support the traditional use of the plant for infectious and skin
conditions (Gangas et al., 2021). Antimalarial Activity · Methanolic leaf extract produced significant,
dose-dependent suppression of parasitaemia in mice infected with chloroquine-sensitive Plasmodium berghei (NK65) in a curative model, confirming
antiplasmodial activity that aligns closely with folk use for malaria
(Abdullahi et al., 2015b; de Villiers et al., 2010). Antidiabetic and Metabolic Effects · In alloxan-induced diabetic rats, methanolic
leaf extract produced a significant, time-dependent reduction in fasting blood
glucose, improvement in glucose tolerance and a moderate hypoglycaemic effect
overall. The study concluded that the extract may be useful as an adjunct in
diabetes management (Abdullahi et al., 2015a). · Subsequent reviews on Vernonia species have
highlighted V. glaberrima as
one of several antidiabetic Vernonieae taxa, often linked to the presence of
triterpenes and flavonoids (Yusuf et al., 2024). Analgesic and Anti-inflammatory Activity · The n-hexane-soluble fraction of methanolic leaf
extract significantly reduced acetic acid–induced writhing in mice and
carrageenan-induced paw oedema in rats, demonstrating both peripheral analgesic
and anti-inflammatory effects and experimentally validating traditional use for
pain and swelling (Abdullahi et al., 2016). · Lupeol isolated from the n-hexane fraction
exhibited strong analgesic activity in acetic acid–induced writhing tests (over
80% inhibition at doses of 12.5–50 mg/kg) and significantly attenuated both
early and late phases of formalin-induced pain, as well as formalin-induced paw
inflammation. The median LD50 for lupeol was greater than 5,000
mg/kg, indicating low acute toxicity (Yusuf et al., 2020). · A hydroethanolic leaf extract displayed
anti-inflammatory and immunomodulatory effects, reducing protein denaturation,
stabilising lysosomal membranes and modulating cyclophosphamide-induced
immunosuppression in experimental models (Ibrahim et al., 2025). Anticancer and Cytotoxic Activity · Methanolic and chloroform leaf extracts and
their purified fractions showed significant cytotoxicity against multiple human
cancer cell lines, including breast (MCF7), cervical (HeLa), liver (HepG2),
colon and melanoma cells. Isolated compounds such as lupeol and
5-methylcoumarin-4-β-glucoside contributed strongly to these effects (Alhassan
et al., 2018; Abubakar et al., 2022). · Molecular docking and in vitro assays implicate
targets such as cyclin-dependent kinase 2 (CDK2) and carbonic anhydrase IX
(CAIX) in the anticancer effects, providing mechanistic support for the
traditional use of the plant against skin cancers (Alhassan et al., 2018). Mosquito Larvicidal and Repellent Activity · Methanolic leaf extract and fractions exhibited
potent larvicidal activity against Aedes aegypti larvae, with aqueous methanol fractions showing LC50 values
as low as approximately 2.8 ppm and sub-fractions achieving up to 75% larval
mortality. Phytochemical analyses associated these effects with flavonoids,
terpenoids, saponins and phenolics (Onugwu et al., 2024). · Leaf extract fractions also demonstrated strong
mosquito-repellent activity against adult Aedes aegypti, with percentage repellency approaching 99% at
the highest tested concentrations, suggesting promising application as a
plant-based mosquito repellent for malaria and arboviral disease control. Antivenom-related Potential · Computational docking and experimental
validation studies on selected leaf phytochemicals from V. glaberrima showed inhibitory potential against key
snake venom toxins, including phospholipase A2 and
metalloproteinases, and reduced venom-induced cellular damage in vitro. These
findings point to a future role for the plant as an adjunct in antivenom
therapy (Yusuf et al., 2024). ⚠ Safety
Considerations: Experimental studies
suggest that leaf extracts of Gymnanthemum glaberrimum are generally well tolerated at doses
showing antimalarial, antidiabetic, analgesic and anti-inflammatory effects.
Nonetheless, high or prolonged dosing can alter liver and kidney parameters in
animals, and long-term, high-dose human use has not been rigorously evaluated.
Use should remain within traditional dose ranges and under guidance of trained
practitioners, especially in individuals with underlying hepatic or renal
disease, during pregnancy or in children. Additional Notes · Taxonomic reclassification: Modern systematic work places Vernonia glaberrima within Gymnanthemum, leading to the currently accepted name Gymnanthemum glaberrimum. This is reflected in Kew’s Plants of the World
Online and the World Flora Online (Kew Science, n.d.). · Conservation: The species is generally common in suitable habitats across
several countries and is not currently listed as threatened in regional floras.
However, local populations may be impacted by agricultural expansion,
overgrazing and frequent burning. · Research gaps: Although considerable progress has been made in elucidating
its phytochemistry and preclinical pharmacology, there is still limited information
on pharmacokinetics, herb–drug interactions and well-designed clinical trials.
Standardised extracts and clear dosing guidelines would support future clinical
development. References
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| Compounds of Vernonia glaberrima | |
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