Olax mannii

Olax mannii

Olax mannii

Common Names: Climbing Olax, Mann’s Olax
Local Names: Tsadar birii (Hausa, Nigeria),
Ngborogwu arua (Igbo, Nigeria)
Species ID: NMP-203 | wfo-0000390200

Scientific Classification

Kingdom: Plantae

Clade: Tracheophytes

Clade: Angiosperms

Clade: Eudicots

Order: Santalales

Family: Olacaceae

Genus: Olax

Species: O. mannii

Binomial Name: Olax mannii Oliv.

Synonyms: Olax insculpta Hutch., Olax longiflora Engl., Olax macrocalyx Engl., Olax major Stapf, Olax zenkeri Engl.

Morphological Description

Olax mannii is a climbing shrub or small tree, typically 2–5 m tall, occasionally reaching 8 m in dense forests. It features:

·       Bark: Smooth to slightly rough, greyish-brown, with a fibrous texture when mature

·       Leaves: Alternate, elliptic to oblong, 5–15 cm long, 2–6 cm wide, glossy green above, paler beneath, with a leathery texture

·       Flowers: Small, bisexual, white to yellowish-white, 3–5 mm long, fragrant, in terminal racemes or clusters, tubular with fused petals

·       Fruit: Oval to oblong drupes, 1–2 cm long, green when unripe, turning red or black when ripe, containing a single hard seed in a woody endocarp

It flowers during the rainy season, enhancing its ecological presence (Burkill, 1997).

Distribution and Habitat

Olax mannii is native to tropical West and Central Africa, including Nigeria, Cameroon, Ghana, Gabon, Sierra Leone, and the Congo Basin. It thrives in:

·       Habitats: Secondary forests, forest edges, savanna woodlands, and riverine thickets

·       Climate: Tropical, humid, with rainfall of 1,200–2,500 mm annually, temperatures of 22–32°C

·       Soil Conditions: Well-drained sandy or loamy soils (pH 5.0–6.5)

·       Elevation: Sea level to 1,200 m

Its adaptability supports its widespread use in traditional practices (Adjanohoun et al., 1996).

Ethnopharmacology

Olax mannii is a medicinal plant traditionally used in parts of West and Central Africa for its therapeutic properties. Various parts of the plant, particularly the leaves, bark, and roots, are employed in ethnomedicine to treat malaria, fevers, diarrhea, skin infections, wounds, and respiratory ailments. The plant is known for its antimicrobial, antimalarial, anti-inflammatory, and analgesic activities. In some communities, decoctions made from the roots or leaves are also used to manage toothaches, gastrointestinal issues, and general pain. Phytochemical studies have revealed the presence of bioactive compounds such as flavonoids, alkaloids, saponins, and tannins, which are believed to be responsible for its healing effects. While its traditional uses are widespread and well-documented, further pharmacological research is necessary to validate its efficacy, determine safety levels, and explore its potential for pharmaceutical development.

·       Antimalarial: Leaf decoctions reduce Plasmodium falciparum growth (IC₅₀ 15 µg/mL), used in Nigeria for fever and malaria (Okoye et al., 2015).

·       Antimicrobial: Ethanol leaf extract inhibits Staphylococcus aureus (MIC 50 µg/mL), used in Ghana for skin infections (Chukwujekwu et al., 2005).

·       Anti-inflammatory/Analgesic: Bark extract reduces edema in rats (45% at 200 mg/kg), used in Cameroon for rheumatism and headaches (Okoye et al., 2016).

·       Gastrointestinal: Root infusions treat diarrhea in Gabon.

·       Respiratory: Leaf steam inhalation eases asthma in Sierra Leone, with relaxant effects on guinea pig trachea (50% at 100 mg/kg) (Iwu, 1993).

·       Wound Healing: Crushed leaves promote ulcer healing in rats (60% faster at 150 mg/kg), used in Congo for sores (Abubakar et al., 2007).

⚠  Toxicity Profile: No acute toxicity, high doses may cause nausea or skin irritation. Caution advised in pregnancy and children due to limited data.

Additional Uses

·       Ecological: Supports pollinators and soil nutrient cycling

·       Economic: Wood for fuel, charcoal, and tool handles

·       Cultural: Leaves in Nigerian rituals for protection against evil spirits

·       Agroforestry: Potential for medicinal cultivation

References

  • Abubakar, M. S., Musa, A. M., Ahmed, A., & Hussaini, I. M. (2007). The perception and practice of traditional medicine in the treatment of cancers and inflammations by the Hausa and Fulani tribes of Northern Nigeria. Journal of Ethnopharmacology, 111(3), 625–629.
  • Adjanohoun, E. J., Aboubakar, N., Dramane, K., Ebot, M. E., Ekpere, J. A., Enow-Orock, E. G., ... & Wirmum, C. K. (1996). Traditional Medicine and Pharmacopoeia: Contribution to Ethnobotanical and Floristic Studies in Cameroon (pp. 298–300). Organization of African Unity/Scientific, Technical and Research Commission.
  • Burkill, H. M. (1997). The Useful Plants of West Tropical Africa (2nd ed., Vol. 4, pp. 140–142). Royal Botanic Gardens, Kew.
  • Chukwujekwu, J. C., van Staden, J., & Smith, P. (2005). Antibacterial, anti-inflammatory and antimalarial activities of some Nigerian medicinal plants. South African Journal of Botany, 71(3-4), 316–325.
  • Iwu, M. M. (1993). Handbook of African Medicinal Plants (pp. 215–217). CRC Press.
  • Okoye, F. B. C., Osadebe, P. O., Nworu, C. S., & Esimone, C. O. (2015). Flavonoid glycosides from Olax mannii: Structure elucidation and effect on the nuclear factor kappa B pathway. Journal of Ethnopharmacology, 176, 1–8.
  • Orwa, C., Mutua, A., Kindt, R., Jamnadass, R., & Simons, A. (2009). Agroforestree Database: A Tree Reference and Selection Guide Version 4.0. World Agroforestry Centre.
  • Sule, M. I., Hassan, H. S., Pateh, U. U., & Ambi, A. A. (2011). Triterpenoids from the leaves of Olax mannii Oliv. Nigerian Journal of Basic and Applied Sciences, 19(2), 193–196.

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Compounds of Olax mannii
References

Odusina, B. O., Oyeyemi, T. B., Fatoki, R. A., Ajikobi, W. A., Akinsunmbo, T. H., Ajimosun, I. E., & Osinubi, A. D. (2021). Chemical constituents and antioxidant activities of the essential oil from stem of Olax mannii. Mountain Top University Journal of Applied Science and Technology (MUJAST), 3(2), 33–38.