Indigofera pulchra.

Indigofera pulchra.

Indigofera pulchra

Common Names: Beautiful Indigo, Pretty Indigo, and Handsome Indigo
Local Names: Romo (Birom, Nigeria), Bakin Bunu (Hausa, Nigeria), Ejaọmode (Yoruba, Nigeria), Bi diangal (Mankanya, Senegal), Mbun (Wolof, Senegal), Njamumwi (Mende, Sierra Leone), Balkeyan (Temne, Sierra Leone)
Species ID: NMP-218 |
wfo-0000194692 | NCBI_Taxonomy ID: 539139

Scientific Classification

Kingdom: Plantae

Phylum: Tracheophyta

Class: Magnoliopsida

Order: Fabales

Family: Fabaceae

Genus: Indigofera

Species: Indigofera pulchra

Synonyms: Anil rufescens (Poir.) Kuntze, Indigofera dosycnium Fenzl, Indigofera dupuisii Micheli, Indigofera pulchra var. andongensis Hiern, Indigofera rufescens Poir., Indigofera polysphaera Baker, Indigofera tenuisiliqua Schweinf. ex Baker f. (Plants of the World Online, n.d.; World Flora Online, n.d.).

Morphological Description

Indigofera pulchra is an erect, stiff, grey-pubescent, softly woody undershrub, typically growing 1–1.5 meters tall, occasionally reaching 2 meters in favorable conditions. Its morphology is adapted to seasonally dry tropical biomes, with variability in leaf structure enhancing its ecological adaptability. Key features include:

·       Stems: Grey-pubescent, softly woody, erect, with a slender, branching habit; young stems green, turning greyish-brown with age.

·       Leaves: Dimorphic, pinnate; upper leaves 1–3-foliolate, lower leaves up to 11-foliolate; leaflets elliptic to obovate, 5–20 mm long, 3–10 mm wide, grey-green, pubescent; stipules lanceolate, 1–2 mm long (Plants of the World Online, n.d.).

·       Flowers: Red to orange corolla, 4–6 mm long, in terminal racemes (sometimes condensed, subcapitate); calyx brownish, 2–3 mm long; standard petal ovate; flowering from July to November in West Africa (Garba et al., 2008).

·       Fruit: Pods cylindrical, 3–5 mm long, 2–3 mm wide, pubescent, brown at maturity, containing 1–2 seeds; seeds ovoid, 1–2 mm long, brown (World Flora Online, n.d.).

·       Roots: Taproot system, fibrous, aiding drought tolerance and soil stabilization in savanna ecosystems (Gerometta et al., 2020).

The plant’s pubescent foliage and compact pods contribute to its resilience in arid environments, while its colorful flowers attract pollinators like bees and butterflies.

Distribution and Habitat

Indigofera pulchra is native to tropical Africa, with a distribution spanning Senegal, Gambia, Guinea, Sierra Leone, Mali, Burkina Faso, Ghana, Nigeria, Cameroon, Chad, Sudan, Ethiopia, Angola, and Tanzania. It thrives in:

·       Savannas: Common in open savanna woodlands with annual rainfall of 400–1,200 mm and temperatures of 25–35°C (Plants of the World Online, n.d.).

·       Open Woodlands: Found in seasonally dry, well-drained soils, often sandy or loamy, with pH 5.0–7.5, at altitudes of 100–1,800 meters.

·       Disturbed Areas: Occurs along roadsides, fallow fields, and rocky outcrops, tolerating moderate disturbance and grazing pressure (Gerometta et al., 2020).

Its wide distribution and adaptability to dry conditions make it a key species in savanna ecosystems, though it is not considered invasive (World Flora Online, n.d.).

Ethnopharmacology

Indigofera pulchra is widely used in traditional African medicine, particularly in Nigeria, Senegal, and Sierra Leone, for various ailments. Ethnopharmacological studies validate several traditional uses, highlighting its potential as a source of bioactive compounds, notably flavonoids, dihydrostilbenes, and saponins. Key medicinal uses include:

·       Antidiarrheal: In northern Nigeria, decoctions of aerial parts are used to treat diarrhea, supported by studies showing dose-dependent protection against castor oil-induced diarrhea in mice (100% protection at 200 mg/kg) and relaxation of rabbit jejunum, likely via histaminergic and cholinergic mechanisms (Garba et al., 2008).

·       Wound Healing: Leaf extracts are applied topically in Sierra Leone and Nigeria to treat infected wounds.

·       Anti-inflammatory: Aerial part decoctions are used in Nigeria for inflammation,

·       Analgesic: In Nigeria, leaf infusions are used for pain relief,

·       Snakebite Antidote: In Senegal and Nigeria, aerial part decoctions are used as a prophylactic against snakebites, with studies confirming venom-neutralizing activity against *Naja nigricollis* venom, possibly due to saponins and steroids (Abubakar et al., 2006).

·       Gastrointestinal Disorders: In northern Nigeria, the plant is used to treat stomach aches and dysentery, supported by phytochemicals like tannins and glycosides that exhibit antispasmodic effects (Garba et al., 2008).

Phytochemical analyses reveal flavonoids (e.g., quercetin, gallic acid), dihydrostilbenes (e.g., 3-methoxy-4,5-methylenedioxy-dihydrostilbene), tannins, saponins, steroids, and glycosides, contributing to its pharmacological activities. However, limited clinical studies and potential toxicity necessitate cautious use (Musa et al., 2011; Garba et al., 2021).

⚠  Toxicity Profile: Limited data exist on the toxicity of Indigofera pulchra, but preliminary studies suggest moderate safety with precautions. Key toxicity details include: Acute Toxicity: The intraperitoneal LD50 of methanolic aerial part extract in mice is 2,154 mg/kg, indicating moderate toxicity; no acute toxicity was observed at oral doses up to 5,000 mg/kg (Garba et al., 2008). Cytotoxicity: Dihydrostilbenes from aerial parts show weak activity against methicillin-resistant *Staphylococcus aureus* (MRSA) but no significant cytotoxicity in mammalian cell lines, suggesting low risk at therapeutic doses (Garba et al., 2021). Human Risk: No human poisoning cases are reported, but prolonged use or high doses may cause gastrointestinal upset or liver stress due to flavonoid and saponin accumulation, particularly in children or pregnant women (Burkill, 1995).

Additional Uses

·       Forage: Aerial parts are used as fodder for livestock in Nigeria and Senegal, particularly during dry seasons, due to its moderate nutritional content.

·       Soil Stabilization: The fibrous root system is planted in Nigeria to prevent erosion on degraded lands, enhancing savanna restoration (Gerometta et al., 2020).

·       Ornamental: Occasionally cultivated in West African gardens for its attractive red-orange flowers, though less common than other Indigofera species (World Flora Online, n.d.).

References

  • Abubakar, M. S., Balogun, E., Abdurrahman, E. M., Nok, A. J., Shok, M., Mohammed, A., & Garba, M. (2006). Ethnomedical treatment of poisonous snakebites: Plant extract neutralized Naja nigricollis venom. Pharmaceutical Biology, 44(5), 343–348.
  • Garba, M., Musa, A. M., Ahmed, A., & Abubakar, M. S. (2008). Preliminary gastrointestinal studies of methanol extract of Indigofera pulchra Willd in rodents. Asian Journal of Scientific Research, 1(6), 598–603.
  • Garba, M., Musa, A. M., Mada, S. B., John, P. A., & Oduola, T. (2021). Dihydrostilbenes from Indigofera pulchra. Natural Product Communications, 3(5), 655–844.
  • Gerometta, E., Grondin, I., Smadja, J., Frederich, M., & Gauvin-Bialecki, A. (2020). A review of traditional uses, phytochemistry and pharmacology of the genus Indigofera. Journal of Ethnopharmacology, 253, 112608.)
  • Musa, A. M., Garba, M., Abubakar, M. S., & Ahmed, A. (2011). Analgesic and anti-inflammatory activities of methanol extract of Indigofera pulchra. Pharmacognosy Journal, 3(20), 12–17.
  • Plants of the World Online. (n.d.). Indigofera pulchra Willd. Retrieved from https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:499881-1
  • World Flora Online. (n.d.). Indigofera pulchra Willd. Retrieved from https://www.worldfloraonline.org/taxon/wfo-0000194692

External Links

More Pictures

 

Compounds of Indigofera pulchra.
References

Achika, J. I., Yusuf, A. J., Ayo, R. G., & Liman, D. U. (2023). Flavonoids from Nigerian indigenous medicinal plants and their bioactivities: a review. Phytomedicine plus, 3(2), 100405.