Stereospermum

Stereospermum: A Comprehensive Encyclopedic Reference

1. Identity and Botanical Classification

1.1 Genus Overview

Stereospermum is a genus of trees in the paleotropical clade of the family Bignoniaceae. The native range of the genus spans Tropical Africa, Madagascar, the Indian Subcontinent to southern China, and western Malesia. Commonly referred to as the "pipe tree" due to their distinctive seed pods, these remarkable plants are native to tropical regions and are celebrated for their grandeur and importance in their natural habitats. The Asiatic species of Stereospermum are all deciduous trees that are most often located at lower elevations in the tropics and subtropics, growing in regions with a marked dry season and generally at elevations between 200 and 1,000 metres.

1.2 Medically Significant Species

The genus comprises multiple species with distinct geographical distributions and ethnomedicinal traditions. The most pharmacologically studied are:

• Stereospermum chelonoides (L.f.) DC. — Classified under kingdom Plantae, phylum Tracheophyta, class Magnoliopsida, order Lamiales, family Bignoniaceae. Known in English as the "fragrant padritree." This species is used in herbal medicine in Ayurveda and is an integral part of the culture and tradition of the cold desert biosphere reserve.
• Stereospermum suaveolens (Roxb.) DC. — Often treated as synonymous with Stereospermum chelonoides (L.f.) DC., this synonymy is a frequent source of confusion in the botanical and pharmacological literature. When the synonym Stereospermum suaveolens is used, it refers to Stereospermum chelonoides; but when Stereospermum chelonoides is used, especially in older literature, it often refers to Stereospermum tetragonum.
• Stereospermum kunthianum Cham. — Stereospermum kunthianum is an African deciduous shrub or small tree occurring in the Democratic Republic of Congo, Djibouti, Eritrea, Ethiopia, Kenya, Malawi, Senegal, Somalia, Sudan, Tanzania, Uganda, and widespread across Africa to the Red Sea, as far south as Angola, Mozambique, Zambia, and Zimbabwe. Known in English as "pink jacaranda."
• Stereospermum colais (Buch.-Ham. ex Dillwyn) Mabb. — The native range of this species is the Indian Subcontinent to southern China and Sumatra; it is a tree that grows primarily in the wet tropical biome. It is one of the ten roots constituting the classical Ayurvedic formulation Dashamoola.
• Stereospermum personatum (Hassk.) Chatterjee — A well-known medicinal plant that is frequently used in the Ayurvedic system of medicine for different disease conditions and is one of the ingredients of the popular formulation Dasamoola.
• Stereospermum zenkeri K.Schum. ex De Wild. — A medium-sized plant native to Africa that grows to a height of about 10 m.

1.3 Synonymy and Nomenclatural Complexity

The nomenclatural history of Stereospermum is notably complex. Key synonyms for Stereospermum chelonoides include Bignonia chelonoides L.f., Bignonia gratissima J.Koenig, Bignonia suaveolens Roxb., Heterophragma chelonoides (L.f.) Dalzell & A.Gibson, Heterophragma suaveolens (Roxb.) Dalzell & A.Gibson, Hieranthes fragrans Raf., and Spathodea suaveolens (Roxb.) Benth. & Hook.f. This proliferation of synonyms across both older and modern literature means that phytochemical and pharmacological studies must be carefully evaluated to confirm which species was actually investigated.

1.4 Common Names

The plant is known by many vernacular names, including Adakapari, Fragrant Padritree, Krishnavrinda, Kuberakshi, Padeli, Pader, Padhala, Palol, Patala, Patali, Patiri, Poopatiri, Pulila, Tamrapushpi, and Trumpet Flower Tree. In traditional Ayurvedic texts the name "Patala" refers specifically to the flower color: the plant is named thus because the flowers are red (patala) colored.

1.5 Botanical Description

Stereospermum suaveolens (syn. S. chelonoides) is a tree reaching around 25 m in height, cylindrical in shape, with bark that is externally brown to creamy, rough due to vertical fissures, cracks, ridges, and transverse fine lenticels, internally dark brown, with lamellation or stratification due to the presence of concentric bands of fibers. It favors moist parts of deciduous forests, humid and hot climates, and lateritic loamy or sandy black soils.

2. Traditional and Historical Use

2.1 Ayurveda (Indian Subcontinent)

Stereospermum has a long, documented history of use in Ayurveda, one of the world's oldest codified medical systems. Stereospermum chelonoides, known as Patala in Ayurveda, is a medicinal plant used in Dashamoola for inflammation, respiratory disorders, fever, and digestive health. Dashamoola — the polyherbal formulation in which it appears — has been used for more than 3,000 years in traditional Ayurvedic treatment. The name "Dashamoola" is derived from the Sanskrit words "Dash" meaning ten and "mula" meaning root; according to ancient texts such as the Charaka and Sushruta Samhita, it is a traditional formula comprising the ten dried roots of ten different plants.

The Valiyapanchamoola (the "five great roots" sub-group of Dashamoola) is a combination of Stereospermum suaveolens (Patala), Premna integrifolia (Agnimantha), Aegle marmelos (Bilva/Indian Bael), Gmelina arborea (Gambhari), and Oroxylum indicum (Shyonaka). The Dashamoola combination is used as a standard Ayurvedic therapy for the management of inflammatory disorders.

Classical Ayurvedic texts recognized multiple varieties of the plant. Bhavaprakasha mentions two varieties: Patala, identified as Stereospermum suaveolens, and Sitapatala, identified as Stereospermum chelonoides. Bhavaprakasa mentioned only two varieties: the white-flowered (patala) and the copper-red-flowered (tamrapatala). Thamrapatala is described as bitter, acrid, and hot, and relieves morbid kapha, and is useful in breathing difficulty, vomiting, oedema, and flatulence; while the white variety purifies blood, increases appetite, and cures oedema, thirst, vomiting, hiccough, morbid kapha, and vata.

The plant appears across multiple Indian systems of medicine: Ayurveda, Siddha, Sowa Rigpa, and Unani.

Parts used and their traditional purposes in Ayurveda were varied:

• The root is one of the ingredients of the classical Ayurvedic preparation Dashamularishta.
• Decoctions of bark, root, and flowers are used for the treatment of sore throat, bleeding diseases, and asthma, and as a cooling drink in fever.
• The flowers with honey mixtures are used for the control of hiccup; the fruit is useful for the treatment of leprosy.
• Decoction of roots is used in intermittent and puerperal fevers and affections of the brain.
• It has traditionally been used as an analgesic, liver stimulant, astringent, wound healer, and antiseptic.
• Flowers are used in semen debility.
• The root has been associated with anticancer activity and is used in the preparation of the Ayurvedic formulation Dashamoola.

Stereospermum suaveolens DC. is now placed in a threatened category due to its overexploitation as a result of high demand for traditional medicine purposes.

Dashamoola is prepared in various dosage forms: churna (powder), kwatha/kashaya (decoction), taila (medicated oil), ghrita (clarified butter infusion), avaleha (electuary), kshirapaka (milk decoction), and arishta (fermented preparation). It is an important ingredient of many popular formulations including Chyavanaprasa, Dhanwantharam tailam, Dasamulakuatutrayadi Kvayam, Dashmoolharitaki, and Dashmoolrasayanam.

2.2 Traditional African Medicine

Stereospermum kunthianum is reputed for its ethnomedicinal use in the treatment of various painful and inflammatory conditions in Nigeria and other West African countries. Decoctions and infusions of the fruits, bark, and roots are used in traditional medicine for pharyngeal affections, leprosy, subcutaneous parasitic infections and other skin afflictions, venereal diseases, diarrhoea, dysentery, and as antiemetics, febrifuges, analgesics, vermifuges, diuretics, and laxatives.

Stereospermum kunthianum is used in traditional medicine to treat bronchitis, pneumonia and coughs, gastritis, wounds, rheumatic arthritis, ulcers, dysentery, leprosy, and venereal diseases in humans. Specific plant parts have dedicated uses: different parts of S. kunthianum are used in traditional medicine to treat human ailments — the pods are chewed with salt to treat coughs and for ulcers, leprosy, skin eruptions, and venereal diseases; the stem bark decoction or infusion is used to cure bronchitis, pneumonia, coughs, rheumatic arthritis, and dysentery; the twigs are chewed to clean teeth and to treat toothache; and the roots and leaves are used against venereal diseases, respiratory diseases, and gastritis.

Stereospermum kunthianum is also used in traditional medicine to treat an array of ailments including febrile convulsions in infants and young children by the rural dwellers in Nigeria. It is known as sansami among the Hausa of North Nigeria and umana among the Tiv of the Middle Belt.

2.3 Traditional Use in Southeast Asia

The genus Stereospermum has been documented across its range to possess pharmacological potentials; however, some species such as Stereospermum neuranthum Kurz, a Thai edible plant, remain only recently explored in terms of bioactivity and phytochemical composition.

3. Key Phytochemical Constituents

3.1 Naphthoquinones and Related Quinones

The major phytoconstituents found in the plant bark are lapachol and apigenin, which exhibit various pharmacological activities. Previous phytochemical studies showed the presence of higher carboxylic acids, β-sitosterol, and saponin in the roots; lapachol, dehydro-α-lapachone, sterekunthal B, sterequinone C, stereochenols A and B in the bark; and stereolensin, scutellarein, 6-hydroxy luteolin, dinatin (4,5,7-trihydroxyl-6-methoxyflavone), and dinatin-7-glucuroniside in the leaves.

Isolation work on the roots of S. suaveolens using ethyl acetate-soluble fractions from a methanol extract, separated by silica gel column chromatography and HPLC, yielded cycloolivil (a lignan reported for the first time from this species), lapachol, and β-sitosterol, with structures elucidated by UV, IR, 1D-NMR, and MS spectroscopy.

In the bark of Stereospermum personatum, researchers isolated additional novel quinones: two novel 1(17)-methyl anthraquinones, sterequinone-A and -D, their biogenetic precursors sterequinone-B and -C, and a new naphthoquinone sterequinone-E, together with the known naphthoquinone sterekunthal-B, from the petroleum ether extract of the stem bark.

From Stereospermum zenkeri, a Cameroonian species: two anthraquinones, zenkequinones A and B, were isolated from the stem bark, along with known sterequinone-F, p-coumaric acid, sitosterol-3-O-β-d-glucopyranoside, and 3β-hydroxyolean-12-en-28-O-β-d-glucopyranoside.

3.2 Flavonoids

The plant contains lapachol, apigenin, dinatin, dinatin-7-glucuroniside, β-sitosterol, saponins, palmitic acid, stearic acid, and oleic acid. Apigenin is a well-characterized flavonoid with a broad range of established biological activities. The major constituents lapachol (a naphthoquinone) and apigenin (a flavonoid) have several pharmacological activities, including antimetastatic, antimicrobial, antiviral, anti-inflammatory, antiparasitic, leishmanicidal, molluscicidal, antitumor, anti-abscess, anti-ulcer, and anticancer properties.

3.3 Lignans, Sterols, and Fatty Acids

The roots of Stereospermum suaveolens were reported to contain p-coumaric acid, triacontanol, 3-cetyl alcohol, oleic acid, palmitic acid, stearic acid, lapachol, dehydroalpha-lapachone, and dehydrotectol in root heartwood; and β-sitosterol and n-triacontal in root bark.

3.4 Additional Phytoconstituents from Leaves

The plant bark contains sterekunthal B, stereochenols A and B, lapachol, dehydro-α-lapachone, and apigenin; and the leaves contain scutellarein, stereolensin, and dinatin (4,5,7-trihydroxyflavone).

3.5 Nutritional Composition of the Fruit

A 2024 study published in Heliyon (PMC-indexed) from CSIR-National Botanical Research Institute, Lucknow, characterised the nutritional profile of the fruit: the fruit was found rich in nutritional composition, having protein (2.41% ± 0.007), fibre (3.46% ± 0.02), and carbohydrate (90.19% ± 1.73), with an energy value of 368.2 ± 3.94 Kcal/100g; elemental analysis resulted in macronutrients Ca, Mg, and Na, and micronutrients Fe, Mn, Zn, and Cu in amounts comparable to common marketed fruits.

4. Proposed Mechanisms of Action

4.1 Anti-inflammatory Mechanisms

Studies in rats indicate that the aqueous extract of Stereospermum kunthianum stem bark possesses anti-inflammatory activity which is probably related to the inhibition of prostaglandin synthesis, which is a possible rationale for its folkloric use as an anti-inflammatory agent. Lapachol and apigenin, the principal biomarkers of the bark, are both established inhibitors of inflammatory cascades in preclinical models.

4.2 Antioxidant and Hepatoprotective Mechanisms

The ethyl acetate fraction from the ethanol extract of S. suaveolens was found to modulate the activity of enzymatic and nonenzymatic antioxidants and enhance the defense against hepatic oxidative stress in STZ-induced diabetic rats. The protective effect was assessed by measuring key liver enzymes (AST, ALT, alkaline phosphatase), bilirubin, and glutathione levels. In diabetes, oxidative stress is mainly due to increased production of reactive oxygen species and a sharp reduction of antioxidant defenses.

4.3 Neuroprotective Mechanisms

In a Parkinson's disease rat model, the Stereospermum suaveolens methanolic extract showed a significant, dose-dependent increase in behavioral activity and improved muscular coordination; significant reduction of lipid peroxidation (LPO), and increased antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and non-enzymatic activity of glutathione (GSH) and total thiol levels were observed in extract-treated groups.

In a global cerebral ischemia model: the Stereospermum suaveolens methanol extract showed neuroprotective activity by a significant decrease in lipid peroxidation (p < 0.001) and an increase in superoxide dismutase (p < 0.01), catalase (p < 0.01), glutathione (p < 0.001), and total thiol (p < 0.001) levels in extract-treated groups compared to the control group; measurement of cerebral infarction area and histopathological studies further supported the protective effect of the extract.

4.4 Anticonvulsant Mechanisms

Although the findings do not provide conclusive evidence, it appears that the aqueous stem bark extract of Stereospermum kunthianum produces its antiseizure effect by enhancing GABAergic neurotransmission and/or action in the brain.

4.5 Antiplasmodial Mechanisms

Antiplasmodial activity of naphthoquinones and one anthraquinone from the lipophilic extract of the root bark of Stereospermum kunthianum has been reported. The antiplasmodial activity of naphthoquinones as a class is consistent with their ability to interfere with mitochondrial electron transport in Plasmodium falciparum. Different structural types of naphthoquinones, such as pyran and furanonaphthoquinones, are found in Bignoniaceae and disclose a broad spectrum of biological activities including antitumor, trypanocidal, anti-inflammatory, antifungal, and antiparasitic activities.

5. Scientific Evidence by Area of Use

5.1 Anti-inflammatory Activity

Preclinical (animal) evidence — S. suaveolens: The anti-inflammatory effect of the ethanol extract of Stereospermum suaveolens bark given orally at doses of 200 and 400 mg/kg body weight was studied in rats using carrageenan-, dextran-, and histamine-induced hind paw edema, and cotton pellet-induced granuloma formation models, with indomethacin at 10 mg/kg as a standard drug. The extract at 400 mg/kg showed maximum inhibition of edema of 64.6%, 53.48%, and 50.06% at the end of 3 hours with carrageenan-, dextran-, and histamine-induced rat paw edema, respectively, and exhibited a significant reduction (34.77%) in granuloma weight. It was concluded that the ethanol extract possesses maximum anti-inflammatory activity in a dose-dependent manner in various experimental models.

Preclinical (animal) evidence — S. kunthianum: A published PMC-indexed study by researchers at the University of Benin documented anti-inflammatory activity of the aqueous stem bark extract of Stereospermum kunthianum in rats using carrageenan-induced paw oedema, leucocyte migration, and exudate models. The findings indicate that the extract possesses anti-inflammatory activity which is probably related to the inhibition of prostaglandin synthesis.

Evidence strength: All published anti-inflammatory evidence is preclinical, conducted in rodent models. No human clinical trials have been identified.

5.2 Antidiabetic and Hepatoprotective Activity

Stereospermum suaveolens is a folk remedy for the treatment of diabetes and liver disorders in southern parts of India. The protective effect of the ethyl acetate fraction of the ethanol extract from S. suaveolens against hepatic oxidative stress was evaluated in streptozotocin (STZ)-induced diabetic rats for 14 days. Administration of the ethyl acetate fraction at 200 and 400 mg/kg produced a significant (P < 0.001) fall in fasting blood glucose level, TBARS, bilirubin, AST, ALT, and SALP, while elevating GSH levels and SOD and CAT activities in diabetic rats; histopathological studies also revealed the protective effect on liver tissues of diabetic rats.

A separate study examined antihyperlipidemic effects in streptozotocin-induced diabetic rats, with the ethyl acetate fraction of S. suaveolens tested against disrupted lipid parameters.

Evidence strength: All antidiabetic and hepatoprotective evidence is from animal (STZ-diabetic rat) models. No human clinical trials have been published on these endpoints.

5.3 Neuroprotective Activity

Two preclinical studies investigated neuroprotection by S. suaveolens:

Parkinson's disease model: To evaluate the neuroprotective effect of Stereospermum suaveolens DC on 6-hydroxy dopamine (6-OHDA)-induced Parkinson's disease, the study was conducted on Sprague-Dawley rats with striatal 6-OHDA lesions; test animals received methanolic extract of Stereospermum suaveolens at doses of 125, 250, and 500 mg/kg for 42 days; behavioral assessment, spontaneous locomotor activity, muscular coordination, antioxidant levels, striatal infraction area, and histopathological studies were carried out.

Global cerebral ischemia model: A study published in Pharmaceutical Biology (2013) tested methanolic extract of S. suaveolens at the same dose levels (125, 250, and 500 mg/kg), with the LD50 found to be 5,000 mg/kg body weight. There was a decreased cerebral infarction size in extract-treated groups as compared to the control group; the extract contains lapachol, apigenin, dinatin, dianatin-7-glucuroniside, and β-sitosterol.

Evidence strength: Preliminary; all evidence is from animal models. No human clinical data have been published on Stereospermum and neurological outcomes.

5.4 Anticonvulsant Activity

A PMC-indexed study (2010) examined the aqueous stem bark extract of S. kunthianum in pentylenetetrazole (PTZ) and maximal electroshock (MES) rodent seizure models. The extract at 100–400 mg/kg (i.p.) significantly delayed (p < 0.05) the onset of pentylenetetrazole-induced clonic seizures but only slightly prolonged the time of death of the mice. The results indicate that the aqueous extract possesses anticonvulsant activity in rodents and therefore tend to suggest that the shrub may be used as a natural supplementary remedy in the management, control, and/or treatment of childhood convulsions; it can be concluded that the aqueous stem bark extract possesses anticonvulsant activity and therefore lends pharmacological credence to the traditionally claimed use in the treatment of childhood convulsions.

Evidence strength: Preliminary; rodent models only. No human studies exist.

5.5 Antiplasmodial and Antiprotozoal Activity

Antiplasmodial activity of naphthoquinones and one anthraquinone from the lipophilic extract of the root bark of Stereospermum kunthianum has been reported (Onegi et al., 2002, published in Phytochemistry). The antimicrobial activity of isolated compounds from Stereospermum zenkeri was evaluated against six multiresistant strains of pathogens; zenkequinone B showed the best antibacterial activity (MIC 9.50 μg/ml) against gram-negative Pseudomonas aeruginosa.

Evidence strength: In vitro and limited in vivo (animal) evidence only. No clinical trials in humans.

5.6 Antidiarrhoeal Activity

A PMC-indexed study (2013) in African Journal of Traditional, Complementary and Alternative Medicines evaluated a flavonoid isolated from S. kunthianum stem bark: the study evaluated the antidiarrhoeal activity of 3,7,4′-trihydroxy-3′-(8″-acetoxy-7″-methyloctyl)-5,6-dimethoxyflavone isolated from the stem bark of S. kunthianum, using normal intestinal transit, castor oil-induced intestinal transit, castor oil-induced diarrhoea tests in mice, and castor oil-induced intestinal fluid accumulation in rats; the animals were pretreated with dimethoxyflavone at 25 mg/kg or 50 mg/kg.

Evidence strength: Preclinical (rodent models); no human trials.

5.7 Analgesic Activity

Stereospermum kunthianum is reputed for its ethnomedicinal use in the treatment of various painful and inflammatory conditions in Nigeria and other West African countries; research has investigated the analgesic and anti-inflammatory activities of dimethoxyflavone isolated from S. kunthianum stem bark.

Evidence strength: Preclinical; no human trials published on analgesic endpoints.

5.8 Antimicrobial Activity

S. kunthianum is used in traditional medicine in Nigeria and other parts of Africa in the treatment of venereal diseases (e.g., syphilis), wounds, refractory cough, malaria, toothache, and leprosy; the antimicrobial activity of the ethanolic leaf extract has been investigated. S. personatum possesses antibacterial, antifungal, and hypoglycaemic properties, and is active against p338 lymphocytic leukemic cells; the plant belongs to the Bignoniaceae family, which is known for its antimicrobial, antiprotozoal, and anti-inflammatory properties.

Evidence strength: In vitro laboratory studies and ethnopharmacological reports; no clinical trial data.

5.9 Antifilarial Activity

Research has evaluated the antifilarial potential of S. suaveolens: a study aimed to evaluate antifilarial activity of Stereospermum suaveolens DC against the human lymphatic filarial parasite Brugia malayi in vitro and in vivo; the ethanolic extract of leaves was tested in vitro on adult worms and microfilariae and the active sample was further evaluated in vivo in B. malayi intraperitoneally transplanted in the jird model and in Mastomys coucha subcutaneously infected with infective larvae.

Evidence strength: Preclinical; in vitro and animal models only.

5.10 Antioxidant Activity

Free radical scavenging activity of S. suaveolens has been evaluated in vitro. Clinical evidence on Stereospermum is currently lacking in the available literature. In vitro antioxidant studies confirm the capacity of plant extracts to scavenge reactive oxygen species, consistent with the presence of polyphenolic and flavonoid constituents including apigenin and scutellarein.

5.11 Nutritional/Dietary Interest

A 2024 study from the CSIR-National Botanical Research Institute characterized Stereospermum chelonoides (L.f.) DC. as a large wild tree bearing edible, yet underutilized fruits consumed by locals in Western parts of India and neighboring countries. The fruit was found rich in nutritional composition with protein (2.41% ± 0.007), fibre (3.46% ± 0.02), and carbohydrate (90.19% ± 1.73) with energy value of 368.2 ± 3.94 Kcal/100g; elemental analysis resulted in macronutrients Ca, Mg, and Na, and micronutrients Fe, Mn, Zn, and Cu in amounts comparable to common marketed fruits.

6. Body Systems and Health Areas Associated with Stereospermum

Based on the totality of traditional use and preclinical research, Stereospermum species are associated with the following body systems and health areas:

• Musculoskeletal and Inflammatory System: Dashamoola (containing Stereospermum) is used widely in Ayurveda for health conditions related to nerves, muscles, bones, and joints; it has potent anti-inflammatory, antioxidant, and moderate analgesic actions, and is used for pain disorders and inflammatory diseases including osteoarthritis, gouty arthritis, and rheumatoid arthritis.
• Respiratory System: Stereospermum root and root bark are described as useful in asthma and bronchitis (Shwasa).
• Digestive System: People take Stereospermum by mouth for indigestion, hiccups, vomiting, and diarrhoea.
• Hepatic System: Stereospermum might lower blood sugar and cholesterol, reduce pain, reduce swelling, lower fevers, and protect the liver from toxins.
• Nervous System: It might also protect the brain from damage caused by reduced blood flow or conditions such as Parkinson's disease.
• Metabolic/Endocrine System (Blood Sugar): S. suaveolens DC. is used in folk medicine for the treatment of diabetes, pain, fever, inflammations, and asthma.
• Skin and Wound Healing: People apply Stereospermum to the skin to heal wounds.
• Reproductive and Urological: Stem bark is noted as diuretic and flowers have been used in semen debility in Ayurvedic tradition.
• Infectious Disease (Antimicrobial, Antiplasmodial, Antiparasitic): Both African and Asian species are used across traditions for infections, and preclinical studies have documented antimicrobial, antiplasmodial, antifilarial, and antiprotozoal activities.

7. Dosage Forms and Dosages Reported in Studies

Note: The following dosages are reported as they appeared in the cited preclinical research and traditional texts; they do not constitute dosing recommendations.

• Anti-inflammatory (rat model, ethanol bark extract, S. suaveolens): 200 and 400 mg/kg body weight administered orally; maximum inhibition of oedema was observed at 400 mg/kg.
• Neuroprotective / Parkinson's disease model (S. suaveolens): The test animals received methanolic extract of Stereospermum suaveolens at doses of 125, 250, and 500 mg/kg for 42 days.
• Global cerebral ischemia model (S. suaveolens): The LD50 of the methanolic extract was found to be 5,000 mg/kg of body weight; the entire test was performed at dose levels of 125, 250, and 500 mg/kg of body weight.
• Antihyperglycaemic / hepatoprotective study (S. suaveolens, ethyl acetate fraction): The ethyl acetate fraction was administered orally to STZ diabetic rats at doses of 200 and 400 mg/kg for 14 days.
• Anticonvulsant (S. kunthianum, aqueous stem bark extract): The extract was administered at 100–400 mg/kg intraperitoneally in rodent seizure models.
• Antidiarrhoeal (isolated dimethoxyflavone from S. kunthianum): Dimethoxyflavone was administered at 25 mg/kg or 50 mg/kg in rodent models.
• Dashamoola Katutraya Kashayam (polyherbal containing Stereospermum): Dashamoola Katutraya Kashayam is usually taken in a dose of 12 to 24 ml, two times a day before meals, with an equal quantity of water, as directed on the label or as prescribed by the practitioner.

8. Safety Considerations and Interactions

8.1 General Safety Profile

Clinical evidence on Stereospermum is currently lacking in the available literature. Formal human safety data are correspondingly absent. The LD50 from acute toxicity testing of the methanolic extract of S. suaveolens in rodents was determined to be 5,000 mg/kg body weight, suggesting a relatively wide margin at the doses used in preclinical studies.

Most research about Stereospermum has focused on the bark and its potential effects.

8.2 Lapachol: A Constituent-Specific Concern

Lapachol, one of the two principal biomarker compounds of the bark, is a naphthoquinone with a well-characterized pharmacological profile. Naphthoquinones including lapachol are found in Bignoniaceae and disclose a broad spectrum of biological activities, including antitumor, trypanocidal, anti-inflammatory, antifungal, and antiparasitic activities. Lapachol is a vitamin K antagonist in higher doses and has been associated with anticoagulant effects in clinical investigations conducted on this compound as an isolated agent; users taking anticoagulant drugs (e.g., warfarin) should be aware of this potential interaction.

8.3 Interaction with Other Medicines

Some Ayurvedic herbs can interact with modern medicines; if both Ayurvedic and allopathic medicines are advised together, it is generally recommended to take the allopathic medicine first, wait 30 minutes, and then take the Ayurvedic medicine. No specific, formally documented pharmacokinetic interactions between Stereospermum preparations and pharmaceutical drugs have been identified in published literature beyond general extrapolation from the constituent profiles.

8.4 Pregnancy and Lactation

The safety profile of Dashmool (the formulation containing Stereospermum) is not well established for pregnant women. No independent clinical data exist specifically on Stereospermum mono-preparations in pregnancy or lactation.

8.5 Threatened Species Status

Stereospermum suaveolens DC. is a valuable medicinal tree species now placed in the threatened category due to its overexploitation. This has implications for the sustainability and quality consistency of raw material, as well as for conservation.

8.6 Preparation-Specific Precautions

Traditional preparation methods have practical significance for safety: raw bark is acknowledged in the literature as potentially irritating, and decoction or powder formulations are the methods endorsed by Ayurvedic practice. Most research about Stereospermum has focused on the bark and its potential effects. No formal standardized extract product has been evaluated in human trials.

9. Overall Evidence Assessment

The totality of published research on Stereospermum species demonstrates a rich ethnopharmacological heritage spanning Ayurveda, African traditional medicine, and Southeast Asian folk medicine. Phytochemical investigations have identified a diverse array of bioactive constituents — most notably lapachol, apigenin, and novel quinones — that plausibly underlie the traditional uses. However, Stereospermum is used most commonly by traditional healers in Ayurveda and traditional African medicine to treat inflammation and infections, but clinical evidence on Stereospermum is currently lacking in the available literature. All pharmacological evidence, spanning anti-inflammatory, antidiabetic, hepatoprotective, neuroprotective, anticonvulsant, antiplasmodial, antimicrobial, antifilarial, and analgesic areas, is currently limited to in vitro and animal models. No randomized controlled trials or systematic clinical investigations in human subjects have been published. The evidence base is therefore best characterized as preliminary, and no conclusions about efficacy or safety in humans can be drawn from the existing literature.

References

• Wikipedia — Stereospermum (genus overview)
• Wikipedia — Stereospermum kunthianum
• Plants of the World Online (Kew) — Stereospermum Cham. (genus)
• Plants of the World Online (Kew) — Stereospermum colais
• GBIF — Stereospermum chelonoides (L.fil.) DC.
• GBIF — Stereospermum tetragonum DC.
• Useful Tropical Plants — Stereospermum tetragonum (synonymy discussion)
• IMPPAT — Stereospermum chelonoides (Indian Medicinal Plants, Phytochemistry And Therapeutics)
• PubMed — Cycloolivil, a lignan from the roots of Stereospermum suaveolens (Pharmacognosy Research, 2015)
• Pharmacognosy Research — Cycloolivil, Lapachol, β-sitosterol isolation from S. suaveolens (full text)
• Pharmaceutical Biology (Taylor & Francis) — Anti-inflammatory effect of Stereospermum suaveolens ethanol extract in rats
• PubMed — Anti-inflammatory effect of Stereospermum suaveolens ethanol extract in rats (abstract)
• PMC — Neuroprotective activity of Stereospermum suaveolens DC against 6-OHDA induced Parkinson's disease model
• Pharmaceutical Biology (Taylor & Francis) — Neuroprotective activity of Stereospermum suaveolens against global cerebral ischemia rat model
• PubMed — Neuroprotective activity of Stereospermum suaveolens DC against 6-OHDA induced Parkinson's disease model (abstract)
• PMC — Protective Effect of Ethyl Acetate Fraction of Stereospermum suaveolens Against Hepatic Oxidative Stress in STZ Diabetic Rats
• PubMed — Protective Effect of Ethyl Acetate Fraction of Stereospermum suaveolens Against Hepatic Oxidative Stress in STZ Diabetic Rats (abstract)
• PMC — Antiinflammatory Activity of Aqueous Extract of Stereospermum kunthianum Stem Bark in Rats
• PMC — Aqueous Stem Bark Extract of Stereospermum kunthianum Protects Against Generalized Seizures in Pentylenetetrazole and Electro-Convulsive Models in Rodents
• PubMed — Aqueous stem bark extract of Stereospermum kunthianum protects against generalized seizures (abstract)
• PMC — Dimethoxyflavone Isolated From the Stem Bark of Stereospermum kunthianum Possesses Antidiarrhoeal Activity in Rodents
• ScienceDirect / Phytochemistry — Anthraquinones from the stem bark of Stereospermum zenkeri with antimicrobial activity
• ScienceDirect / Phytochemistry — 1-Methyl anthraquinones and their biogenetic precursors from Stereospermum personatum
• PMC — Nutritional characteristics of Stereospermum chelonoides (L.f.) DC., an underutilized edible wild fruit (Heliyon, 2024)
• ScienceDirect / Heliyon — Nutritional characteristics of Stereospermum chelonoides (L.f.) DC. (2024)
• ResearchGate — Plant developed analytical profile of Stereospermum suaveolens in Indian Traditional Knowledge (IJTKN, 2015)
• ResearchGate — Review of Phytochemical, Pharmacological and Toxicological Profile of Stereospermum kunthianum (2016)
• IJPSR — A Potential Role of Stereospermum suaveolens DC for Multiple Diseases: A Brief Analysis
• ResearchGate — A Potential Role of Stereospermum suaveolens DC for Multiple Diseases: A Brief Analysis
• Food For Health — Stereospermum monograph
• Ayurwiki — Stereospermum chelonoides / Patala
• Ayushvedah — Stereospermum suaveolens / Stereospermum colais drug profile
• ResearchGate — Dashamoola: A Systematic Overview
• ScienceDirect — Phytochemical rich extract from Dashamoola with antioxidant, antidiabetic and anti-inflammatory potential
• African Journal of Traditional, Complementary and Alternative Medicines — Stereospermum kunthianum medicinal uses (Sanogo, 2011)
• Journal of Chemistry (Wiley) — Naphthoquinones from Stereospermum neuranthum Kurz Bark: In Vitro Antibacterial Activity, α-Glucosidase Inhibition, and Molecular Docking (2026)