Bougainvillea

Other Names

Bagan BilashBaganbilasBogambilyaBogambilya (Tagalog)Bong giayBonggambilyaBooganbelBougainvillaeaBougainvillea brachycarpaBougainvillea bracteataBougainvillea brasiliensisBougainvillea glabraBougainvillea glabra var. sanderianaBougainvillea peruvianaBougainvillea rubicundaBougainvillea speciosaBougainvillea spectabilisBougainvillea spectabilis var. glabraBougainvillea virescensBougainvillea × buttianaBougainvilléeBougainvillierBouganvilaBugainvillaeaBugambileaBugambiliaBuganviliaBuganvillaBuganvilleaBuganvillea (Italian)Buganvillea lisaBugenvilBugenvil (Malay)BuginvilaBuginvillaeaBunga kertasBunggangbilyaCansarinaCeboleiroChereiDaniaDrillingsblumeEnredadera de papelFelilaFlor de veranoFlor-de-papelFuang fahGreat BougainvilleaHoa giayJiu chong geJosepha augustaJukuaJuvúKagithala puvvuKatsjoxhuanKembang kertasLesser BougainvilleaMao bao jinNapoleónPapelilloPaper flowerPaperflowerPataguinhaPau-de-roseiraPokok bunga kertasPrimaveraPurple bugambiliaRisoRiso do pradoRodos çiçeğiRoseiroRosetaSan jiao huaSanta RitaSempre-lustrosaShpupukuishonatTrês-mariasTrinitariaVeraneraVeranillaYe zi hua三角梅九重葛叶子花属簕杜鵑紙花

Synopsis

Bougainvillea (Bougainvillea spectabilis Willd. / Bougainvillea glabra Choisy)

1. Identity, Botanical Classification, and Natural Sources

The genus Bougainvillea was named by the French naturalist and explorer Philibert Commerson, who discovered it for the first time in Rio de Janeiro, Brazil, in 1768, naming it in honor of his compatriot Louis Antoine de Bougainville, French explorer and navigator. The genus belongs to the family Nyctaginaceae and, according to "The Plant List," contains approximately 18 species. Of these, Bougainvillea spectabilis, B. glabra, and B. peruviana are the three most important horticultural species and the most studied.

Bougainvillea spectabilis Willd. (Great Bougainvillea; Paper Flower) and Bougainvillea glabra Choisy (Lesser Bougainvillea; Smooth Bougainvillea) are the two species most intensively investigated for medicinal and phytochemical properties. Both are placed in family Nyctaginaceae, order Caryophyllales. There are around more than 100 cultivars and hybrids that have not been studied.

Bougainvillea is a plant of ornamental importance, endemic to South America. It has been pantropically introduced and is now distributed in warm regions of Mexico, Asia, Australia, the Caribbean, South Africa, the United States, and other countries.

1.1 Morphological Characteristics

It is a perennial climbing shrub 1–7 m tall, with branches that have curved spines 5–15 mm long; simple leaves, dark green, somewhat glossy on the upper side, with a 1 cm long petiole, adaxially glabrous and abaxially pubescent. The plant is recognized worldwide for its horticultural importance due to the color of its bracts, commonly known as "flowers," which are made up of bracts — the striking ornamental parts — and the true flowers, which are white and small.

1.2 Parts Used and Common Preparation Forms

Different plant parts are used medicinally and in supplement preparations. The most commonly employed parts, based on the scientific literature, are the leaves, bracts (commonly but incorrectly called "flowers"), true flowers, stem bark, and roots. Different parts of the plant, including leaves, flowers, and bark, are mainly used as herbal medicine.

Common traditional preparation forms include:

Aqueous decoction and infusion (tea/tisane): B. glabra is used in traditional medicine to treat respiratory diseases such as cold, flu, cough, bronchitis, and asthma, as well as for gastrointestinal problems such as diarrhea and dysentery.
Commercial syrups: There are currently some natural bougainvillea-based syrups on the market to treat respiratory tract discomfort, but generally these products are used only as supplements since there are no scientific studies that guarantee efficacy and safety.
Standardized extracts: Research preparations include ethanolic, methanolic, dichloromethane, aqueous, and hydroalcoholic extracts of various plant parts, prepared under laboratory conditions for pharmacological study.
Topical formulations: Ethanolic leaf extracts have been formulated as creams for topical antioxidant applications in research settings.

2. Traditional and Historical Use

2.1 Mexico and Latin America

The flowers, alone or in combination with other medicinal plants, have long been used in Mexican traditional medicine for the treatment of coughs and respiratory problems. Traditional medicinal applications include managing conditions such as nausea, diarrhea, hypotension, gastrointestinal disorders, inflammatory diseases, and pain. Within Latin American communities, the plant is also known by the colloquial names "buganvilia" and "veranera."

The extract and decoction of this plant have been used as fertility control among the tribal people in many countries.

2.2 India (Ayurvedic and Folk Practice)

In Mandsaur, India, bougainvillea is used to help reduce heartburn, treat sore throat, leucorrhea, blood vessel disorders, and hepatitis. Local traditional practitioners in Mandsaur (India) use the leaves of Bougainvillea as medicine for a variety of gastrointestinal disorders like diarrhea and acidity. The plant is traditionally grown in living fences in the northwestern Himalayas, where it provides a range of medicinal and other uses.

2.3 Thailand

In Thailand, flowers are included in the daily diet to cure stomachache and nausea. In Thailand, the flowers of B. glabra are utilized to treat stomachache, nausea, and diarrhea.

2.4 Africa

In Nigeria, the plant is used to treat inflammation and as an analgesic. To improve intestinal disorders, extracts of B. glabra are used in Africa.

2.5 Bangladesh

The juice from the leaves of B. glabra is orally taken with rhizome juice of Curcuma caesia for a few days to treat helminthiasis in Bangladesh.

2.6 Broader Ethnobotanical Summary

Bougainvillea glabra is traditionally employed against several diseases such as diarrhea, hypotension, intestinal disorders, stomachache, nausea, inflammation-related ailments, and in pain management. Despite the great variety of traditional uses, the study of the chemical and pharmacological properties of B. glabra is limited. Chemical studies of the Bougainvillea genus only began in earnest in 1970, using extracts from different organs of the plant.

3. Phytochemistry: Key Constituents and Active Compounds

3.1 Overview of Compound Classes

Phytochemical analysis of different parts of B. glabra has unveiled 105 phytochemicals, belonging to phenolic, flavonoid, betacyanin, terpenoid, glycoside, and essential oils classes of secondary metabolites. Numerous phytochemical investigations of plants in this genus confirm the presence of aliphatic hydrocarbons, fatty acids, fatty alcohols, volatile compounds, phenolic compounds, peltogynoids, flavonoids, phytosterols, terpenes, carbohydrates, and betalains.

The phytochemical substances extracted from stem, flowers, and leaves of B. spectabilis include alkaloids, flavonoids, furanoids, glycosides, phenols, phlobotannins, quinones, saponins, steroids, tannins, and terpenoids. Other active constituents are bougainvinones, peltogynoids, essential oils including methyl salicylate, terpinolene, and α-(E)-ionone, as well as pinitol, β-sitosterol, quercetin, and quercetin-3-O-rutinoside.

3.2 D-Pinitol (3-O-Methyl-chiro-inositol)

D-Pinitol is widely regarded as one of the most pharmacologically significant compounds in Bougainvillea. B. spectabilis contains various phytoconstituents, including flavonoids, phenolics, alkaloids, tannins, volatile oil, saponins, terpenoids, steroids, and D-pinitol. D-pinitol, also known as 3-O-methyl-chiro-inositol, is a prominent phytoconstituent found in significant amounts within the leaves of B. spectabilis and is considered the key contributor to the plant's antidiabetic properties. It exhibits insulin-like properties and protects pancreatic tissue from oxidative stress caused by free radicals, while also possessing hepatoprotective, antihyperlipidemic, and anti-inflammatory activities.

3.3 Betacyanins (Betalains)

Betacyanins from the bracts of Bougainvillea glabra were isolated and characterized by a combination of spectroscopic techniques (DAD-HPLC, NMR, LC-MS, GC-MS, electrospray MS, tandem MS) as gomphrenin I (betanidin 6-O-β-glucoside) and various derivatives of bougainvillein-v (betanidin 6-O-β-sophoroside), including mono- and diglucosylsophorosides acylated with 4-coumaric and caffeic acid (mono- and diesters). Besides the betacyanins, B. glabra bracts accumulated large amounts of flavonols (kaempferol and quercetin conjugates), reaching ratios of flavonol to betacyanin of 1:1.

Using preparative ion-pair high-speed countercurrent chromatography coupled with electrospray ionization mass spectrometry (IP-HSCCC/ESI-MS-MS), six high molecular weight acyl-oligosaccharide-linked betacyanins were identified from bracts of a violet bougainvillea collected in Guadalajara, Mexico.

3.4 Bougainvinones (Peltogynoids and Flavones)

The cytotoxic activity of eight new compounds named bougainvinones 78–85 isolated and elucidated from stem bark was evaluated. The extract from B. spectabilis purple was evaluated using KB, HeLa S-3, HT-29, MCF-7, and HepG2 cell lines. The results showed that compound 84 exhibited cytotoxicity against cancer cell lines, and compounds 79 and 80 exhibited cytotoxicity against the KB cell line.

3.5 Flavonoids and Polyphenols

HPLC–PDA quantification of B. glabra extracts revealed the identification of nine different polyphenolics, among which the flower extracts were richest. The flower methanolic extract contained the highest amount of catechin (6.31 μg/g), gallic acid (2.39 μg/g), and rutin (1.26 μg/g). Quercetin, a quercetin derivative, and momordin IIC (quinoside D) were also isolated from aerial parts of B. glabra using 1D and 2D NMR spectroscopy.

3.6 Bouganin (Ribosome-Inactivating Protein)

The observation that leaf extracts of Bougainvillea possess antiviral properties led to the purification and characterization of a protein named bouganin, which exhibits typical characteristics of type 1 ribosome-inactivating proteins (RIPs). Bouganin has a higher activity on DNA with respect to ribosomal RNA, low systemic toxicity, and immunological properties quite different from those of other RIPs. Bouganin is synthesized as a pro-peptide consisting of 305 amino acids, the first 26 of which act as a leader signal, while the 29 C-terminal amino acids are cleaved during processing. The mature protein consists of 250 amino acids.

3.7 Antimicrobial Compound Classes

Properties with antimicrobial activity are attributed to the presence of active compounds such as flavonoids, tannins, alkaloids, phenols, betacyanins, terpenoids, glycosides, and essential oils.

4. Pharmacology and Scientific Evidence by Area

Important context: Most of the pharmacological activities of crude extracts from this plant have been reported. However, very few studies have reported the isolation of compounds responsible for the observed biological potential. Moreover, the toxicity studies of this plant still need to be explored comprehensively to ensure its safety parameters. The overwhelming majority of evidence to date derives from in vitro (cell culture) and in vivo (animal model) studies; clinical (human) trials are essentially absent from the current literature.

4.1 Antidiabetic / Antihyperglycemic Activity

This is one of the best-studied pharmacological areas for Bougainvillea and is strongly linked to the constituent D-pinitol.

Mechanism: D-pinitol (3-O-methyl-chiroinositol), an active principle of the traditional antidiabetic plant Bougainvillea spectabilis, is claimed to exert insulin-like effects. Research has investigated its effect on glucose homeostasis in animal models of diabetes and on glucose transport by cultured muscle cells. The possible mechanism of action of aqueous leaf extract of B. spectabilis may be correlated with the reminiscent effect of insulin, which is due to the presence of D-pinitol. D-pinitol does not directly increase insulin activity, but it may be associated with the process that links insulin with glucose transport.

Animal study evidence: One study investigated the effects of aqueous extract of B. spectabilis leaves on blood glucose, glycosylated hemoglobin, lipid profile, oxidative stress, DNA damage, and liver and kidney functions in streptozotocin-induced diabetes in Wistar rats. Daily administration of the aqueous extract for 28 days resulted in significant reduction in hyperglycemia and hyperlipidemia. The extract also exhibited significant antioxidant activity and restored kidney and liver functions to normal, proving to be non-toxic at the tested dose. The dose used was 100 mg/kg body weight.

One study found that B. spectabilis aqueous and methanolic extracts showed good oral glucose tolerance and significantly reduced intestinal glucosidase activity. These extracts also showed a significant increase in glucose-6-phosphate dehydrogenase activity and hepatic/skeletal muscle glycogen content after 21 days of treatment. Immunohistochemical analysis observed regeneration of insulin-producing cells and a corresponding increase in plasma insulin and C-peptide levels.

In STZ-diabetic mice, D-pinitol at 100 mg/kg (oral) acutely decreased hyperglycemia by 22% at 6 hours.

Evidence strength: Preclinical (animal and cell culture) evidence is moderately consistent. Although the identification of D-pinitol as a potential bioactive compound responsible for antidiabetic effects is promising, further investigation is necessary to gain a more comprehensive understanding of the variations in antidiabetic properties among cultivars, and to validate findings and potentially facilitate use of the extract as a complementary or alternative therapy for diabetes management. No published randomized controlled trials in humans are currently available.

4.2 Antioxidant Activity

Studies have evaluated the chemical constituents, antioxidant properties, and in vitro cytotoxic effects of ethanolic and aqueous extracts derived from the flowers of B. spectabilis. Characterization through FTIR, GC–MS, and NMR revealed the presence of various flavonoids, phenolics, and other bioactive compounds. Antioxidant activity was confirmed via DPPH radical scavenging assays, correlating positively with total phenolic and flavonoid contents.

The aqueous extract of B. spectabilis exhibited 45.73% and 69.42% inhibition by the DPPH and ABTS methods, respectively. One study recorded a potentially powerful antioxidant activity for B. glabra leaf extract, while also showing a good inhibitory effect against acetylcholinesterase (AChE; 2.40 mg GALAE/g) and butyrylcholinesterase (BChE; 1.95 mg GALAE/g).

Evidence strength: In vitro antioxidant activity is well-documented across multiple assay systems and is attributed to the rich polyphenol and betacyanin content of the plant. Evidence is preclinical only; translation to human clinical benefit has not been demonstrated.

4.3 Anti-inflammatory Activity

In traditional medicine, particularly in the Kolli Hills of Tamil Nadu, B. spectabilis is widely used to treat inflammation, further emphasizing its ethnopharmacological importance.

Experimental evidence: The anti-inflammatory activities of methanolic extract of leaves of B. spectabilis have been evaluated in experimental animal models of inflammation. Tested doses in animal models included 20 and 50 mg/kg of a freeze-dried extract prepared in propylene glycol and orally administered.

Extracts of B. glabra have been reported to work by inhibiting tyrosinase and TNF activity, and are recognized as antioxidant, antimicrobial, and anti-inflammatory agents.

Evidence strength: Evidence is confined to in vitro and in vivo (rodent) models. No human clinical trials on anti-inflammatory endpoints have been published.

4.4 Antimicrobial Activity

This area of research covers traditional uses, phytochemistry, antimicrobial potential, and antibiofilm activity of B. glabra bracts and flowers — plant organs that are widely used in traditional medicine but have been little investigated scientifically.

Dichloromethane and methanol extracts of Bougainvillea glabra aerial and flower parts have been analyzed for enzyme inhibition potential against key enzymes involved in diabetes (α-amylase), skin problems (tyrosinase), and inflammatory disorders (lipoxygenase).

Extracts that contain betalains have been reported to present a variety of activities, including the inhibition of the growth of bacteria. In laboratory assays, flower extracts have demonstrated inhibitory activity against organisms including Escherichia coli, Bacillus subtilis, Candida albicans, and Staphylococcus aureus.

Evidence strength: Antimicrobial evidence is entirely in vitro. The minimum inhibitory concentrations vary significantly between studies and extract types. The antimicrobial potential of the involucre (bract tissue) of this plant has not been fully studied, despite research showing a high phytochemical presence of secondary metabolites such as alkanes, phenols, terpenes, and betalains. No clinical antimicrobial trials exist.

4.5 Antifertility Activity

Bougainvillea spectabilis (Family: Nyctaginaceae), commonly referred to as Great Bougainvillea or Paper Flower, is one of the traditional medicinal plants with potential antifertility activity. The aqueous extract and decoction of this plant have been used as fertility control among the tribal people in many countries.

Animal study evidence: One study evaluated the effect of oral administration of B. spectabilis leaves at 800 mg/kg/day on reproductive organs and fertility of male and female Swiss albino mice for 30 days. The plant reduced caudal epididymal sperm count from 5.05 × 10⁶ per ml in the control group to 0.65 × 10⁶ per ml in the treatment group (a reduction of 87.13%). Histological examination revealed a reduction in the size of seminiferous tubules, reduced thickness of germinal epithelial cells, and hypertrophy of interstitial cells of Leydig.

Evidence strength: Preclinical (rodent) only. The dose used (800 mg/kg/day) was very high and may not correspond to practical human use. No human data exist. This activity is a significant safety consideration for individuals of reproductive age (see Section 7).

4.6 Anticancer / Cytotoxic Activity

The antiproliferative activity of hexane, dichloromethane, acetonitrile, ethyl acetate, methanol, and butanol extracts from stems and leaves of B. spectabilis against U373 (glioblastoma) cells was evaluated. The dichloromethane extract showed lower antiproliferative activity compared to the others.

Bouganin and immunotoxin research: The sequencing of bouganin and knowledge of its three-dimensional structure allowed the generation of a non-immunogenic mutant of bouganin. These features make bouganin a very attractive tool as a component of immunotoxins (ITs), chimeric proteins obtained by linking a toxin to a carrier molecule. The availability of a de-immunized form of bouganin led to the construction of immunotoxins showing promising antitumor activity in experimental models and in a Phase I clinical trial. This represents the only documented transition to human-phase investigation for any Bougainvillea-derived compound, and it relates to a highly engineered protein derivative — not the crude plant extract as used in supplementation.

Evidence strength: In vitro cytotoxicity data exist for several bougainvinone compounds and crude extracts. The bouganin immunotoxin work represents a specialized pharmaceutical research avenue. There are no clinical studies demonstrating anticancer effects from dietary supplementation with Bougainvillea plant extracts.

4.7 Hepatoprotective Activity

A range of hepatoprotective activities has been attributed to B. spectabilis, alongside antibacterial, anticancer, antidiabetic, antifertility, antifungal, anti-inflammatory, antihyperlipidemic, antioxidant, antiulcer, and thrombolytic activities, based on reviews of the traditional uses and phytochemical properties. Animal studies on STZ-induced diabetic rats suggest the aqueous leaf extract restores liver function markers toward normal values, as noted in Section 4.1.

Evidence strength: Preclinical only. No human hepatoprotective trials have been reported.

4.8 Antihyperlipidemic Activity

D-pinitol exhibits insulin-like properties and protects pancreatic tissue from oxidative stress caused by free radicals, while also possessing hepatoprotective, antihyperlipidemic, and anti-inflammatory activities. In the 28-day STZ-rat study referenced in Section 4.1, significant reduction in triglyceride levels was observed alongside the antihyperglycemic effect.

Evidence strength: Preclinical (animal models). No human lipid-lowering trials have been published.

4.9 Tyrosinase and Enzyme Inhibition (Skin and Metabolic Enzymes)

One study of B. glabra leaf extract reported a tyrosinase-inhibiting effect of 48.23 mg CAE/g, and amylase and glucosidase inhibitory effects of 0.30 mmol ACAE/g and 0.03 mmol ACAE/g, respectively. This suggests that B. glabra may be a promising source for effective phytochemicals that act as antioxidants and enzyme inhibitors, which may play a role in reversing the aging process and age-related ailments like diabetes. Tyrosinase inhibition is relevant to hyperpigmentation management in dermatological applications.

Evidence strength: In vitro only.

4.10 Antiviral Activity

The first experimental evidence of the antiviral effect of Bougainvillea dates back to the 1980s, when it was demonstrated that the infection of tobacco plants by tobacco mosaic virus (TMV) was prevented by leaf extracts. The antiviral mechanism was subsequently traced in part to bouganin and related ribosome-inactivating proteins.

Evidence strength: Early antiviral evidence is from plant bioassays. Some in vitro antiviral work on mammalian viruses exists in the literature, but human clinical antiviral evidence is absent.

5. Body Systems and Health Areas Associated with Bougainvillea

Metabolic / Endocrine system: Blood glucose regulation, insulin sensitivity, lipid metabolism — primarily via D-pinitol.
Respiratory system: Bougainvillea is widely known in traditional medicine to treat respiratory diseases such as cough, asthma, and bronchitis.
Gastrointestinal system: Traditionally employed against diarrhea, hypotension, intestinal disorders, stomachache, and nausea.
Immune / anti-infective: Antimicrobial, antifungal, antiviral, and antibiofilm properties explored in laboratory models.
Reproductive system: Documented antifertility effects in animal models; traditional use as a contraceptive.
Hepatic system: Hepatoprotective effects in animal models of chemically induced hepatotoxicity.
Dermatological: Tyrosinase inhibition (relevant to pigmentation); traditional topical use for inflammation and wound healing; antioxidant activity with skin-care formulation interest.
Oncological (research-stage): Bouganin-based immunotoxin research; in vitro cytotoxicity of bougainvinones.

6. Dosage Forms and Dosages Reported in Studies

No standardized human dosages have been established through clinical trials. The following dosages and preparations are those reported exclusively in preclinical research, stated here solely as reported in the source literature:

Aqueous leaf extract (rats, antidiabetic study): 100 mg/kg body weight daily for 28 days in streptozotocin-induced diabetic Wistar rats.
Leaf extract (mice, antifertility study): 800 mg/kg/day orally for 30 days in Swiss albino mice.
Methanolic leaf extract (animal, anti-inflammatory): 20 and 50 mg/kg, freeze-dried extract prepared in propylene glycol and orally administered.
D-pinitol (mice, antidiabetic): 100 mg/kg orally in STZ-diabetic mice, producing acute blood glucose reduction of 22% at 6 hours.

Commercially available bougainvillea-based syrups exist for respiratory discomfort, but there are no scientific studies that guarantee their efficacy and safety.

7. Safety Considerations and Notable Interactions

7.1 Antifertility Risk

The antifertility data from animal studies constitute a meaningful safety signal. Administration of B. spectabilis leaves at 800 mg/kg/day in male mice for 30 days dramatically reduced sperm count (by 87.13%) and caused histological changes in testicular tissue. While this dose is very high, the antifertility use is consistent across multiple traditional systems, and the safety implications for persons of reproductive age remain uncharacterized in humans. The safety of taking products made from this plant during pregnancy and lactation has not been established.

7.2 Skin Irritation from Sap and Thorns

Bougainvillea sap may cause serious skin rashes, and the thorns may injure the skin. A prick from the plant's sharp thorns can lead to dermatitis, a skin rash typically caused by an allergic reaction. Symptoms of dermatitis caused by bougainvillea can resemble those of poison oak or poison ivy, and may include pain, itching, stinging or burning skin, blisters, scaly rash, swelling, and sores. This applies primarily to handling of the live plant, but is relevant to producers of raw plant-based extracts.

7.3 Lack of Comprehensive Toxicological Characterization

Most of the pharmacological activities of crude extracts from B. glabra have been reported, but very few studies have identified the specific compounds responsible for observed biological effects. The toxicity studies of this plant still need to be explored comprehensively to ensure its safety parameters.

7.4 Variability Due to Seasonal and Geographic Factors

When characterizing an extract, seasonal, local, and ontogenetic variations must be reported when collecting the species, since these influence the phytochemical profile of the plant and therefore the pharmacological response. This variability is a key confounding factor across all studies and means that results from one extract cannot be assumed to generalize to commercial supplement products.

7.5 Absence of Human Clinical Safety Data

No published randomized controlled trials in humans have evaluated either the efficacy or the safety/tolerability of Bougainvillea extracts as dietary supplements. The gap between traditional use and scientifically validated safe human doses remains wide. More studies of the phytochemical, pharmacological, and toxicological properties and their mechanisms of action, safety, and efficacy in all Bougainvillea species, cultivars, and hybrids are advisable for future research.

7.6 Potential Drug–Herb Interactions (Mechanistically Inferred)

Based on documented pharmacological mechanisms in animal models, mechanistic interaction risks that would warrant further study include concurrent use with antidiabetic medications (due to demonstrated hypoglycemic effects of D-pinitol and leaf extracts) and anticoagulants or antihypertensive drugs (given reported antihyperlipidemic and vasodepressor activities in animal models). No direct drug–herb interaction studies in humans have been published for Bougainvillea.

References

Health Conditions

Health conditions that Bougainvillea may help support.

No conditions available.

Body Systems

Body systems that Bougainvillea may help support.

No body systems available.