 Gen info
- Oroxylum indicum is a species of flowering plant belonging to the monotypic genus Oroxylum and the family Bignoniaceae.
- In south India, listed as rare, endangered, and threatened.
- Etymology: The genus name derives from Greek words Oros meaning mountain, and xylon meaning wood or tree. The species name indicum refers to India, where the tree is naturally found. (4)
- Long fruits curve downward and resemble the wings of a large bird or dangling sickles or swords in the night, hence, the name "tree of Damocles. (2)
 Botany
• A semi-deciduous tree, up to 27 m tall. Trunk has grey-brown bark and large leaf scars. Foliage: Leaves are compound, 2 – 4-pinnate, imparipinnate, about 50 – 130 (200) cm long. Leaflets are ovate to oblong (4 – 11 cm long and 3 – 9 cm wide) with entire leaf margin, acute to acuminate leaf tip, unequal to cuneate leaf base and 4 – 5 pairs of lateral veins. Glands are present and scattered on the underside of young and some mature leaves, near the veins axils. Leaflets wilt starting from the tip to the base of the leaf. Leafless stalks break apart at the joints and resemble limb bones as they falls. Flowers: Inflorescence occurs at the terminal in raceme, about 25 – 150 cm long. Flowers are large (7 – 10 cm long), brownish yellow to dirty violet colour, funnel-shaped. Each flower has 5 reflexed lobes, 5 stamens which is hairy at the base, 1 style which is 4 – 6 cm long, and superior ovary. Flower is bad-smelling, opens at night and wilts before sunrise. Each raceme has 1 – 2 flowers opening at any one time. The calyx persist and turn woody after the flowers have faded. Fruit: Fruit is a woody capsule that is sword-shaped (45 – 120 cm long and 6 – 10 cm wide) and pendulous. Pod turns black when ripe. Seeds are round and large (5 – 9 cm long and 2.5 – 4 cm wide), with thin transparent wings. Flowers and fruits may be found on the same tree as each branch can blooms independently of the others. (4)
• O. indicum is a small or medium sized deciduous tree up to 12 m in height with soft light brown or grayish brown bark with corky lenticels. The leaves are very large, 90-180 cm long 2-3 pinnate with 5 or more pairs of primary pinnae, rachis very fast, cylindrical, swollen at the junction of branches, leaflets 2-4 pairs ovate or elliptic, acuminate, glabrous. The large leaf stalks wither and fall off the tree and collect near the base of the trunk, appearing to look like a pile of broken limb bones. The flowers are reddish purple outside and pale, pinkish-yellow within, numerous, in large erect racemes. The flowers bloom at night and emit a strong, stinky odor which attracts bats. The tree has long fruit pods that curved downward, hang down from the branches, looking like the wings of a large bird or dangling sickles or sword in the night. Fruits are flat capsules, 0.33-1 m long and 5-10 cm broad and sword shaped. When the pod bursts open the seeds flutter to the ground, often traveling some distance, looking like butterflies. The seeds are numerous, flat and winged all around like papery wings, except at the base. The plant flowers in June-July and bears fruits in November. The fresh root bark is soft and juicy; it is sweet, becoming bitter later. On drying, the bark shrinks, adhere closely to the wood and becomes faintly fissured. (5)
Distribution
- Native to the Philippines.
- Also native to
Andaman Is., Assam, Bangladesh, Borneo, Cambodia, China South-Central, China Southeast, East Himalaya, India, Jawa, Laos, Lesser Sunda Is., Malaya, Myanmar, Nepal, Sri Lanka, Sulawesi, Sumatera, Thailand, Vietnam, West Himalaya. (1)
- Grows primarily in the wet tropical biome.
- Ornamental cultivation for its strange appearance.
- In some countries, considered endangered due to over-exploitation in the herbal market.
 Constituents
- Chemical constituents from different plant parts included baicalein-7-O-diglucoside (Oroxylin B), baicalein-7-O-glucoside, chrysin, apegenin, prunetin, sitosterol, oroxindin, biochanin-A, ellagic acid, baicalein and its 6- and 7-glucorinides, scutellarein, tetuin, anthraquinone, and aloe-emodin. (5)
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In an HPLC study of seeds and plant tissue cultured sample for quantitative contents of three major flavones viz. baicalin, baicalein, and chrysin, baicalin was found highest among the three flavones in all extracts. Seed yielded highest baicalin (24.24% w/w), followed by shoot extract (14.78% w/w). Chrysin amounts were lower, while baicalein was lowest. (8)
- Stem bark and leaves contain flavonoids (chrysin, oroxylin A, baicalein), oroxyloside methyl ester and chrysin-7-O-methyl glucoside. Seeds contain ellagic acid. Root bark contains chrysin, baicalein, biochanin A, and ellagic acid. Fruit pods contain oroxylin A, chrysin, triterpene carboxylic acid and ursolic acid. (13)
- Phytochemical screening of 95% ethanol extract from dried powder of bark yielded alkaloids, flavonoids, tannins, and glycosides. (see study below) (15)
- Seeds extracted in acetone, benzene, chloroform, methanol, and water (A,B,C,M,W) showed presence of alkaloids, flavonoids, tannins, glycosides, sterols, phenols, saponins, fats, and oils. Root bark extracted in A,B,C,M,W yielded flavonoids, alkaloids, glycosides, tannins, sterols, phenols, lignins, saponins, fats, and oils, with absence of quinones. (23)
- Leaves contained baicalein; baicalein-7-O-glucoside; baicalein-7-O-diglucoside; baicalein-7-O-glucuronide; chrysin; chrysin-diglucoside; chrysin-7-O-glucuronide; oroxylin-A; scutellarin; baicalein-6-0-glucuronide. Leaf oil of Sonapatha showed the presence of Ar-tumerone, methyl hexadecanoate, aurenan-2-one, and isopropyl butanoate. (23)
- Preliminary phytochemical screening of 50% ethanolic extract of seeds revealed presence of carbohydrate, phenolic compounds, phytosterols, alkaloids, and flavonoids
. (see study below) (
 Properties
- Studies have suggested antioxidant, antibacterial, anti-obesity, cognitive enhancing, cytotoxicity, apoptotic, analgesic, anti-metastatic, antidiabetic, antiulcer, antidyslipidemic, anti-allergic, hepatoprotective, wound healing, adipogenesis and lipase inhibitory, anti-angiogenic properties.
Parts used
Leaves, bark, seeds, fruits.
Uses
Edibility
- Leaves, flower buds, pods, and stems are edible.
-
In Thailand and Laos, the large young pods, called Lin mai or Lin fa in Loei, are eaten; first grilled over charcoal, then the inner tender seeds are scraped and eaten with lap. Among the Bodos of northeast. known as karongkandai, the flowers and fruits as eaten as a bitter side dish with rice. Among the Karem people, the buds are boiled and pickled. The tender seeds are used in various local dishes. (2)
Folkloric
- In the Philippines, bark used for treatment of rheumatism and dysentery. Root bark used as diaphoretic.
- In Chinese medicine, seeds used for treatment of ulcers, boils, liver and stomach problems.
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In India, decoction of bark used to treat intestinal helmintic infections. Root bark is used in compound formulations in Ayurveda and other folk remedies. (2)
- In Myanmar, bark decoction used for treatment of arthritis, jaundice, dysentery, diarrhea, indigestion, and rheumatism. In Malaysia, decoction of leaves drunk to relieve stomachache, rheumatism, and wounds. (4)
- Root bark used for treatment of stomatitis, tuberculosis, nasopharyngeal cancer. Leaves used as stomachic, carminative, and flatulent. Leaf decoction used for treating rheumatic pain, enlarged spleen, ulcer, cough, bronchitis. Mature fruits used for pharyngodynia, heart disorders, gastropathy, bronchitis, hemorrhoids, cough, jaundice, dyspepsia, small pox, leucoderma, and cholera. Seeds used as purgative. Bark decoction used for gastric ulcers. Paste from bark powder applied to mouth cancer, scabies, and other skin diseases. Medicated oil in sesame oil base instilled into ears to mitigate otitis pain. (5)
- Macerated fresh bark applied to allergic dermatitis.
- In Nepal, root decoction used for diarrhea and dysentery. Seeds used as digestive. Seed paste applied to boils and wounds. Roots used as astringent, anti-inflammatory, aphrodisiac, expectorant, anthelmintic, and tonic. (13)
- In Bangladesh, bark used for treatment of jaundice: Juice obtained from crushed bark is mixed with one cup of water and drunk twice daily for a week. (26)
Others
- Superstition: In the Himalayas, sculptures or garlands made from seeds are hung from the roof of homes in belief that they provide protection. (2)
- Crafts: Kelantese and Javanese peoples forge a type of keris (kris) in the shape of the plant's seed pod, called the keris buah beko. (2)
- Mythology: The Onge name for the tree is talaralu. (Onge language, known as Önge, is one of the two known Ongan languages spoken by the Onge people (one of the aboriginal peoples of India) of Little Andaman Island in India.) According to Onge myth, the first Onge people, also named Onge, was created by Eyuge (monitor lizard) from the oroxylum wood.
More trees were planted in pairs, giving rise to both Onge men and women. (2) (3)
- Veterinary: Paste made from bark applied to animal wounds to kill maggots.
Studies
• Cognitive Enhancing Effect / Sabroxy® / Clinical Trial: A two-arm, parallel-group, 12-week, randomized, double-blind, placebo controlled trial evaluated the effects of Oroxylum indicum on cognitive function in 82 older adult volunteers with self-reported cognitive complaints. Dose of 500 mg of standardized extract twice daily and placebo were used. Compared to placebo, O. indicum was associated with greater improvements in episodic memory, and on several computer-based cognitive tasks such as immediate word recall and numeric working memory, and a faster rate of learning on location learning task. Results suggest a potential herbal candidate for improvement of cognitive function in older adults. (6)
• Antibacterial / Root and Stem: Study evaluated the antibacterial activity of alcohol extracts of root and stem against E. coli, Klebsiella, Proteus, Pseudomonas, and S. aureus. The stem extract showed maximum zone of inhibition against S. aureus, Klebsiella sps., Pseudomonas aeruginosa, while the root extract showed zone of inhibition only against S. aureus and Proteus sp. (7)
• Anti-Obesity Potential / Bark: Study evaluated the adipogenic and pancreatic lipase (PL) inhibition potential of six Indian Ayurvedic medicinal plants by in vitro anti-adipogenic assay using 3T3-L1 preadipocytes and pancreatic lipase (PL) inhibition assay for hexanes, dichloromethane, ethyl acetate, and methanolic extracts of O. indicum. The ethyl acetate extract of bark showed most active anti-adipogenesis (59.12% lipid accumulation compared to control at 50 µg/ml dose) and PL inhibition (89.12% inhibition at 250 µg/mL dose) assays. Three bioactive flavonoids were isolated viz. oroxylin A, chrysin and baicalein, which inhibited lipid accumulation in 3T3-L1 preadipocytes. Oroxylin A and chrysin also inhibited PPARγ and C/EBPα, major adipogenic transcription factors, in 3T3L-1 preadipocytes during adipogensis process. Results suggest anti-obesity potential. (9)
• Antioxidant / Leaves: Study evaluated the invitro free radical scavenging potential of different extracts of leaves o Oroxylum indicum using DPPH assay. The scavenging effect of plant extracts and standard (L-ascorbic acid) on DPPH radical decreases in order of: L-ascorbic acid > ethyl acetate > methanol > water, at 97.4%, 61.4%, 40.8%, and 29.2% at concentration of 100 µg/mL, respectively. Results showed concentration dependent free radical scavenging activity. (10)
• Therapeutic Potential of Baicalein / Review: Review systematically presented invivo and invitro studies on Oroxylum indicum and baicalein. The research reported the biological activities and therapeutic potential of baicalein from O. indicum for anticancer, antibacterial, antihyperglycemic, neurogenesis, cardioprotective, anti-adipogenesis, anti-inflammatory, and wound healing effects. The review provides insight on O. indicum and baicalein as complementary therapy, and recommends more clinical research to confirm efficacy and safety of baicalein as therapeutic medicine for patients. (11)
• Cytotoxic / Apoptotic / Antioxidant / Antimicrobial / Bark: Study evaluated different solvent extracts of stem bark of O. indicum (SBOI) for phenolic and flavonoid content, antioxidant, antimicrobial, cytotoxic and apoptotic activities. The MeOH extract yielded highest amount of total phenolic (320.7 mg GAE/g extract) and flavonoid (346.6 QE/g extract). In vitro antioxidant activity was highest in the MeOH (IC50 22.7 µg/mL) (p<0.05). Only the MeOH extract exhibited both antibacterial and antifungal activity. On cytotoxicity testing, the petroleum ether extract showed maximum cytotoxicity (IC50 112.3 µg/mL, p<0.05) and apoptotic activity (33.2%) on HeLa cells. (12)
• Antioxidant / Protective against Oxidative DNA Damage / Bark: Study evaluated methanolic and aqueous extracts of bark for antioxidant property, cytotoxicity, and protection against oxidative DNA damage. Both extracts showed dose-dependent inhibition of lipid peroxidation, considerable free radical scavenging and ferric reducing abilities. The extracts exhibited extensive cytotoxicity against MDA-MB-435S and Hep3B cell lines. Both exhibited moderate levels of DNA protection against oxidative stress. Total phenolic content showed significant correlations with free radical scavenging and reducing power, as well as lipid peroxidation inhibition (p<0.05). (14)
• Analgesic / Bark: Study evaluated the analgesic activity of ethanol extract of O. indicum from dried powdered bark. Phytochemical screening yielded alkaloids, flavonoids, tannins, glycosides. At doses of 250 and 500 mg/kg, the extracts showed significant (p<0.05) analgesic effect in all test methods (hot plate, acetic acid-induced writhing and formalin). Ketorolac (10 mg/kg) was use as standard. The analgesic activity may be attributable to flavonoids and tannins. (15)
• Cytotoxicity / Apoptotic / Anti-Metastatic / Human Breast Cancer Cells: Study evaluated the chemopreventive properties of hot and cold non-polar extracts (petroleum ether and chloroform) with MDA-MD-231 (cancer cells) and WRL-68 (non-tumor cells) by XTT assay. Results showed non-polar extracts, especially petroleum ether hot extract, can effectively target ER-negative breast cancer cells to promote apoptosis, without harming normal cells by cancer-specific cytotoxicity. Study suggests potential as candidate precursors to harness or alleviate ER-negative breast cancer progression even in advanced stages of malignancy. (16)
• Anti-Inflammatory / NF-kB Signaling Inhibitors / Flavonoids / Stem Bark: Study screened 40 plant extracts from 17 species of Vietnamese traditional medicinal plants for treatment of inflammatory disorders for NF-kB inhibitory activity using TNF-α-stimulated KEK-293 cells transfected with a NF-kB-driven luciferase reported. The screening identified the dichlormethane extract of O. indicum as promising sources of NF-kB inhibitors. Hispidulin, baicalein, chrysin, and oroxylin A, isolated from Oroxylum indicum, were identified as inhibitors of NF-kB activation. (17)
• Antidiabetic / Anti-Inflammatory / Antiulcer / Antidyslipidemic / Stem Bark: Study evaluated the anti-inflammatory, antiulcerative, antihyperglycemic, and antidyslipidemic activities of stem bark extracts of Oroxylum indicum. A petroleum ether (PET) and n-BuOH fractions showed high percentage of protection against ethanol-induced gastric mucosal damage. At dose of 400 mg/kbw of methanol extract decreased blood glucose level by 37%, compared to glibenclamide at 77%, with no additive effect on combination therapy. In anti-dyslipidemic testing, after 8 weeks of treatment, simvastatin, extract, and combination therapy, total cholesterol was reduced by 44, 28, and 48%, triglycerides by 32, 15, and 35%, with HDL increase by 34, 13, 36%. In carageenan anti-inflammatory study, all different doses of extract showed considerable depletion of paw thickness (p<0.01). After six hours, ibuprofen (20 mg/kbw) showed 53.33% inhibition, while methanol extracts at 100, 200, and 400 mg/kbw decreased paw edema by 37.50, 48.34, and 55.83%. Results showed potent and remarkable anti-inflammatory and antiulcer activities, moderate antidiabetic and antidyslipidemic properties, and liver enzyme-concentration lowering effects. (18)
• Protection of Neuroblastoma SH-SY5Y cells against ß-Amyloid-Induced Cell Injury: ß-amyloid peptide is the major component of senile plaques, which serves a critical role in the development and progression of Alzheimer's disease (AD) by generating reactive oxygen species (ROS), which leads to oxidative stress. Study evaluated the protective effect of O. indicum extract against Aß25-35-induced oxidative stress and cell injury using SH-Sy5Y cells as a model. Exposure of cells to 20 µM Aß25-35 significantly increased cellular oxidative stress, evidenced by increased ROS levels, and also increase caspase-3/7 activity and LDH release, and caused viability loss. Treatment with O. indicum not only attenuated the generation of ROS and suppressed caspase-3/7 activity but also reduced neurotoxicity of Aß25-35 in a concentration-dependent manner, evidenced by increased cell viability and decreased LDH release. Treatment also increase superoxide dismutase (SOD) and catalase (CAT) activity, and increased phosphorylation of Akt and cAMP-responsive element binding protein (CREB) and contributed to upregulation of Bcl-protein. In combination, results suggest O. indicum extract could protect SH-SY5Y cells against Aß25-35 -induced cell injury, partly, via inhibition of oxidative stress, increasing SOD and CAT, attenuating caspase 3/7 activity, and promoting cell survival pathway, Akt/CREB/Bcl-2. The approach may be useful in preventing neurotoxicity induced by Aß in AD and related neurodegenerative diseases. (19)
• Alleviation of ß-Glucuronidase Activity / Bark: Study evaluated the stem bark extract of O. indicum for its role in reducing oxidative stress and ß-glucuronidase enzyme activity. The antioxidant study showed the extract has the capability to down-regulate oxidative stress, while ß-glucuronidase assay displayed IC50 at 174.36 µg/mL. All the major phyto-compounds derived from the bark of O. indicum for insilico ADME and docking studies showed a tendency to interact with ß-glucuronidase receptor. (20)
• Anti-Allergic / Oroxylin A / Roots: Oroxylin A is a flavone present in Oroxylum indicum and Scutellaria baicalensis. Roots of both plants have shown anti-allergic effects. Study evaluated the beneficial effects of oroxylin A on allergic asthma using female Balb/c mice and rat RBL-2H3 mast cells. Oroxylin A administration decreased the number of inflammatory cells, especially eosinophils, and reduced expression and secretion of Th2 cytokines, including IL-4 and IL-13, in lung tissues and bronchoalveolar lavage fluid. Histologic findings showed oroxylin A reduced inflammatory signs and mucin production in lungs. Results suggest potential as an anti-allergic therapeutic. (21)
• Hepatoprotective / Antioxidant / Leaves: Study evaluated the invitro antioxidant and hepatoprotective activity of different extracts of O. indicum leaves. Hepatotoxicity was induced by CCl4 with resultant increase in SGOT, SGPT, ALP, and total bilirubin, with significant decrease in total protein. The ethanol extract showed good antioxidant activity in all assays viz., DPPH, nitric oxide radical scavenging, hydroxyl radical scavenging, and reducing power assay. Extract treatment led to significant alteration in biochemical parameters towards normal. Results showed good antioxidant and hepatoprotective activity. (22)
• Anti-Viral / Chikungunya Virus Infection: Study evaluated the potential anti-viral activity of Oroxylum indicum extract towards CHIKV-infected Vero cells. The virucidal effect of O. indicum aqueous extract was demonstrated when pre-treated cells exhibited a significant anti-CHIKV activity (p<0.05). The aqueous extract showed potential to inhibit the virus and act as prophylactic agent against CHIKV. (24)
• Acute Oral Toxicity Study / Leaves: Study evaluated the acute oral toxicity of ethanol leaf extract of O. indicum in C57BL/6 male mice. Doses of 1000, 2000, and 5000 mg/kbw were used, with normal saline as control, and 5% DMSO as vehicle. Results showed O. indicum leaf ethanolic extract did not show any toxicological effects up to 5000 mg/kbw in the mice model, and is safe for therapeutic use. (25)
• Sub-Acute Oral Toxicity Study / Leaves: Study evaluated the sub-acute oral toxicity of ethanol extract of O. indicum leaves in C57BL/6 mice using doses of 100, 200, and 500 mg/kbw for 28 days, in accordance with OECD Guideline 420. Treatment with increasing doses up to 500 mg/kbw did not cause toxicological effects and is considered safe for consumption and therapeutic use. (26)
• Ameliorative Effect on Tobacco Extract-Induced Cell Damage / Roots: Study evaluated the ameliorative effects of aqueous and n-butanol fractions of root extract of O. indicum on tobacco extract (TE) injured lymphocytes. Cell viability was significantly enhanced when TE injured cells were treated with the aqueous extract. Both extracts showed high occurrence of baicalein and chrysin. Survival rate of damaged lymphocytes was enhanced after root extract treatment. Cell viability enhancement of the lymphocytes after treatment was attributed to antioxidants present in both extracts. Of the two, the aqueous fraction exhibited better ameliorative effect. (28)
• Wound Healing / Leaves: Study evaluated the phytochemical constituents and wound healing properties of aqueous and ethanol extract of leaves in invivo and invitro models. Ethanol extract of leaves showed higher total phenolic content (164 mg GAE/g) compared to aqueous extract (30 mg GAE/g). Ethanol extract of leaves also showed higher total flavonoid content (101 mg CE/g). LT-TOF-MS/MS analysis of leaves extract yielded important compounds such as orientin, chrysin, pinoquercetin, cupressuflavone, puerarin xyloside, forsythiaside, and paederoside. Results showed promising wound healing activity using in vitro scratch wound-healing assay and in vivo excisional wound model, evidenced by significantly increased rate of wound contraction (p<0.05). (29)
• Inhibition of Adipogenesis and Lipase Activity / Fruit Pods: Study evaluated the effects of O. indicum extract (OIE) on the adipogenic and biomolecular change in 3T3-L1 adipocytes. Phytochemical screening yielded flavonoids, alkaloids, steroids, glycosides, and tannins. The OIE exhibited dose dependent reduction of lipid accumulation and demonstrated dose-dependent inhibitory effect upon lipase activity. Results showed the OIE derived from fruit pods is capable of inhibiting lipid and carbohydrate accumulation in adipocytes and has potential to inhibit an enzyme associated with fat absorption. Results suggest potential for exploitation of OIE for the management of the overweight or obese. (30)
• Anti-Angiogenic / Petiole, Seed, Fruit Wall, Stem Bark, Roots: Study evaluated the anti-angiogenic property of petiole, leaf, seed, fruit wall, stem bark and root extracts of O. indicum using chick embryo chorio allantoic membrane (CAM) assay. Results showed significant inhibition of vascular endothelium growth factor (VEGF) and induced neovascularization was recorded. All parts tested, except for the leaf extract, showed maximum anti-angiogenic effect. (31)
• Antidiabetic / Seed: Study evaluated antidiabetic effect of seeds of O. indicum. The seeds showed significant effect (p<0.001) by lowering the blood glucose level in chemically induced diabetic animals. (see constituents above) (32)
Availability
Wild-crafted.
- Powder, tablets, peel and leaf extracts in the cybermarket.
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