 Gen info
- The plant is the iconic symbol of the island of Madagascar.
-
Ravenala is a genus of flowering plants with a single species, Ravenala madagascariensis.
- It is not a true palm. In part it resembles a banana plant with long leaf stalks and deep green leaves.
- The scientific name derives from Malagasy ravinala meaning "forest leaves." (4)
- The common name Traveler's Tree derives from the botanical design of the bracts and leaf folds where rainwater is collected; water that can be consumed by thirsty travelers, hence, the name Traveler's Palm.
(3)
- The water is often rendered undrinkable by mosquito larvae infestation and contamination. (3)
- While it has earned the name "Traveler's tree" for providing water to travelers, which is captured at the base of the fan-like leaves, up to a quart per leaf, the water, alas, is usually buggy and/or fermented from various debris. A better source of liquid is the sap, which can be tapped from the base of the leaf stalks,
and which can be boiled down to a syrup. (24)
 Botany
• Traveler's tree is an evergreen tree with an open, fan-like crown, growing to a height of 20 meters Young palms have no visible trunk, which is underground. In adult plants the trunk emerges above ground, raising the symmetrical leaf fan. Green trunk grows up to 1 foot in diameter with distinctive trunk leaf scar rings. Leaves are large, banana-like, deep green, 2.5 to 4 meters long and 80 to 150 centimeters wide, on a stout petiole 3 to 6 meters long, Leaves extend out symmetrically in a fan-shaped formation of 20 or more leaves. Flowers are small, in foot-long inflorescence held in bracts; every 2 or 3 days, a new flower opens in an inflorescence, normally opening at night. Fruits are brown with blue seeds.
Distribution
- Introduced.
- Widely cultivated.
- Ornamental cultivation.
- Endemic to island of Madagascar.
- In Mauritius, it is considered an invasive plant species and a threat to the native forest.
(15)
- Four forms identified in the wild: (1) Malama: rare, in understorey of undisturbed rain forest, (2) Hiranirana: more abundant, in forest gaps and disturbed primary forest, (3) Bemavo, the most common form, on deforested slopes, forming the Ravenala forests; growing to a height of 30 meters, and (4) Horonorona: grows in deforested lowland sites, small and develops many suckers, most common as ornamental cultivation. (3) (4)
 Constituents
- Study of hexane extract of leaves isolated two new compounds: (2E, 7R, 11R) phytyl-3, 7, 11, 15-tetramethylhexadec-2-enyl pentadecanoate (1) and (24S, 31S)-cycloartan-31, 32-diol (2) together with the known cycloartanol triterpene (3) which was isolated for the first time from this plant. (5)
- Phytochemical screening of leaves yielded carbohydrates, flavonoids, glycosides, alkaloids, phenols, tannins, saponins, proteins, and steroids, with absence of terpenoids, quinones, and furans.
(6)
- Metabolic profiling yielded 19 phenolic compounds from different classes viz., flavone glycosides flavonol, glycosides, and flavanol aglycones. Bioassay guided purification of leaf n-BuOH partition isolated seven compounds viz., narcissin, rutin, epiafzelechin, epicatechin, isorhamnetin 7-O-glucoside, kaempferol, and isorhamnetin-7-O-rutinoside. (see study below)
(11)
- A computer analysis of ground and powdered palm dissolved in solution
using N-ezane yielded organic compounds with cellulose 46.82%, hemi-cellulose 25.70%, lignin 22.46%, and extractives 5.02%. (12)
- Centesimal analysis of blue plant arils indicated a lipid-rich composition (81.45%), carbohydrates (7.03%), moisture (3.71%). ash (0.78%),
and proteins/peptides (7.1%). GC-MS analysis of fatty acid methyl esters obtained from lipid fraction showed composition of 41% palmitic, 14% stearic, 34% oleic, and 7% linoleic acids. (see study below) (16)
- Phytochemical screening of leaves extracts revealed tannins (0.31%), flavonoids (16.32%), phlobatannins (0.36%), cardiac glycosides (0.08%), cyanogenic glycosides (47%), and anthraquinones (16.20)
. (see study below) (17)
- Study of seed and aril for oil content yielded
4.1% and 68.7% resoectively. Oils showed high levels of oleic (39%0 and palmitic (34-42%) acids. Sterol fraction of seed yielded 7 sterols, mainly ß-sitosterol [83-46-5] (65%), whereas sterol fraction of aril oil yielded 12 sterols, mainly stigmasterol [83-48-7] (18%), 24-methyl-5-α-cholest-7-en-3-ß-ol [4198-70-3] (16%), α-spinasterol [481-18-5] (28%, and Δ7-avenasterol [23290-26-8] (19%). (see study below) (22)
Properties
- Copious nectar production.
- Seed oil considered antiseptic.
- Studies have suggested
antioxidant, antidiabetic, hypolipidemic, anti-acetylchonlinesterase, renoprotective, hyaluronidase inhibitory, antithrombolytic, membrane stabilizing, insulin-releasing, antitumor, mosquito larvicidal, skin hydrating properties.
- See toxicity concern below. (25)
Parts used
Leaves, seed oil.
 Uses
Edibility
- Seed is edible, rather tasteless.
- Fruit, raw. Edible blue arils are tasteless..
- Among the local people in Ambalabe, Madagascar, the heart is cooked and eaten as vegetable.
- Of the different varieties, the heart of Bemavo is widely preferred because it is sweeter. (4)
- Young leaves reported edible; cooked, although bitter.
Folkloric
- No reported medicinal use in the Philippines.
-
Seed oil used as antiseptic.
- In the Ambalabe communities of Madagascar, young leaves used for dizziness and stomachaches. (4)
- Used for the treatment of diabetes and kidney stone problems. (5) (6)
- Islanders of the Indian Ocean drink tea made for young leaves for treatment of diabetes. Seeds used as antiseptic. Leaves also used for diarrhea. (13)
- Used for a wide range of ailments, such as coughs, stomachache, urinary retention, diabetes, diarrhea, edema, kidney stones and hypertension. (15)
- In the Maroantsetra region of Madagascar,
used for treatment of anorexia: the pith of the shoot is cooked and eaten with meal to restore one's lost appetite. (20)
Others
- Seed oil: Yields a seed oil sometimes used for cooking. Oil content of seeds and arils is 4% ad 68% respectively.
- Sugar: Can be extracted from the sap of the trunk.
- Leaves: Used a roofing and as packing material. (3)
- Construction: Stems, bark, petioles used in house construction for walls, floors, posts and rafters. (3) For floors, Bemavo is preferred because it has the biggest trunk. For roofs, Horonorona is preferred because of its longevity. (4)
- Fodder: Heart used as fodder by domestics. (•) Pith of shoot added to feed of cattle and pigs to fatten them up. (20)
- Crafts: (s) Construction: Floor, trunk; roofs, leaves; wall petioles and trunk; beehives, trunk; chicken coops, leaves; gable, trunk; doors, petioles; medicine young leaves and heart; crafts.
Studies
• Cycloartanol / Antidiabetic: Study of hexane extract of leaves yielded two new compounds (1 and 2), together with the known cycloartanol triterpene (3) which was isolated for the first time from this plant. The presence of cycloartanol justifies its use in traditional medicine in the treatment of diabetes. (see constituents above) (5)
• Antioxidant / Leaves: Study evaluated the antioxidant activity of leaf extracts of R. madagascariensis against oxidative stress in RBCs of alloxan induced diabetic rats. Chronic administration of ethanol extract at 400 mg/kbw showed significant reduction (p<0.001) in lipid peroxidation level. Reduced GSH content and catalase activity were significantly increased (p<0.001) on treatment in a dose dependent manner. (7)
• Antidiabetic / Leaves: Study evaluated n-hexane, ethyl acetate, ethanol and aqueous leaf extracts of Ravenala madagascariensis for antidiabetic activity. Ethanolic and aqueous extracts showed significant inhibitory effect on glucose diffusion in vitro. in in vivo evaluation, on alloxan induced diabetic rats, both extracts showed significant antidiabetic activity, with the ethanolic extract showing more effective reduction in blood glucose (p<0.001) during acute and prolonged treatment, comparable to standard glibenclamide. (8)
• Hypolipidemic / Renoprotective / Leaves: Study evaluated the effect of ethanolic and aqueous leaf extract of RM on cardiovascular and renal complications on alloxan induced diabetes. Results showed significant improvement in the altered lipid profile of diabetic animals exhibiting impaired metabolic functions. There was significant decrease in TC, TG, LDL and VLDL with a significant increase in HDL (p<0.001) by both extracts in a dose dependent manner. The ethanol extract was more effective than the aqueous extract. Histological examination of kidneys supported the results of hematological evaluation. (9)
• Insulin Secretagogue Effect / Roots: Study evaluated the cytotoxicity profile and insulin secretagogue effect of ethanolic extract of roots of R. madagascariensis. The extract showed negligible cytotoxicity at 20-40 µg/ml. On insulin secretion assay the extract significantly (p<0.05) stimulated insulin release in a dose dependent manner even at the presence of glucose at lower and higher concentrations (5 and 10 mM). (10)
• Hyaluronidase Inhibitors: Hyaluronidase enzyme (HAase) play an important role in the dissolution or disintegration of hyaluronic acid (HA) and in maintaining a healthy state of skin. Study reports on bioassay-guided isolation, metabolic profiling and docking studies of hyaluronidase inhibitors from Ravenala madagascarienis. A crude hydroalcoholic (70%) extract of leaves and its n-butanol partition showed higher HAase activity with 64.3% inhibition. Docking study showed narcissin, rutin, and quercetin 3-O-glucoside all interact with HAase through hydrogen bonding. Results highlight the plant and its flavonoids as promising hyaluronidase inhibitors in natural cosmetology preparations for skin care. (see constituents above) (11)
• Antithrombolytic Activity / Membrane Stabilizing Activity / Leaves: Study evaluated R. madagascariensis for antithrombolytic and membrane stabilizing activities. Methanolic crude leaf extract and aqueous soluble fraction exhibited percentage clot lysis activity of 45.32 ± 0.82 and 32.67 ± 0.74%, respectively (Chowdhury et al, 2013). (14)
• Antioxidant / Anti-Enzymatic / Cytotoxic: Study evaluated the phytochemical and pharmacological properties of Ravenala madagascariensis. The aqueous extract showed most prominent antioxidant activity by DPPH, FRAP, CUPRAC, metal chelating, and phosphomolydenum assay, while the methanol extract showed best antioxidant potential by ABTS assay. The ME was most active against acetylcholi-nesterase. All extracts were active against α-amylase enzyme, while the ethyl acetate extract showed best α-glucosidase inhibition. Extracts also showed cytotoxicity against HT29 cells. IC of ME was 506.99 µg/mL. HPLC-ESI-Q-TOF-MS-MS analysis characterized 41 metabolites. Based on heat map, flavonoids were found in greater proportion in the extracts, and most activity was attributed to the flavonoid portion of the extracts. (15)
• Blue Pigment / Anti-Enzymatic / Cytotoxic: Study evaluated the morphological and physiochemical properties of the brightly blue colored arils of the seeds. Data analysis and comparison to the NCBI BLAST data bank indicated a phytocyanin domain-containing protein, responsible for the blue coloration of Ravenala arils due to copper coordination with the protein. (see constituents above) (16)
• Antibacterial / Leaves: Study evaluated the antibacterial activities of leaf extracts of traveler's tree, using ethanol, n-hexane, hot and cold water extracts in doses of 25-200 mg/ml against selected human pathogenic bacteria using agar well diffusion method. The ethanol extract showed highest zone of inhibition (10.80 mm) on Proteus mirabilis (ATCC 25933). The ethanol extract remarkably suppressed growth of P. vulgaris, Serratia marcescens, Klebsiella pneumonia, Citrobacter freundii, Proteus mirabilis, among others. Hot and cold water extracts exhibited no effect. (see constituents above) (17)
• Antidiabetic: Study evaluated the antidiabetic activity of three plants used for diabetes management in Guinea viz., Ravenala madagascariensis, Anchomanes difformis, and Rhizophora racemosa hyperglycemic-rendered rats. Oral doses of 2000 mg/kg of dry extracts in mice showed no acute toxicity or adverse effect. At 400 mg/kg dose, all three plants showed significant hypoglycemic effect. Average blood glucose level for R. madagascariensis as 99.6 to 82.3 mg/dL (p<0.05). (18)
• Antitumor / Pancreatic Cell Lines / Leaves: Pancreatic cancer is the 7th leading cause of cancer-related deaths in developed countries with average survival rate of less than 9%. Up to 80% of patients with pancreatic cancer are found to be diabetic at time of diagnosis. Study evaluated the antitumor effect of successive ethanolic leaf extract over two pancreatic cancer cell lines PANC1 and WE1990 by MTT assay, which showed excellent cytotoxic effect with IC50s of 12.58 and 18.9 µg/mL respectively. Results validate the antitumor potential of R. madagascariensis leaf extract against pancreatic cancer. (19)
• Mosquito Larvicidal / Culex quinquefasciatus / Leaves: Study evaluated the larvicidal activities of crude and solvent extracts of R. madagascariensis against filarial vector Culex quinquefasciatus under laboratory conditions. Results showed 78.67% mortality of 1st instar larvae at 0.5% concentration of crude extract. The 150 ppm concentration of solvent extract showed 100% mortality against 1st instar larvae after 72 h. 250 ppm showed significant mortality against 3rd and 4th instars larvae. Study suggests a potential novel resource of target specific larvicide against Cx. quinquefasciatus larvae. (21)
• Fruit Oil / Seed and Aril: Study evaluated oils extracted from various parts (seed and aril) of R. madagascariensis for fatty acid and sterol contents. The oils, partly solidified, can be used as edible food products. The fatty acid content is intermediary between palm oil and cocoa butter. It has potential as a new source of vegetable butter. (see constituents above) (22)
• Cosmetic Hydrating Agent / Invention: Sap from the Ravenala madagascariensis is used as hydrating active agent in a cosmetic composition, to restore, maintain, or reinforce the hydration state of the skin and to prevent or retard the appearance of skin dryness. The active agent was obtained from 0.0001% to 2% dry weight of a hydroalcoholic extract from young leaves of less than 45 days age. The extract of sap and aqueous alcoholic extract of young lea es both exhibit interesting cosmetic properties. The extracts showed efficacy in regulating water flows in the epidermis. Labeling of the AQP3 (Aauaporins 3) demonstrated the remarkable activity of active agents on the regulation and/or functionality of the AQP3 aquaportins. Activity results in better hydration of the basal layers of the epidermis. (23)
• No Antifungal Activity / Toxicity Study / Leaves: Study evaluated the antifungal and toxicological activities of leaves extracts (ethanol, n-hexane, hot water and cold water) at concentrations of 25-200 mg/ml against selected human pathogenic fungi using agar well diffusion method. The extract of leaves did not inhibit growth of fungal isolates used in the study. The extracts did not show hematologic toxicity in rats, but deleterious effects were observed on vital organs such as liver and kidney of studied rats. Toxicity observed may be due to presence of high percentage of cyanogenic glucoside (47%). Study cautions all extracts could be potential deleterious to human health at 200 mg/ml concentration when consumed orally. (25)
Availability
- Ornamental cultivation.
- Seeds in the cybermarket. |
