Family • Mimosaceae - Acacia - Samanea saman (Jacq.) Merr. - RAIN TREE - Yu shu

Acacia is a name shared by many species of Philippine plants, both scientific and common names: (1) Acacia concinna, acacia, a prickly shrub found in La Union, Benguet, and Ilocos Sur provinces of northern Luzon; (2) Albizzia lebbect, acaci, langil, mimosa; (3) Samanea saman, rain tree, acacia, for Acacia concinna; (4) Acacia farnesiana, aroma; (5) Acacia glauca, ipil-ipil; (6) Acacia niopo, kupang; (7) Acacia crassicarpa.

Scientific names

Samanea saman (Jacq.) Merr.
Albizia saman (Jacq.) F. Muell.
Mimosa saman Jacq.
Inga saman Willd.
Pithecolobium saman Benth.
Enterolobium saman Prain
Yu shu (Chin.)

Common names

Acacia (Span., Tag.)
Akasya (Tag., Ilk.)
Palo de China (Span.)
Cow tamarind (Engl.)
False powder puff (Engl.)
Rain tree (Engl.)
Saman (Puerto Rico)
Monkey pod (Engl.)

Other vernacular names

CAROLINIAN: Filinganga
CHAMORRO: Tronkon mames
FIJI: Vaivai ni vavalangi, vavai ni vavalagi, sirsa.
FRENCH: Gouannegoul, arbre depluie
GUAM: Trongkonmames.
HAWAII: Ohai, pu ohai
JAPANESE: America-nemu
SAMOA: Tamalini, tamaligig
TONGAN: Kasia kula, mohemobe
YAPESE: Gumor ni spanis



Acacia is a large umbraculiform tree growing to a height of 20 to 25 meters. Bark is rough and furrowed. Branches are widespread. Leaves are evenly bipinnate and hairy underneath. Pinnae are 8 to 12 and 15 centimeters long or less. Leaflets are 12 to 16 in the upper pinnae, 6 to 10 in the lower ones, decreasing in size downward, hairy beneath, with the mid-nerve diagonal, and oblong-rhomboid, 1.5 to 4 centimeters long. Flowers are pink, borne in dense, peduncled, axillary, solitary, fascicled heads. Fruits are pods, straight, somewhat fleshy, indehiscent, 15 to 20 centimeters long, 2 centimeters wide, with a pulpy sweet mesocarp.

– Throughout the Philippines in waste places along roads and trails in fallow, rice paddies, etc.
– Widely planted as a shade tree.
– In some places, spontaneous.
– Introduced here about 1860 from tropical America.
– Now pantropic in cultivation.

· Saponin-like alkaloid pithecolobin has been isolated from the bark and the seed.
· Alkaloids are said to be abundant in the bark, stems, leaves, and seeds.
· Leaves and stems have saponin and tannin; gum from the trunk.
· Pods are rich in starch and sugar, with a fair proportion of albuminoid substances.
· Bark has no tannin. Trunk yields an inferior gum.

– Slightly acidic tasting, cooling.
– Antipyretic, antimicrobial, stomachic, astringent, antidermatoses, laxative, antimalarial, sedative.

Parts utilized
· Entire plant.
· Collect from May to October.
· Rinse and sun-dry.

Mesocarp of the fruit is sweetish, sometimes eaten by children.
· In the Philippines, a decoction of the inner bark or fresh cambium and leaves is used to treat diarrhea.
· Acute bacillary dysentery, enteritis, diarrhea: use 15 to 30 gms dried material in decoction.
· Also for colds, sore throat, headache.
· A decoction of the inner bark or fresh cambium and leaves is used to treat diarrhea.
· Anaphylactic dermatitis, eczema, skin pruritus: use decoction of fresh material and apply as external wash.
· Latex used as gum arabic for gluing.
· Seeds chewed for sore throat; inner bark decoction and fresh leaves used for colds and diarrhea.
· In Pakistan infusion of leaves used as laxative. Decoction of inner bark used for diarrhea, colds, and intestinal ailments.
· In Jamaica leaf infusion used for treating blood pressure.
· In Tropical Africa seeds are chewed for treating gum and throat inflammations.
· In Venezuela rain tree is a traditional remedy for colds, diarrhea, headache, intestinal ailments and stomach ache.
· Root decoction used in hot baths for stomach cancer.
· In the West Indies, the leaf infusion is used as a laxative and seeds chewed for sore throat.
· The alcoholic extract of leaves used for tuberculosis.
· In Columbia, the fruit decoction is used as a sedative.

Additional Sources and Suggested Readings

(1) Preliminary phytochemical screening and antimicrobial activity of Samanea saman / R. Naveen Prasad, S.Viswanathan, J. Renuka Devi et al / Journal of Medicinal Plants Research Vol. 2(10), pp. 268-270, October, 2008

(2) Medicinal Uses for Samanea saman / National Tropical Botanical Garden

(3) In vitro Antibacterial Potential of Alkaloids of Samanea saman Against Xanthomonas and Human Pathogenic Bacteria / M P Raghavendra et al / World Journal of Agricultural Sciences 4 (1):100-105,2008

(5) Invitro antioxidant testing of the extracts of Samanea saman (Jacq.) Merr / P Arulpriya, P Lalitha and S Hemalatha / Pelagia Research Library, Der Chemica Sinica, 2010, 1 (2): 73-79

(6) Insecticidal Property of Acacia Seeds and Bark Against Termites / Inverstigatory Project / Lumbang National High School

(8) Common names / Species Profiles for Pacific Island Agroforestry

(9) Evaluation of anti-ulcer activity of Samanea saman (Jacq) merr bark on ethanol and stress induced gastric lesions in albino rats / Suresh Arumugam, Senthil Velan Selvaraj, Suresh Velayutham, Senthil Kumar Natesan, Karthikeyan Palaniswamy / Indian Journ of Pharmacology, 2011, Vol 43, No 5, pp 586-590.

(11) Samanea saman (Jacq.) Merr / Common names / Pacific Island Ecosystems at Risk / PIER


(13) Comparative phytochemical and antimicrobial screening of some solvent extracts of Samanea saman (fabaceae or mimosaceae) pods / Obasi Nnamdi L., Egbuonu Anthony C. C., Ukoha Pius O. and Ejikeme Paul M. / African Journal of Pure and Applied Chemistry Vol. 4(9), pp. 206-212, October 2010

(14) Tannins and other phytochemical of the Samanaea saman pods and their antimicrobial activities / Pius O. Ukoha1*, Egbuonu A. C. Cemaluk, Obasi L. Nnamdi and Ejikeme P. Madus / African Journal of Pure and Applied Chemistry Vol. 5(8), pp. 237-244, August 2011

(15) Studies in the nyctinastic movement of the leaf pinnae of Samanea saman (Jacq. ) Merrill / II. The behaviour of upper and lower half-pulvini / J. H. Palmer and G. F. Asprey / PLANTA, Vol 51, No 6 (1958), 770-785 / DOI: 10.1007/BF01941003

(16) Antioxidant, Antimicrobial and Cytotoxic Activities of Samanea saman (Jacq.) Merr. / Afia Ferdous, Mohammad Zafar Imam and Tajnin Ahmed / S. J. Phar. Sce. 3(1): 11-17

(18) SOME BIOLOGICAL EVALUATIONS ON SAMANEA SAMAN / IQBAL AZHAR, M. MOHTASHEEMUL HASAN, FARAH MAZHAR AND M.S. ALI* / Pakistan Journal of Pharmacology Vol.26, No.1, January 2009, pp.47-53

(19) Antiemetidc Acticity of Leaves Extracts of Five Leguminous Plants / Ahmed Salman et al / IJRAP 3(2), Mar-Apr 2012.

(20) Antimicrobial Activity of Spermine Alkaloids From Samanea Saman against Microbes Associated with Sick Buildings / Sundis M. Sahib Ajam, Baharuddin Salleh, Suleiman Al- khalil and Shaida F. Sulaiman / 2012 International Conference on Environment, Chemistry and Biology IPCBEE vol.49 (2012) / DOI: 10.7763/IPCBEE. 2012. V49. 30

(21) Study on antioxidant and organprotective effects of leaves of samanea saman (jacq.) merr.(rain tree) / PATEL
JIGNESH KANUBHAI / Dissertation, 2011 /

(22) Extraction And Isolation Of The Alkaloids From The Samanea Saman (Acacia) Bark: Its Antiseptic Potential /
Gonzales, Maria Victoria M., Tolentino, Angelina G. / INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 3, ISSUE 1, JANUARY 2014 ISSN 2277-8616

(24) Antiemetic Activity of Leaves Extracts of Five Leguminous Plants / Ahmed Saman et al / IJRAP, 3(2), March-April 2012

(25) Acacia (Samanea saman (JACK) MERR) pods as feeds for broilers / Barcelo Patricia M., Libong Juanito E., Coloma Evalyn T. / Agriculture, Forestry and Fisheries, 2013; 2(6): 235-23 / doi: 10.11648/j.aff.20130206.16

(26) EVALUATION OF ANTIDIABETIC ACTIVITY OF SAMANEA SAMAN (JACQ.) MERR / Babin D Reejo*, P. Natarajan, A. Thangathirupathi / International Journal of Research in Pharmaceutical and Nano Sciences. 3(4), 2014, 352- 356.

(27) Isolation of Pithecolobine from the Leaf Extracts of Samanea saman (Jacq.) Merr and it’s in vitro antitubercular screening and related infections / Shanmugakumar SD, Satheesh Kumar G / IJIPSR 2 (6), 2014, 1096-1106

(28) Role of polyphenols in nephroprotective potential of Samanea saman (jacq.) Merr leaves on experimentally induced renal injury / Jignesh Patel K, Shanmukha I, Vijay Kumar M Ramachandra Setty S, Rajendra SV*. / IAJPR. 2013; 3(3): 2571-258

– Wood: Valued for its shade. Popularly used in carving, making tables, wood basins and bowls. Hats are made from the shavings of the wood.
– Fodder: Seasonally copious pods with sweet pulp that can be grounded and converted to fodder and alcohol as an energy source. It is a valuable source of feed for cattle and horses. It is also an important honey plant like most mimosaceous trees.
– High sugar content of the pod can be utilized for producing alcohol by fermentation.

 Preliminary phytochemical screening and antimicrobial activity of Samanea saman: A study of the aqueous plant extract on three organisms (Escherichia coli, Staphylococcus aureus and Candida albicans) showed inhibitory activity against all the tested organisms. Phytochemical screening revealed tannins, flavanoids, saponins, steroids, cardiac glycosides and terpenoids. The study validates the use of the plant in traditional medicine. (1)
• Antibacterial: A methanol extract from leaves showed a highly significant antibacterial activity in vitro for Xanthomonas pathovars and for human pathogenic bacteria. (3)
• Larvicidal: Of 112 medicinal plant species collected in Thailand, Samanea saman (stem bark) was one of 14 plants that exhibited high toxicity to the fourth instar larvae of Aedes aegypti in preliminary screening. (4)
• Antioxidant: (1) Several extracts of Samanea saman showed the highest antioxidant potential in both DPPH and reducing power assay. (2) Study showed a methanolic extract to have radical scavenging activity with values higher than ascorbic acid. Phytochemicals yielded carbohydrates, phytosterols, saponin, phenolic compounds, and tannin. (5)
• Anti-Termite: Study of ethanolic extracts of seeds and bark of Acacia collected from the Laurel Farm in Lipa city yielded saponins, tannins, alkaloids, reducing agents – glycosides, carbohydrates. Results showed termite killing activity comparable to solignum. (6)
 Anti-Ulcer / Bark: Study of bark extract in albino rats showed significant dose-dependent antiulcer activity comparable to standard drugs. (9)
• Toxicity and Tolerance to Metals: Increased concentration of different metals significantly reduced germination which was more prominent for Pb and Cd as compared to Cu and Zn. (12)
• Bioactivity Analysis: Bioactivity analysis assays on hexane (HE) and methanol (ME) extract of leaves showed: (1) Both had moderate bacterial activity against P. aeruginosa (2) HE antifungal activity against Fusarium solani, ME against Trichophyton longifusus (3) Cytotoxicity in brine shrimp lethality assay (4) HE Insecticidal activity against R. dominica and T. granarium.
• Antimicrobial / Phytochemical Screening: Study of various extracts for antimicrobial activity against B. subtilis, S. aureus E. coli, P. aeruginosa and Candida albicans. Only the methanol extract showed inhibitory activity against Bacillus subtilis and Staphylococcus aureus. Various extracts showed varying amounts of alkaloids, saponins and resins, with an absence of acidic compounds. Flavonoids were moderately present in the ethyl acetate extract. Findings suggest the use of S. saman pods in ethno-medication. (13)
• Pods / Tannins / Antimicrobial / Tea: Screening of n-hexane extract of pods showed a moderate presence of secondary metabolites. Pods yielded the characteristic reddish brown solid tannins, which on analysis showed to be the condensed (catechol) type. Tannin components were cyanidin, catechin, epicachin, anthocyanin monoglycones, delphinidine and malidin. Tannins in the ethyl acetate fraction showed the highest antimicrobial activity, including C. albicans. Results suggest the ground pods could be a significant source of natural antimicrobials and antifungals that can be used in the formulation of a novel tannin/energy rich nutraceutical tea. (14)
• Antioxidant / Antimicrobial / Cytotoxic: Study bark extracts showed good antioxidant and cytotoxic potential of chloroform and hexane soluble fractions and antimicrobial activity of carbon tetrachloride fraction. (16)
• In vitro Anthelmintic Activity: Study of alcohol and aqueous extracts of the bark of S. saman was tested against Pheretima posthuma. Results showed anthelmintic activity in the same concentration as albendazole. (17)
• Insecticidal Activity: Study on insecticidal activity showed the hexane extract with 50% mortality against Rhyzopeertha dominica and Tribolium granarium. (18)
 Antiemetic Activity: A methanolic extract of leaves showed 76.41% inhibition of emesis measured as reduction in number of retches in chicks. Chlorpromazine decreased the retches by 33.97%. (19)
• Antimicrobial / Spermine Alkaloids / Sick Buildings Microbes: Study of an 80% methanolic extract of Samanea saman leaves yielded two known macrocyclic spermine alkaloids, pithecolobines 1 and 2. Results showed the isolated compounds, especially pithecolobine 2, might a potential plant-based formulation for management of microbes in sick enclosed buildings. (20)
• Antioxidant / Organprotective / Leaves: Study evaluated the polyphenol and flavonoidal contents and organprotective effects of leaves of Samanea saman. Results showed concentration dependent in vitro and in vivo antioxidant activities in all test models. Study also showed a 70% alcoholic extract of leaves possess hepatoprotective, nephroprotective and gastroprotective activities attributed to the plant polyphenolic compounds—flavonoids and tannins. (21)
 Alkaloids / Bark / Antibacterial: Study showed the bark of Samanea saman to contain a high yield of alkaloid. The crude extracts and alkaloid-rich fraction exhibited complete inhibition against Staphylococcus aureus. (22)
 Analgesic / Leaves: Study evaluated the analgesic effects of methanol extract of leaves of Samanea saman and Prosopis cineraria using a tail immersion test. Both extracts showed significant analgesic effects when compared with pethidine. (23)
• Antiemetic / Leaves: Study evaluated the antiemetic activity of methanol extracts of five leguminous plants. All the extracts showed antiemetic activity, (24)
• Pods as Boiler Feed: Samanea saman is a good source of protein and energy. The pod meal contains a about 13.75% protein, 89.25 to 1.175% dry matter, 2.98 to 1.63 ether extract, 2.19 to 14.54% crude fiber, 0.23 to 3.27% ash and 6.44 to 55.67% nitrogen extract. Leaves and pods can be tapped as sources of feeds for ruminants during drought periods when feeds are scarce. (25)
 Anti-Diabetic / Leaves: Study evaluated methanolic leaf extract of S. saman for potential anti-diabetic activity by in- vitro α-amylase inhibition and in-vivo epinephrine induced diabetic rats. Results showed significant reduction of blood sugar levels with significant inhibition of α-amylase. (26)
 Pithecolobine / Antimycobacterial / Leaves: A bioactive compound, pithecolobine isolated from the fraction of ethyl acetate:methanol (80:20) showed remarkable antimycobacterial activity. (27)
• Nephroprotective / Polyphenols / Antioxidant / Leaves: Study investigated a hydroalcoholic extract of leaves for its protective effects on paracetamol induced renal damage in rats. Extract of leaves improved all the induced changes in physical, tissue and blood parameters, together with significant reversal of elevated LPO and reduced tissue GSH level. Results were attributed to the presence of antioxidant principles. (28)