Eurycoma longifolia (commonly called tongkat ali or pasak bumi) is a flowering plant in the family Simaroubaceae, native to Indonesia, Malaysia, and, to a lesser extent, Thailand, Vietnam, and Laos. It is also known under the names penawar pahit, penawar bias, bedara merah, bedara putih, lempedu pahit, payong ali, tongkat baginda, muntah bumi, petala bumi (all the above Malay); bidara laut (Indonesian); babi kurus (Javanese); cây bá bệnh (Vietnamese) and tho nan (Laotian). Many of the common names refer to the plant's medicinal use and extreme bitterness. "Penawar pahit" translates simply as "bitter charm" or "bitter medicine". Older literature, such as a 1953 article in the Journal of Ecology, may cite only "penawar pahit" as the plant's common Malay name.
Eurycoma longifolia is a small, evergreen tree growing to 15 m (49 ft) tall with spirally arranged, pinnate leaves 20–40 cm (8–16 inches) long with 13–41 leaflets. The flowers are dioecious, with male and female flowers on different trees; they are produced in large panicles, each flower with 5–6 very small petals. The fruit is green ripening dark red, 1–2 cm long and 0.5–1 cm broad.
Biological effects 
A 2010 ethnopharmacological inventory study on Eurycoma longifolia stated: "The plant parts have been traditionally used for its antimalarial, aphrodisiac, anti-diabetic, antimicrobial and antipyretic activities…"
Even though there are many other legitimate medical areas of interest in Eurycoma longifolia (as evident from the quote included above), most Southeast Asians consume it for the plant's impact on sexual conduct. Already in 2001, Malaysian scientific researchers opened their peer-reviewed, Medline-archived report on Eurycoma longifolia's effect on lab rats with the statement "that Eurycoma longifolia Jack commonly known as Tongkat Ali has gained notoriety as a symbol of man's ego and strength by the Malaysian men because it increases male virility and sexual prowess during sexual activities."
An news article on the website of the scientific journal Nature Medicine referred to Eurycoma longifolia as Malaysia's home-grown Viagra and cited "increased sexual desire, enhanced performance and general well-being". This journal article is also indexed on Medline, but without abstract.
Some scientific studies found that it enhances sexual characteristics and performance in rodents. Other laboratory animal tests have produced positive indications, with one extract having been observed to increase sexual activity in mature rats, including arousal, sniffing, and mounting behavior.
In an experiment conducted on male rats, it was found that eurycoma longifolia increases sperm count. The authors also reported that the plasma testosterone level of Eurycoma longifolia extract treated rats "was significantly increased when compared with that of the control and infertile animals."
Another group of scientists confirmed that Eurycoma longifolia has the capacity to "reverse the inhibitory effects of estrogen on testosterone production and spermatogenesis."
An Italian study on Eurycoma longifolia noted improved sexual performance in lab animals and concluded that the "effect could be mainly ascribed to increased testosterone levels."
After scientists investigating Eurycoma longifolia's effect on sexual parameters had established that sexualizing effects went hand-in-hand with increased testoterone tone, researchers in the field of sports medicine started to look into the anabolic potential of the plant.
In a placebo-controlled human study with healthy young men in a weight-training program, it was found that "the lean body mass of the treatment group showed a significant increment, from 52.26 (7.18) kg to 54.39 (7.43) kg (p = 0.012)." Furthermore, "the increase in strength in the treatment group was larger than in the placebo group (6.78% and 2.77% respectively)… The mean arm circumference of the treatment group increased significantly by 1.8 cm after the supplementation… but there was no significant increase in the placebo group." The results of the study were published in the peer-reviewed British Journal of Sports Medicine.
The anabolic impact of Eurycoma longifolia has been confirmed in the animal model, when the size and weight of just one muscle was measured in treated and untreated rats of equal size. "Results showed that 800 mg/kg of butanol, methanol, water and chloroform fractions of E. longifolia Jack significantly increased (p<0.05) the levator ani muscle…"
Because of Eurycoma longifolia's testosterone-enhancing capacity, it has been included, at least by name, in numerous supplements, marketed primarily to bodybuilding men. One such product lists Eurycoma longifolia as one of more than 30 unquantified ingredients.
In such formulas, the minimal Eurycoma longifolia part isn't a therapeutic dose by any standard, as the quassinoids of Eurycoma longifolia are characterized by poor oral bioavailability.
A study into this aspect concluded: "The results indicate that eurycomanone is poorly bioavailable when given orally… the absolute bioavailability of the compound was low with 10.5%… its poor oral bioavailability may be due to poor membrane permeability in view of its low P value and/or high first-pass metabolism."
In vivo studies with lab animals used root powder of 250, 500, or 1000 mg per kg of body weight, or 200 to 800 mg/kg twice daily, or 50, 100, and 200 mg of Eurycoma longifolia extract per kg of body weight. At the higher dosages (800 mg of the water, chloroform, methanol, or butanol extracted fraction of Eurycoma longifolia per kg of body weight), the effects were more pronounced for both sexual motivation and levator ani size increase.
Taiwanese scientists isolated 65 biochemical compounds from the roots of Eurycoma longifolia, of which ten exhibited "strong cytotoxicity" towards human lung and breast cancer cell lines.
Apart from the better-known quassinoids, the same group of scientist also isolated beta-carboline alkaloids, several of which were active against lung and breast cancer cell lines.
Investigating the activity of 24 Eurycoma longifolia quassinoids against cancer cell lines, including lung cancer cells, medical researchers in Japan found that eurycomalactone was as effective against cancer cells as the established anti-cancer drug doxorubicin.
The same group of researchers also discovered several new biochemical compounds in Eurycoma longifolia and screened them for cytotoxic properties. They concluded that different fractions were effective against different cancers.
One extract has since been co-patented by the government of Malaysia and the Massachusetts Institute of Technology. However, the idea that products of nature on which there exists a large body of knowledge among indigenous peoples can be the subject of intellectual property rights, even of national governments, has long been challenged in peer-reviewed law journals.
Fake Eurycoma longifolia products have been pulled off the shelves in several countries but are still sold over the Internet, mostly shipped from the UK. In a medical journal article, published March 2010, it was noted that "estimates place the proportion of counterfeit medications sold over the Internet from 44% to 90%" with remedies for sexual dysfunction accounting for the greatest share. It is therefore recommended that buyers of Eurycoma longifolia request from Internet vendors conclusive information, and proof, on the facilities where a product has been manufactured.
In Malaysia, the common use of Eurycoma longifolia as a food and drink additive, coupled with a wide distribution of products using cheaper synthetic drugs in lieu of Eurycoma longifolia quassinoids, has led to the invention of an electronic tongue to determine the presence and concentration of genuine Eurycoma longifolia in products claiming to contain it.
On the other hand, consumers who lack the sophisticated electronic tongue equipment invented in Malaysia for testing the presence of Eurycoma longifolia, but want more clarity on whether the product they obtained is indeed Eurycoma longifolia or a fake, can use their own tongue to taste the content of capsules for the bitterness of the material. Quassinoids, the biologically active components of Eurycoma longifolia root, are extremely bitter. They are named after quassin, the long-isolated bitter principle of the quassia tree. Quassin is regarded the bitterest substance in nature, 50 times more bitter than quinine. Anything that isn't bitter, and strongly so, cannot contain quassinoids from Eurycoma longifolia .
In the US, the FDA has banned numerous products such as Libidus, claiming to use Eurycoma longifolia as principal ingredient, but which instead are concoctions designed around illegal prescription drugs, or even worse, analogues of prescription drugs that have not even been tested for safety in humans, such as acetildenafil. In February 2009, the FDA warned against almost 30 illegal sexual enhancement supplements, but the names of these products change quicker than the FDA can investigate them. Libidus, for example, is now sold as Maxidus, still claiming Eurycoma longifolia (tongkat ali) as principal ingredient.
The government of Malaysia has banned numerous fake products which use drugs like sildenafil citrate instead of tongkat ali in their capsules. To avoid being hurt by bad publicity on one product name, those who sell fake tongkat ali from Malaysia have resorted to using many different names for their wares.
The governments of Canada and Singapore have issued warnings against the product XP Tongkat Ali Supreme for containing the prescription drug tadalafil which can be life-threatening in some individuals.
Products claiming various Eurycoma longifolia extract ratios of 1:20, 1:50, 1:100, and 1:200 are sold. Traditionally Eurycoma longifolia is extracted with water and not ethanol. However, the use of selling Eurycoma longifolia extract based on extraction ratio may be confusing and is not easily verifiable.
In expectation of a competitive edge, some manufacturers are claiming standardization of their extract based on specific ingredients. Alleged standards / markers are the glycosaponin content (35–45%) and eurycomanone (>2%). While eurycomanone is one of many quassinoids in Eurycoma longifolia, saponins, known in ethnobotany primarily as fish poison played no role in the academic research on the plant.
See also 
- Kacip fatimah - Female equivalent to Tongkat Ali
- "Eurycoma longifolia information from NPGS/GRIN". www.ars-grin.gov. Retrieved 2008-03-14.
- Medicinal Plants, International Technology Center, United Nations International Development Organisation, UNIDO, Trieste, Italy
- Free Indonesian and Malay dictionary search
- Wyatt-Smith, J. (August 1953). "The Vegetation of Jarak Island, Straits of Malacca". Journal of Ecology 41 (2): 207–225. doi:10.2307/2257036. JSTOR 2257036.
- Bhat, R; Karim, AA (2010). "Tongkat Ali (Eurycoma longifolia Jack): a review on its ethnobotany and pharmacological importance". Fitoterapia 81 (7): 669–79. doi:10.1016/j.fitote.2010.04.006. PMID 20434529.
- Ang, HH; Cheang, HS (2001). "Effects of Eurycoma longifolia jack on laevator ani muscle in both uncastrated and testosterone-stimulated castrated intact male rats". Archives of pharmacal research 24 (5): 437–40. doi:10.1007/BF02975191. PMID 11693547.
- Cyranoski, David (2005). "Malaysian researchers bet big on home-grown Viagra". Nature Medicine 11 (9): 912. doi:10.1038/nm0905-912a. PMID 16145563.
- Ang, HH; Ngai, TH; Tan, TH (2003). "Effects of Jack on sexual qualities in middle aged male rats". Phytomedicine 10 (6–7): 590–3. doi:10.1078/094471103322331881. PMID 13678248.
- Ang, Hooi Hoon; Cheang, Hung Seong; Yusof, Ahmad Pauzi Md. (2000). "Effects of Eurycoma longifolia Jack (Tongkat Ali) on the Initiation of Sexual Performance of Inexperienced Castrated Male Rats". Experimental Animals 49 (1): 35–8. doi:10.1538/expanim.49.35. PMID 10803359.
- Ang, HH; Lee, KL; Kiyoshi, M (2004). "Sexual arousal in sexually sluggish old male rats after oral administration of Eurycoma longifolia Jack". Journal of basic and clinical physiology and pharmacology 15 (3–4): 303–9. doi:10.1515/JBCPP.2004.15.3-4.303. PMID 15803965.
- Chan, KL; Low, BS; Teh, CH; Das, PK (2009). "The effect of Eurycoma longifolia on sperm quality of male rats". Natural product communications 4 (10): 1331–6. PMID 19911566.
- Wahab, NA; Mokhtar, NM; Halim, WN; Das, S (2010). "The Effect of Eurycoma Longifolia Jack on Spermatogenesis in Estrogen-Treated Rats". Clinics 65 (1): 93–8. doi:10.1590/S1807-59322010000100014. PMC 2815289. PMID 20126351.
- Shuid, Ahmad Nazrun; Abu Bakar, Mohd Firdaus; Abdul Shukor, Tajul Ariff; Muhammad, Norliza; Mohamed, Norazlina; Soelaiman, Ima Nirwana (2010). "The anti-osteoporotic effect of Eurycoma Longifolia in aged orchidectomised rat model". The aging male 14 (3): 150–4. doi:10.3109/13685538.2010.511327. PMID 20874437.
- Zanoli, P; Zavatti, M; Montanari, C; Baraldi, M (2009). "Influence of Eurycoma longifolia on the copulatory activity of sexually sluggish and impotent male rats". Journal of Ethnopharmacology 126 (2): 308–13. doi:10.1016/j.jep.2009.08.021. PMID 19703544.
- "Joint Conference of BASEM and BASES". British Journal of Sports Medicine 37 (5): 464–70. 2003. doi:10.1136/bjsm.37.5.464.
- Listed ingredients: 5-Methyl Methoxy Isoflavone, Acetyl L-Carnitine, Alpha Lipoic Acid, Arginine Alpha-Ketoglutarate, Aspartate, Avena Sativa, Borage Oil, (GLA), Calcium-D-Glucarate, Calcium Phosphate, Catuaba Bark, Cellulose Fiber & Gum, Chasteberry Ext. (Vitex Agnus Castus), Chrysin, Coleus Forskohlii (Forskohlin), Damiana, Deer Antler, Eurycoma Longfolia, Genistein, Ginger Root Extract (Zingber Offande) Indole-3-Carbinol, Ipriflavone, Maca (Root) (Lepidm Meyeni) Magnesium Octadecnanoate, Muira Puama, Passion Flower, Prickly Pear Extract, Quercatin Dihydrate, Saw Palmetto, Schisandra Chinensis, Stinging Nettle, Suma (Beta Ecdysone), Turmeric, Stearic Acid
- Low, BS; Ng, BH; Choy, WP; Yuen, KH; Chan, KL (2005). "Bioavailability and pharmacokinetic studies of eurycomanone from Eurycoma longifolia". Planta medica 71 (9): 803–7. doi:10.1055/s-2005-871259. PMID 16206032.
- Ang, HH; Ngai, TH; Tan, TH (2003). "Effects of Eurycoma longifolia Jack on sexual qualities in middle aged male rats". Phytomedicine : international journal of phytotherapy and phytopharmacology 10 (6–7): 590–3. doi:10.1078/094471103322331881. PMID 13678248.
- Ang, H. H.; Lee, K. L. (2002). "Effect of Eurycoma longifolia Jack on orientation activities in middle-aged male rats". Fundamental & clinical pharmacology 16 (6): 479–83. doi:10.1046/j.1472-8206.2002.00106.x.
- Ang, HH; Lee, KL (2002). "Effect of Eurycoma longifolia Jack on libido in middle-aged male rats". Journal of basic and clinical physiology and pharmacology 13 (3): 249–54. doi:10.1515/JBCPP.2002.13.3.249. PMID 12670032.
- Mohd Ridzuan, MA; Sow, A; Noor Rain, A; Mohd Ilham, A; Zakiah, I (2007). "Eurycoma longifolia extract-artemisinin combination: parasitemia suppression of Plasmodium yoelii-infected mice". Tropical biomedicine 24 (1): 111–8. PMID 17568384.
- Farouk, AE; Benafri, A (2007). "Antibacterial activity of Eurycoma longifolia Jack. A Malaysian medicinal plant". Saudi medical journal 28 (9): 1422–4. PMID 17768473.
- Li, Y; Liang, F; Jiang, W; Yu, F; Cao, R; Ma, Q; Dai, X; Jiang, J et al. (2007). "DH334, a beta-carboline anti-cancer drug, inhibits the CDK activity of budding yeast". Cancer biology & therapy 6 (8): 1193–9. PMID 17622795.
- Kuo, Ping-Chung; Damu, Amooru G; Lee, Kuo-Hsiung; Wu, Tian-Shung (2004). "Cytotoxic and antimalarial constituents from the roots of Eurycoma longifolia". Bioorganic & Medicinal Chemistry 12 (3): 537–44. doi:10.1016/j.bmc.2003.11.017.
- Kuo, Ping-Chung; Shi, Li-Shian; Damu, Amooru G.; Su, Chung-Ren; Huang, Chieh-Hung; Ke, Chih-Huang; Wu, Jin-Bin; Lin, Ai-Jeng et al. (2003). "Cytotoxic and Antimalarial β-Carboline Alkaloids from the Roots ofEurycoma longifolia". Journal of Natural Products 66 (10): 1324–7. doi:10.1021/np030277n. PMID 14575431.
- Miyake, K; Li, F; Tezuka, Y; Awale, S; Kadota, S (2010). "Cytotoxic activity of quassinoids from Eurycoma longifolia". Natural product communications 5 (7): 1009–12. PMID 20734929.
- Miyake, K; Tezuka, Y; Awale, S; Li, F; Kadota, S (2010). "Canthin-6-one alkaloids and a tirucallanoid from Eurycoma longifolia and their cytotoxic activity against a human HT-1080 fibrosarcoma cell line". Natural product communications 5 (1): 17–22. PMID 20184012.
- Miyake, K; Tezuka, Y; Awale, S; Li, F; Kadota, S (2009). "Quassinoids from Eurycoma longifolia". Journal of Natural Products 72 (12): 2135–40. doi:10.1021/np900486f. PMID 19919052.
- Tee, TT; Azimahtol, HL (2005). "Induction of apoptosis by Eurycoma longifolia jack extracts". Anticancer research 25 (3B): 2205–13. PMID 16158965.
- U.S. Patent 7,132,117Inventors: T.G. Sambandan, ChoKyun Rha, Azizol Abdul Kadir, Norhaniza Aminudim, Johari Md. Saad. Assignees: Government of Malaysia, Massachusetts Institute of Technology.
- Huft, Michael J. (October 1995). "Indigenous People and Drug Discovery Research: A Question of Intellectual Property Rights". Northwestern University Law Review 89.
- Jackson, G.; Arver, S.; Banks, I.; Stecher, V. J. (2010). "Counterfeit phosphodiesterase type 5 inhibitors pose significant safety risks". International Journal of Clinical Practice 64 (4): 497–504. doi:10.1111/j.1742-1241.2009.02328.x. PMC 3069491. PMID 20088883.
- Abdullah, M.Z.; Rahman, A.S.A.; Shakaff, A.Y.M.; Noor, A.M. (2004). "Discrimination and classification of Eurycoma longifolia Jack in medicinal foods by means of a DSP-based electronic taste sensor". Transactions of the Institute of Measurement and Control 26: 19. doi:10.1191/0142331204tm0103oa.
- Jiwajinda, S; Santisopasri, V; Murakami, A; Sugiyama, H; Gasquet, M; Riad, E; Balansard, G; Ohigashi, H (2002). "In vitro anti-tumor promoting and anti-parasitic activities of the quassinoids from Eurycoma longifolia, a medicinal plant in Southeast Asia". Journal of Ethnopharmacology 82 (1): 55–8. doi:10.1016/S0378-8741(02)00160-5. PMID 12169407.
- Ang, H (2000). "Eurycolactones A–C, novel quassinoids from Eurycoma longifolia". Tetrahedron Letters 41 (35): 6849. doi:10.1016/S0040-4039(00)01159-X.
- Tada, H; Yasuda, F; Otani, K; Doteuchi, M; Ishihara, Y; Shiro, M (1991). "Nouveaux quassinoïdes antiulcéreux à partir d'Eurycoma longifolia". European Journal of Medicinal Chemistry 26 (3): 345. doi:10.1016/0223-5234(91)90069-Y.
- Scientific Committee on Food Opinion of the Scientific Committee on Food on quassin SCF/CS/FLAV/FLAVOUR/29 Final
- FDA Warns Consumers About Dangerous Ingredients in "Dietary Supplements" Promoted for Sexual Enhancement
- FDA Warning Letter
- Hidden Risks of Erectile Dysfunction "Treatments" Sold Online
-  This no-follow link to a spam site is included only as evidence and reference that the illegal drug Libidus is now sold as Maxidus, still with the claim that it is mostly Eurycoma longifolia.
- "Etumax products banned by ministry".
- Foreign Product Alert – XP Tongkat Ali Supreme
- Howes, F. N. (1930). "Fish-Poison Plants". Bulletin of Miscellaneous Information 1930 (4): 129–53. doi:10.2307/4107559. JSTOR 4107559.
- Bradley, C. E. (October 1956). "Yerba de la fleche—Arrow and fish poison of the American southwest". Economic Botany 10 (4): 362–6. doi:10.1007/BF02859766.
- Ang, Hooi-Hoon; Lee, Ee-Lin; Cheang, Hui-Seong (2004). "Determination of Mercury by Cold Vapor Atomic Absorption Spectrophotometer in Tongkat Ali Preparations Obtained in Malaysia". International Journal of Toxicology 23 (1): 65–71. doi:10.1080/10915810490269654. PMID 15162849.