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Family Simaroubaceae
Long jack
Eurycoma longifolia Jack
ALI'S UMBRELLA
TONGKAT ALI
A li zhi zhang

Scientific names Common names
Eurycoma latifolia Ridl. Ali's umbrella (Engl..)
Eurycoma longifolia Jack Long jack ? (Engl.)
Eurycoma merguensis Planch. Malaysian ginseng (Engl.)
Eurycoma tavoyana Wall. [Invalid]  
Eurycoma longifolia Jack is an accepted name. The Plant List

Other vernacular names
BAHRAIN: Langir siam.
INDONESIAN: Pasak bumi, Bedara pahit, Bidara laut.
JAPANESE: Babi kurus.
LAOTIAN: Tho nan.
MALAY: Akar pasak bumi, Batang pasak bumi, Kayu dali, Penawar pahit, Sengkayap, Tongkat ali, Umpudumaidu, Wonod mondou.
THAI: Tung saw, Ian-don, Hae phan chan, Phiak, Plaa lai phuenk.
VIETNAMESE: Cay ba benh, Hau phat, Ba binh.

Gen info
- Tongkat Ali (E. longifolia Jack) is one of the most well-known herbal folk medicine in Southeast Asia.
- While Tongkat Ali is popularly
related to Eurycoma longifolia, there are three other plants species locally sharing the same common name, viz., Entomophthora apiculata, Polyalthia bullata, and Goniothalamus sp. (5)
- The name "Tongkat ali" literally means "Ali's walking stick," which refers to its aphrodisiac property. Some authors claim the "stick" refers to the long twisted roots harvested for its medicinal value. (5)
- There are over 200 E. longifolia products registered with the National Pharmaceutical Control Bureau of Malaysia (NPCB, 2016). It is now currently sold as a Traditional Herbal Medicine in Malaysia. Approximately 21,000 kg are harvested by collectors per year, with a demand of more than 54,000 kg per year. (5)

Botany
Eurycoma longifolia is a medium-sized slender shrub that can reach a height of 10 meters, often unbranched with reddish brown petioles. Leaves are compound even pinnate, up to i meter in length. Each compound leaf consisting of 30 to 40 leaflets, lanceolate to obovate-lanceolate. Each leaflet is about 15 to 20 centimeters long, 1.5 to 6 centimeters wide, much paler on the underside. Inflorescence is axillary, in large brownish red panicles, pubescent with fine soft, granular trichomes Flowers are dioecious. Petals are small, finely pubescent. Fruit is a drupe, hard, ovoid, with a distinct ridge, yellowish brown when young and brownish red when ripe. (3)

Distribution
- Native to Indochina (Cambodia, Laos, Malaysia, Myanmar, Thailand and Vietnam) (3)
- Also found in the Philippines.
- An understorey plant of lowland forests.

Constituents
- Studies of roots have isolated 65 phenolic compounds. Various classes of bioactive compounds include quassinoids, ß-carboline alkaloids, canthin-6-one alkaloids, triterpene-type tirucallane, squalene derivatives, and eurycolactone, eurycomalactone, layrycolactone, biphenyl neolignan and bioactive steroids. (5)
- Quassinoids isolated from the roots include various types of eurycomanone (pasakbumin-A), eurycomanols, pasakbumin-B, hydroxyklaineanones, eurycomalactones, eurycomadilactones, eurylactones, laurycolactones, longilactones, and hydroxyglaucarubol. (5)
- Alkaloids isolated include 5,9-dimethoxycanthin-6-one; 9,10-dimethoxycanthin-6-one, 11-hydroxy-10-methoxycanthin-6-one; 10-hydroxy-9-methoxycanthin-6-one; and 9-methoxy-3-methylcanthin-5,6-dione. (5)
- Study of stems isolated ten new structurally diverse quassinoids (1-10) and 14 known compounds, New compounds were two eurycomanone-type C20 quassinoids (1,2), one klaineanone-type C20 quassinoid (3), one C19 quassinoid (4) with a 1,2-seco-1-nor-6(5→10)-abeo-picrasan-2,5-olide skeleton, and six eurycomalactone-type C19 quassinoids (5−10). (see study below) (9)

Properties
Studies have suggested antimicrobial analgesic, anti-inflammatory, anticaner, antihyperglycemic, aphrodisiac, male fertility enhancing, antioxidant, adaptogenic, antitumor, ergogenic properties.

Parts used
Roots, fruits, bark, leaves.

Uses

Folkloric
- Popular in many Southeast Asian folk medicine, particularly, for its aphrodisiac effects.
- Used for malaria, for washing itches. Fruits used in dysentery. Bark used as vermifuge. Taproots used to treat high blood pressure. Root bark used for diarrhea and fever.
- Roots used for sexual dysfunction, aging, malaria, cancer, diabetes, leukemia, osteoporosis, stress, syphilis, among many others. (
5)
- Roots used as aphrodisiac, antibiotic, appetite stimulant and health supplement. Also used to combat stress and improve physical strength. (
5)
- Used to treat lumbago and indigetion; also, as a tonic after delivery.

Studies
Effect on Stress Hormones and Stress / Trial / Roots:
Study evaluated the effect of supplements with standardized hot-water extract of Tongkat Ali roots for 4 weeks on 63 subjects (32 men, 31 women). Results showed significant improvement in the TA group for tension (-11%), anger (-12%), and confusion (-15%). Stress hormone profile (salivary cortisol and testosterone) showed significant improvement with reduced cortisol exposure (-16%) and increase testosterone status (+37%). Results indicate daily supplementation of root extract improves stress hormone profile and certain mood parameters. (4)
Male Fertility Enhancement Effect: Water-soluble E. longifolia extracts have been reported to enhance male fertility, in measures of higher semen volumes, spermatozoa count, and motility in rodents and human trials. A standardized extract F2 of E. longifolia and major quassinoids, especially eurycomanone improved rat spermatogenesis by affecting the hypothalamic-pituitary-gonadal axis. Eurycomanone, major quassinoid in a root extract, significantly increased testosterone production in a dose-dependent manner. It enhanced testosterone steroidogenesis at rat testicular Leydig's cells by inhibiting the conversion of testosterone to estrogen. The cumulation of studies have suggests that quassinoids from E longifolia has potential for development of phytomedicines for treatment of testosterone-deficient idiopathic male infertility and steriliy. (5)
Toxicological Studies / Review: Safety studies have shown that Tongkat Ali concentrations used therapeutically (2.5 µg/mL) appear to not have any detrimental effects on human spermatozoa in vitro. However, at concentrations higher than 100 µg/mL, cytotoxic effects may occur.. While some animal studies showed no effect on offsprings, an acute study in mice (Satayavivad et al) on an ethanolic extract found an oral LD50 between 1500-2000 mg/kb while an aqueous extract showed an LD50 of more than 3000 mg/kg. This study authors showed ethanolic and aqueous extract were not toxic at 200 mg/kg and 300 mg/kg, respectively. Dosages above 1200 mg/kbw showed significant hepatotoxic effects. Acute toxicity studies found the n-butanol fraction as most toxic, attributed to eurycomanone. The studies suggested that LD50s and daily effective doses vary among fractions, and the water-based fraction is considered the safest. (5)
Effect on Male Osteoporosis due to Androgen Deficiency: Androgen deficiency (hypogonadism) is one of the major factors of male osteoporosis which can be treated with testosterone replacement therapy (TRT). Study evaluated the efficacy of E. longifolia as alternative treatment to treat and prevent male osteoporosis. EL exerts androgenic effects that enhance testosterone level and stimulate osteoblast proliferation and osteoclast apoptosis to maintain bone remodelling activity and reduce bone loss. EL has potential as complementary treatment for male osteoporosis without the side effects associated with TRT. (6)
Detection of Adulteration on Using DNA Barcoding & HPLC Analysis: Study evaluated the extent of adulteration of E. longifolia herbal medicinal products (HMPs) using DNA barcoding validated by HPLC analysis. DNA barcoding revealed 37% of HMPs were authentic while 27% were adulterated. HPLC analysis showed a situation in which a species identified as authentic was found not to contain the expected chemical compound. Integration of DNA barcoding with HPLC analysis will help provide information on safety and efficacy of HMPs. (7)
Aphrodisiac Effect: Of all the traditional uses, the sexual enhancing effect is the one that has gained notoriety. A study investigated the potential of the plant to increase sexual motivation of sexually naive male rats. Results showed repeated and chronic dosing of E. longifolia fractions enabled rats to cross an electric grid, along with an improvement in the amount of mounting, intromission and ejaculation. (7)
Antitumor / Quassinoids: Antitumor activity is one of the mos impressive property of quassinoids. Many quassinoids exhibited antitumor activity in different potencies. The mechanism of action may be through inhibition of protein synthesis by inhibition of ribosomal peptidyl transferase activity that leads to the termination of chain elongation (Hall et all, 1982, 1983; Willingham et al 1981; Freshno et al, 1978).  (8)
Quassinoids / Anti HT-1080 Human Fibrosarcoma Cell Line / Stems: Study of stems isolated ten new structurally diverse quassinoids (1-10) and 14 known compounds, All the isolates were evaluated for cytotoxicity toward the highly metastatic HT-1080 human fibrosarcoma cell lines. Compounds 11, 23, and 24 showed potent cytotoxicity with IC50 values 0.93- 1.1 µM. (see constituents above) (9)
Effect on UDP-Gucoronosyltransferase Activity / Root: Studies have been done to reveal the influence of herbal preparations on drug metabolism, especially on UGT- and glutathione-S-transferase activities. Study evaluated the effect of E. longifolia root extract on enzyme activity in phase II drug metabolism on Sprague-Dawley rats, especially on uridine 5'-diphospho-glucuronosyltransferase (UGT) activity, in vivo and in vitro. The extract significantly (p<0.05) reduced the UGT enzyme activity both in vivo and in vitro. The ELE (IC50 0.74 µg/ml) had a lower potency than positive control Na diclofenac (IC50 0.17 µg/ml). (10)
Anti-Tumor / K-562 Leukemic Cell Line / Roots: Study evaluated the in vitro and in vivo anti-proliferative and apoptotic potentials of E. longifolia on K-562 leukemic cell line. The K-562 cells were isolated from patients with chronic myelocytic leukemia (CML) and were treated with various root fractions. TAF273 showed growth inhibition with IC50 of 19 µg/ml. It induced apoptosis in a dose and time dependent manner. It also arrested cell cycle t G1 and S phases.. TAF273 showed potent anti-proliferative activity in in-vivo and in-vitro models of CML. Results suggest potent of TAF273 as a novel therapeutic strategy for CML management. (11)
Effect on Lipolysis in Collegiate Athletes / Pilot Study: Study evaluated whether acute consumption of E. longifolia extract would influence lipolysis among athletes. Assessment was done with treadmill exercise test, measurements of free fatty acid, glycerol and triglycerides. Results showed EL supplementation could promote fat lipolysis, resulting with better energy yield. E. longifolia has potential as an ergogenic aid to improve performances and boost energy production. (12)
Antioxidant / Anti-Inflammatory: Study evaluated a hydroalcoholic extract of Eurycoma longifolia for antioxidant and in-vitro anti-inflammatory properties. DPPH assay showed significant antioxidant activity in all tested concentrations. Human RBC(HRBC) stabilization method showed significant anti-inflammatory activity in all concentrations tested, with activity increasing in a concentration dependent manner. (13)
Effect on Sperm Quality / Eurycomanone: Study evaluated the effects of a standardized methanol extract of Eurycoma longifolia containing quassinoid constituents of 13α(21)-epoxyeurycomanone (1), eurycomanone (2), 13α,21-dihydroeurycomanone (3) and eurycomanol (4) on epididymal spermatozoa profile of normal and Andrographis paniculata induced infertile rats. Results showed increase in sperm count (p<0.01). The extract significantly reversed low count, poor motility and abnormal morphology of spermatozoa induced by A. paniculata fraction (p<0.001). Plasma testosterone level significantly increased (p<0.01). The eurycomanone (2) may have contributed towards the improvement of sperm quality. (14)
Antibacterial / Root: Study evaluated the antibacterial activity of E. longifolia root using an ethanolic extract against bacterial strains. The ethanolic root extract showed positive results against Gram positive bacteria (S. aureus and B. cereus) and Gram negative bacteria (S. typhi). B. ceereus and S. typhi showed inhibition zones of 11.76 mm and 14.3 mm at extract concentration of 150 mg/mL, respectively, which were higher than positive control. (15)
Immune System Enhancer or Stimulator / Invention: The invention is a composing comprising an effective amount of Eurycoma longifolia extract for the production of a preparation to stimulate and/or enhance the immune system. Ingredients include eurycomanone, protein, polysaccharide and glycosaponin. Effects measure the number of T-cells, improving scores on SIV (a comprehensive index of overall immune function), and lowering of immunological age (immune function based on T-cell number and proliferative activity, reducing fatigue and stress). (16)
Ergogenic Potential / Review: This review presents studies on the ergogenic potential of Eurycoma longifolia. A double-blind randomized study showed no significant difference in physiological responses and exercise performance during endurance cycling between herbal drink consumption and placebo. It was suggested that lack of carbohydrates in the herbal drink or or low concentration of herbs may explain the absence of significant difference. Another study suggested that longer supplement time, 150 mg daily for 5 weeks, can increase fat free mass, muscle strength, and size (Hamzah and Yusof). Other reports on its aphrodisiac property has been attributed on the plant's ability to stimulate the production of androgen hormones, especially testosterone. Of course, testosterone use to enhance athletic performance is prohibited in sports. Further studies are suggested to further the knowledge on the ergogenic potential of the plant. (17)
Antimicrobial / Anticariogenic / Root: Study evaluated the antibacterial and antifungal activities of root extract against three common oral pathogens viz., Candida albicans, Streptococcus mutans, and Lactobacillus casei. Results showed inhibition of growth of C. albicans and S. mutans at concentration of 200 mg/ml with zones of inhibition of 16.0 and 7.0 mm, respectively. MIC for both was 25 mg/ml. Results potential use of E. longifolia as new oral care product. (18)
Blood Glucose Lowering / Root: Study evaluated the blood glucose lowering effect of aqueous root extracts in STZ induced diabetic rats. Results showed lowering of blood glucose by 38% (p<0.05). Fraction 2 showed anti-diabetic activity with ED50 value of 1.71 mg/kbw after 15 days of treatment. (19)
Inhibitor of CDK2 Methylation / Quassinoid / Root: In Indonesia, the plant is used as antitumor by triggering cell apoptosis and reactivating the silence tumor suppressor gene caused by hypermethylation, inhibiting cancer cell proliferation. Study sought to define the role of quassinoid from Eurycooma longifolia as an inhibitor of CDK2 methylation in silico. Results showed the quassinoid has an affinity as inhibitor of CDK2. In the study, Sunitinid as positive control ligand, showed better value compared to quassinoid, meaning it has better ability to bind than quassinoid. (20)
Improvement of Quality of Life and Sexual Well Being in Men / Randomized Clinical Trial: Eurycoma longifolia is reputed as aphrodisiac and treatment for decreased male libido. A randomized, double-blind, placebo controlled, parallel group study evaluated the clinical evidence of E. longifolia in 109 patients aged 30-55 years randomized to E. longifolia and placebo medication. The freeze-dried water extract of roots resulted in significant improvements in libido, sexual performance, satisfaction, and physical functioning. E. longifolia showed strong impact on seminal fluid parameters, i.e., semen volume and sperm motility. The daily dose of 300 mg of extract for three months was well tolerated and compared to placebo. (21)
Potential Adaptogen of Male Sexual Health: Review analyzed and summarized the literature of various databases of human clinical trials on the clinical significance and therapeutic feasibility of EL in improving male sexual health. There is convincing evidence for the prominence of EL in improving the male sexual health. The findings of human clinical trials revealed a promising efficacy of EL in treating erectile dysfunction in sexually sluggish males by improving penile erection, erectile hardness and sexual performance. Critical analysis of literature assessed is that the sex boosting effects of EL are due to its testosterone enhancing effects in males. (22)
Effect on Uric Acid Excretion / Stem: Study evaluated the effect and mechanism of E. longifolia stem 70% ethanol extract and its active compounds on uric acid excretion in potassium oxonate (PO) induced hyperuricemic rats model and adenin-PO induced hyperuricemia mice model. EL significantly reduced reduced blood uric acid levels, prevented pathological changes of kidney in PO induced hyperuricemia animal model, and improved renal urate transports. The mechanism, partly clarified, was related to the suppressing effect of URAT1 by quassinoid in EL. This is the first study to demonstrate the role of EL in hyperuricemia by promoting renal uric acid excretion. (23)
Etana / Herbal Combination for Erectile Dysfunction: Study evaluated Etana, an herbal combination of five extracts viz., Panax quinquelotius (Ginseng), Eurycoma longifolia (Tongkat Ali), Epimedium grandiflorum (Horny goat weed), Centella asiatica (Gotu Kola) and flower pollen extracts. Most of the extracts have a long historical and traditional use for erectile dysfunction (ED). Study evaluated its effect on the enhancement of erectile function in male rats, measuring penile erection, genital grooming, copulation mounting, and penile erection index (PEI). Maximum response was observed at 7.5 mg/kg of Etana. The PEI was significantly (p<0.001) higher than each single component and than the sum of any two herbal components of Etana. Compared to sildenafil citrate, Etana produced more pronounced PEI than 0.36 mg/kg, but similar to 0.71 mg/kg of sildenafil. Acute and sub-acute toxicity studies showed no toxic effects. (24)
Effect on Spermatogenesis in Estrogen-Treated Rats: Study evaluated the effect of EL on testicular histology and sperm count in estrogen-treated male rats. Rats treated with EL alone exhibited significantly higher sperm counts and sperm motility compared to control. Results suggest a potential agent for reversing the effects of estrogen by increasing spermatogenesis and sperm counts in rats after 14 consecutive days of treatment. (25)
Anti-Inflammatory / Alkaloid Enriched Extract / Roots: Study evaluated the in-vitro and in-vivo anti-inflammatory effects of an alkaloid enriched extract (ELA) from roots by examining inhibitory activities against NO production, iNOS, and COX-2 expressions in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The ELA exhibited significant anti-inflammatory activity via suppression of pro-inflammatory mediators such as NO, iNOS, and COX-2 and protects mice from LPS-induced mortality i septic shock model. (26)
Effect on Corpus Cavernosum / Root: Study evaluated the mechanisms of action of E. longifolia in rat corpus cavernosum. Fraction DCM-1 was able to antagonize angiotensin II-induced contraction to cause corpus carvernosum relaxation via inhibition of angiotensin III type receptor and enhance bradykinin-induced relaxation through inhibition of angiotensin-converting enzyme. (27)
Analgesic / Anti-Inflammatory / Roots: Study evaluated the analgesic and anti-inflammatory effects of methanolic extract of EL roots in vivo in mice. The root extract showed analgesic effects in the acetic acid test in a dose dependent manner. It showed an anti-inflammatory effect inc carrageenan-induced edema in mice comparable to diclofenac. Results showed the extract alleviated pain and inflammation via inactivation of the NF-kB signaling pathway. (28)
Phytoandrogenic Properties / Natural Alternative to Testosterone Replacement: Testosterone deficiency syndrome (TDS) is characterized by many symptoms, including low libido, increase fat mass, fatigue, erectile dysfunction or osteporosis, affecting up to 80% with age-dependent decline of serum testosterone levels. Conventional treatment is testosterone replacement therapy (TRT), with both benefits and significant adverse effects, along with concerns on prostate cancer. Tongkat ali has been touted as a natural alternative to TRT, shown to restore serum testosterone levels, improving sexual health, along with positive effects on bone healing, and a significant antihyperglycemic effect. At therapeutic levels, no significant adverse effects have been reported. Tongkat ali may be a safe alternative to TRT.   (29)

Availability
= Wild-crafted.
- Herbal supplements, extracts in the cybermarket.

Mqy 2020

                                                     PHOTOS / ILLUSTRATIONS
IMAGE SOURCE: Photograph / File: Tongkat Ali (Eurycoma longifolia) / Mokkie / May 2014 /book / Creative Commons 3.0 / click on image to go to source page / Wikimedia Commons
OTHER IMAGE SOURCE: Photograph / Closeup / Flower / Eurycoma longifolia / Alex Yee / click on image to go to souce page / © Wiki.nus
OTHER IMAGE SOURCE: Photograph / Roots / click on image to go to source page / © FREAKYFITNESS: fitness for regular folks / FREAKYFITNESS

Additional Sources and Suggested Readings
(1)

Eurycoma longifolia Jack / Synonyms / The Plant List
(2)
Sorting Eurycoma names / /Maintained by: Michel H. Porcher / MULTILINGUAL MULTISCRIPT PLANT NAME DATABASE / Copyright © 1995 - 2020 / A Work in Progress. School of Agriculture and Food Systems. Faculty of Land & Food Resources. The Univers ity of Melbourne. Australia.
(3)
Eurycoma longifolia / Wikipedia
(4)
Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects / Shawn M Talbott, Julie A Talbott, Annie George, and Mike Pugh / J Int Soc Sports Nutr., 2014; 10 / doi: 10.1186/1550-2783-10-28 / PMCID: PMC3669033 / PMID: 23705671
(5)
Review on a Traditional Herbal Medicine, Eurycoma longifolia Jack (Tongkat Ali): Its Traditional Uses, Chemistry, Evidence-Based Pharmacology and Toxicology / Shaheed Ur Rehman, Kevinn Choe, and Hye Hyun Yoo / Molecules, 2016 Mar; 21(3): 331 / doi: 10.3390/molecules21030331 / / PMID: 26978330 / PMCID: PMC6274257
(6)
Eurycoma longifolia: Medicinal Plant in the Prevention and Treatment of Male Osteoporosis due to Androgen Deficiency / Nadia Mohd Effendy, Norazlina Mohamed, Norliza Muhammad, Isa Naina Mohamad, and Ahmad Nazrun Shuid / Evid Based Complement Alternat Med., 2012; 125761.  / doi: 10.1155/2012/125761 / PMID: 22844328 / PMCID: PMC3403331
(7)
Assessing product adulteration of Eurycoma longifolia (Tongkat Ali) herbal medicinal product using DNA barcoding and HPLC analysis / Bashir Mohammed Abubakr, Faezah Mohd Salleh, Mohd Shahir Shamsir Omar, Alina Wagiran / Pharmaceutical Biology, 2018; 56(1) / https://doi.org/10.1080/13880209.2018.1479869
(8)
Advances in Studies on Chemistry, Pharmacological Effect, and Pharmacokinetics of Eurycoma longifolia / Hou Wen-bin, Xiao Xue-feng, Guo Wei, Zhang Tie-jun / Chinese Herbal Medicines, 2011; 3(3): pp 186-195 / DOI: 10.3969/j.issn.1674-6384.2011.03.004
(9)
Quassinoids from Eurycoma longifolia / Katsunon Miyake, Yasuhiro Tezuka, Suresh Awale, Feng Li, and Shigetoshi Kadota / Journal of Natural Products, 2009; 72(12): pp 2135-2140 / https://doi.org/10.1021/np900486f
(10)
In vitro and in vivo effect of Eurycoma longifolia root extract on UDP-glucuronosyltransferase activity / Purwantiningsih Purwantiningsih, Abas Hj Hussin, Sabariah Ismail, Kit Lam Chan / Journal of Applied Pharmaceutical Science, Sept 2019; 9(09): pp 077-083 / DOI: 10.7324/JAPS.2019.90911
(11)
Anti-Tumor Activity of Eurycoma longifolia Root Extracts against K-562 Cell Line: In Vitro and In Vivo Study / Omar Saeed Ali Al-Salahi, Dan Ji, Amin Malik Shah Abdul Majid, Chan Kit-Lam, Wan Zaidah Abdullah, Abdelhamid Zaki, Shah Kamal Khan Jamal Din, Narazah Mohd Yusoff, Aman Shah Abdul Majid / PLOS ONE, 9(1): e83818.  / https://doi.org/10.1371/journal.pone.0083818
(12)
Effect of Eurycoma Longifolia Jack Extract on Lipolysis in Collegiate Athletes: Pilot study / P J Lim, C S Gan, T K Khong, S H Hamzah, A Yusof / 3rd International Conference on Movement, Health and Exercise. MoHE 2016. IFMBE Proceedings, Vol 58.
(13)
Antioxidant and Anti-Inflammatory Activity of Eurycoma longifolia Jack, A Traditional Medicinal Plant in Malaysia / C P Varghese, C Ambrose, S C Jin, Y J Lim, and T Keisaban / International Journal of Pharmaceutical Sciences and Nanotechnology, Jan-Mar 2013; 5(4): pp 1875-1878
(14)
The Effect of Eurycoma longifolia on Sperm Quality of Male Rats / Kit-Lam Chan, Bin-Seng Low, Chin-Hoe Teh and Prashanta K. Das / Natural Products Communication, 2009; 4(10): pp 1331-1336
(15)
In Vitro Antibacterial Activity of Eurycoma Longifolia Jack (Tongkat Ali) Root Extract / Faisal GG, Zakaria SM, Najmuldeen GF / IMJM: International Medicinal Journal of Malaysia, June 2015; 14(1)
(16)
Eurycoma longifolia extract and its use in enhancing and/or stimulating immune system  / Annie George, Yuuki Kawasaki, Azreen Abas / 2015 / WO2016036232A2
(17)
Review Ergogenic Effect of Long Jack, Eurycoma Longifolia / Thasanee Khanijou, Wannee Jiraungkoorskul / Pharmacogn. Rev., 2016; 10: pp 139-142 / DOI: 10.4103/0973-7847.194041
(18)
Effects of Eurycoma Longifolia Jack (Tongkat Ali) Alcoholic Root Extract Against Oral Pathogens / Irani Binti Alloha, Nurul ‘Ain Liyana Binti Aziz, Ghasak Ghazi Faisal, Zurainie Abllah, Mohd Hafiz Arzmi / Pharmacognosy Journal,2019; 11(6): pp 1299-1302. / DOI:10.5530/pj.2019.11.201
(19)
ACTIVITY OF ETHYL ACETATE FRACTIONS OF TONGKAT ALI ROOTS (EURYCOMA LONGIFOLIA, JACK) ON BLOOD GLUCOSE LEVELS IN STREPTOZOTOCIN INDUCED DIABETIC RATS / H. Yusuf, K. Hasballah  and K. Fitri Jamil  / International Journal of Pharmaceutical Sciences and Reserach
(20)
Effect of Active Compound of Pasak Bumi Root (Euricoma longifolia, Jack) as an inhibitor of CDK2 methylation: In Silico Study / E Y Rahman, M Ali, B B Purnomo, N Kania, D H Utomo and P W Nurikhwan / Journal of Physics: Conference Series 1374 (2019) 012004 / doi:10.1088/1742-6596/1374/1/012004
(21)
Randomized Clinical Trial on the Use of PHYSTA Freeze-Dried Water Extract of Eurycoma longifolia for the Improvement of Quality of Life and Sexual Well-Being in Men / Shaiful Bahari Ismail, Wan Mohd Zahiruddin Wan Mohammad, Annie George, et al / Evidence-Based Complementary and Alternative Medicine, Vol 2012, Article ID 429268 /  https://doi.org/10.1155/2012/429268
(22)
Eurycoma Longifolia as a potential adoptogen of male sexual health: a systematic review on clinical studies / Hnin Ei Thu, Ahmad Nazrun Shuid et al / Chinese Journal of Natural Medicines, Jan 2017; 16(1): pp 71-80 / https://doi.org/10.1016/S1875-5364(17)30010-9
(23)
Effect of Eurycoma longifolia Stem Extract on Uric Acid Excretion in Hyperuricemia Mice / Ruixia Bao, Mengyang Liu, Dan Wang, Shaoshi Wen, Haiyang Yu, Yi Zhong, Zheng Li, Yi Zhag, and Tao Wang / Frotniers in Pharmacology / https://doi.org/10.3389/fphar.2019.01464
(24)
A new herbal combination, Etana, for enhancing erectile function: an efficacy and safety study in animals / N Qinna, H Taha, AA Badwan et al / International Journal of Impotence Research, 2009; 21: pp 315-320 / https://doi.org/10.1038/ijir.2009.18
(25)
The effect of Eurycoma longifolia Jack on spermatogenesis in estrogen-treated rats / Norhazlina Abdul Wahab, Norfilza M Mokhtar, Wan Nurul Heriza A Halim, Srijit Das / Clinics, 2010; 65(1) São Paulo http://dx.doi.org/10.1590/S1807-59322010000100014 
(26)
Anti-inflammatory effects of alkaloid enriched extract from roots of Eurycoma longifolia Jack / Dao Thi Thanh Hien, Tran Phi Long, Tran Phuong Thao, Jeong-Hyung Lee et al / Asian Pacific Journal of Tropical Biomedicine, 2019; 9(1): pp 18-23 / DOI: 10.4103/2221-1691.250265
(27)
Effects of Root Extracts of Eurycoma longifolia Jack on Corpus Cavernosum of Rat / Tee B H, Hoe S Z, Cheah S H, Lam S K / Med Princ Pract, 2017; 26: pp 258-265  / https://doi.org/10.1159/000464363
(28)
Antiinflammatory and analgesic effects of Eurycoma longifolia extracts / Young Min Han, Sang Uk Woo, Min Sun Choi, Yu Na Park, Seung Hyuun Kim, Hyungshin Yim, Hye Hyun Yoo / Archives of Pharmacal Research, 2016; 39(3): pp 421-428 / DOI: 10.1007/s12272-016-0711-2
(29)
Phytoandrogenic properties of Eurycoma longifolia as natural alternative to testosterone replacement therapy / A George, R Henkel / Andrologia, 46(7) / https://doi.org/10.1111/and.12214

                                                                          DOI
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                                                            List of Understudied Philippine Medicinal Plants

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