Standardized quassinoid-rich Eurycoma longifolia extract improved spermatogenesis and fertility in male rats via the hypothalamic-pituitary-gonadal axis.
Level 5 - mechanism / opinion, no new human data
Animal and in vitro study (no human data)
PubMed 23261482 · doi:10.1016/j.jep.2012.11.013
What was done
Powdered roots of *Eurycoma longifolia* were extracted and separated into crude extracts and four fractions (F1–F4) standardized by major quassinoid content. Male rats received oral administration of the bioactive fraction (F2, 25 mg/kg), crude aqueous extract (W, 250 mg/kg), or control. Outcomes included sperm count and quality, testicular morphometry at stage VII of spermatogenesis, fertility and fecundity indices, and plasma hormone concentrations (testosterone, LH, FSH, estrogen) up to day 104. In vitro effects of isolated quassinoids (including eurycomanone) on testosterone release were assessed in cultured rat Leydig-rich interstitial cells.
What was found
Oral administration of F2 (25 mg/kg) and crude extract W (250 mg/kg) significantly increased sperm concentration compared to control (P < 0.05). In F2-treated rats, stage VII spermatocytes and round spermatids increased (P < 0.05), alongside elevations in estimated spermatozoa production rate and Leydig cell counts (P < 0.001). Increases were observed in fertility index, fecundity index, and pup litter size. Plasma testosterone was significantly elevated at day 26 (P < 0.05) and day 52 (P < 0.01), but was no longer significantly different from control by day 104. Testicular testosterone peaked in F2-treated animals and exceeded plasma levels. Plasma LH and FSH increased (P < 0.001), while plasma estrogen decreased. In vitro, eurycomanone and 13α(21)-dihydroeurycomaone significantly stimulated testosterone release from Leydig cells (P < 0.05). Absolute numerical baseline and endpoint values were not provided in the abstract.
Why it matters
These findings suggest that eurycomanone-rich fractions drive the pro-fertility and androgenic actions of *Eurycoma longifolia* via modulation of the hypothalamic-pituitary-gonadal axis in male rodents.
Limits
The findings are derived entirely from rat and in vitro models, which cannot establish efficacy or safety in humans. The abstract does not report the total number of animals, specific control group details, or absolute quantitative values and error margins. Plasma testosterone elevation dissipated by day 104.
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