Effect of Eurycoma longifolia standardised aqueous root extract-Physta® on testosterone levels and quality of life in ageing male subjects: a randomised, double-blind, placebo-controlled multicentre study

Eurycoma longifolia (Tongkat Ali) supplementation enhances sleep and wake consolidation in wild-type, but not in narcoleptic mice

Tongkat Ali (TA), also known as Eurycoma longifolia, has been used as a traditional herbal medicine for anti-aging, evidenced by clinical trials presenting the beneficial effects on energy, fatigue, and mood disturbance. We have recently shown that TA supplementation dose-dependently enhances the rest-activity pattern in C57BL/6 mice. Since destabilization of wakefulness and sleep is one of the typical symptoms of not only the elderly but also narcolepsy, we performed sleep analysis with and without dietary TA extract supplementation in middle-aged (10-12 months old) wild-type (WT) and narcoleptic DTA mice. We found that TA supplementation enhanced diurnal rhythms of locomotion and temperature in a time-of-day-dependent manner in WT mice but attenuated in DTA mice. In WT mice, TA supplementation consolidated wakefulness with a long bout duration and led to less entries into the sleep state during the active period, while it consolidated NREM sleep with long bout duration during the resting period. Neither disturbed sleep and wake cycles nor cataplexy was sufficiently improved in DTA mice. EEG spectral analysis revealed that TA supplementation enhanced slow wave activity (SWA) at both delta and low delta frequencies (0.5-4.0 and 0.5-2.0 Hz) during the light period, suggesting TA extract may induce vigilance during the active period, which then elicits a rebound effect during the resting period. Interestingly, DTA mice also slightly, but significantly, increased SWA at low frequencies during the light period. Taken together, our results suggest that TA supplementation enhances the Yin-Yang balance of sleep, temperature, and locomotion in WT mice, while its efficacy is limited in narcoleptic mice.

Eurycomanone from Eurycoma longifolia Jack upregulates neurotrophin-3 gene expression in retinal Müller cells in vitro

Photoreceptor degeneration decreases light sensitivity and leads to vision loss and various retinal diseases. Neurotrophin-3, originating from Müller glial cells in the retina, plays a key role in protecting photoreceptors from damage induced by light or hypoxia. This neuroprotective approach is important because there are no established methods to regenerate lost photoreceptors. Dietary supplements are one of the useful methods for improving eye health. Eurycoma longifolia (E. longifolia) Jack, which is native to the tropical forest of Malaysia and other Southeast Asian countries, exhibits several medicinal properties. In the present study, we demonstrated that the water extract of E. longifolia roots enhanced neurotrophin-3 gene expression in primary rat Müller cells. Using a stepwise bioassay-guided fractionation and purification of E. longifolia root extracts, we isolated the active compound underlying neurotrophin-3 gene-enhancing activities. Mass spectrometry and nuclear magnetic resonance spectral data identified the compound as eurycomanone. This study provides evidence for the efficacy of E. longifolia and eurycomanone in enhancing neurotrophin-3 expression in Müller cells in vitro. Although the biological significance of this effect and its underlying mechanism remain to be elucidated, this study suggests that E. longifolia may be promising for improving eye health and must be further investigated.

Ameliorative effects of elderberry (Sambucus nigra L.) extract and extract-derived monosaccharide-amino acid on H2O2-induced decrease in testosterone-deficiency syndrome in a TM3 Leydig cell

With aging, men develop testosterone-deficiency syndrome (TDS). The development is closely associated with age-related mitochondrial dysfunction of Leydig cell and oxidative stress-induced reactive oxygen species (ROS). Testosterone-replacement therapy (TRT) is used to improve the symptoms of TDS. However, due to its various side effects, research on functional ingredients derived from natural products that do not have side effects is urgently needed. In this study, using the mitochondrial dysfunction TM3 (mouse Leydig) cells, in which testosterone biosynthesis is reduced by H2O2, we evaluated the effects of elderberry extract and monosaccharide-amino acid (fructose-leucine; FL) on mRNA and protein levels related to steroidogenesis-related enzymes steroidogenic acute regulatory protein (StAR), cytochrome P450 11A1(CYP11A1, cytochrome P450 17A1(CYP17A1), cytochrome P450 19A1(CYP19A1, aromatase), 3β-hydroxysteroid dehydrogenase (3β-HSD), and 17β-hydroxysteroid dehydrogenase(17β-HSD). We analyzed elderberry extract and extract-derived FL for changes in ROS scavenging activity and testosterone secretion. Elderberry extract and FL significantly reduced H2O2-induced intracellular ROS levels, improved testosterone secretion, and increased the mRNA and protein expression levels of steroidogenesis-related enzymes (StAR, 3b-HSD, 17b-HSD, CYP11A1, CYp17A1). However, the conversion of testosterone to estradiol was inhibited by elderberry extract and extract-derived FL, which reduced the mRNA and protein expression of CYP19A1. In conclusion, elderberry extract and FL are predicted to have value as novel functional ingredients that may contribute to the prevention of TDS by ameliorating reduced steroidogenesis.

Botanicals in health and disease of the testis and male fertility: A scoping review

BACKGROUND

Male factor infertility often results from testicular disorders leading to inadequate sperm quantity and quality. Both beneficial and detrimental effects of botanical products, especially herbal medicines, on testicular functions and male fertility have been reported in the literature.

PURPOSE

This scoping review aims to map the main clinical evidence on different impacts of botanical entities on the testis and to critically appraise relevant randomized controlled trials (RCTs) published in the recent 5 years, so as to inform the future.

METHODS

Systematic reviews, meta-analyses and RCT reports on botanical impacts on testicular functions and male fertility were retrieved and synthesized from Pubmed, Web of Science, Scopus, Embase, ProQuest, Cochrane Library and Google Scholar up to 10th May 2022. RCTs published since 2018 were critically appraised against good practice guidelines for RCT and for reporting herbal studies.

RESULTS

We identified 24 systematic reviews and meta-analyses published since 2005, by authors from Iran (25%), China (21%), USA (12.5%) and 9 other countries. All but two were published in English. Only 3 systematic review protocols were identified, all published in English from China in the recent 3 years. We identified 125 RCTs published in six languages, mainly English (55%) and Chinese (42%). They were published since 1994 from 23 countries on all the six inhabitable continents, with China (46%), Australia (8%), USA (8%), India (7%) and Iran (5%) being the leading contributors. 72% and 28% RCTs published in English were on efficacy (botanicals vs placebo) and comparative effectiveness (a botanical vs other treatments), respectively. In contrast, 98% RCT reports in Chinese were on comparative effectiveness, with merely 2% on efficacy. Among all the 125 RCTs, 57% were studies in patients with semen abnormality and/or male infertility, 22% investigated herbal effects in healthy men, 14% were on patients with male sexual dysfunction and hypogonadism, and 7% were conducted in men with non-sexual disorders. Since 2018, 32 RCTs have been published, in English (69%) or Chinese (31%). Nineteen RCT reports from China, India, Japan and Korea all studied herbal formulae while the 13 RCT reports from Australia, Brazil, Czech and Italy, Iran, Malaysia, Spain, the UK and the USA all exclusively studied extracts of a single species. Putting geo-cultural differences aside, gossypol and extracts of Tripterygium wilfordii Hook. f. were found to be detrimental to the testis and male fertility, while the extracts of Withania somnifera (L.) Dunal and traditional Chinese medicine Qilin Pill, etc., might improve testosterone levels and semen parameters, thus could be therapeutic for male sexual dysfunction and infertility. However, all still require further evaluation in view of recurring weaknesses in quality control of herbal materials, RCT design and reporting. For example, only 9%-23% of the RCTs published since 2018 provided information on voucher samples, chemical profiling, herbal authentication and herbal extraction.

CONCLUSION

Research on botanicals and the testis has been reported worldwide, demonstrating clear geo-cultural differences in studied plant species, botanical types, study objectives and quality of research design, implementation and reporting. Due to a few recurring weaknesses in the literature, this study is unable to recommend the use of any specific botanicals, however, current evidence does indicate that botanicals can be double-edged swords to the testis and male fertility. To secure better clinical evidence, future studies must faithfully implement existing and emerging good practice guidelines.

Eurycoma longifolia (Jack) Improves Serum Total Testosterone in Men: A Systematic Review and Meta-Analysis of Clinical Trials

Background and Objectives: Male hypogonadism is a clinical disorder characterized by reduced serum testosterone in men. Although treatment using herbal medicines, including Eurycoma longifolia, has been investigated, the benefits remain unclear. This study aims to investigate the efficacy of E. longifolia as a sole intervention to increase testosterone levels in males. Materials and Methods: We conducted a systematic review and meta-analysis of randomized clinical trials (RCTs) according to the PRISMA guidelines. Relevant articles were retrieved from the databases PubMed, Scopus, Web of Science, Cochrane, Ovid/Embase, and Google Scholar. Results: After literature screening, a total of nine studies was included in the systematic review. Five RCTs were included in the meta-analysis. A significant improvement in total testosterone levels after E. longifolia treatment was mostly reported in both healthy volunteers and hypogonadal men. The random model effect revealed a significant increase (SMD = 1.352, 95% CI 0.565 to 2.138, p = 0.001) in the total testosterone levels in men receiving E. longifolia supplementation, which was confirmed in the hypogonadism subgroup. Conclusions: This systematic review and meta-analysis of the literature supports the possible use of E. longifolia supplementation for enhancing testosterone production. Although more research is required before its use in clinical practice, this may represent a safe and promising therapeutic option, particularly in hypogonadal men.