Unlocking the Potential of Plants: Natural Solutions for Male Sexual Health

Erectile Dysfunction (ED) is characterized by the persistent inability to achieve or maintain sufficient erections for satisfactory sexual activity. Its etiology involves multiple factors, including vascular, neurological, endocrine, and psychological aspects, significantly impacting quality of life. Given the potential side effects of chemical drugs, natural medicines derived from traditional medicine have emerged as important complementary or alternative options due to their relatively high safety and potential efficacy. This review focuses on natural medicines with potential to improve ED, including Eurycoma longifolia, Turnera diffusa, yohimbine hydrochloride, Ptychopetalum olacoides, Lepidium meyenii, Curculigo orchioides, Cynomorium songaricum, Cuscuta chinensis, Cistanche deserticola, Epimedium brevicornu, Apium graveolens seeds, and Serenoa repens. Studies indicate their diverse mechanisms of action, such as improving corpus cavernosum blood flow, regulating sex hormones, exerting antioxidant and anti-inflammatory effects, protecting endothelial function, and modulating neural activity. Natural medicines show significant potential in ED treatment, but further research is needed to clarify their active components, mechanisms of action, and standardization protocols. 

Keywords: Erectile dysfunction; natural product extracts; phytotherapy

Eurycoma longifolia Extract 

Eurycoma longifolia is a representative plant in Southeast Asian traditional medicine for improving male sexual function, with its core medicinal value derived from various active components in its roots. It is also known as "Malaysian ginseng" in different regions of Southeast Asia, highlighting its traditional medicinal significance. Root extracts of Eurycoma longifolia have long been used in Southeast Asian traditional medicine, primarily as a natural enhancer of male sexual function, particularly renowned for its aphrodisiac properties. Traditionally, local populations have used it to increase male testosterone levels, enhance libido, improve erectile function, and alleviate sexual dysfunction. Modern scientific research supports this traditional use: its active components directly target key physiological aspects of male sexual health by promoting testosterone release, increasing free testosterone concentration, relaxing corpus cavernosum smooth muscle, and exerting antioxidant effects. Thus, it has been long used as a traditional aphrodisiac herb and is now commonly included in dietary supplements to help restore hormonal balance, boost sexual vitality, and improve related sexual dysfunctions, making it a representative natural plant resource in male sexual health. Studies have found that Eurycoma longifolia root extract has potential value in improving male ED. Controlled trials show that males with ED of varying ages and severity exhibit improvements in erectile function scores, erection hardness, intercourse frequency, and sexual satisfaction after use, with more pronounced effects in moderate ED cases. However, the overall improvement has not yet reached the clinically recognized minimum effective level. Its mechanisms of action mainly include three aspects: regulating testosterone to promote the release of more free testosterone; improving erectile function by relaxing corpus cavernosum smooth muscle through relevant components; and providing antioxidant protection to reduce oxidative damage to the reproductive system. In terms of safety, relevant trials have not found serious adverse reactions; the incidence of adverse events is comparable to that of placebo, with normal liver and kidney function indicators, making short-term use relatively safe. 

Turnera diffusa Extract 

Turnera diffusa is an evergreen shrub native to Mexico and Central America, with a centuries-old history of traditional medicinal use in local cultures, known as a "natural aphrodisiac." Its dried leaves are the main medicinal part, containing active components such as volatile oils, flavonoids (e.g., chrysin, apigenin), and sterols, which improve male sexual function through multiple pathways. Flavonoids enhance testosterone levels through dual mechanisms: (1) Promoting synthesis: Activating the hypothalamic-pituitary-gonadal (HPG) axis to stimulate luteinizing hormone (LH) release, prompting the testes to secrete more testosterone; reducing loss: Inhibiting aromatase activity to prevent testosterone conversion to estrogen, maintaining effective androgen concentrations. Animal experiments show that rats administered Turnera diffusa exhibit significantly increased serum testosterone, LH, and follicle-stimulating hormone (FSH) levels, effectively alleviating drug-induced sex hormone disorders. (2) Protecting reproductive tissues and repairing spermatogenic function: Improving seminiferous tubule structure, increasing sperm count and Leydig cells, and repairing damaged spermatogenesis. (3) Antioxidant defense: Enhancing the activity of antioxidant enzymes such as glutathione (GSH) and superoxide dismutase (SOD) to reduce free radical damage to testicular tissue. This multi-mechanistic synergy, combined with its long history as an aphrodisiac among Mexican indigenous peoples and applications in improving physical and mental vitality and assisting in depression treatment, makes Turnera diffusa a potentially effective herb for alleviating male sexual dysfunction. 

Yohimbine Extract 

Yohimbine hydrochloride is a natural indole alkaloid extracted from the dried bark of the African Rubiaceae plant Pausinystalia yohimbe, with total alkaloid content in the bark reaching up to 6.1%. It is commonly used in the form of hydrochloride and has long been clinically applied to treat male ED, primarily by enhancing sympathetic nerve activity to optimize erectile function. Clinical studies show that yohimbine alone can effectively improve erectile function, with more significant effects when combined with L-arginine, trazodone, etc. However, its effect on overall sexual function (e.g., libido, sexual satisfaction) is limited when used alone but can be effectively enhanced when combined with other treatments. Animal experiments have confirmed its efficacy: in a rat model of cold stress-induced ED, yohimbine shortens mount, intromission, and ejaculation times, increases ejaculation frequency, and reduces mating intervals, thereby enhancing sexual arousal, motivation, and mating ability in rats[8]. Its mechanisms involve both peripheral and central levels. Peripherally, it induces vasodilation of the corpus cavernosum by blocking α₂-adrenergic receptors on cavernous smooth muscle or arteries, inhibiting contraction signals, with the vasodilatory effect being dose-dependent. Centrally, it may enhance sexual motivation by promoting norepinephrine release or activate non-adrenergic, non-cholinergic pathways (e.g., NO-sGC pathway, K(ATP) channels) to synergistically promote erections. Notably, its efficacy is independent of reproductive hormone regulation; changes in hormones such as testosterone, FSH, and LH do not affect its effects, as it primarily acts directly on sexual behavior regulation and local penile tissue function. In summary, yohimbine hydrochloride shows considerable potential in treating male sexual dysfunction, particularly in combination therapy regimens. 

Ptychopetalum olacoides Extract 

Ptychopetalum olacoides, commonly known as Muira Puama, is a medicinal plant endemic to the Amazon rainforest. In Brazilian traditional medicine, its root bark and stems have long been used as male sexual function enhancers. Its active components include steroids, alkaloids, and terpenoids, which improve male sexual function through multiple pathways: regulating the hormonal system to increase testosterone levels and enhance libido; promoting relaxation of corpus cavernosum smooth muscle and improving genital blood flow through vasodilation to aid erections. Clinical studies indicate that it has a certain improving effect on male sexual dysfunction: it can increase sexual impulse frequency and subjective desire intensity in individuals with hypoactive sexual desire disorder (HSDD); for patients with mild to moderate organic or mixed ED, it enhances erection hardness and duration, with effects independent of common erectile drug pathways. However, early studies showing approximately 50% improvement in erectile function are limited by small sample sizes and insufficient control of confounding factors, requiring more rigorous trials for validation. Some studies use its combination with other components (e.g., Ptychopetalum olacoides extract HV-430 with Ginkgo biloba), and the synergistic effects may amplify the actions of individual components, requiring cautious interpretation. Overall, Ptychopetalum olacoides shows potential in improving male libido and mild erectile issues. Future research is needed to clarify its efficacy and mechanisms, promoting its development as a more reliable natural adjuvant. 

Lepidium meyenii Extract 

Lepidium meyenii, a Brassicaceae plant native to high-altitude regions of the Peruvian Andes, is traditionally used to enhance fertility, sexual function, and alleviate menopausal symptoms. Its core active components are macaenes and macamides, unique polyunsaturated fatty acids and amide compounds, along with polysaccharides, sterols, and alkaloids. Studies show that black maca has the highest content of active components (three times that of yellow maca) and exerts more significant regulatory effects on sexual function. Peruvian maca regulates male sexual function through multiple targets via its unique active components macaenes and macamides, improving libido and erectile function. Animal experiments show that lipid extracts of maca significantly increase sexual behavior frequency in normal mice and shorten erection latency in castrated rats. Clinical studies indicate that mild ED patients exhibit significant improvements in the International Index of Erectile Function (IIEF-5) after oral administration of maca powder; long-term use in healthy males can enhance libido. 

Serenoa repens Extract 

Serenoa repens, also known as the American dwarf palm, is native to the southeastern United States and the Caribbean. Its medicinal value primarily comes from ripe berries. Supercritical CO₂ extraction yields standard saw palmetto oil (SPO) and β-sitosterol-rich extract (VISPO, with β-sitosterol content up to 3%), the latter being the core active component. In male health, Serenoa repens has dual effects. On one hand, it improves benign prostatic hyperplasia (BPH) by reducing chronic inflammation in prostate tissue, inhibiting abnormal cell proliferation, and lowering serum testosterone levels to reduce prostate stimulation. Experiments show that 400mg/kg VISPO administered to testosterone-induced BPH rats reduces the prostate weight-to-body weight ratio to 1/2.43 of the control group (or by approximately 58.8%), with a growth inhibition rate of 90.9%, showing efficacy comparable to the clinical drug finasteride and superior to SPO[13]. On the other hand, it potentially helps with male ED by inhibiting phosphodiesterase 5 (PDE5) to reduce cyclic guanosine monophosphate (cGMP) degradation, aiding corpus cavernosum smooth muscle relaxation; and increasing inducible nitric oxide synthase (iNOS) to promote nitric oxide (NO) synthesis, enhancing genital blood perfusion. Animal experiments show that after 7 days of intragastric administration of Serenoa repens extract, electrically induced erectile responses in rats and rabbits increase with dose, with effects similar to sildenafil (Viagra). 

Curculigo orchioides Extract

Curculigo orchioides, also known as Kali Musli, is a perennial herb of the Amaryllidaceae family, native to subtropical regions such as the Himalayas and Western Ghats in India and China. Its rhizome, a traditional medicinal part, has a long history of use in Ayurvedic and Chinese medicine dating back to the Tang Dynasty, traditionally used as an aphrodisiac and tonic to improve impotence, lumbar and knee weakness, with effects of "nourishment and vitality enhancement." Curculigo orchioides contains rich active components, mainly phenols and phenol glycosides (e.g., curculigoside, a core indicator for quality control), triterpenes, and triterpenoid saponins. Phenols and triterpenes are considered closely related to sexual function enhancement. Its mechanisms for improving male sexual function include three aspects: exhibiting androgen-like activity to increase testosterone and LH levels, promoting the growth of reproductive organs such as the prostate and seminal vesicles, and enhancing spermatogenic function; regulating sexual behavior by shortening sexual arousal time, increasing mount frequency, and improving penile erectile ability, possibly related to neurotransmitter regulation or blood flow improvement; and reducing oxidative stress damage to the reproductive system through antioxidant effects, indirectly supporting sexual function. Experimental studies confirm these effects: male rats administered 100mg/kg ethanol extract of Curculigo orchioides for 30 consecutive days show a 15.98% increase in prostate weight, 14.42% increase in seminal vesicle weight, penile erectile index elevated from 22.44±3.1 to 80.64±7.1, 75.44% reduction in mount latency, and 4-fold increase in mount frequency, with significantly improved mating ability. Its efficacy is superior to testosterone and comparable to sildenafil, providing scientific support for its traditional aphrodisiac use and making it a potential adjuvant for male sexual dysfunction. 

Cynomorium songaricum Extract 

Cynomorium songaricum is a parasitic plant in arid regions of northwestern China, with its dried fleshy stem as the traditional medicinal part. It has a long history of use in Chinese and Sino-Korean traditional medicine, first recorded in the Yuan Dynasty text Supplements to the Interpretation of Materia Medica, traditionally used to replenish kidney yang, nourish essence and blood, treat impotence, and lumbar and knee weakness, with effects of "securing yang, consolidating essence, and enhancing male potency." Cynomorium songaricum contains various active components related to improving male sexual function, mainly flavonoids (e.g., catechin, proanthocyanidin), triterpenes (e.g., ursolic acid), and polysaccharides. Flavonoids and polysaccharides exert antioxidant effects by scavenging free radicals, enhancing antioxidant enzyme activity, reducing oxidative damage to the reproductive system, protecting vascular endothelium, and providing a favorable blood flow basis for erections; triterpenes regulate the gonadal axis, promote testosterone secretion, inhibit abnormal secretion of related hormones, and enhance libido and sexual function. Its mechanisms for enhancing male sexual function include: regulating hormone levels by promoting testosterone synthesis and balancing gonadotropins to support libido and erections; improving the reproductive organ microenvironment by increasing sperm count (37.8% increase in epididymal sperm count in experimental rats) and testicular weight (7.89% increase), regulating prostate receptor expression to prevent glandular hyperplasia from affecting sexual function; and protecting corpus cavernosum vascular smooth muscle through antioxidant and anti-inflammatory effects to promote blood flow and support erections. Studies show that aqueous extracts of Cynomorium songaricum increase serum testosterone levels, improve sperm quality, and shorten erectile response time in animals. Triterpenes and flavonoids are key active components, exerting synergistic multi-target effects, making it a potential adjuvant for male sexual dysfunction. 

Cuscuta chinensis Extract 

Cuscuta chinensis Lam. is an annual parasitic herb of the Convolvulaceae family, widely distributed in China, including Northeast, North, Northwest, and Southwest regions. It typically parasitizes Fabaceae and Asteraceae plants, with its dried mature seeds as the traditional medicinal part. Recorded in ancient Chinese medical texts with a long medicinal history, it was listed as a top-grade herb in Shennong's Classic of Materia Medica for its effects of "nourishing liver and kidney, and replenishing essence," with a thousand-year history of use in improving male sexual dysfunction and infertility. Active components include flavonoids (e.g., quercetin), polysaccharides, and steroids (e.g., β-sitosterol). Flavonoids regulate the hormonal system, promote testosterone secretion, and enhance corpus cavernosum smooth muscle contraction; polysaccharides scavenge free radicals, protect testicular spermatogenic structures, and improve sperm motility; steroids exert anti-inflammatory effects and regulate the reproductive organ microenvironment. In treating male sexual dysfunction, Cuscuta chinensis acts through multiple pathways. It activates the hormonal regulatory system to promote testosterone secretion, enhance libido and erectile function—for example, Wuzi Yanzong Pills containing Cuscuta chinensis increase erectile index by over 40% in impotence patients; its flavonoids protect penile vascular endothelium, promote blood perfusion, and improve erections; it also inhibits excessive release of related substances to prolong ejaculation latency and enhance sexual pleasure. For male infertility, Cuscuta chinensis shows significant efficacy. It promotes the expression of related factors in testes to increase sperm count (37.8% increase in epididymal sperm count in experimental rats); reduces sperm DNA damage, improves sperm motility—clinical studies show that combined use with Epimedium increases progressive sperm motility by 28.5% in asthenozoospermia patients, with a spouse pregnancy rate of 42.3%; it also inhibits spermatogenic cell apoptosis to maintain stable sperm count. Animal experiments and clinical applications confirm its efficacy: male rats show a 52% increase in testosterone levels, 2.3-fold increase in erection frequency, and significant improvements in sperm motility and count after administration; traditional formulas such as Datuosi Ziwan show an 87% efficacy rate in treating kidney-yang deficiency-induced impotence in middle-aged and elderly patients, and Yijing Bushen Decoction treats oligospermia with a 38.7% spouse pregnancy rate after 3 months. Widely used in traditional classic formulas, modern research confirms that Cuscuta chinensis acts through multiple mechanisms such as hormone regulation and antioxidant effects, with bidirectional regulatory properties suitable for patients with both yin and yang deficiency, and an adverse reaction rate below 5%, making it a high-quality adjuvant for improving male sexual function and reproductive capacity. 

Cistanche deserticola Extract

Cistanche deserticola is a parasitic plant of the Orobanchaceae family, mainly growing in arid regions of northwestern China, and often parasitizes the roots of Haloxylon ammodendron. Its dried fleshy stem is known as "desert ginseng" and was recorded in Shennong’s Classic of Materia Medica for its effects of "replenishing kidney yang and nourishing essence and blood." It has been used for over a thousand years to improve male sexual dysfunction and infertility. The active components of Cistanche deserticola mainly include phenylethanoid glycosides (e.g., echinacoside, verbascoside), polysaccharides, and iridoids, among which phenylethanoid glycosides are the key to its aphrodisiac effects. Phenylethanoid glycosides can promote testosterone secretion, dilate the blood vessels of the corpus cavernosum to increase blood flow, and improve erectile hardness; polysaccharides have strong antioxidant capacity, which can reduce oxidative damage to the reproductive system and protect seminiferous tubules; iridoids and other components regulate the balance of sex hormones and enhance libido. In terms of aphrodisiac effects, Cistanche deserticola supports erectile function by promoting testosterone synthesis and balancing hormones. Its components can dilate blood vessels, increasing penile blood flow to 1.8 times the normal level, and also protect nerves, making it particularly suitable for patients with diabetic erectile dysfunction (ED). In the treatment of infertility, it promotes the proliferation of spermatogonia, increasing the testicular weight of rats by 7.89% and the epididymal sperm density by 37.8%; it improves sperm quality and reduces DNA fragmentation—when combined with other medicinal materials, it can increase the progressive sperm motility rate of patients with asthenozoospermia by 28.5%, with a spouse pregnancy rate of 42.3%; at the same time, it inhibits the apoptosis of spermatogenic cells, reducing the apoptosis rate by more than 40%. Animal experiments show that after male rats are administered the aqueous extract of Cistanche deserticola for 30 days, their testosterone levels increase by 52%, the number of erections rises by 2.3 times, and sperm motility and count are improved by 35% and 41%, respectively. Clinically, formulas containing Cistanche deserticola achieve an 87% effective rate in treating kidney-yang deficiency-induced impotence in middle-aged and elderly patients, and can improve erectile function scores; when used to regulate oligospermia, the average sperm density increases by 2.1×10⁶/ml after 3 months, with a spouse pregnancy rate of 38.7%. Traditionally, Cistanche deserticola is commonly used in classic formulas such as Bawei Shenqi Pills. Modern studies have confirmed that it acts through multiple mechanisms including hormone regulation and antioxidation, and has high safety, making it suitable for patients with both yin and yang deficiency. It provides a reliable natural auxiliary treatment option for male reproductive health.

Epimedium brevicornu Extract 

Epimedium brevicornu Maxim. is a perennial herb belonging to the Berberidaceae family. Native to central-northern to southeastern China, it mostly grows in shady and moist slopes or under forests, with its aerial parts (roots, stems, and leaves) used for medicinal purposes. Its medicinal history dates back to Shennong’s Classic of Materia Medica, and it is a classic medicinal herb for the traditional practice of "tonifying the kidney and enhancing yang". Due to over-harvesting, it has become a near-threatened species and requires rational protection. Its core active components are flavonoids, among which icariin is the key to exerting its efficacy, accounting for 20%-30% of total flavonoids. In addition, it contains polysaccharides, alkaloids, and other components, which jointly act on male reproductive health. In improving male sexual dysfunction, Epimedium exerts its effects through multiple mechanisms: Hormone regulation: At low doses, it increases estrogen levels via estrogen receptors (ERs); at high doses, it significantly promotes testosterone secretion, activates the gonadal axis, and enhances libido and erectile ability. Experiments show that rat serum testosterone levels increased by 52% and the number of erections increased by 2.3 times. Vasodilation: By promoting nitric oxide (NO) release, it increases blood flow in the corpus cavernosum by 1.8 times, an effect similar to that of sildenafil. Clinically, drugs containing Epimedium can increase the erectile index of patients with impotence by more than 40%. Neural regulation: It inhibits the excessive release of 5-hydroxytryptamine (5-HT) to prolong ejaculation latency. When combined with other drugs, it can prolong the ejaculation time of patients with premature ejaculation from 1.2 minutes to 3.5 minutes. Regarding infertility, Epimedium has extremely strong antioxidant capacity, with a free radical scavenging rate of 91.73%. It can enhance the activity of antioxidant enzymes, reduce oxidative damage to the reproductive system, protect the structure of seminiferous tubules, and reduce the apoptosis rate of spermatogenic cells by more than 40%. Animal experiments show that sperm motility and count in rats improved by 35% and 41%, respectively; when icariin was added to boar semen during preservation, the sperm viability remained above 60% after 7 days, which was much higher than the 38% in the control group[16]. In clinical application, Compound Xuanju Capsules (containing Epimedium) have an effective rate of 87% for impotence due to kidney-yang deficiency, with erectile function scores increased by an average of 8.2 points; when used for regulating premature ejaculation, spouse satisfaction increased by 62%. In summary, with its flavonoid components and multi-target effects, Epimedium exhibits significant efficacy in improving male sexual dysfunction and enhancing fertility, providing scientific support for the traditional theory of "tonifying the kidney and enhancing yang".

Apium graveolens Seed Extract 

Apium graveolens seeds, derived from the Apiaceae plant celery, are traditionally used to enhance male sexual function based on multiple active components and multi-target mechanisms. Core active components include phthalides (e.g., 3-butylphthalide), flavonoids (luteolin, apigenin), and phytosterols. Phthalides dilate blood vessels; flavonoids exert strong antioxidant and anti-inflammatory effects; phytosterols may regulate testosterone synthesis, collectively forming the material basis for improving sexual function. Aphrodisiac mechanisms mainly include: (1) Dilating corpus cavernosum blood vessels by inhibiting angiotensin-converting enzyme and promoting NO release to improve blood perfusion and enhance erectile function; (2) Scavenging reactive oxygen species to reduce oxidative stress damage to reproductive cells and protect the reproductive system; (3) Inhibiting inflammatory factors (e.g., COX-2) to alleviate chronic prostatitis interference with sexual function. Related studies show that Apium graveolens seed extract increases sexual behavior frequency in male rats, exhibits strong antioxidant activity as measured by oxygen radical absorbance capacity (ORAC), and synergizes with zinc and selenium to promote spermatogenesis and motility, providing scientific support for its traditional aphrodisiac use . 

Conclusion and Outlook 

In summary, natural medicines such as Eurycoma longifolia and Epimedium brevicornu show potential in improving male ED through multiple mechanisms including hormone regulation, blood flow improvement, and antioxidant effects, with some (e.g., yohimbine hydrochloride) having clear clinical evidence. However, most drugs face issues such as unclear active components, undetermined mechanisms, and small sample sizes in clinical trials. Future research should clarify core components and targets, conduct large-scale randomized controlled trials, establish standardized extraction and dosage protocols, explore synergistic effects of combination therapies, and promote natural medicines as evidence-based alternatives for ED treatment. 

References

[1] Rehman SU, Choe K, Yoo HH. Review on a Traditional Herbal Medicine, Eurycoma longifolia Jack (Tongkat Ali): Its Traditional Uses, Chemistry, Evidence-Based Pharmacology and Toxicology. Molecules. 2016 Mar 10;21(3):331. 

[2] Eissa MA, Farag MA, Saleh DO, Shabana ME, Abou El-Ezz RF, El-Kersh DM. Metabolome classification of Tongkat Ali (Eurycoma longifolia jack) and its commercial products via UHPLC-QTOF-MS-MS and its protective effect against 5-flurouracil-Induced testicular toxicity in male rats. J Ethnopharmacol. 2025 Jan 30;337(Pt 2):118904. 

[3] Farag MA, Ajayi AO, Taleb M, Wang K, Ayoub IM. A Multifaceted Review of Eurycoma longifolia Nutraceutical Bioactives: Production, Extraction, and Analysis in Drugs and Biofluids. ACS Omega. 2022 Dec 30;8(2):1838-1850. 

[4] Thu HE, Mohamed IN, Hussain Z, Jayusman PA, Shuid AN. Eurycoma Longifolia as a potential adoptogen of male sexual health: a systematic review on clinical studies. Chin J Nat Med. 2017 Jan;15(1):71-80. 

[5] Kotirum S, Ismail S B, Chaiyakunapruk N. Efficacy of Tongkat Ali (Eurycoma longifolia) on erectile function improvement: Systematic review and meta-analysis of randomized controlled trials[J]. Complementary therapies in medicine, 2015, 23(5): 693-698. 

[6] Zhao J, Dasmahapatra A K, Khan S I, et al. Anti-aromatase activity of the constituents from damiana (Turnera diffusa)[J]. Journal of Ethnopharmacology, 2008, 120(3): 387-393. 

[7] Tousson E, Hafez E, Zaki S, et al. Evaluation of the testicular protection conferred by damiana (Turnera diffusa Willd.) against amitriptyline-induced testicular toxicity, DNA damage and apoptosis in rats[J]. Biomedicine & Pharmacotherapy, 2020, 132: 110819. 

[8] Zhao Y, Zhang Y, Li Y, et al. Yohimbine hydrochloride inhibits benign prostatic hyperplasia by downregulating steroid 5α-reductase type 2[J]. European Journal of Pharmacology, 2021, 908: 174334. 

[9] Saad M A, Eid N I, Abd El-Latif H A, et al. Potential effects of yohimbine and sildenafil on erectile dysfunction in rats[J]. European journal of pharmacology, 2013, 700(1-3): 127-133. 

[10] Melnyk J P, Marcone M F. Aphrodisiacs from plant and animal sources—A review of current scientific literature[J]. Food research international, 2011, 44(4): 840-850. 

[11] Zheng B L, He K, Kim C H, et al. Effect of a lipidic extract from Lepidium meyenii on sexual behavior in mice and rats[J]. Urology, 2000, 55(4): 598-602. 

[12] Shin B C, Lee M S, Yang E J, et al. Maca (L. meyenii) for improving sexual function: a systematic review[J]. BMC complementary and alternative medicine, 2010, 10(1): 44. 

[13] Yang S, Chen C, Li Y, et al. Saw palmetto extract enhances erectile responses by inhibition of phosphodiesterase 5 activity and increase in inducible nitric oxide synthase messenger ribonucleic acid expression in rat and rabbit corpus cavernosum[J]. Urology, 2013, 81(6): 1380. e7-1380. e13. 

[14] Kim SJ, Kim MR, Hwang SY, Bae WJ, Kim S, Hong SH, Lee JY, Hwang TK, Wang Z, Kim SW. Preliminary report on the safety of a new herbal formula and its effect on sperm quality. World J Mens Health. 2013 Dec;31(3):254-61. 

[15] Yan F, Dou X, Zhu G, Xia M, Liu Y, Liu X, Wu G, Wang H, Zhang B, Shao Q, Wang Y. Cistanoside of Cistanche Herba ameliorates hypoxia-induced male reproductive damage via suppression of oxidative stress. Am J Transl Res. 2021 May 15;13(5):4342-4359. 

[16] Kim SJ, Kim MR, Hwang SY, Bae WJ, Kim S, Hong SH, Lee JY, Hwang TK, Wang Z, Kim SW. Preliminary report on the safety of a new herbal formula and its effect on sperm quality. World J Mens Health. 2013 Dec;31(3):254-61. 

[17] Modaresi M, Ghalamkari G. The effect of celery (Apium graveolens) extract on the reproductive hormones in male mice[J]. APCBEE Procedia, 2012, 4: 99-104. 

[18] Charles D J. Antioxidant properties of spices, herbs and other sources[M]. Springer Science & Business Media, 2012. 

[19] Nie Y, Dong X, He Y, Yuan T, Han T, Rahman K, Qin L, Zhang Q. Medicinal plants of genus Curculigo: traditional uses and a phytochemical and ethnopharmacological review. J Ethnopharmacol. 2013 Jun 3;147(3):547-63. 

[20] Tao R, Miao L, Yu X, Orgah JO, Barnabas O, Chang Y, Liu E, Fan G, Gao X. Cynomorium songaricum Rupr demonstrates phytoestrogenic or phytoandrogenic like activities that attenuates benign prostatic hyperplasia via regulating steroid 5-α-reductase. J Ethnopharmacol. 2019 May 10;235:65-74.