Abstract
Date palm pollen (DPP) is the male reproductive dust of palm flowers used as dietary supplement especially as aphrodisiac and fertility enhancer in both women and men from ancient times. Although there are few clinical trials evaluating the beneficial effects of DPP in humans, various experimental studies have been conducted on the reproductive effects of DPP. Among the compounds isolated from DPP are amino acids, fatty acids, flavonoids, saponins, and estroles. The present review summarizes comprehensive information concerning the phytochemistry and pharmacological activities of DPP and its application in fertility disorders.
Date palm (Phoenix dactylifera L., from the family Palmae) pollens (DPPs) are the male reproductive cells of palm flowers. It is interesting to note that approximately 1000 tons of DPPs are reproduced every year by millions of palm trees grown in the Arabic regions. 1 DPPs were used by the early Egyptians and Chinese people as a rejuvenating medicinal agent. They are also used worldwide as dietary supplements. 2 DPPs and male palm flowers were traditionally claimed to be aphrodisiacs and fertility enhancers. DPPs have been used in the Middle East as a natural drug for treatment of male infertility and promoting fertility in women. 3 According to Iranian traditional medicine, this part of date has refreshing and nutritional value and is beneficial for the treatment of infertility in both males and females. 4 Moreover, it is widely used for curing male infertility. 5
The present review summarizes comprehensive information concerning the phytochemistry and pharmacological activity of DPPs in the reproductive system and fertility disorders.
Phytochemical Constituents
Amino acids are the major constituents of this plant. Amino acids including aspartic, threonine, glutamine, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, histidine, lysine, arginine, and serine were detected in Egyptian DPPs. Also, nutritive elements and vitamins such as B1, B2, and B12 have been detected in 4 types of Egyptian DPPs, with varying amounts depending on its type. 2 It was reported that palm pollen grains contain considerable amounts of vitamins A, E, and C; minerals such as zinc, selenium, iron, molybdenum, copper, manganese, cobalt, and nickel; amino acids such as leucine and lysine; and fatty acids including palmitic, linoleic, myristic acids. 6,7 Mohamadi et al demonstrated that the pollen possessed about 1.47% oil composed mainly of oleic acid (68.04%). 8
Considerable amount of rutin is obtained from the alcoholic extract of the pollen. 9,10 Besides rutin, 4 other flavonoids were isolated from the ethyl acetate fraction (isorhamnetin, apigenin, luteolin, and naringin), 11 and quercetin was identified in the alcoholic extract of DPPs. 10 Polyamide column chromatography of the methanolic extract showed 6 phenolic compounds: caffeic acid, gallic acid, catechin, coumaric acid, chlorogenic acid, and quercetin. 12
A noncrystalline estrogenic substance was also detected in DPP extracts. 13 Estrone and cholesterol were isolated from date palm seeds and pollen. 10,14,15 High-performance liquid chromatography analysis of the hexane fraction from Egyptian DPPs revealed the presence of estrone, estradiol, and estriol. 11 Investigation of DPP revealed the presence of β-amyrin and β-sitosterol. Also, a steroidal saponin glycoside having glucose and rhamnose as sugar moiety and 2 glucoproteins with unknown structure were isolated from DPPs. 10 El-Ridi showed that DPPs have gonadotrophic hormones including follicle stimulating hormone and luteinizing hormone. 16
Pharmacological Activities
Table 1 lists the pharmacological activities attributed to DPPs.
Pharmacological Activities of Date Palm Pollens.
Abbreviations: ND, not determined; DPP, date palm pollen; FSH, follicular stimulating hormone; LH, luteinizing hormone; ALP, alkaline phosphatase; GPT, glutamic-pyruvate transaminase; GOT, glutamate-oxaloacetate transaminase; Cd, cadmium; GSH, glutathione peroxidase; SOD, superoxide dismutase; CAT, catalase; MDA, malondialdehyde; NO, nitric oxide; STD, seminiferous tubules diameter.
aA scoring system for assessing spermatogenesis in testicular biopsy.
DPPs showed gonadotrophic activity and caused increase in the weight of female sex organs. 1 DPP water suspensions could compensate decreased luteinizing hormone and follicle stimulating hormone in adult female rats exposed to lead acetate. 17 Aqueous extract increased the amount of testosterone, estrogen, and progesterone and secondary and antral follicle numbers in adult female mice. 18
DPPs revealed spermatogenic activity. 1 Administration of DPPs to male rats and rabbits caused increase in sperm count, sperm quality, with a concomitant increase in the weights of testis and epididymis. 19 –21 Aqueous extract of DPP in various doses improved sexual behavior, serum testosterone, intratesticular testosterone, body weight, and spermatogenesis in male rats. 22 –25
Extract of pollen grains significantly inhibited the cisplatin-induced genotoxicity and retained sperm motility and sperm count at the normal level. These findings suggest the preventive role of the pollen grains against the chemotherapeutic-induced infertility in males. 26
El-Desoky et al showed the effect of DPPs on sexual hormonal balance, cholesterol, total lipids, total protein, albumin, globulin, and liver functions in control male and female rats, and castrated and ovariectomized rats. 27 DPPs restored spermatogenesis, sex organ weight, sperm motility, estradiol level, decreased catalase, glutathione peroxidase, and superoxide dismutase, and attenuated the toxic effects of cadmium on the male reproductive system by activating testicular endocrine and antioxidant systems. 28,29 Methanolic extract of DPPs protected testis structure and had a balancing effect on diabetes-induced change of the level of testosterone hormone in diabetic male rats. 30
DPP suspension showed increase in the proportion of male infants than female infants. The authors attributed this effect to the rich content of potassium and sodium available in DPPs. 31
There are little clinical trials about the effectiveness of DPPs on infertility. Two clinical trials showed that DPPs markedly improved sperm parameters (count, motility), sexual desire, and increased hormones (luteinizing hormone, follicle stimulating hormone, testosterone) in infertile men. 32,33
In an in vitro study, aqueous extract of DPPs with various doses during 2 weeks had no toxic effects on viability percentage and the proliferation rate of neonatal mouse testicular cell suspension compared with the control group. 34
Discussion
Traditional and folk medicines of different countries have great potential for introducing new natural remedies for various pathological disorders. 35 –39 One of these remedies is pollen from Phoenix dactylifera L, which has been used in Iran ad Arabic countries for male infertility. Experimental studies showed that DPPs increase sperm count and motility and also sperm quality. 1,19 It could also reduce chemical-induced toxicity on the male reproductive system. 26,28 The pharmacological effects of DPPs are not limited to males, and it has also demonstrated activities on female sex organs. 1,10,18,27 Phytochemical studies showed the presence of sterol derivatives, flavonoids, and various amino acids in the pollen, 6 –16 which may be responsible for these pharmacological activities. Despite various experimental studies, there are few clinical trials on DPPs and its beneficial effects on fertility. Thus, more clinical trials are needed to confirm the activities attributed to DPPs.
Footnotes
Author Contributions
RR designed study and edited the manuscript. MT and MH collected data and wrote the manuscript.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Ethical Approval
This study did not require ethical approval as no animal or human subjects were involved.