Search

US-12616193-B2 - 5-(1H-indol-3-yl)-oxazole, -oxadiazole and -furan derivatives as enhancers of sperm motility

US12616193B2US 12616193 B2US12616193 B2US 12616193B2US-12616193-B2

Abstract

The invention relates to the use of compounds of formula (I), stereoisomers, and physiologicaily tolerable salts thereof, to enhance the motility of sperm obtained from a non-human mammal: wherein in formula I: X is —NR′— (in which R′ is H or C 1-3 alkyl. e.g. —CH 3 ), —O—, —S— or —CH 2 —; Y is —S—, —O—, —NR″— (in which R″ is H or C 1-3 alkyl, e.g. —CH 3 ), or —CH 2 —; Z 1 and Z 2 are independently selected from N and CH; R1 to R3 are independently selected from hydrogen, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, —OH, —CN, —NO 2 and —NR 12 R 13 ; R 4 is hydrogen, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, or —OH; R 5 is hydrogen, halogen, C 1-6 alkyl, C 1-6 alkoxy, or C 1-6 haloalkyl; R 6 and R 7 are independently selected from hydrogen, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, —OH, —CN, —NO 2 and —NR 12 R 13 ; R 8 is hydrogen, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, —CN, —NO 2 or —NR 12 R 13 ; R 9 is hydrogen or C 1-4 alkyl; R 10 and R 11 are independently selected from hydrogen and C 1-3 alkyl; or R 10 and R 11 , together with the intervening —O— and ring atoms, are joined to form a dioxolane ring; and R 12 and R 13 are independently selected from H and C 1-3 alkyl. The compounds find particular use in animal husbandry to increase the rate of fertilization in artificial insemination of livestock, especially pigs. They can also be used to prepare, pre-treat or store semen for use in artificial insemination procedures.

Inventors

  • Ken Roger ROSENDAL
  • Tuva Holt HERENG
  • Steffi LUNDVALL
  • Espen Marcelius GJEMS
  • Håvard Hildeng HAUGE
  • Bjørn Steen SKÅLHEGG

Assignees

  • SPERMATECH AS

Dates

Publication Date
20260505
Application Date
20210430
Priority Date
20200430

Claims (20)

  1. 1 . A method of enhancing the motility of sperm obtained from a non-human mammal, said method comprising the step of contacting said sperm with an effective amount of a compound of formula (I), a stereoisomer, or a physiologically tolerable salt thereof: wherein: X is —NR′—, —O—, —S— or —CH 2 —; wherein R′, when present, is H or C 1-3 alkyl; Y is —S—, —O—, —NR″—, or —CH 2 —; wherein R″, when present, is H or C 1-3 alkyl; Z 1 and Z 2 are independently selected from N and CH; R 1 to R 3 are independently selected from hydrogen, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, —OH, —CN, —NO 2 and —NR 12 R 13 ; R 4 is hydrogen, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, or —OH; R 5 is hydrogen, halogen, C 1-6 alkyl, C 1-6 alkoxy, or C 1-6 haloalkyl; R 6 and R 7 are independently selected from hydrogen, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, —OH, —CN, —NO 2 and —NR 12 R 13 ; R 8 is hydrogen, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, —CN, —NO 2 or —NR 12 R 13 ; R 9 is hydrogen or C 1-4 alkyl; R 10 and R 11 are independently selected from hydrogen and C 1-3 alkyl; or R 10 and R 11 , together with the intervening —O— and ring atoms, are joined to form a dioxolane ring; and R 12 and R 13 , when present, are independently selected from H and C 1-3 alkyl.
  2. 2 . The method of claim 1 , wherein: X is —NR′ or —O—; and R′, when present, is H or —CH 3 .
  3. 3 . The method of claim 1 , wherein: Y is selected from —S—, —O—, —NR″—, and —CH 2 ; and R″, when present, is H or —CH 3 .
  4. 4 . The method of claim 1 , wherein said compound is a compound of formula (II), or a stereoisomer or physiologically tolerable salt thereof:
  5. 5 . The method of claim 1 , wherein both Z 1 and Z 2 are N, or one of Z 1 and Z 2 is N and the other of Z 1 and Z 2 is CH.
  6. 6 . The method of claim 1 , wherein both Z 1 and Z 2 are N.
  7. 7 . The method of claim 1 , wherein said compound is a compound of formula (III), or a stereoisomer or physiologically tolerable salt thereof:
  8. 8 . The method of claim 1 , wherein R 1 to R 3 are independently selected from hydrogen, halogen, C 1-4 alkyl, and C 1-4 haloalkyl.
  9. 9 . The method of claim 1 , wherein R 4 is hydrogen, halogen, C 1-4 alkyl, or C 1-4 haloalkyl.
  10. 10 . The method of claim 1 , wherein R 5 is hydrogen, halogen, C 1-4 alkyl, or C 1-4 haloalkyl.
  11. 11 . The method of claim 1 , wherein R 6 and R 7 are independently selected from hydrogen, halogen, C 1-4 alkyl, and C 1-4 haloalkyl.
  12. 12 . The method of claim 1 , wherein R 8 is hydrogen, halogen, C 1-4 alkyl, or C 1-4 haloalkyl.
  13. 13 . The method of claim 1 , wherein R 9 is hydrogen or —CH 3 .
  14. 14 . The method of claim 1 , wherein R 10 and R 11 are independently selected from hydrogen and C 1-3 alkyl.
  15. 15 . The method of claim 1 , wherein R 10 and R 11 , together with the intervening —O— and ring atoms, are joined to form a dioxolane ring.
  16. 16 . The method of claim 1 , wherein said compound is a compound of formula (IV), or a stereoisomer or physiologically tolerable salt thereof:
  17. 17 . The method of claim 1 , wherein the compound is the following compound: or a stereoisomer, or physiologically tolerable salt thereof.
  18. 18 . The method of claim 1 , wherein the contacting said sperm with an effective amount of a compound enhances progressive sperm motility.
  19. 19 . A method of treating or preparing sperm for use in an artificial insemination procedure, said method comprising: (a) providing a sperm sample from a non-human mammalian male subject; and (b) contacting said sperm sample with the compound according to claim 1 optionally in combination with one or more physiologically tolerable carriers, excipients or diluents selected from the group consisting of sugars, antibiotics, proteins, membrane protecting agents, antioxidants, phospholipids, glycerol, citric acid, solvents, and buffers.
  20. 20 . The method as claimed in claim 19 , wherein the compound is the following compound: or a stereoisomer, or physiologically tolerable salt thereof.

Description

FIELD OF THE INVENTION The present invention relates to the use of compounds to enhance sperm motility. It finds particular application in animal husbandry to increase the rate of fertilization in artificial insemination of livestock, especially pigs. The invention can also be used to prepare, pre-treat or store semen for use in artificial insemination procedures. BACKGROUND OF THE INVENTION Due to its low price and high nutritional content, pork is the most widely consumed meat worldwide and its production rate is increasing in order to meet the continuously increasing demand. The worldwide production of meat for human consumption, especially pork and beef, is reliant on methods of artificial insemination to produce sufficient livestock to meet consumer demand. Natural breeding requires more male animals and is labor intensive for farmers. However, artificial breeding in which female animals are artificially inseminated requires fewer males, has higher success rates, is more time-efficient, and reduces the costs to the farmer. Artificial insemination also allows for selective breeding which may be used when rearing livestock animals, or in the breeding of high value animals (e.g. race horses) or endangered species, for example. Artificial insemination is commonly practiced in the breeding of livestock, especially pigs and cattle, and often requires the storage of collected semen in liquid nitrogen, i.e. cryopreservation, prior to use. Cryopreservation of semen is widely used in the beef industry, but is less common in the pork industry as semen from pigs (i.e. boar) can be more temperature-sensitive than bull sperm. The temperature sensitivity of boar sperm may be due to a lower cholesterol to phospholipid ratio as compared to stallion, bull or ram semen, for example. A higher cholesterol content leads to a reduced susceptibility to decreased temperatures. Cryopreservation of boar sperm can change its protein profile. This can lead to the loss of sperm surface proteins and inactivation of membrane-bound enzymes which may result in decreased sperm cell viability and motility. Cryopreservation may also lead to early onset of the acrosome reaction which occurs in the acrosome of the sperm as it approaches the egg and which is essential for fertilization to occur. Furthermore, cryopreservation of boar sperm prior to fertilization may lead to sperm cell apoptosis, DNA fragmentation and the production of reactive oxygen species. Following cryopreservation, boar sperm has only 40-70% of the fertility rate of fresh sperm. Despite these problems, cryopreservation must still be used when transporting boar sperm or when it is necessary for it to be stored for any prolonged period. Storage may be required, for example, to keep the genetic variation as well as valuable genes. Moreover, porcine fertility is dependent on the month of the year. During warm months, pigs produce less offspring and boar sperm collected during these months is more prone to be affected by freezing. These fluctuations during the year lead to economic losses for the pork industry. To reduce this economic burden, and increase the quality of life for pigs, other preservation methods for boar sperm which do not affect the sperm quality (sperm count, motility and viability) are needed. To be able to store boar semen for a few days, extenders are added to the semen samples. Extenders contain buffers and nutrients which prolong the half-life of the semen, but they do not improve the sperm cell's motility as compared to freshly collected semen. One strategy to increase fertilization and litter size is to increase the motility of sperm cells. Holt et al. (J Androl 1997, 18:312-323) showed a clear correlation between sperm motility and results of on-farm inseminations in boars. If the sperm cells have a higher motility, they will have a higher chance of travelling up the female reproductive tract and reaching the eggs. Sperm motility has different modes: hyperactivation, progressive motility and standard motility. All three parameters are important in the fertilization process. The invention seeks to address at least some of these problems in the art and, in particular, to provide compounds that are capable of enhancing sperm motility, function and/or activity. More specifically, it seeks to provide compounds which can be used to enhance the conception rate and/or litter size in artificial insemination of non-human mammals (e.g. livestock). SUMMARY OF THE INVENTION The inventors have now surprisingly found certain compounds that function as “sperm activators”. When added to fresh boar semen or boar semen samples which have been stored at a reduced temperature for several days, these have been found to enhance sperm motility. The addition of such “activators” has also been found to result in higher fertility and offspring rates in artificial insemination of pigs. The “activator” compounds disclosed herein are particularly suitable for use in the breeding