Between them the defendants face 51 counts including rape and trafficking.
They deny the charges which relate to girls aged between 11 and 15 and cover a period from 2004 to 2012.
Noel Lucas QC, prosecuting, told jurors the defendants groomed the girls, then controlled them, using them for their own sexual gratification and selling them to other men for sex.
He said the men deliberately targeted girls who had unsettled home lives which which made it less likely anyone would exercise normal parental control over them or be looking out for them.
Jurors were told sometimes the girls were targeted while they were drinking or playing truant. Mr Lucas said the girls became dependent on their abusers after becoming addicted to drugs.
They were then groomed in a variety of ways, such as being given gifts, the court heard.
Mr Lucas said: “The attention lavished on the girls at the outset was of course entirely insincere as it was merely a device, you may conclude once you hear the evidence, to exploit their vulnerability.”
The defendants plied the girls with alcohol and introduced them to drugs, including cannabis, cocaine and sometimes heroin, the court heard.
The jury was told the girls became addicted to drugs, making them dependent on their abusers.
Mr Lucas said the men sometimes used extreme physical and sexual violence on the girls.
He said: “The depravity, and I use that word with care, of what was done to the complainants was extreme.
“The facts in this case will make you feel uncomfortable.”
The court was told the girls were taken to empty private houses and guest houses where others would pay to have sex with them, often in groups.
The men came from as far afield as Bradford, Leeds, London and Slough.
The girls were also taken to other towns and cities, including London and Bournemouth. One girl was just 12 when she was forced into prostitution, the court heard.
The prosecution said one victim described the lifestyle as a “living hell”.
Mr Lucas said: “The girls were usually given so many drugs that they were barely aware of what was going on. Indeed, they say it was the only way they could cope with what was going on.
“Between acts of abuse sometimes stretching over a number of days, the Oxford men ensured girls were guarded so that they could not escape.”
The trial is expected to last until April. The defendants are all in custody.
The defendants are:
- Kamar Jamil, 27, of Aldwych Road, Oxford
- Akhtar Dogar, 32, of Tawney Street, Oxford; and his brother Anjum Dogar, 30, of Tawney Street, Oxford
- Assad Hussain, 32, of Ashurst Way, Oxford
- Mohammed Karrar, 38, of Kames Close, Oxford; and his brother Bassam Karrar, 33, of Hundred Acres Close, Oxford
- Mohammed Hussain, 24, of Horspath Road, Oxford
- Zeeshan Ahmed, 27, of Palmer Road, Oxford
- Bilal Ahmed, 26, of Suffolk Road, Maidenhead