The 19-year-old made his debut for the Ecuadorian outfit in September 2021, and has since featured 34 times for the club in his homeland, scoring one goal over a two-year period.
Zambrano has represented his nation at youth level, playing for Ecuador in the Under-20 World Cup earlier in the year, with La Tri being knocked out in the round of 16 by South Korea.
The midfielder impressed for his country at that particular tournament, and it is understood that performances for club and on the international stage have seen European sides enquire for his services.
LDU Quito director Esteban Paz revealed to Radio Cobertura via ESPN that Luton had a bid for Zambrano rejected in this summer's transfer window.
"The transfers did not close completely. They were important figures, but the bonuses were not convenient," said Paz during an interview earlier this month.
"In any case, the teams remain interested and in contact for when a new market opens," continued Paz when questioned on the future of 19-year-old Zambrano.
It is believed that Luton are therefore still keen admirers of the midfielder despite the transfer window being shut, and the Hatters could resume their hunt for the youngster in January.
The report also claims that Eredivisie giants Ajax had a bid turned down for Zambrano, meaning that Luton could face intense competition for the player when the transfer window reopens next year.
A move for Zambrano is a change from the signing strategy that we have seen from the Premier League newcomers since their promotion from the Championship, with the Hatters largely targeting players who have impressed in the lower divisions of England.
Chiedozie Ogbene, Tahith Chong and Mads Andersen made the switch to Kenilworth Road from Rotherham United, Birmingham City and Barnsley respectively, while full-back Ryan Giles joined the club from Wolverhampton Wanderers following an impressive loan stint at Middlesbrough in the Championship last season.
In terms of the midfield area that Zambrano could have occupied, Rob Edwards's men moved late in the summer window to recruit Belgium international Albert Sambi Lokonga on a season-long loan from Arsenal.
The 23-year-old made his debut for the Hatters in a 1-0 loss at Craven Cottage against Fulham on Saturday, with Carlos Vinicius netting the only goal of the contest in West London.
Luton are currently rooted to the foot of the Premier League standings having failed to earn any points from their opening quartet of top-flight fixtures - a meeting with Wolverhampton Wanderers awaits this weekend.