The Magpies signed four new players in the January transfer window.
The Magpies were busy in this season’s mid-season window, with four new players all having arrived at St James’ Park.
Manager Steve McClaren secured Jonjo Shelvey, Henri Saivet, Andros Townsend and Seydou Doumbia as he looked to add fresh talent to his squad as they seek to avoid relegation this season.
And Jenas says he has been impressed by the work they have done, adding that he believes Doumbia in particular may do well out of the four signings.
"I have been impressed with the work they have done,” he told BBC Sport.
“They have brought players in who know the league, like Jonjo Shelvey, who is creative. The one player I am most excited about is Andros Townsend, who is direct and has pace and can score goals."
"I think Seydou Doumbia might do well. Strikers are loved up there, and I think the tempo of the Premier League might suit him."
Newcastle will certainly be keen to see Doumbia doing well, with goals having been a particular problem for them this season.
They have managed just 25 goals in 23 games so far this season, the fourth lowest tally in the division.
In particular their strikers have struggled, with Ayoze Perez, Aleksandar Mitrovic and Papiss Cisse only having managed 11 between them in the Premier League.
That means they are desperate for a striker to come in and score regularly in the game remaining, and they will hope that Doumbia can be that man.