At stumps, Syed Mohammed was batting on 50 scored off 142 balls with six boundaries to his credit.
He added 66 runs for the sixth wicket with former Karnataka left-hander Amit Verma (42) after Assam, who were put into bat by opposition skipper Harbhajan Singh, were left reeling at 115 for five.
Right-arm seamer Kaul took four for 81 in 26 overs while left-arm seamer Barinder Sran bagged two for 67 from 21 overs.
Harbhajan, who did not get a single game during the recently-concluded T20 International series in Australia, was very economical with figures of one for 11 in 11 overs as he removed left-handed opener Pallav Das (46), caught behind by wicketkeeper Uday Kaul.
Harbhajan's decision to bowl on winning the toss was fully justified as seven out of the eight wickets were snapped up by the medium pacers.
Sran, who recently played the ODI series in Australia, complemented Siddharth well as he extracted some good movement off the surface.
Even as third seamer Deepak Bansal (one for 36 in 18 overs) kept up the pressure while bowling in tandem with his skipper as Assam could never build a partnership of significance.
Brief Scores:
Assam 1st Innings 233/8 (Syed Mohammed 50 batting, Amit Verma 42, Siddharth Kaul 4/81, Barinder Sran 2/67, Deepak Bansal 1/36, Harbhajan Singh 1/11) vs Punjab.
Image: Siddharth Kaul
Photograph courtesy: Siddharth Kaul/Facebook