The activity results showed that most of the compounds produced significant effects on the growth of the tested bacterial and fungal strains. The structure- antimicrobial activity relationship of the compounds revealed that quinazolinone precursors (I) and (II) conjugated with GWGVP ((XV), (XX), (XXV), and (XXX)), GYGVP ((XVI), (XXI), (XXVI), and (XXXI)), and GFGVP ((XXVII), (XXII), (XXVII), and (XXXII)) showed potent activities compared to conjugates of GDGVP ((XXVIII), (XXIII), (XXVIII), and (XXXIII)) and GTGVP ((XIX), XXIV), (XXIX), and (XXXIV)) and respective standard drugs. This could be due to aromaticity of the amino acids Trp, Tyr, and Phe, which are considered to play an important role in antimicrobial effects. It can be suggested that the presence of more hydrophobic units along with other non-polar amino acids provide amphipathicity to the compounds, which may help them in binding to the bacterial cell membranes followed by disruption. This becomes more evident with the loss of activity when the three aromatic and hydrophobic amino acids are substituted by more polar and charged Asp and Thr units. Among the above three hybrid analogues, tryptophan conjugates exhibited high potency, which may be due to the large aromaticity, hydrophobicity, light instability, and the ability to stabilize the amphiphilic structure necessary for antimicrobial activity. Further debenzylation of these compounds ((XXV), (XXVI), (XXVII), (XXX), (XXXI), and (XXXII)) resulted in more polar structures, which showed slight superior results than the benzylated analogues (XV), (XVI), (XVII), (XX), (XXI), and (XXII). This increased activity could be due to their higher polarity, which helps the molecules to establish a larger network for penetration through the cell membranes of microbes. Further, the increase in chain length of quinazolinones decreased the activity. Overall, the antimicrobial activity decreases in the order of X = Trp > Tyr > Phe > Thr > Asp.

The activity results showed that most of the compounds produced significant effects on the growth of the tested bacterial and fungal strains. The structure- antimicrobial activity relationship of the compounds revealed that quinazolinone precursors (I) and (II) conjugated with GWGVP ((XV), (XX), (XXV), and (XXX)), GYGVP ((XVI), (XXI), (XXVI), and (XXXI)), and GFGVP ((XXVII), (XXII), (XXVII), and (XXXII)) showed potent activities compared to conjugates of GDGVP ((XXVIII), (XXIII), (XXVIII), and (XXXIII)) and GTGVP ((XIX), XXIV), (XXIX), and (XXXIV)) and respective standard drugs. This could be due to aromaticity of the amino acids Trp, Tyr, and Phe, which are considered to play an important role in antimicrobial effects. It can be suggested that the presence of more hydrophobic units along with other non-polar amino acids provide amphipathicity to the compounds, which may help them in binding to the bacterial cell membranes followed by disruption. This becomes more evident with the loss of activity when the three aromatic and hydrophobic amino acids are substituted by more polar and charged Asp and Thr units. Among the above three hybrid analogues, tryptophan conjugates exhibited high potency, which may be due to the large aromaticity, hydrophobicity, light instability, and the ability to stabilize the amphiphilic structure necessary for antimicrobial activity. Further debenzylation of these compounds ((XXV), (XXVI), (XXVII), (XXX), (XXXI), and (XXXII)) resulted in more polar structures, which showed slight superior results than the benzylated analogues (XV), (XVI), (XVII), (XX), (XXI), and (XXII). This increased activity could be due to their higher polarity, which helps the molecules to establish a larger network for penetration through the cell membranes of microbes. Further, the increase in chain length of quinazolinones decreased the activity. Overall, the antimicrobial activity decreases in the order of X = Trp > Tyr > Phe > Thr > Asp.

The activity results showed that most of the compounds produced significant effects on the growth of the tested bacterial and fungal strains. The structure- antimicrobial activity relationship of the compounds revealed that quinazolinone precursors (I) and (II) conjugated with GWGVP ((XV), (XX), (XXV), and (XXX)), GYGVP ((XVI), (XXI), (XXVI), and (XXXI)), and GFGVP ((XXVII), (XXII), (XXVII), and (XXXII)) showed potent activities compared to conjugates of GDGVP ((XXVIII), (XXIII), (XXVIII), and (XXXIII)) and GTGVP ((XIX), XXIV), (XXIX), and (XXXIV)) and respective standard drugs. This could be due to aromaticity of the amino acids Trp, Tyr, and Phe, which are considered to play an important role in antimicrobial effects. It can be suggested that the presence of more hydrophobic units along with other non-polar amino acids provide amphipathicity to the compounds, which may help them in binding to the bacterial cell membranes followed by disruption. This becomes more evident with the loss of activity when the three aromatic and hydrophobic amino acids are substituted by more polar and charged Asp and Thr units. Among the above three hybrid analogues, tryptophan conjugates exhibited high potency, which may be due to the large aromaticity, hydrophobicity, light instability, and the ability to stabilize the amphiphilic structure necessary for antimicrobial activity. Further debenzylation of these compounds ((XXV), (XXVI), (XXVII), (XXX), (XXXI), and (XXXII)) resulted in more polar structures, which showed slight superior results than the benzylated analogues (XV), (XVI), (XVII), (XX), (XXI), and (XXII). This increased activity could be due to their higher polarity, which helps the molecules to establish a larger network for penetration through the cell membranes of microbes. Further, the increase in chain length of quinazolinones decreased the activity. Overall, the antimicrobial activity decreases in the order of X = Trp > Tyr > Phe > Thr > Asp.

The activity results showed that most of the compounds produced significant effects on the growth of the tested bacterial and fungal strains. The structure- antimicrobial activity relationship of the compounds revealed that quinazolinone precursors (I) and (II) conjugated with GWGVP ((XV), (XX), (XXV), and (XXX)), GYGVP ((XVI), (XXI), (XXVI), and (XXXI)), and GFGVP ((XXVII), (XXII), (XXVII), and (XXXII)) showed potent activities compared to conjugates of GDGVP ((XXVIII), (XXIII), (XXVIII), and (XXXIII)) and GTGVP ((XIX), XXIV), (XXIX), and (XXXIV)) and respective standard drugs. This could be due to aromaticity of the amino acids Trp, Tyr, and Phe, which are considered to play an important role in antimicrobial effects. It can be suggested that the presence of more hydrophobic units along with other non-polar amino acids provide amphipathicity to the compounds, which may help them in binding to the bacterial cell membranes followed by disruption. This becomes more evident with the loss of activity when the three aromatic and hydrophobic amino acids are substituted by more polar and charged Asp and Thr units. Among the above three hybrid analogues, tryptophan conjugates exhibited high potency, which may be due to the large aromaticity, hydrophobicity, light instability, and the ability to stabilize the amphiphilic structure necessary for antimicrobial activity. Further debenzylation of these compounds ((XXV), (XXVI), (XXVII), (XXX), (XXXI), and (XXXII)) resulted in more polar structures, which showed slight superior results than the benzylated analogues (XV), (XVI), (XVII), (XX), (XXI), and (XXII). This increased activity could be due to their higher polarity, which helps the molecules to establish a larger network for penetration through the cell membranes of microbes. Further, the increase in chain length of quinazolinones decreased the activity. Overall, the antimicrobial activity decreases in the order of X = Trp > Tyr > Phe > Thr > Asp.