Anti-adhesive activity of Aframomum melegueta major phenolics on lower respiratory tract pathogens

Area of Science:

• Pharmacognosy
• Natural Products Chemistry
• Microbiology

Background:

• Aframomum melegueta seeds are recognized for their phenolic compounds with potential health benefits.
• Staphylococcus aureus infections pose a significant health challenge, necessitating novel therapeutic strategies.
• The anti-adhesive properties of natural products are being explored to combat bacterial infections.

Purpose of the Study:

• To investigate the anti-adhesive effects of Aframomum melegueta seed extracts and isolated compounds against Staphylococcus aureus.
• To identify and characterize bioactive compounds responsible for the observed anti-adhesive activity.
• To assess the potential of these compounds in preventing bacterial adhesion without promoting resistance.

Main Methods:

• Methanolic extraction and fractionation (n-butanol, chloroform) of Aframomomum melegueta seeds.
• Bioassay-guided isolation of compounds from the active chloroform fraction using NMR and HREIMS.
• In vitro assessment of anti-adhesive activity of extracts, fractions, and isolated compounds against Staphylococcus aureus using lung carcinoma cell lines.
• Determination of inhibition percentages at various concentrations.

Main Results:

• The methanolic extract and its chloroform fraction demonstrated significant concentration-dependent anti-adhesive effects against Staphylococcus aureus.
• The chloroform fraction showed up to 70.34% inhibition of adhesion at 100 µg/mL.
• A new diarylheptanoid (1) and eight known compounds (2-9) were isolated. Compounds 1, 6-paradol (5), [6]-shogaol (7), [8]-gingerol (8), and dihydro[6]paradol (9) exhibited significant anti-adhesive activity (up to 85.4% inhibition at 50 µg/mL).

Conclusions:

• Aframomomum melegueta seeds contain compounds with potent anti-adhesive activity against Staphylococcus aureus.
• The identified compounds, particularly the new diarylheptanoid and known gingerols/shogaols, are promising candidates for developing anti-adhesion therapies.
• The ability to reduce bacterial adhesion without affecting bacterial growth is a key advantage, potentially mitigating resistance development.