Antibacterial and cytotoxic activities of different wild bitter gourd cultivars (Momordica charantia L. var. abbreviata Seringe)

Wild bitter gourd (Momordica charantia L. var. abbreviata Seringe, MCA), which is normally smaller than cultivated bitter gourd (Momordica charantia L., MC), both belong to the family Cucurbitaceae. The fresh fruits of MC and MCA are frequently used as vegetables in Taiwan. Water (H) and methanolic (M) extracts of sixteen cultivars from Taiwanese indigenous MCA (10 mg/mL) were tested for their antibacterial activities toward the methicillin-resistant Staphylococcus aureus subsp. aureus (ATCC 33591), Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 10536), and Salmonella enterica subsp. enterica (ATCC 19126), and for their cytotoxic activities toward human fibrosarcoma HT 1080 cells. None of the extracts showed inhibitory activity against methicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa, however, several H and M extracts (even H extracts that were heated at 100°C for 5 min) showed inhibitory activity against the growth of Escherichia coli and Salmonella enterica. For cytotoxic activities toward human fibrosarcoma HT 1080 cells, H extracts (1 mg/mL) from mature D, E, and F cultivars, and M extracts (1 mg/mL) from mature D and E cultivars showed similar cytotoxic activities compared to that of 10 μg/mL of doxorubicin. The use of MCA extracts as natural food additives to control food-borne pathogens and/or their development as health foods for chemoprevention in the future is discussed.