Maculosin

Maculosin (Cyclo (Tyr-Pro)) is a host-specific phytotoxin for spotted knapweed from Alternaria alternata. Maculosin is a quorum-sensing molecule involved in cell-cell communication. Maculosin also acts as a signaling molecule regulating virulence gene expression. Maculosin shows antimicrobial, antifungal, antioxidant and anti-cancer properties^{[1][2][3][4][5][6][7][8][9]}.Maculosin (Cyclo (Tyr-Pro)) is a host-specific phytotoxin for spotted knapweed from Alternaria alternata. Maculosin is a quorum-sensing molecule involved in cell-cell communication. Maculosin also acts as a signaling molecule regulating virulence gene expression. Maculosin shows antimicrobial, antifungal, antioxidant and anti-cancer properties^{[1][2][3][4][5][6][7][8][9]}. In Vitro:Maculosin shows cytotoxic activity against the human liver cancer cell lines, with an IC₅₀ of 48.90 µg/mL^[3].
Maculosin (0-128 μg/mL) shows stronger antioxidant activity than the commercially used Butylated hydroxyanisole (BHA) (HY-B1066), with IC₅₀s of 2.16  and 4.8 µg/mL^[3].
Maculosin (0-128  μg/mL, 24 h) shows no toxicity (LD₅₀, <128 µg/mL) in brine shrimp lethality assay (BSLA)^[3].
Maculosin (10-100 μg/mL) reduces the growth of the plant pathogenic bacteria X. axonopodis and R. solanacearum (MICs = 31.25 μg/mL) as well as the pathogenic oomycetes P. cactorum, P. capsici, P. cinnamomi, P. infestans, and P. ultimum^[4][5].
Maculosin inhibits the growth of M. luteus, M. smegmatis, S. cerevisiae, C. albicans, C. neoformans, and A. niger when used in combination with Pyrrolnitrin (HY-133704) or Banegasin^[6].
Maculosin (0.5-100 μg/mL) shows antibacterial activity against certain multidrug-resistant pathogenic bacteria, with MICs of 5-15 mg/mL^[7].
Maculosin shows specific antioxidant activity, with the DPPH scavenging activities of 38.22% at 7.5 μg/mL^[8].
Maculosin (10 μM-1 mM) exhibits lesion inductive abilities when applied to knapweed leaves and hypocotyls^[9].