The compounds were characterized as two diketopiperazines
, cyclo-L-Ala-L-Leu (1)  and cyclo(L-Tyr-L-Pro) (2) ; two nucleosides, cordycepin (3) and Ara-A(4) .
produced by an marine Bacillus species inhibits Vibrio parahaemolyticus.
Bauermeister et al., "A Simple Defined Medium for the Production of True Diketopiperazines
in Xylella Fastidiosa and Their Identification by Ultra-Fast Liquid Chromatography-Electrospray Ionization Ion Trap Mass Spectrometry," Molecules, vol.
Several PAI1 inhibitors have been found, including diketopiperazines
XR334, XR330 , XR1853, XR5082 , and XR5118 and ketopiperazines XR334, XR330 , XR1853, XR5082 , and XR5118 .
Both natural and synthetic diketopiperazines
have a wide variety of biological activities, including antitumor  (Nicholson et al.
By comparison with the published literature , this component was tentatively identified as diketopiperazines
Kittakoop et al., "New diketopiperazines
from the entomopathogenic fungus Verticillium hemipterigenum BCC1449," The Journal of Antibiotics, vol.
Citromycetins and bilains A-C: new aromatic polyketides and diketopiperazines
from Australian marine-derived and terrestrial Penicillium spp.