Abstract
The effects of squamocin (1), bullatacin (2) and motrilin (3), 3 bis‐tetrahydrofuran Annonaceous acetogenins, isolated from Annona purpurea (Annonaceae), were investigated on several photosynthetic activities in spinach thylakoids. The results indicated that compounds 1–3 significantly inhibited both ATP synthesis and uncoupled electron transport. In addition, they enhanced light‐activated Mg2+‐ATPase, and basal electron flow. Therefore, acetogenins 1–3 behave as uncouplers and Hill reaction inhibitors. Natural products 1–3 did not affect photosystem I (PSI) activity but they inhibited photosystem II (PSII) electron flow. The study of the partial PSII reactions from H2O to DCPIPox, H2O to SiMo and diphenylcarbazide to DCPIP established that the site of inhibition was at the oxygen‐evolving complex (OEC). Chlorophyll a fluorescence measurements confirmed the behavior of the Annonaceous acetogenins as water‐splitting enzyme inhibitors.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
