Annonaceous acetogenins: Naturally occurring inhibitors of ATP synthesis and photosystem II in spinach chloroplasts [squamocin, bullatacin, motrilin]

• Published in: Physiologia plantarum Vol. 111; no. 2; pp. 262 - 268
• Main Authors: Chavez, D, Mata, R, Iglesias-Prieto, R, Lotina-Hennsen, B. (Mexico Univ. (Mexico))
• Format: Journal Article
• Language: English
• Published: Copenhagen Munksgaard International Publishers 01.02.2001; Blackwell
• Subjects: Agrochemicals products; ANNONA PURPUREA; Biological and medical sciences; FOTOSISTEMAS; Fundamental and applied biological sciences. Psychology; Pesticides used against invertebrates; PHOTOSYSTEME; PHOTOSYSTEMS; Phytopathology. Animal pests. Plant and forest protection; Pollution effects and side effects of agrochemicals on crop plants and forest trees. Other anthropogenic factors; Pollution effects. Side effects of agrochemicals; SPINACIA OLERACEA; THYLAKOIDE; THYLAKOIDS; TILACOIDES; Insecticide; Pesticides; Enzyme inhibitor; Biosynthesis; Uncoupler; Spinacia oleracea; Tetrahydrofuran polymer; Chenopodiaceae; Photosystem 2; Phytotoxicity; Vegetable crop; Enzymatic activity; Structure activity relation; Dicotyledones; Angiospermae; Spermatophyta; Inhibition; Experimental plant; ATP; Chloroplast
• ISSN: 0031-9317; 1399-3054
• DOI: 10.1034/j.1399-3054.2001.1110219.x

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.