Furanoditerpene ester and thiocarbonyldioxy derivatives inhibit photosynthesis

The Triterpenes 3β-Lup-20(29)-en-3-ol and 3β-Lup-20(29)-en-3-yl Acetate and the Carbohydrate 1,2,3,4,5,6-Hexa-O-acetyl-dulcitol as Photosynthesis Light Reactions Inhibitors

“…McCarthy [ 12 ] concluded on the action of energy transfer inhibitor that “since all of these activities were shown to be catalyzed by the same enzyme (CF1), it appears that the chloroplast membrane confers special properties on CF1” in accord with our result, compound 1 enhanced Ca 2 + -ATPase activity in isolated CF1 and inhibits the Mg 2 + -ATPase activity bound to thylakoids membrane. We found that this enzyme is also targeted by others natural products like 2-methoxyethyl-7β-hydroxy-6-oxovouacapan-17β-oate and 3-methylbut-2-enyl-7β-hydroxy-6-oxovouacapan-17β-oate [ 8 ], epifriedelinol and canophyllol [ 9 ], as well as by other compounds like Dio-9, phlorizin, tri- n -butyltinchloride [ 12 ]. Ammonium chloride was used as positive control.…”

“…Any photosynthetic sample in any physiological state exhibits upon illumination a fast fluorescence rise leading to a transient F 0 -K-J-I-P from initial fluorescence intensity F 0 to a maximal intensity F P or F M with saturating light intensity. Between these two extremes the fluorescence intensity Ft shows intermediate steps as follows: F J appears at about 2 ms; F I appears at about 30–50 ms; and F M appears at about 300–500 ms; K-band appears at about 300 μs in heat-stressed samples [ 13 , 14 ] or in the influences of chemicals or secondary metabolites [ 8 , 9 , 15 , 16 , 17 ]. Strasser [ 18 ] concluded that the appearance of the K-band is satisfactorily explained by an imbalance between the electron flow to the acceptor side and the electron flow from the donor side leading to the accumulation of Y Z + .…”

“…As part of our study of bioactive metabolites from species of the Flacourtiaceae and Celastraceae plant families, the present investigation describes the isolation, identification, and photosynthetic inhibitory activities of two triterpenes: lupeol, 3β-lup-20(29)-en-3-ol ( 1 ), 3β-lup-20(29)-en-3-yl acetate ( 2 ) and the carbohydrate 1,2,3,4,5,6-hexa- O -acetyldulcitol ( 3 ) ( Figure 1 ) obtained from M. acanthophylla ; compound 1 was also isolated from X. flexuosa . Although a relatively large number of highly phytotoxic allelochemicals are derived from the terpenoid pathway [ 6 , 7 ], the mode of action of some terpenoids indicate that they participate in plant-plant interactions, and few of them have been found to affect photosynthesis [ 8 , 9 ]. Chlorophyll a fluorescence kinetics of photosystem II analysis indicated that the primary target of synthetic herbicides is the photosynthetic apparatus on the acceptor side of photosystem II (PSII), by displacing the quinone Q B from the D 1 protein demonstrated by Velthuys [ 10 ].…”

Ácido myrsinoico a e derivado: inibidores da fotossíntese in vitro

“…Os compostos que inibem o transporte de elétrons em todas as suas etapas (basal, fosforilante e desacoplado) atuam como inibidores da reação de Hill, através do bloqueio e/ou redução do transporte de elétrons pelo lado aceptor de elétrons (neste caso, o MV). Na literatura são encontrados outros produtos naturais que se comportam de maneira similar: ácido trachiloban-19-oico, 31 xantorrizol, 25 tricolorin A, 24 N-metil-flindersina, 11 6-(3,3-dimetilaliloxi)-4-metoxi-5-metilfitalideo, 32 butil 7b-hidroxi-6-oxovouacapan-17b-oate, 33 canofilol 34 e 1,2,3,4,5,6-hexa-O-acetildulcitol. 35 Dados obtidos após medidas polarográficas permitiram localizar o sítio de ação dos compostos sobre o FS II.…”