ORIGINAL ARTICLE Caffeic acid and caffeine attenuate toxicity associated with malonic or methylmalonic acid exposure in Drosophila melanogaster José Luiz Portela 1 & Matheus Chimelo Bianchini 1 & Daniel H. Roos 1 & Daiana Silva de Ávila 1 & Robson Luiz Puntel 1 Received: 12 May 2020 /Accepted: 7 September 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract The deficiency in the activity of the mitochondrial enzyme methylmalonyl-CoA mutase (MCM, EC 5.4.99.2) leads to a condition called methylmalonic academia, which is characterised by the accumulation of methylmalonic (MMA), malonic (MA) or other organic acids. Importantly, we have recently found that supplementation with Ilex paraguariensis aqueous extract offered protection against toxicity associated with MMA or MA exposure to Drosophila melanogaster. Of note, caffeic acid (CA) and caffeine (CAF) were the major phytochemicals found in our Ilex paraguariensis crude extract. Therefore, here, we have exploited CA and/or CAF to test the hypothesis that supplementation with the isolated compounds (either alone or combined) could exert a protective effect against MMA or MA-induced toxicity in flies. Therefore, flies were exposed to MA (5 mM) or MMA (5 mM) and concomitantly treated with CA (1.39 μg/mL), CAF (1.27 μg/mL) or CA + CAF for 10 days for survival, and for 4 days for behavioural and biochemical assays. CA, CAF and CA + CAF treatments completely abolished the mortality associated with either MMA or MA exposure. Moreover, CA and CAF, either alone or combined, completely abolished behavioural changes, and completely protect against changes in thiobarbituric acid reactive substances (TBARS) levels, catalase (CAT) activity and MTT reduction ability, associated with MA or MMA exposure. In turn, CAF restored SOD activity in the head of flies exposed to MA or MMA. However, CA and CAF (either alone or combined) significantly decreased acetylcholin- esterase (AChE) activity per se, while CAF alone protected from changes in AChE activity (in head tissue) associated with MA or MMA. Finally, CA and/or CAF were able to protect from a decrease in glucose and triglyceride levels associated with both MA and MMA exposures in haemolymph. Together, our data confirm the hypothesis that supplementation with CA and/or CAF offers protection against detrimental changes associated with MMA or MA exposure in flies, being responsible, at least in part, for the protective effect of I. paraguariensis crude extract which was reported previously. Keywords Oxidative stress . Behavioural changes . Neurotoxicity . Anticholinesterase Introduction Methylmalonic acidaemia is an inherited disorder resulting from a deficiency in the activity of the mitochondrial enzyme methylmalonyl-CoA mutase (MCM, EC 5.4.99.2). Affected subjects are unable to metabolise certain molecules properly, leading to the accumulation of methylmalonic acid (MMA) (Chandler and Venditti 2005; Melo et al. 2011; Panigrahi et al. 2017). From a biochemical point of view, this condition is characterised by several metabolic changes that include hypoglycaemia in about 40% of affected subjects (Filippi et al. 2009), as well as hypotriglyceridaemia (Brusque et al. 2001). However, part of the pathophysiology of this disease can be associated with other organic acids, including malonic acid (MA) (Okun et al. 2002; Kolker and Okun 2005; Melo et al. 2011). From a mechanistic point of view, some pieces of evidence suggest that exposure to MMA or MA is associated with oxidative stress and mitochondrial dysfunction (Chandler and Venditti 2005; Kolker and Okun 2005; Kalonia et al. 2010a; Kalonia et al. 2010b; Melo et al. 2011; Kumar et al. 2013; Panigrahi et al. 2017; Quintanilla et al. 2017; Velusamy et al. 2017). Importantly, the accumulation of MMA or MA in the brain is associated with neurodegener- ation (Kolker and Okun 2005; Melo et al. 2011; Kumar et al. 2013). * Robson Luiz Puntel robson_puntel@yahoo.com.br; robsonpuntel@unipampa.edu.br 1 Campus Uruguaiana, Programa de Pós-Graduação em Bioquímica (PPGBioq), Universidade Federal do Pampa, Campus Uruguaiana BR-472 Km 7, Uruguaiana, RS CEP 97500-970, Brazil Naunyn-Schmiedeberg's Archives of Pharmacology https://doi.org/10.1007/s00210-020-01974-3