L'Acido malico (1) è un acido dicarbossilico che si trova nei frutti acerbi e produce un gusto gradevole acidulo.
Fu scoperto nel 1785 in una mela da Carl Wilhelm Scheele, un ricercatore svedese nato nel 1742 e scomparso nel 1786, autore di numerose scoperte tra le quali il manganese, il cloro, l'acido tartarico, la glicerina e l'acido lattico, che lo catalogò semplicemente come acido della mela.
Nel 1787, Lavoisier ed il suo gruppo di ricercatori, attribuirono a questo acido il nome di acido malico.
Nel 1834 il chimico Théophile Jules Pelouze (1807-1867) lo distillò e ne scoperse due composti : l'acido maleico e l'acido para-maleico.
Si trova anche nel corpo umano, nell'acido citrico.
A cosa serve e dove si usa
Alimentazione
Viene usato dall'industria alimentare per conferire ai cibi il gusto acidulo. Ingrediente inserito nella lista degli additivi alimentari europei come E296.
Cosmetica
Agente tampone. E' un ingrediente che può portare una soluzione alcalina o acida a un determinato livello di pH e impedirne la modifica, in pratica uno stabilizzatore di pH che può resistere efficacemente all’instabilità ed all'eventuale cambiamento del pH.
Sicurezza cosmetica
L'acido malico è risultato irritante nei test clinici, con meno irritazione osservata all'aumento del pH del materiale applicato, non ha causato tossicità riproduttiva, si è rivelato un forte irritante oculare in esperimenti su animali (2)
Medicina
Utilizzato per il trattamento della xerostomia, una malattia che riduce l'emissione di saliva dalle ghiandole salivali (3), fibromialgia, un disturbo che provoca dolore muscoloscheletrico e affaticamento (4).
L'integrazione di acido l-malico entro un intervallo appropriato ha un potenziale significativo per la prevenzione e il trattamento di alcune malattie (5)
Acido malico studi
Formula molecolare: C4H6O5
Linear Formula HO2CCH2CH(OH)CO2H
Peso molecolare: 134.087 g/mol
CAS: 97-67-6 6915-15-7
EC Number: 202-601-5
PubChem Substance ID 329750312
MDL number MFCD00064212
Beilstein Registry Number 1723539
Sinonimi:
- DL-malic acid
- Butanedioic acid, hydroxy-
- 2-Hydroxybutanedioic acid
- 2-Hydroxysuccinic acid
- malate
- Malic acid, DL-
- Musashi-no-Ringosan
- alpha-Hydroxysuccinic acid
- Hydroxybutandisaeure
- dl-Hydroxybutanedioic acid
- Caswell No. 537
- Succinic acid, hydroxy-
- R,S(+-)-Malic acid
- 2-Hydroxyethane-1,2-dicarboxylic acid
- Deoxytetraric acid
- hydroxysuccinic acid
Bibliografia______________________________________________________________________
(1) L. Guyton de Morveau, A. Lavoisier, C. Berthollet, A. Fourcroy, Méthode de nomenclature chimique, Cuchet, Paris, 1787, p. 150
(2) Fiume Z. Final report on the safety assessment of Malic Acid and Sodium Malate. Int J Toxicol. 2001;20 Suppl 1:47-55. doi: 10.1080/109158101750300946.
Abstract. Malic Acid functions in cosmetic formulations as a pH adjuster, and Sodium Malate functions as a skin conditioning agent-humectant. Malic Acid is reportedly used in almost 50 cosmetic formulations across a range of product types at low concentrations, whereas Sodium Malate is used in only one. As a pH adjuster, Malic Acid is used at low concentrations. One commercial method of preparing Malic Acid is hydration of fumaric acid or maleic acid, and then purified to limit the amount of the starting material present. Because Malic Acid is a component of the Kreb's cycle, another method is fermentation. Malic Acid was relatively nontoxic in acute toxicity studies using animals. In a chronic oral study, feeding Malic Acid to rats resulted only in weight gain changes and changes in feed consumption. Malic Acid did not cause reproductive toxicity in mice, rats, or rabbits. Malic Acid was a moderate to strong skin irritatant in animal tests, and was a strong ocular irritant. Malic Acid was not mutagenic across a range of genotoxicity tests. Malic Acid was irritating in clinical tests, with less irritation seen as pH of the applied material increased. Patients patch tested with Malic Acid, placed on a diet that avoided foods containing Malic or citric acid, and then challenged with a diet high in Malic and citric acid had both immediate urticarial and delayed contact dermatitis reactions. These data were considered sufficient to determine that Malic Acid and Sodium Malate would be safe at the low concentrations at which these ingredients would be used to adjust pH (even though Sodium Malate is not currently used for that purpose). The data, however, were insufficient to determine the safety of these ingredients when used in cosmetics as other than pH adjusters and specifically, the data are insufficient to determine the safety of Sodium Malate when used as a skin conditioning agent-humectant. The types of data required for the Expert Panel to determine the safety of Sodium Malate as a skin-conditioning agent are: concentration of use data; dermal irritation and sensitization data; and ocular irritation data, if available. The data needed to assess the safety of Malic Acid or Sodium Malate for some function other than as a skin-conditioning agent cannot be specified without knowing the intended function. Were these ingredients to be used as exfoliants, for example, data similar to that included in the Cosmetic Ingredient Review safety assessment of Glycolic Acid would be needed. Until these data are available, it is concluded that the available data are insufficient to support the safety of these ingredients in cosmetic formulations for functions other than use as a pH adjuster.
(3) Liu G, Qiu X, Tan X, Miao R, Tian W, Jing W. Efficacy of a 1% malic acid spray for xerostomia treatment: A systematic review and meta-analysis. Oral Dis. 2023 Apr;29(3):862-872. doi: 10.1111/odi.14116.
(4) Ferreira I, Ortigoza Á, Moore P. Magnesium and malic acid supplement for fibromyalgia. Medwave. 2019 May 28;19(4):e7633. Spanish, English. doi: 10.5867/medwave.2019.04.7632.
Abstract. Introduction: Fibromyalgia is characterized by myalgia and a combination of different symptoms including pain, fatigue, insomnia, morning rigidity, depression and a reduction in every-day functioning. Its aetiology is not clear, but it has been suggested that deficiency in certain minerals such as magnesium may play a role both in the physiopathology and in contributing to the symptoms. Methods: We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. Results and conclusions: We identified seven systematic reviews which included 11 primary studies of which one was a randomized trial. Our conclusion is that the use of magnesium and malic acid in patients with fibromyalgia makes little or no difference on pain and on depressive symptoms.
(5) Lu J, Zhang S, Wu S, Gao C. l-malic acid: A multifunctional metabolite at the crossroads of redox signaling, microbial symbiosis, and therapeutic innovation. Arch Biochem Biophys. 2025 Oct;772:110554. doi: 10.1016/j.abb.2025.
Acido malico 
2-hydroxydicarboxylic acid 
