Potential Activity Mechanisms of Aesculus hippocastanum Bark: Antioxidant Effects in Chemical and Biological In Vitro Models

Abstract

The bark of Aesculus hippocastanum is an herbal remedy used in conditions connected with vascular insufficiency; however, there is a lack of data concerning its mechanisms of action. The present work is a preliminary investigation into some of the potential directions of the bark activity. The phytochemically (qualitative UHPLC-PDA-MS/MS and quantitative UHPLC-PDA assays) characterized extract and its four main constituents (esculin, fraxin, (‒)-epicatechin and procyanidin A2) were first evaluated in terms of their antioxidant capacity. All analytes demonstrated dose-dependent scavenging potential towards the most common in vivo oxidants, with particularly advantageous capacity of the extract and its flavan-3-ol constituents against peroxynitrite (3.37–13.26 mmol AA/g), hydroxyl radical (5.03–8.91 mmol AA/g) and superoxide radical (3.50–5.50 mmol AA/g). Moreover, even at low concentrations (1–5 µg/mL), they protected components of human plasma against oxidative damage inflicted by peroxynitrite, preventing oxidation of plasma protein thiols and diminishing the tyrosine nitration and lipid peroxidation. High efficiency of the analytes was also demonstrated in preventing the peroxynitrite-induced nitrative changes of fibrinogen (up to 80% inhibition for (‒)-epicatechin at 50 µg/mL), an important protein of coagulation cascade. Additionally, the extract and its constituents had, at most, moderate inhibitory activity towards platelet aggregation induced by ADP and only negligible influence on clotting times. The results show that, among the investigated properties, the antioxidant activity might, to the highest extent, be responsible for the bark efficacy in vascular disorders, thus supporting its application in those conditions; they also indicate the directions for future research that would allow for better understanding of the bark activity.

Comparative Metabolomics of Reproductive Organs in the Genus Aesculus (Sapindaceae) Reveals That Immature Fruits Are a Key Organ of Procyanidin Accumulation and Bioactivity

“…The antioxidant effects seen in the study correlate with those of published work, although some differences have occurred due to the methodology and type of extract that was used in the study [26]. The high density of procyanidins may be an explanation for the higher activity in fruit extracts as this compound is often associated with antioxidant effects [21]. The large standard deviation that was seen not only in the antioxidant results, but the antifungal assay too, could also be explained by the minor difference in chemistry across species.…”

“…Aside from aescin other chemical constituents within horse chestnuts have bioactivity [14][15][16][17], i.e., the similarly named aesculin, not to be confused with aescin, is a coumarin glycoside that is well known for anticancer and antimicrobial effects [18,19]; fraxins have hepatoprotective properties and the ability to positively affect the immune system [18,20]; procyanidins have long been associated with health benefits as antioxidants, vascular protective compounds [21], and are protective against neurodegenerative diseases [22]; and kaempferol and quercetin derivatives inhibit biofilm formation and alleviate pain and inflammation [23]. Overall, the combination of the bioactive compounds gives horse chestnut extracts numerous beneficial effects.…”

Flavanols from Nature: A Phytochemistry and Biological Activity Review

“…Compound 18 demonstrated dose-dependent scavenging potential and have particularly advantageous capacity against peroxynitrite (3.37–13.26 mmol AA/g), hydroxyl radical (5.03–8.91 mmol AA/g) and superoxide radical (3.50–5.50 mmol AA/g) (ascorbic acid (AA) was used as positive control.) [ 85 ]. Many flavan-4-ol glycosides also showed remarkable antioxidant and free radical scavenging properties.…”

Assessment of antimicrobial activity of ethanolic and aqueous extracts ofAesculus hippocastanumL. (horse chestnut) bark against bacteria isolated from urine of patients diagnosed positive to urinary tract infections

“…Most of the research conducted on A. hippocastanum focused on its properties to regulate circulatory system imbalances and relieve attacks of hemorrhoids [33]. In a study conducted by…”

“…Owczarek et al [33] on the composition of A. hippocastanum bark, it has been reported that this plant presents mainly two groups of compounds: coumarins and proanthocyanidins. Among the coumarins there was mainly esculin (over 17%) and fraxin (over 7%) while among the proanthocyanidins, the authors found epicatechin (over 6%) and procyanidin A2 (over 5%) (Figure 2) [33]. Owczarek et al [33] finally conclude that, in total, about 40% of the A. hippocastanum bark extract could be attributed to simple phenolics compounds detectable by LC-PDA.…”