Characterization and Cytotoxicity Assessment of the Lipophilic Fractions of Different Morphological Parts of Acacia dealbata

Abstract

Acacia dealbata biomass, either from forest exploitation or from the management of invasive species, can be a strategic topic, namely as a source of high-value compounds. In this sense, the present study aimed at the detailed characterization of the lipophilic components of different morphological parts of A. dealbata and the evaluation of their cytotoxicity in cells representative of different mammals' tissues. The chemical composition of lipophilic extracts from A. dealbata bark, wood and leaves was evaluated using gas chromatography-mass spectrometry (GC-MS). Terpenic compounds (representing 50.2%-68.4% of the total bark and leaves extracts, respectively) and sterols (60.5% of the total wood extract) were the main components of these extracts. Other constituents, such as fatty acids, long-chain aliphatic alcohols, monoglycerides, and aromatic compounds were also detected in the studied extracts. All the extracts showed low or no cytotoxicity in the different cells tested, demonstrating their safety profile and highlighting their potential to be used in nutraceutical or pharmaceutical applications. This study is therefore an important contribution to the valorization of A. dealbata, demonstrating the potential of this species as a source of high value lipophilic compounds.

Insights for the Valorization of Biomass from Portuguese Invasive Acacia spp. in a Biorefinery Perspective

“…Specific bioactivity for spinasterol, dihydrospinasterol and respective glucosides were also referred, such as antitumorigenic potential and therapeutic potential in modulating the diabetic neuropathy evidenced by spinasterol, potent inhibitory effect on the Epstein-Barr virus early antigen attributed to dihydrospinasterol, and anticarcinogenic and cytotoxic potential exhibited by dihydrospinasterol glucoside [43]. Recently, a broader characterization of the lipophylic fraction was performed for A. dealbata bark [27]. Terpenic compounds (lupenone and lupenyl acetate) represent the major lipophilic family in A. dealbata bark (3451 mg/kg of dry bark), followed by long-chain aliphatic alcohols (1083 mg/kg of dry bark), fatty acids (1060 mg/kg of dry bark) (with more than 10% of these being unsaturated fatty acids), monoglycerides (692 mg/kg of dry bark), sterols (484 mg/kg of dry bark), aromatic compounds (29 mg/kg of dry bark) and others (744 mg/kg of dry bark), among which was α-tocopherol (a type of vitamin E) (46 mg/kg of dry bark) [27].…”

“…Recently, a broader characterization of the lipophylic fraction was performed for A. dealbata bark [27]. Terpenic compounds (lupenone and lupenyl acetate) represent the major lipophilic family in A. dealbata bark (3451 mg/kg of dry bark), followed by long-chain aliphatic alcohols (1083 mg/kg of dry bark), fatty acids (1060 mg/kg of dry bark) (with more than 10% of these being unsaturated fatty acids), monoglycerides (692 mg/kg of dry bark), sterols (484 mg/kg of dry bark), aromatic compounds (29 mg/kg of dry bark) and others (744 mg/kg of dry bark), among which was α-tocopherol (a type of vitamin E) (46 mg/kg of dry bark) [27]. Terpenic compounds, and more specifically lupenone, were reported to have good therapeutic potential in inflammation, virus infection, diabetes, cancer, and treatment of Chagas disease [46], and the positive effects of unsaturated fatty acids on the cardiovascular, respiratory, gastrointestinal, renal and immune systems are well known [47].…”

“…Terpenic compounds, and more specifically lupenone, were reported to have good therapeutic potential in inflammation, virus infection, diabetes, cancer, and treatment of Chagas disease [46], and the positive effects of unsaturated fatty acids on the cardiovascular, respiratory, gastrointestinal, renal and immune systems are well known [47]. A cytotoxicity screening of the above-described lipophilic A. dealbata bark extract in several mammalian cell lines representing brain, immune system, skin, lung and liver cells, revealed encouraging results regarding its future incorporation in oral or topic pharmaceutical or nutraceutical formulations since there is a lack of toxicity in liver hepatocytes (HepG2), epidermis keratinocytes (HaCaT) and dermis fibroblasts (NIH/3T3) [27].…”

“…as a raw material. As a rule, wood has a lower organic solvent and water-soluble extractives, including polyphenols, when compared to bark [27,43,48,49]. However, these extractives may contain bioactive secondary metabolites that can be exploited for incorporation in formulations of nutraceuticals, cosmetics or other high-value applications.…”

“…The steryl glucosides spinasteryl glucodside (12-80 mg/kg of dry bark) and dihydrospinasteryl glucoside (20-79 mg/kg of dry bark) were also identified in significant amounts in the wood of all studied species, and campesteryl glucoside was identified only in A. longifolia wood (36 mg/kg of dry wood) [43]. A more extensive characterization of the lipophilic fraction of A. dealbata wood revealed that sterols (spinasterol, sitostanol and dihydrospinasterol) represent the major lipophilic family in A. dealbata wood (total of 590 mg/kg of dry wood), followed by fatty acids (290 mg/kg of dry wood, with almost 41% of them being unsaturated fatty acids), long-chain aliphatic alcohols (44 mg/kg of dry wood), aromatic compounds (27 mg/kg of dry wood) and monoglycerides (18 mg/kg of dry wood) [27]. This lipophilic fraction exhibited none or low cytotoxicity at the tested doses in different mammalian cell lines representing brain, immune system, skin, lung and liver cells, highlighting the potential to be further exploited for oral or topic nutraceutical or pharmaceutical applications, given the lack of toxicity observed in liver hepatocytes (HepG2), epidermis keratinocytes (HaCaT) and dermis fibroblasts (NIH/3T3) [27].…”