Antioxidant profile and HS-SPME/GC-MS-TOF analysis of volatile compounds of Alnus acuminata Ssp. Arguta bark

Alnus acuminata ssp. arguta (Schlecht.) Furlow (Betulaceae) (aile) is a widely used wild plant in the Mexican traditional medicine to treat acute inflammation, as astringent, antimicrobial and for treatments of syphilis. In vivo studies have demonstrated an anti inflammatory action and diarylheptanoids as components of the methanol extract of the stem bark. This extract exhibited antioxidant activity using four in vitro model systems: DPPH^·, ABTS^·+, FRAP^· radical scavenging activities and inhibition of lipoperoxidation in β-carotene bleaching assay. Total phenol content of the methanol extract was determined using standard spectrophotometric methods (Folin-Ciocalteu, 22.5 ± 1 mg GAE/g of stem bark) and IC₅₀ values of 0.04 mg/mL and 0.2 mg/mL in DPPH and ABTS assays were four fold lower and fivefold higher than reference compounds respectively. In FRAP test, the extract showed weak antioxidant activity, and good response in the β-carotene bleaching test.

The volatile composition of Alnus acuminata stem bark was determined by solid-phase microextraction/mass spectrometry analysis. Forty three compounds, among others, alcohols, aromatic compounds, terpenoids and ketones were identified using this technique. The presence of antioxidant phenolic compounds in this plant may justify some of its medicinal properties.