Biological Activities and Phenolic Profile of Bursera microphylla A. Gray: Study of the Magdalena Ecotype

<i>Bursera microphylla</i> A. Gray (Burseraceae) is a medicinal plant native to Sonora, Mexico, with antioxidant, anti-inflammatory, and antiproliferative properties. However, the pharmacological potential of its ecotypes remains underexplored. This study evaluated the biological activity and chemical composition of ethanolic extracts from the fruit and stem of the Magdalena ecotype. Total phenolic content was quantified using the Folin-Ciocalteu method, and phenolic profiles were characterized by ESI-IT-MS. Antioxidant activity was assessed by DPPH and FRAP assays; anti-inflammatory activity was evaluated by measuring nitric oxide (NO) and tumor necrosis factor-alpha (TNF-α) levels in LPS-activated RAW 264.7 macrophages. Antiproliferative activity was tested against LS180, C-33 A, and ARPE-19 cell lines using the MTT assay. Fruit extract exhibited higher phenolic content (180.6 ± 22.0 mg GAE/g) and ferric-reducing power (FRAP = 2034.3 ± 89.7 μM Fe(II)/g), whereas the stem extract showed stronger DPPH scavenging capacity (IC₅₀ = 52.9 ± 0.02 μg/mL). For the first time, gallic acid glucoside, kaempferol rhamnoside, quercetin rhamnoside, and isorhamentin xyloside were identified in <i>B. microphylla</i> fruit extract. Furthermore, the fruit extract significantly reduced NO production (93.6 ± 4.6 μg/mL) and TNF-α levels (IC₅₀ = 101.5 ± 9.1 μg/mL). It also showed strong cytotoxicity against C-33 A (IC₅₀ = 0.6 ± 0.07 μg/mL) and LS180 (0.7 ± 0.01 μg/mL), with lower cytotoxicity in ARPE-19 cells (77.9 ± 4.3 μg/mL). These findings highlight the therapeutic potential of the Magdalena ecotype, likely associated with its phenolic and other bioactive metabolites that require further investigation.