Phytochemical Profiling and Antioxidant, Anticancer, and Antimicrobial Activities of Lavandula multifida L. Extracts.

Lavandula multifida L., commonly known as Egyptian lavender or fern leaf lavender, is widely recognized and used as a medicinal plant throughout Mediterranean countries. While L. multifida has been extensively studied, research has largely centered on its essential oil, with limited data available on the composition and bioactivities of its organic extracts. This study characterized the phytochemical profiles of L. multifida extracts and evaluated their antioxidant capacity, effects on cancer cell viability, and antimicrobial activity using multiple in vitro assays. Phytochemical characterization included the quantification of total phenolic and flavonoid contents and HPLC/ESI-QTOF-MS profiling of methanolic (LM), aqueous (LAQ), and ethyl acetate (LEA) extracts. Antioxidant activity was assessed using four complementary in vitro assays (DPPH, ABTS, FRAP, and TAC). The effects of the extracts on cell viability were assessed using the MTT assay in human triple-negative breast cancer (MDA-MB-231) and colon adenocarcinoma (HCT116) cell lines, while antimicrobial activity was determined using the agar well diffusion and broth microdilution methods. Phytochemical profiling of L. multifida extracts revealed diverse metabolites dominated by fatty acids (mainly oxylipins), together with phenolic acids, flavonoids, terpenes, and other minor constituents. The methanolic extract showed the strongest DPPH scavenging effect (IC50 = 14.19 µg/mL), LAQ showed the highest FRAP value (246.62 µg TE/mg), and LEA demonstrated the greatest ABTS (IC50 = 28.07 µg/mL) and TAC (367.16 µg AAE/mg) activities. LEA also produced the greatest reductions in cell viability, reaching approximately 97% in HCT116 cells and 83% in MDA-MB-231 cells, with corresponding IC50 values of 27.85 ± 2.48 and 63.71 ± 3.05 µg/mL, respectively. LM and LAQ showed the largest bacterial inhibition zones, while LEA, despite weaker diffusion activity, exhibited the greatest potency (MIC = 0.5-2 mg/mL; MBC = 0.5-5 mg/mL) and a unique antifungal effect (MIC = 2 mg/mL; MFC = 4 mg/mL). These findings underscore the potential of L. multifida extracts as a natural reservoir of bioactive compounds with notable antioxidant, anticancer, and antimicrobial activities, suggesting their relevance for future pharmaceutical development.