Antioxidant and antimicrobial properties of Lavandula maroccana Murb.: A comprehensive evaluation of extracts from different plant parts

Lavandula maroccana Murb., an endemic Moroccan aromatic plant, remains largely unexplored for its phytochemical composition and biological activities. This study aimed to evaluate the antioxidant and antimicrobial properties of different plant parts (leaves, flowers, stems, and roots) using various solvent extraction systems. Extracts were obtained using methanol, ethanol, hexane, and water. Total phenolic content (TPC) and total flavonoid content (TFC) were quantified. Antioxidant capacity was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, total antioxidant capacity (TAC), and ferrous ion chelating activity assays. Antimicrobial efficacy was tested against Gram-positive and Gram-negative bacteria and one yeast strain. Leaf extracts demonstrated the highest bioactive compound content and antioxidant activity. Aqueous leaf extract exhibited superior performance with TPC (21.45 ± 0.02 mg GAE/g), TFC (13.04±0.00 mg QE/g), TAC (26.97±0.01 mg AAE/g), ABTS scavenging (IC 50 : 0.14±0.01 mg/mL), and chelating power (IC 50 : 0.41±0.01 mg/mL). Methanol leaf and root extracts showed potent DPPH activity (IC 50 : 0.06±0.00 mg/mL). Hexane extracts displayed the lowest antioxidant capacity. For antimicrobial activity, flower and root hexane extracts exhibited the strongest effects with MIC values as low as 1.56 mg/mL against B. subtilis , E. coli , and P. aeruginosa . Methanol and ethanol extracts demonstrated broad-spectrum activity (MIC: 1.56-12.5 mg/mL) against bacteria and C. tropicalis . Aqueous extracts showed no antimicrobial activity except limited leaf activity. Solvent polarity and plant part selection critically influence bioactive extraction, with leaves optimal for antioxidants (aqueous) and flowers/roots for antimicrobials (hexane/methanol), positioning L. maroccana as a promising natural source for pharmaceutical applications. • Leaves showed the highest phenolic content and antioxidant activity. • Aqueous extracts excelled in TAC, ABTS scavenging, and Fe 2+ chelation. • Methanol/ethanol extracts showed superior DPPH radical scavenging. • Flower and root hexane extracts exhibited notable antimicrobial effects. • Lavandula maroccana is a promising source of natural bioactive compounds.