Moringa oleifera leaves: could solvent and extraction method affect phenolic composition and bioactivities?

Area of Science:

• Phytochemistry
• Pharmacology
• Natural Products Chemistry

Background:

• Moringa oleifera is a plant with significant therapeutic potential.
• Understanding the optimal extraction of its bioactive compounds is crucial for its application.
• Cultivation of M. oleifera in Tunisia presents an opportunity for local natural product research.

Purpose of the Study:

• To evaluate the impact of different extraction methods (DM, SM) and solvents (DCM, EAc, But, Aqu) on M. oleifera leaf phenolic profiles.
• To assess the antioxidant, antibacterial, and cytotoxic activities of the various M. oleifera leaf extracts.
• To identify key phenolic compounds responsible for the observed biological activities.

Main Methods:

• Extraction of M. oleifera leaves using direct maceration (DM) and successive maceration (SM) with four solvents.
• Quantification of total phenolic content (TPC) and total flavonoid content (TFC).
• LC-MS analysis for phenolic compound identification, and biological assays including DPPH, metal chelating, FRAP, MIC against bacteria, and cytotoxicity against A549 lung cancer cells.

Main Results:

• The butanol (But) extract obtained via successive maceration (SM) showed the highest TPC (103.06 mg GAE/g DE).
• This But-SM extract exhibited the strongest antioxidant (DPPH IC50 = 0.26 mg/mL), antibacterial (MIC = 250 µg/mL), and cytotoxic (GI50 = 69.9 µg/mL) activities.
• LC-MS identified 28 out of 33 tested phenolic compounds, with rutin, quercetin, and syringic acid being most abundant in the But-SM extract.

Conclusions:

• Extraction method and solvent significantly affect the phenolic composition and biological activities of M. oleifera leaves.
• Successive maceration using butanol is an effective method for extracting potent bioactive compounds from Tunisian M. oleifera.
• The findings highlight the potential of M. oleifera extracts for antioxidant, antimicrobial, and anticancer applications.