Production of Malheuran A, a Geranylated Flavonoid with Antimicrobial and Anti-Inflammatory Activities, in Hairy Root Cultures of Dalea purpurea

Phenolic compounds, such as stilbenes and flavonoids, from Dalea spp. exhibit diverse biological activities, including antimicrobial, anti-inflammatory, and cytotoxicity properties. To this end, the objectives of this study were to establish hairy root cultures of D. purpurea and assess its capacity to produce these bioactive compounds. The co-treatment of the hairy root cultures with the elicitors methyl-β-cyclodextrin, magnesium chloride, methyl jasmonate, and hydrogen peroxide led to the production and secretion of the geranylated flavanone malheuran A, which was confirmed by mass spectrometry and NMR spectroscopy analyses. The highest amount (104.3 ± 6.9 mg/L) of malheuran A was detected at 192 h after elicitor treatment. The elicited hairy roots were re-elicited for 192 h with the same combination of elicitors, and they produced a substantial amount of malheuran A (91.9 ± 6.8 mg/L). Malheuran A, purified from extracts of the hairy root culture medium, showed potent antimicrobial activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci. It also demonstrated anti-inflammatory effects by suppressing nitrite production in LPS-stimulated RAW 264.7 macrophages. These findings show that various elicitor treatments can boost malheuran A production in hairy root cultures, making them a sustainable bioproduction platform for this bioactive specialized metabolite.