What question did this study set out to answer?

This study aims to evaluate the potential of Pelargonium graveolens hairy roots as a source of phenolic compounds and cosmeceutical ingredients.

June 3, 2026Open Access

Hairy Root-Derived Metabolites from Pelargonium graveolens L'Hér.: Phytochemical Insights and Cosmeceutical Properties

Key Points

This study aims to evaluate the potential of Pelargonium graveolens hairy roots as a source of phenolic compounds and cosmeceutical ingredients.
Inoculated sterile leaf explants with Agrobacterium rhizogenes strains A4 and ATCC15834.
Measured transformation efficiency, biomass yield, phenolic accumulation, and antioxidant activity.
Conducted cosmeceutical evaluations for tyrosinase and elastase inhibition.
A4 strain achieved higher hairy root induction at 83.33% compared to ATCC15834 at 56.66%.
A4-HR-L6 accumulated 172.02 µg GAE/g DW of total phenolics, significantly higher than ATCC15834-HR-L9's 96.56 µg GAE/g DW.
Antioxidant assays showed A4 extracts had a lower IC₅₀ of 112.85 µg/mL in DPPH tests and notable enzyme inhibition with IC₅₀ of 64.15 µg/mL for tyrosinase.

Abstract

In response to the growing demand for sustainably sourced plant bioactives, this study investigates Pelargonium graveolens L'Hér. as a potential source of phenolic compounds through Agrobacterium rhizogenes -mediated hairy root transformation. Sterile leaf explants were inoculated with strains A4 and ATCC15834 to enhance secondary metabolite production, and T-DNA integration was confirmed by PCR amplification of rol B and rol C genes. The transformed roots were evaluated for transformation efficiency, biomass yield, phenolic accumulation, antioxidant activity, and cosmeceutical potential. The A4 strain exhibited significantly higher hairy-root induction (83.33 ± 6.66%) than ATCC15834 (56.66 ± 3.33%). Comparative analysis showed that A4-HR-L6 root line accumulated greater biomass (14.54 ± 0.41 g FW; 1.43 ± 0.07 g DW/30 mL) and higher total phenolics (172.02 ± 3.19 µg GAE/g DW) and flavonoids (48.06 ± 2.84 µg QE/g DW) than ATCC15834-HR-L9 root line (9.67 ± 1.02 g FW; 0.92 ± 0.09 g DW/30 mL; 96.56 ± 1.05 µg GAE/g DW; 43.45 ± 4.29 µg QE/g DW). HPLC-DAD profiling revealed enrichment of sinapic acid (4163.60 ± 47.73 mg/100 g DW), gallic acid (318.99 ± 12.52 mg/100 g DW), and quercetin-glucoside (929.46 ± 89.66 mg/100 g DW) in A4-HR-L6, while ATCC15834-HR-L9 contained higher 4-hydroxybenzoic (474.03 ± 27.84) and vanillic acids (474.17 ± 42.12) and kaempferol (21834.34 ± 631.52). Antioxidant assays confirmed superior activity for A4 extracts with lower IC₅₀ in DPPH (112.85 ± 7.53 µg/mL) and ABTS (33.79 ± 4.05 µg/mL) tests and higher TAC (133.41 ± 4.53 mg AAE/g DW). Elevated SOD (1.056 ± 0.031 mM/min/mg FW) and POD (7.56 ± 0.43 mM/min/mg FW) activities were also recorded. Cosmeceutical evaluation showed strong inhibition of tyrosinase (IC₅₀ = 64.15 ± 5.91 µg/mL) and elastase (IC₅₀ = 97.84 ± 6.35 µg/mL), with SPF = 10.20 ± 0.61 (90.19% UVB blocking). Correlation analysis linked antioxidant and enzyme inhibition parameters with phenolic accumulation (r = –0.40 to –0.80) and enzymatic activity (r ≥ 0.90). Collectively, these findings demonstrate that A4-mediated transformation markedly enhances phenolic biosynthesis, antioxidant defenses, and cosmeceutical potential in P. graveolens hairy roots.

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