Phenolic Profile and Volatiles of in vitro Propagated Lavandula angustifolia Mill. Seedlings

An effective in vitro propagation protocol was designed for Lavandula angustifolia Miller, a medicinal aromatic plant that is a prominent source of volatile organic compounds (VOCs). Murashige and Skoog media were supplemented with various concentrations of Plant Growth Regulators (PGRs), and the growth parameters of the nodal segments were examined. Nodal explants formed callus when they were supplemented with 2 mg/L of 6-Benzylaminopurine (BAP). The superior hormonal concentration of Murashige and Skoog (MS) media for the proliferation of shoots from callus cultures (39.33%) was 5 mg/L of 2-Isopentenyl adenine (2iP), and the favorable media for the growth of L. angustifolia callus cultures was 1 and 2 mg/L of BAP, with a 98% formation rate in each case. The callus cultures and in vitro propagated L. angustifolia seedlings obtained from various PGR concentrations of MS media were exposed to qualitative and quantitative analysis in terms of phenolic profiles, flavonoids, High-performance liquid chromatography (HPLC) analysis of phenolic acids, and headspace-SPME analysis for volatiles. Such analysis revealed that micropropagated seedlings grown in media containing 1 mg/L of 6-Furfurylaminopurine (KIN) accumulated the highest yield (11.95 ± 0.01 mg GAE/g) of phenolic acids. In contrast, the lowest concentration (2.17 ± 0.04 mg GAE/g) was detected in 0.5 mg/L of BAP + 0.5 mg/L of Naphthaleneacetic acid (NAA) media. The plantlets grown in 0.5 mg/L of BAP + 0.5 mg/L of NAA media showed the highest flavonoid yield (31.67 ± 0.06 μg/g QE/g). In contrast, callus samples exhibited the lowest yield (11.59 ± 0.02 μg/g QE/g) of flavonoids in MS media supplemented with a concentration of 0.5 mg/L of BAP. HPLC analysis revealed the variability of phenolic acid contents within the callus cultures as well as plantlets, with gallic acid, 4-OH benzoic acid, chlorogenic acid, vanillic acid, caffeic acid, cinnamic acid, and rosmarinic acid being the prominent constituents. The presence of twenty-two chemicals was revealed by headspace-SPME analysis. Eucalyptol, nonanal, borneol, carvone, and β-caryophyllene were the most abundant. This study demonstrated that micropropagation of L. angustifolia may be an effective method to produce large numbers of genetically identical plantlets for the production of high-value bio compounds.