Shahid Bahonar University of Kerman and Iranian Biotechnology Society Agricultural Biotechnology Journal 2228-6705 18 4 2026 12 22 Effect of chitosan on in vitro growth and bioactive metabolite production in Lavandula angustifolia Mill. Effect of chitosan on in vitro growth and bioactive metabolite production in Lavandula angustifolia Mill. 553 574 5663 10.22103/jab.2026.27369.1943 FA Mohammed A. Mohammed Department of Biotechnology, College of Sciences, University of Anbar, Ramadi 31001, Iraq 0000-0002-7693-8252 Baraa H. Saleh Department of Biology, College of Education for Women, University of Anbar, Ramadi 31001, Iraq 0009-0002-3968-5185 Ahmed O. Mashaan Department of Biotechnology, College of Sciences, University of Anbar, Ramadi 31001, Iraq 0009-0001-4524-6106 M. S. Alrawi Department of Pharmacology and Toxicology, College of Pharmacy, University of Anbar, Ramadi 31001, Iraq 0000-0002-6247-3511 Ali F. Almehemdi Department of Conservation Agriculture, Center of Desert Studies, University of Anbar, Ramadi 31001, Iraq. 0000-0003-1840-1681 Journal Article 2026 06 05 ObjectiveLow production of bioactive metabolites remains one of the major limitations in commercial production of Lavandula angustifolia. Chitosan has been proposed as an effective elicitor for enhancing secondary metabolite biosynthesis under in vitro conditions. This study aimed to evaluate the effect of chitosan, a biological derivative of chitin, on the growth and active compound content of lavender plants cultured in vitro. Materials and methodsA completely randomized design with four chitosan concentrations (0, 50, 100, and 200 mg L⁻¹) was used. Moreover, ten biological replicates per treatment were used for in vitro cultured Lavandula angustifolia plantlets. Vegetative growth parameters, including plant height, branch number, leaf number, fresh weight, and dry weight were recorded, after four weeks of culture. GC–MS was used for analysing volatile metabolites and HPLC was applied for quantifying phenolic compounds. Results The results of the current study showed that plant growth and metabolite accumulation are significantly influenced by chitosan (p < 0.05). Using chitosan (100 mg L⁻¹) produced the highest biomass, except for number of branches that the greatest number of branches was recorded at 50 mg L⁻¹. This treatment, in comparison with the control increased plant height (90%), fresh weight (199%), and dry weight (142%). At this concentration, the highest levels for quercetin, rosmarinic acid, luteolin, apigenin, caffeic acid, and ferulic acid were 95.6 ppm, 90.5 ppm, 88.7 ppm, 83.9 ppm, 81.4 ppm, and 70.6 ppm, respectively. In contrast, 50 mg L⁻¹ chitosan induced the accumulation of 2-nitroethyl propionate, whereas 200 mg L⁻¹ reduced both growth and phenolic accumulation, indicating inhibitory effects at higher concentrations.ConclusionThe current research showed that chitosan can successfully increase the growth and secondary metabolite production of Lavandula angustifolia cultured in vitro in a concentration-dependent manner. Overall, 100 mg L⁻¹ was the optimum concentration because it produced the highest biomass and phenolic accumulation, although the maximum branch number was observed at 50 mg L⁻¹. Our results showed that supplementing in vitro culture media with 100 mg L⁻¹ chitosan can be used as a practical strategy for improving the production of valuable bioactive compounds in lavender. For validation of the underlying mechanisms and support commercial application, it would be better to perform further molecular and greenhouse studies. ObjectiveLow production of bioactive metabolites remains one of the major limitations in commercial production of Lavandula angustifolia. Chitosan has been proposed as an effective elicitor for enhancing secondary metabolite biosynthesis under in vitro conditions. This study aimed to evaluate the effect of chitosan, a biological derivative of chitin, on the growth and active compound content of lavender plants cultured in vitro. Materials and methodsA completely randomized design with four chitosan concentrations (0, 50, 100, and 200 mg L⁻¹) was used. Moreover, ten biological replicates per treatment were used for in vitro cultured Lavandula angustifolia plantlets. Vegetative growth parameters, including plant height, branch number, leaf number, fresh weight, and dry weight were recorded, after four weeks of culture. GC–MS was used for analysing volatile metabolites and HPLC was applied for quantifying phenolic compounds. Results The results of the current study showed that plant growth and metabolite accumulation are significantly influenced by chitosan (p < 0.05). Using chitosan (100 mg L⁻¹) produced the highest biomass, except for number of branches that the greatest number of branches was recorded at 50 mg L⁻¹. This treatment, in comparison with the control increased plant height (90%), fresh weight (199%), and dry weight (142%). At this concentration, the highest levels for quercetin, rosmarinic acid, luteolin, apigenin, caffeic acid, and ferulic acid were 95.6 ppm, 90.5 ppm, 88.7 ppm, 83.9 ppm, 81.4 ppm, and 70.6 ppm, respectively. In contrast, 50 mg L⁻¹ chitosan induced the accumulation of 2-nitroethyl propionate, whereas 200 mg L⁻¹ reduced both growth and phenolic accumulation, indicating inhibitory effects at higher concentrations.ConclusionThe current research showed that chitosan can successfully increase the growth and secondary metabolite production of Lavandula angustifolia cultured in vitro in a concentration-dependent manner. Overall, 100 mg L⁻¹ was the optimum concentration because it produced the highest biomass and phenolic accumulation, although the maximum branch number was observed at 50 mg L⁻¹. Our results showed that supplementing in vitro culture media with 100 mg L⁻¹ chitosan can be used as a practical strategy for improving the production of valuable bioactive compounds in lavender. For validation of the underlying mechanisms and support commercial application, it would be better to perform further molecular and greenhouse studies. https://jab.uk.ac.ir/article_5663_ac71e0079799a57cc6616312cbbbaf84.pdf