Controlled Application of Far-Red Light to Improve Growth and Bioactive Compound Yield in Centella asiatica

This study examined how far-red (FR) light supplementation influences triterpene glycoside accumulation in Centella asiatica grown under different light intensities (50–200 μmol·m⁻²·s⁻¹) over 5 weeks. Four major compounds—madecassoside, asiaticoside, madecassic acid, and asiatic acid—were quantified. Results from three-way ANOVA showed that light intensity and time significantly affected the accumulation of all compounds, with FR light selectively enhancing glycoside levels but not triterpene acids. Although total glycoside content declined over time, plants under 200FR conditions retained the highest levels by week 5. Principal component analysis suggested that FR light modulates resource allocation between growth and secondary metabolism. These findings advance our understanding of light-mediated regulation in phytochemical biosynthesis and offer a basis for optimizing cultivation strategies in controlled environments. Notably, the compound-specific responses to FR suggest differential regulation within the triterpene biosynthetic pathway, opening avenues for targeted enhancement of medicinally important compounds.