Applied Chemical Engineering

Growth-stage specific metabolic adaptations in Capsicum annum: Secondary metabolite dynamics and antioxidant plasticity

Haider Abbas AbdulRedha

Department of Biology, Faculty of science, University of Kufa, Najaf , 540011, Iraq

Maallah T. AL-Husseini

Department of Biology, Faculty of science, University of Kufa, Najaf , 540011, Iraq

Intisar Razzaq Sharba

Department of Biology, Faculty of science, University of Kufa, Najaf , 540011, Iraq

Harith R. Al-Mousawi

Department of Biology, Faculty of science, University of Kufa, Najaf , 540011, Iraq

Naser Jawad Kadhim

Department of Biology, Faculty of science, University of Kufa, Najaf , 540011, Iraq

DOI: https://doi.org/10.59429/ace.v8i4.5759

Keywords: Growth-stage adaptation; Capsicum annum; metabolic plasticity; bioactive compounds; oxidative stress.

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Abstract

This study examines growth-stage-dependent variations in secondary metabolites and antioxidant capacity in Capsicum annum. Analytical techniques including spectrophotometry were employed to quantify phenolics, tannins, flavonoids, anthocyanins, alkaloids, and DPPH radical scavenging activity. Results revealed significant metabolic shifts (p < 0.05) across vegetative (V) and flowering (F) stages, driven by tissue-specific demands and developmental priorities. A marked increase in phenolic content was observed in roots (1.32 to 3.24 mg/100g), stems, and leaves during flowering, correlating with oxidative stress mitigation. Fruits exhibited minimal phenolics (0.31 mg/100g), reflecting resource allocation to seed maturation. Tannins dominated vegetative roots (4354.16 mg/100g) and stems (3670.83 mg/100g), declining during flowering (roots: 2726.39 mg/100g) as defense investments shifted toward reproduction. Flavonoids increased in flowering roots (237.62 mg/100g) but remained elevated in vegetative leaves (333.16 mg/100g), supporting UV protection. Anthocyanins peaked in vegetative roots (11.40 mg/100g) and flowering flowers (11.40 mg/100g), serving dual roles in stress resistance and pollinator attraction. Alkaloids were highest in vegetative stems (842.67 mg/100g) and leaves (2373.33 mg/100g), with fruiting-stage fruits accumulating maximum levels (2536.00 mg/100g) for seed defense. Antioxidant activity (IC₅₀) varied by tissue: stems improved during flowering (IC₅₀: 2.75 to 1.95 mg), while roots declined (6.87 to 9.02 mg). Fruits displayed potent crude extract activity (IC₅₀: 0.97 mg), linked to phenolic accumulation. These findings demonstrate C. annum’s adaptive metabolic strategies—vegetative tissues prioritize structural defense, while flowering stages emphasize stress tolerance and reproductive resource allocation. Tissue-specific trends (e.g., root defense hubs, fruit UV protection) underscore ecological and physiological trade-offs. Statistically validated results (LSD thresholds exceeded) inform targeted harvesting (e.g., alkaloid-rich fruits) and bioprospecting for nutraceuticals. This work enhances understanding of plant metabolic plasticity, offering strategies to optimize crop resilience and bioactive compound utilization.

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