# A Comparative Analysis of Nutritional Composition in Acer truncatum Leaves and Seeds Over the Growing Stages

## TL;DR

This study shows when to best harvest Acer truncatum leaves and seeds to maximize their nutritional and bioactive compound content.

## Contribution

The study provides a detailed, stage-specific analysis of phytochemical and fatty acid dynamics in Acer truncatum for optimized harvesting.

## Key findings

- Leaves had highest flavonoids, chlorogenic acid, and gallic acid in May, while vitamin C and amino acids peaked in September.
- Seeds showed optimal fatty acid composition on September 30, with total flavonoids and quercetin peaking in late September.
- Multivariate analysis confirmed May as the best time for leaf harvest and September 30 for seeds.

## Abstract

Acer truncatum is a valuable source of bioactive compounds, yet the dynamics of these components throughout its growth cycle remain poorly characterized, limiting the optimization of harvest timing for maximal yield. This study quantified key phytochemicals in leaves and seeds across growth stages. In leaves, total flavonoids, chlorogenic acid, and gallic acid reached their highest levels in May (5.62% ± 0.1%, 3.38 ± 0.31, and 6.87 ± 0.14 mg/g, respectively). Quercetin was highest in June (1.80 ± 0.17 mg/g), whereas vitamin C and free amino acids peaked in September (38.73 ± 1.40 and 85.76 ± 0.56 mg/g, respectively) and moisture content peaked in April (74.34% ± 0.17%). For seeds, total flavonoids and quercetin content were highest on September 30 and September 15, respectively, whereas total amino acids and moisture peaked on August 31. No significant temporal variation was detected in chlorogenic acid, gallic acid, or kaempferol. Regarding fatty acids (FA) in seeds, total FA, unsaturated FA (UFA), and monounsaturated FA (MUFA) increased through Sep 30 (reaching 85.36 ± 1.67, 76.63 ± 1.65, and 50.83 ± 1.24 g/100 g, respectively) and then declined slightly. In contrast, polyunsaturated FA (PUFA) decreased to a minimum on September 30 (25.80 ± 0.90 g/100 g) before rising markedly by October 15 (40.60 ± 2.13 g/100 g), whereas saturated FA (SFA) remained stable. These findings demonstrate that the accumulation of characteristic components in
A. truncatum
is markedly influenced by growth stage. Multivariate analyses and integrated nutritional quality evaluation confirmed that May was optimal for leaves, whereas September 30 was the optimal harvest time for seeds. In a word, the present study not only enhances the database of characteristic components during various growth stages of
A. truncatum
, but also establishes a theoretical foundation for the development of diverse harvesting and processing technologies for
A. truncatum
.

This study reveals that the accumulation of bioactive compounds in Acer truncatum leaves and seeds is highly dependent on growth stage. Multivariate analysis determined May as the optimal harvest time for leaves, and September 30 for seeds, when key phytochemicals and fatty acids were at their peaks. These findings provide a crucial basis for optimizing harvest timing to maximize yield and quality.