Quality Characteristics and Antitussive and Expectorant Effects of Bambusae Succus Prepared by Different Processing Methods Based on Component-Pharmaceutical Effect Associations

• • Dry distillation achieved the highest total phenolic content (24.77%) and guaiacol (5.98%) and syringol (6.96%) levels, compared to fire treatment (14.93%, 4.68%, 2.22%) and water boiling (3.65%, below detection limits). This directly correlates with enhanced antioxidant and anti-inflammatory capacity, critical for COPD management where oxidative stress drives pathology. • • In COPD mice, dry distillation significantly prolonged cough latency (P<0.05) and increased phenol red excretion (P<0.01), outperforming fire treatment and water boiling. The expectorant effect was statistically superior, indicating that thermal degradation of lignin into bioactive phenolics is essential for mucociliary clearance enhancement. • • Water boiling failed to generate guaiacol and syringol due to insufficient temperature for lignin pyrolysis, resulting in a phenolic profile similar to fresh bamboo. This explains its weaker therapeutic effect and highlights a processing threshold: temperatures below 200°C are inadequate for converting lignocellulosic precursors into active phenolics. • • Dry distillation uniquely produced 4-ethylguaiacol and maltol, which activate Nrf2/HO-1 and inhibit NLRP3 inflammasome, respectively. These mechanisms target both oxidative stress and inflammation, offering a dual-action therapeutic strategy that is absent in water-boiled preparations.