Bamboo juice, known as "zhuli" in Chinese culture, is a traditional drink and herbal medicine used for treating cough and phlegm. BJOLs are widely available in China, but their composition remains poorly understood. Previous studies using GC/MS have identified phenols, amino acids, inorganic elements, and organic acids, with some suggesting amino acids and guaiacol as major components. However, the specific components responsible for the purported therapeutic effects remain unclear. This study aimed to conduct a comprehensive qualitative and quantitative analysis of the main components of fresh bamboo juice and BJOLs to identify the active compounds responsible for cough relief and evaluate the potential safety concerns related to preservatives present in commercially available products. The study included the analysis of nine common BJOL products sold in China, focusing on identifying and quantifying the main constituents and preservatives, as well as analyzing carbohydrate content.

Limited research exists on the detailed composition of bamboo juice. Previous studies, employing techniques like GC/MS, identified various components such as phenols, amino acids, inorganic elements, and organic acids. Some studies highlighted amino acids and guaiacol as major constituents. Despite the common use of BJOLs for cough relief in Chinese hospitals, the specific active components responsible for this effect have not been convincingly identified. This lack of clear understanding of the active components motivates the current research to fill this knowledge gap through advanced analytical techniques.

Fresh bamboo juice from *P. edulis* and nine BJOL samples from the Chinese market were analyzed. The fresh bamboo juice underwent extraction and preparative separation using column chromatography (HP-20, RP-C18, Sephadex LH-20) and preparative HPLC to isolate 26 compounds. These compounds were identified using UV, NMR, and MS techniques. The methodology involved UPLC-Q-TOF-MS for quantitative analysis of the 26 compounds, with method validation including determination of LOD, LOQ, accuracy, and intraday/interday precision. For preservatives (benzoic acid, ethylparaben, sorbic acid), HPLC-PAD was used for quantification. Carbohydrates (arabinose, glucose, xylose, mannose) were determined using ion chromatography. The study details specific chromatographic conditions, including mobile phases, flow rates, column types, and detection wavelengths for each analytical technique. NMR data was used to confirm the identity of preservatives isolated from the BJOLs. The paper provides detailed descriptions of sample preparation, extraction methods, and analytical procedures.

Twenty-six compounds were isolated and identified from fresh bamboo juice. Carbohydrates were identified as the major components, with a total content of 191.13 g L⁻¹. The most abundant non-carbohydrate compounds were compound 12 (35.33 ± 0.10 mg L⁻¹), compound 13 (20.71 ± 0.11 mg L⁻¹), and compound 22 (47.15 ± 0.06 mg L⁻¹). Guaiacol, previously reported as a major component in some studies, was not detected. In contrast to fresh bamboo juice, BJOLs showed significantly different compositions with much lower concentrations of the identified compounds, suggesting dilution. High levels of benzoic acid (up to 2754.25 mg L⁻¹), ethylparaben (up to 471.44 mg L⁻¹), and sorbic acid (up to 1797.48 mg L⁻¹) were detected in BJOLs, exceeding recommended limits set by FAO/WHO. The carbohydrate content in BJOLs (10,967.70–33,230.78 mg L⁻¹) was also significantly lower than that in fresh bamboo juice. The differences in composition between fresh bamboo juice and BJOLs suggest substantial processing and the addition of preservatives.

The findings challenge the assumption that the therapeutic effects of BJOLs are solely attributed to the components naturally present in bamboo juice. The high concentrations of preservatives in BJOLs suggest that their purported cough-relieving effects may stem from the antimicrobial properties of these additives. While some of the identified compounds in fresh bamboo juice might have potential biological activity, their concentrations are too low to account for the observed effects. The absence of guaiacol in this study contradicts some previous reports. The significant compositional differences between fresh bamboo juice and BJOLs raise concerns regarding the authenticity and safety of commercially available products. The high levels of preservatives in BJOLs are a potential food safety issue and may outweigh any potential benefits of the natural bamboo juice constituents. Future research should focus on evaluating the specific effects of these preservatives and their potential long-term health implications.

This study provides the first comprehensive identification and quantification of 26 compounds in fresh bamboo juice. Carbohydrates were found to be the dominant components. However, commercial BJOLs contain excessively high levels of preservatives, exceeding international safety guidelines. The results suggest that the therapeutic effects attributed to BJOLs may be linked to these preservatives rather than the natural components of bamboo juice. Future work should focus on developing standardized production processes for BJOLs that ensure both safety and efficacy, eliminating the excessive use of preservatives.

The study is limited to the analysis of nine BJOL samples from the Chinese market, limiting the generalizability of the findings to other regions or brands. Further research with a larger sample size and a wider range of BJOL products is needed. The study also focuses primarily on the chemical composition and does not directly investigate the biological activity of the identified compounds or the efficacy of BJOLs in treating coughs.